Earth doi: 10.3390/earth5010005
Authors: Diego Portalanza Carlos Ortega Liliam Garzon Melissa Bello Cristian Felipe Zuluaga Caroline Bresciani Angelica Durigon Simone Ferraz
This study examines heat wave projections across Ecuador’s Coastal, Highlands, and Amazon regions for 1975–2004 and 2070–2099 under Representative Concentration Pathways (RCP) scenarios 2.6, 4.5, and 8.5. Employing dynamic downscaling, we identify significant increases in heatwave intensity and maximum air temperatures (Tmax), particularly under RCP 8.5, with the Coastal region facing the most severe impacts. A moderate positive correlation between Tmax and climate indices such as the Pacific Decadal Oscillation (PDO) and the Oceanic Niño Index (ONI) suggests regional climatic influences on heatwave trends. These findings highlight the critical need for integrated climate adaptation strategies in Ecuador, focusing on mitigating risks to health, agriculture, and ecosystems. Proposed measures include urban forestry initiatives and the promotion of cool surfaces, alongside enhancing public awareness and access to cooling resources. This research contributes to the understanding of climate change impacts in Latin America, underscoring the urgency of adopting targeted adaptation and resilience strategies against urban heat island effects in Ecuador’s urban centers.
]]>Earth doi: 10.3390/earth5010004
Authors: Yadiel Noel Bonilla-Roman Salvador Francisco Acuña-Guzman
Utilization of remote sensing-derived meteorological data is a valuable alternative for tropical insular territories such as Puerto Rico (PR). The study of ecosystem resilience in insular territories is an underdeveloped area of investigation. Little research has focused on studying how an ecosystem in PR responds to and recovers from unique meteorological events (e.g., hurricanes). This work aims to investigate how an ecosystem in Western Puerto Rico responds to extreme climate events and fluctuations, with a specific focus on evaluating its innate resilience. The Antillean islands in the Caribbean and Atlantic are vulnerable to intense weather phenomena, such as hurricanes. Due to the distinct tropical conditions inherent to this region, and the ongoing urban development of coastal areas, their ecosystems are constantly affected. Key indicators, including gross primary production (GPP), normalized difference vegetation index (NDVI), actual evapotranspiration (ET), and land surface temperature (LST), are examined to comprehend the interplay between these factors within the context of the Culebrinas River Watershed (CRW) ecosystem over the past decade during the peak of hurricane season. Data processing and analyses were performed on datasets provided by Moderate Resolution Imaging Spectroradiometer (MODIS) and Landsat 8–9 OLI TRIS, supplemented by information sourced from Puerto Rico Water and Energy Balance (PRWEB)—a dataset derived from Geostationary Operational Environmental Satellite (GOES) data. The findings revealed a complex interrelationship among atmospheric events and anthropogenic activities within the CRW, a region prone to recurrent atmospheric disruptions. NDVI and ET values from 2015 to 2019 showed the ecosystem’s capacity to recover after a prolonged drought period (2015) and Hurricanes Irma and Maria (2017). In 2015, the NDVI average was 0.79; after Hurricanes Irma and Maria in 2017, the NDVI dropped to 0.6, while in 2019, it had already increased to 0.8. Similarly, average ET values went from 3.2339 kg/m2/day in 2017 to 2.6513 kg/m2/day in 2018. Meanwhile, by 2019, the average ET was estimated to be 3.8105 kg/m2/day. Data geoprocessing of LST, NDVI, GPP, and ET, coupled with correlation analyses, revealed positive correlations among ET, NDVI, and GPP. Our results showed that areas with little anthropogenic impact displayed a more rapid and resilient restoration of the ecosystem. The spatial distribution of vegetation and impervious surfaces further highlights that areas closer to mountains have shown higher resilience while urban coastal areas have faced greater challenges in recovering from atmospheric events, thus showing the importance of preserving native vegetation, particularly mangroves, for long-term ecosystem stability. This study contributes to a deeper understanding of the dynamic interactions within urban coastal ecosystems in insular territories, emphasizing their resilience in the context of both natural atmospheric events and human activity. The insights gained from this research offer valuable guidance for managing and safeguarding ecosystems in similar regions characterized by their susceptibility to extreme weather phenomena.
]]>Earth doi: 10.3390/earth5010003
Authors: Ankita Mukherjee Maya Kumari Varun Narayan Mishra
This study employs the Soil and Water Assessment Tool (SWAT) model to evaluate soil loss within the Shilabati and Dwarkeswar River Basin of West Bengal, serving as a pilot investigation into soil erosion levels at ungauged stations during the post-monsoon season. Detailed data for temperature, precipitation, wind speed, solar radiation, and relative humidity for 2000–2022 were collected. A land use map, soil map, and slope map were prepared to execute the model. The model categorizes the watershed region into 19 sub-basins and 227 Hydrological Response Units (HRUs). A detailed study with regard to soil loss was carried out. A detailed examination of soil erosion patterns over four distinct time periods (2003–2007, 2007–2012, 2013–2017, and 2018–2022) indicated variability in soil loss severity across sub-basins. The years 2008–2012, characterized by lower precipitation, witnessed reduced soil erosion. Sub-basins 6, 16, 17, and 19 consistently faced substantial soil loss, while minimal erosion was observed in sub-basins 14 and 18. The absence of a definitive soil loss pattern highlights the region’s susceptibility to climatic variables. Reduced soil erosion from 2018 to 2022 is attributed to diminished precipitation and subsequent lower discharge levels. The study emphasizes the intricate relationship between climatic factors and soil erosion dynamics.
]]>Earth doi: 10.3390/earth5010002
Authors: Gideon Tadesse Muralitharan Jothimani
The utilization of groundwater has emerged as an indispensable asset in facilitating economic advancement, preserving ecological integrity, and responding to the challenges posed by climate change, especially in regions characterized by aridity and semi-aridity. The sustainable management of water resources requires an assessment of the geographical and temporal patterns of groundwater recharge. The present study employed the GIS-based WetSpass-M model to model the water balance components by utilizing hydro-meteorological and biophysical data from the Wabe catchment, which spans an area of 1840 km2 in central Ethiopia, for a long time. The objective of this study was to assess the long-term average annual and seasonal groundwater recharge for the catchment area utilizing the WetSpass-M model. The input data were collected through remote sensing data and surveys in the field. The model was employed to gain insights into the process of groundwater recharge in a particular region and to facilitate effective management, prudent utilization, and sustainable planning of water resources in the long run. Water balance components were estimated using seasonal fluctuations in evapotranspiration, surface runoff, and groundwater recharge. The Wabe catchment’s summer, winter, and mean long-term yearly groundwater recharge were determined to be 125.5 mm, 78.98 mm, and 204.51 mm, respectively. The model indicates that summer seasons account for 86.5% of the mean annual precipitation, while winter seasons account for 13.5%. On the other hand, the groundwater system percolates 14.8% of the total annual rainfall (1374.26 mm). While evapotranspiration accounts for 51% of total precipitation and surface runoff accounts for 34.1%, the Wabe catchment’s mean annual evapotranspiration and surface runoff values are simulated at 701.11 mm and 485.58 mm, respectively. The findings suggest the use of the WetSpass-M model to precisely calculate the water balance components within the Wabe catchment.
]]>Earth doi: 10.3390/earth5010001
Authors: Timofey Leshukov Aleksey Larionov Ekaterina Nastavko Philipp Kaizer Konstantin Legoshchin
Overburden rock massifs resulting from open-pit coal mining are very common objects in the world’s mining regions. These locations pose a significant challenge as the global mining industry expands. These dumps are capable of self-burning for quite a long time. The displacement and sliding of these massifs can cause catastrophic consequences. In addition, these objects emit a significant amount of greenhouse gases into the atmosphere. Therefore, it is necessary to manage such objects and implement appropriate measures to limit their impact on the environment. In this work, we studied soil radon volume activity (VAR) and radon flux density (RFD) on the surface of the overburden rock massif of coal-bearing mining rocks and also made visual fixation of disturbances in the body of the massif, which appeared in the process of its movement. We found anomalies of VAR and RFD on the surface of the overburden extending from north to south. These anomalies were extended along the strike of the faults found in the body of the massif. Additionally, the radon anomalies coincided with the anomalies of methane gas emission previously measured for this object. Thus, we determined that the exit of gases from the body of the massif is carried out through fault (weakened) zones in the body of the massif. According to the results of the study, we propose to carry out radon monitoring in order to detect the spontaneous ignition process of the massif or the increase of its mobility. This will also allow us to take appropriate measures to stabilize the massif or to extinguish the dump before or simultaneously with the biological stage of reclamation.
]]>Earth doi: 10.3390/earth4040045
Authors: Samantha Greaves Caroline Harvey Yasuhiro Kotera
Climate change and its impact are being acknowledged through extensive media coverage. Knowledge gaps between mental health and climate change have been highlighted, which is an increasingly prevalent issue. Furthermore, mental health impacts such as climate anxiety and its implications on behaviour remain unclear. The study aimed to investigate the effect of climate change exposure on affect and pro-environmental behavioural intentions in a randomised controlled trial. An online survey was completed by 100 adult participants and included measures of affect and pro-environmental behavioural intentions pre- and post-exposure. Participants were randomly allocated to a group that saw a climate change video (n = 55) or a group that saw a non-climate change video (n = 45). The findings were that participants in the climate change group showed a significant increase in negative affect and pro-environmental behavioural intention scores post-video exposure compared to the non-climate change video group. This suggests that climate change video exposure negatively influences affect but also potentially increases the intention to act pro-environmentally. These findings have the potential to support policies and societal change; however, further investigation into the type of contents, actual behaviour change, and impacts on diverse populations (e.g., minority groups) is needed.
]]>Earth doi: 10.3390/earth4040044
Authors: Sayaka Yoshikawa
Large-scale land use/land cover changes have occurred in Mato Grosso State (hereafter MT), Brazil, following the introduction of extensive mechanized agriculture and pastoral activities since the 1980s. Author investigated what kind of agro-pastoral activities which are both cattle ranching and top five crops (soybean, sugarcane, corn, cotton and rice) that are closely related to land use change on lands experiencing conversion land use change (such as deforestation and the increase in deeply anthropogenically influenced areas) at each municipal district in MT. Then, this study identifies the volume of exports including contribution ratio by municipal districts where land use changed due to agro-pastoral activities. The patterns of vegetation change indicated that cattle ranching, corn, cotton, rice croplands in the northwest, and soybean and sugarcane fields in the central areas are the main contributors to deforestation. It is shown that land use change due to soybean or corn cultivation occurs mainly in the west and the southeast, respectively. Corn cultivation is associated with a greater increase in anthropogenically influenced areas than soybean cultivation. The municipal districts that export each agro-pastoral product with land use change are limited. Exports of soybeans, corn, and cotton in the municipal districts associated with deforestation had increased dramatically after experienced land use change. For example, Sapezal, which has experienced deforestation, was the only municipal district associated with export of corn to only Switzerland. Since 2007, the number of export partners has increased to 56 countries with the export volume increased 2300 times. These findings highlight the overall non-sustainability of environmental resource development activities in MT.
]]>Earth doi: 10.3390/earth4040043
Authors: Mehmet Tekin Yurur Sultan Kocaman Beste Tavus Candan Gokceoglu
The Sivrice earthquake (Mw 6.8) occurred on 24 January 2020 along the East Anatolian Fault (EAF) zone of Türkiye, and epicentral information and focal mechanism solutions were published by two national and six international seismic stations. Here, we analyzed epicentral locations and the major fault trace using aerial photogrammetric images taken two days after, and synthetic aperture radar (SAR) interferometry. Although the focal mechanism solutions were similar, the epicenters were largely displaced. Several bright lineaments with a stair-like geometry were observed in aerial images of the Euphrates River channel along the fault trace. These lineaments, also called en echelon fractures in structural geology, are like right-lateral segments of a fault plane aligning the river channel, cut and offset by those similar in trend with the EAF and with alignments of a left lateral sense, as is the EAF motion sense. We interpret that the river local channel follows a right-lateral fault structure. The traces were lost a few days later, which proves the essentiality of remote sensing technologies for obtaining precise information in large regions. The time series analysis for one year period from Sentinel-1 SAR data also illustrated the displacements in the region sourced from the earthquake.
]]>Earth doi: 10.3390/earth4040042
Authors: Athuman R. Yohana Edikafubeni E. Makoba Kassim R. Mussa Ibrahimu C. Mjemah
In developing countries like Tanzania, groundwater studies are essential for water resource planning, development, and management. Limited hydrogeological information on groundwater occurrence, availability, and distribution in Urambo District is termed a key factor that hinders groundwater development. This research was aimed at the evaluation of groundwater potential zones in a granitic gneiss aquifer in Urambo District by integrating six indicators (transmissivity, specific capacity, static water level, yield, total dissolved solids, and geology) that were developed and applied in the study area. The indicators were further combined, and a groundwater potential index map (GWPIM) was prepared using relative weights derived from the analytical hierarchy process (AHP). The results show that 67% and 27% of the study area are categorized as moderate and high groundwater potential zones, respectively. Groundwater is controlled by both Quaternary sediments (sands and gravels) and weathered to fractured granitic gneiss. Quaternary sediments host the major shallow aquifers (<35 m) with relatively high transmissivity, specific capacity, and yield (1.5 m2/day, 16.36 m2/day, and 108 m3/day, respectively). Granitic gneiss is not strongly fractured/weathered and forms an aquifer with a relatively low yield of about 10.08 m3/day. The findings were validated using three boreholes, and the results are consistent with the developed GWPIM. Such findings are of great importance in groundwater development as the techniques applied can be extended to other areas in Tanzania as well as other countries that experience similar geological environments.
]]>Earth doi: 10.3390/earth4040041
Authors: Christos D. Tsadilas
The wide acceptance that Climate Change (CC) is a reality, often taking extreme forms, has led to the development of strategies to mitigate climate change and the need to adapt to the new climate conditions. Greece has already developed a National Strategy for Adaptation to Climate Change (NSACC), which has started to be implemented in 2016 in the 13 regions of the state by implementing relevant projects. The Primary Sector of Agriculture (PSA) is one of the most vulnerable sectors to CC in Greece. This analysis describes the main points of the national strategy for mitigation and adaptation, focusing on the adaptation strategy for the PSA. Most of the information included in the analysis comes from a multidisciplinary study organized by the Bank of Greece (BoG), which was used as a guide for the formulation of the NSACC. The analysis includes a comprehensive summary of the PSA adaptation policy to CC, an assessment of climate evolution in Greece with emphasis on the characteristics related to the PSA, estimations of the CC impact on plant and animal production, and the whole organization of the national effort for adaptation to CC. The entire organization of the work followed the framework of the BoG study and the methodologies used in this paper.
]]>Earth doi: 10.3390/earth4040040
Authors: Robert B. Sowby
In a 36-year period that coincides with my lifetime, Great Salt Lake, one of the world’s largest terminal lakes and a critical ecosystem in the Western Hemisphere, went from its largest to its smallest recorded size. In this opinion piece, I argue that the fundamental problem is that we Utahns and other stakeholders have treated Great Salt Lake as an afterthought instead of an asset. I describe the conditions that led to this point, some transformations now taking place, and the new hope that the lake will recover.
]]>Earth doi: 10.3390/earth4030039
Authors: Ankush Rani Saurabh Kumar Gupta Suraj Kumar Singh Gowhar Meraj Pankaj Kumar Shruti Kanga Bojan Đurin Dragana Dogančić
The main aim of this study is to comprehensively analyze the dynamics of land use and land cover (LULC) changes in the Bathinda region of Punjab, India, encompassing historical, current, and future trends. To forecast future LULC, the Cellular Automaton–Markov Chain (CA) based on artificial neural network (ANN) concepts was used using cartographic variables such as environmental, economic, and cultural. For segmenting LULC, the study used a combination of ML models, such as support vector machine (SVM) and Maximum Likelihood Classifier (MLC). The study is empirical in nature, and it employs quantitative analyses to shed light on LULC variations through time. The result indicates that the barren land is expected to shrink from 55.2 km2 in 1990 to 5.6 km2 in 2050, signifying better land management or increasing human activity. Vegetative expanses, on the other hand, are expected to rise from 81.3 km2 in 1990 to 205.6 km2 in 2050, reflecting a balance between urbanization and ecological conservation. Agricultural fields are expected to increase from 2597.4 km2 in 1990 to 2859.6 km2 in 2020 before stabilizing at 2898.4 km2 in 2050. Water landscapes are expected to shrink from 13.4 km2 in 1990 to 5.6 km2 in 2050, providing possible issues for water resources. Wetland regions are expected to decrease, thus complicating irrigation and groundwater reservoir sustainability. These findings are confirmed by strong statistical indices, with this study’s high kappa coefficients of Kno (0.97), Kstandard (0.95), and Klocation (0.97) indicating a reasonable level of accuracy in CA prediction. From the result of the F1 score, a significant issue was found in MLC for segmenting vegetation, and the issue was resolved in SVM classification. The findings of this study can be used to inform land use policy and plans for sustainable development in the region and beyond.
]]>Earth doi: 10.3390/earth4030038
Authors: Marlus Sabino Adilson Pacheco de Souza
Understanding how climatic variables impact the reference evapotranspiration (ETo) is essential for water resource management, especially considering potential fluctuations due to climate change. Therefore, we used the Sobol’ method to analyze the spatiotemporal variations of Penman–Monteith ETo sensitivity to the climatic variables: downward solar radiation, relative humidity, maximum and minimum air temperature, and wind speed. The Sobol’ indices variances were estimated by Monte Carlo integration, with sample limits set to the 2.5th and 97.5th percentiles of the daily data of 33 automatic weather stations located in the state of Mato Grosso, Brazil. The results of the Sobol’ analysis indicate considerable spatiotemporal variations in the sensitivity of ETo to climatic variables and their interactions. The dominant climatic variable responsible for ETo fluctuations in Mato Grosso is incident solar radiation (53% to 93% of annual total sensitivity—Stot), which has a more significant impact in humid environments (70% to 90% of Stot), as observed in the areas of the Amazon biome in the state. Air relative humidity and wind speed have higher sensitivity indices during the dry season in the Cerrado biome (savanna) areas in Mato Grosso (20% and 30% of the Stot, respectively). Our findings show that changes in solar radiation, relative humidity, and wind speed are the main driving forces that impact the reference evapotranspiration.
]]>Earth doi: 10.3390/earth4030037
Authors: Abdessamad Jari Achraf Khaddari Soufiane Hajaj El Mostafa Bachaoui Sabine Mohammedi Amine Jellouli Hassan Mosaid Abderrazak El Harti Ahmed Barakat
Landslides are among the most relevant and potentially damaging natural risks, causing material and human losses. The department of Aube in France is well known for several major landslide occurrences. This study focuses on the assessment of Landslide Susceptibility (LS) using the Frequency Ratio (FR) as a statistical method, the Analytic Hierarchy Process (AHP) as a Multi-Criteria Decision-Making (MCDM) method, and Random Forest (RF) and k-Nearest Neighbor (kNN) as machine learning methods in the Aube department, northeast of France. Subsequently, the thematic layers of eight landslide causative factors, including distance to hydrography, density of quarries, elevation, slope, lithology, distance to roads, distance to faults, and rainfall, were generated in the geographic information system (GIS) environment. The thematic layers were integrated and processed to map landslide susceptibility in the study area. On the other hand, an inventory of landslides was carried out based on the database created by the French Geological Survey (BRGM), where 157 landslide occurrences were selected, and then RF and kNN models were trained to generate landslide maps (LSMs) of the study area. The generated maps were assessed by using the Area Under the Receiver Operating Characteristic Curve (ROC AUC). Subsequently, the accuracy assessment of the FR model revealed more accurate results (AUC = 66.0%) than AHP, outperforming the latter by 6%, while machine learning models results showed that RF gave better results than kNN (<7.3%) with AUC = 95%. Following the analysis of LS mapping results, lithology, distance to the hydrographic network, distance to roads, and elevation were the four main factors controlling landslide susceptibility in the study area. Future mitigation and protection activities within the Aube department can benefit from the present study mapping results, implicating an optimized land management for decision-makers.
]]>Earth doi: 10.3390/earth4030036
Authors: Brian Herreño Federico De la Colina María José Delgado-Iniesta
The integration of soil into ecology in the current climate crisis is essential for correct environmental management. Soil is a part of ecosystems; above all, it is a component of the biosphere. It is necessary to establish a definition of soil that integrates biota and biodiversity without losing sight of the historical development of edaphology, the science that studies soil. In this opinion article, we proposes a definition for all soils grouped together in the edaphosphere, which is, in fact, a subsystem of the biosphere. In addition, we highlight the importance of the definition of soil provided by Vasily Dokuchaev, the founder of edaphology, with respect to the integration of soil into the biosphere and the differences between the concepts of pedosphere and edaphosphere.
]]>Earth doi: 10.3390/earth4030035
Authors: Anang Widhi Nirwansyah Bianca Inez-Pedro Abdel Mandili Suwarno Elly Hasan Sadeli
The UN Convention on the Rights of the Child, Article 12, states that young people should be able to participate in issues that affect them. In this study, the indigenous Orang Rimba community examines the natural resources of their area through mapping so that the community can be more aware of environmental changes and at the same time their culture can be preserved. This research employs participatory resource mapping (PRM) to gather information about how young Orang Rimba view the forest in relation to customs. The study includes workshops on using GPS and GIS as well as resource mapping activities in the forest ecosystem. Through the participatory resource mapping, the study successfully maps 12 sacred places, 6 animal sites, and 14 medicinal plants in a short survey. The young Orang Rimba were also capable of addressing current environmental issues, including deforestation events, and simultaneously protecting the forest through local cultural practices. The study recommends involving indigenous communities in natural resource protection and awareness through mapping activities from a young age.
]]>Earth doi: 10.3390/earth4030034
Authors: Wassfi H. Sulaiman Yaseen T. Mustafa
Groundwater availability in the Zakho Basin faces significant challenges due to political issues, border stream control, climate change, urbanization, land use changes, and poor administration, leading to declining groundwater quantity and quality. To address these issues, this study utilized the Analytic Hierarchy Process (AHP) and geospatial techniques to identify potential groundwater sites in Zakho. The study assigned weights normalized through the AHP eigenvector and created a final index using the weighted overlay method and specific criteria such as slope, flow accumulation, drainage density, lineament density, geology, well data, rainfall, and soil type. Validation through the receiver operating characteristic (ROC) curve (AUC = 0.849) and coefficient of determination (R2 = 0.81) demonstrated the model’s accuracy. The results showed that 17% of the area had the highest potential as a reliable groundwater source, 46% represented high-to-moderate potential zones, and 37% had low potential. Flat areas between rivers and high mountains displayed the greatest potential for groundwater development. Identifying these potential sites can aid farmers, regional planners, and local governments in making precise decisions about installing hand pumps and tube wells for a regular water supply. Additionally, the findings contribute to the development of a sustainable groundwater management plan, focusing on improving water usage and protecting water-related ecosystems in the region. Identification of the optimum influencing factors, arrangement of the factors in a hierarchy, and creation of a GWPI map will allow further planning for groundwater preservation and sustainability. This project can be conducted in other areas facing droughts.
]]>Earth doi: 10.3390/earth4030033
Authors: Mirza Kaleem Beg Navneet Kumar S. K. Srivastava E. J. M. Carranza
A high concentration of fluoride (F−) in drinking water is harmful and is a serious concern worldwide due to its toxicity and accumulation in the human body. There are various sources of fluoride (F−) and divergent pathways to enter into groundwater sources. High F− incidence in groundwater was reported in Raigarh district of Central India in a sedimentary (Gondwana) aquifer system. The present study investigates the hydrogeochemistry of groundwater in the Tamnar area of Raigarh district to understand the plausible cause(s) of high F− concentration, especially the source(s) and underlying geochemical processes. Groundwater samples, representing pre-monsoon (N = 83), monsoon (N = 20), and post-monsoon (N = 81) seasons, and rock samples (N = 4) were collected and analyzed. The study revealed that (i) groundwater with high F− concentration occurs in the Barakar Formation, which has a litho-assemblage of feldspathic sandstones, shales, and coal, (ii) high F− concentration is mainly associated with Na-Ca-HCO3, Na-Ca-Mg-HCO3, and Na-Mg-Ca-HCO3 types of groundwater, (iii) the F− concentration increases as the ratio of Na+ and Ca2+ increases (Na+: Ca2+, concentration in meq/l), (iv) F− has significant positive correlation with Na+ and SiO2, and significant negative correlation with Ca2+, Mg2+, HCO3−, and TH, and (v) high F− concentration in groundwater is found in deeper wells. Micas and clay minerals, occurring in the feldspathic sandstones and intercalated shale/clay/coal beds, possibly form an additional source for releasing F− in groundwater. Feldspar dissolution coupled with anion (OH− or F−) and cation (Ca2+ for Na+) exchange are probably the dominant geochemical processes taking place in the study area. The higher residence time and temperature of groundwater in deeper aquifers also play a role in enhancing the dissolution of fluorine-bearing minerals. Systematic hydrogeochemical investigations are recommended in the surrounding area having a similar geologic setting in view of the potential health risk to a large population.
]]>Earth doi: 10.3390/earth4030032
Authors: Wennepinguere Virginie Marie Yameogo You Lucette Akpa Jean Homian Danumah Farid Traore Boalidioa Tankoano Zezouma Sanon Oumar Kabore Mipro Hien
Spatio-temporal analysis of rainfall trends in a watershed is an effective tool for sustainable water resources management, as it allows for an understanding of the impacts of these changes at the watershed scale. The objective of the present study is to analyze the impacts of climate change on the availability of surface water resources in the Nakanbe–Wayen watershed over the period from 1981 to 2020. The analysis was conducted on in situ rainfall data collected from 14 meteorological stations distributed throughout the watershed and completed with CHIRPS data. Ten precipitation indices, recommended by the ETCCDI (Expert Team on Climate Change Detection and Indices), were calculated using the RClimDex package. The results show changes in the distribution of annual precipitation and an increasing trend in annual precipitation. At the same time, a trend towards an increase in the occurrence and intensity of extreme events was also observed over the last 4 decades. In light of these analyses, it should be emphasized that the increase in precipitation observed in the Nakanbe–Wayen watershed is induced by the increase in the occurrence and intensity of events, as a trend towards an increase in persistent drought periods (CDD) is observed. This indicates that the watershed is suffering from water scarcity. Water stress and water-related hazards have a major impact on communities and ecosystems. In these conditions of vulnerability, the development of risk-management strategies related to water resources is necessary, especially at the local scale. This should be formulated in light of observed and projected climate extremes in order to propose an appropriate and anticipated management strategy for climate risks related to water resources at the watershed scale.
]]>Earth doi: 10.3390/earth4030031
Authors: Enrique Fernández Escalante José David Henao Casas Carlos Moreno de Guerra Per María Dolores Maza Vera Carles Moreno Valverde
Conducting an accurate hydrological water balance at the regional and country-wide scales is paramount to assessing available water resources and adequately allocating them. One of the main components of these balances is the anthropogenic recharge of groundwater either intentionally, through managed aquifer recharge (MAR), or unintentionally, where infiltration from dams and dykes can play a significant role. In Spain, proper management of water resources is critical due to the arid to semiarid conditions prevalent in most of the territory and the relevance of water resources for maintaining a robust agricultural sector. Previous work estimated country-wide recharge from MAR at 150 to 280 Mm3/year. Recently, water authorities pointed out that, according to hydrological water balances, the total unintentional recharge volume from water courses may exceed 500 Mm3/year. The present research aims to present a new inventory of transverse structures (also referred to as small dams and dykes) in Spain and use it to estimate country-wide unintentional recharge. The inventory, compiled by the Spanish Ministry for the Ecological Transition and the Demographic Challenge, has 27,680 structures and includes construction and impoundment characteristics, which allow for estimating the wet perimeter and the infiltration area. To this end, structural data from the inventory were crossed through map algebra in a GIS environment with thematic layers, such as lithology, permeability, the digital elevation model, the transverse structures’ wetted area, the average groundwater levels, and a clogging correction factor. Two analytical formulas to compute infiltration from small dams and dykes were tested. The resulting volume of unintentional recharge from transverse structures ranges between 812.5 and 2716.6 Mm3/year. The comparison against regional and national water balances suggests that the lowest value of the range (i.e., 812.5 Mm3/year) is probably the most realistic. Anthropogenic recharge from MAR and transverse structures is likely in the range of 1012.5–1514.8 Mm3/year. This rough figure can help close the hydrological balance at the national and river basin levels and contribute to calibrating regional models. Furthermore, they provide an order of magnitude for anthropogenic recharge at a national scale, which is difficult to obtain.
]]>Earth doi: 10.3390/earth4030030
Authors: Jaini Umrigar Darshan J. Mehta Tommaso Caloiero Hazi Md. Azamathulla Vijendra Kumar
Environmental flows are defined as the flow required into a stream to maintain the river’s ecosystem. The notion of Environmental Flow Allocation (EFA) ensures that a sufficient amount of water is delivered to the stream to maintain ecological integrity. The objective of this study is to examine environmental flows and determine the best acceptable strategy for providing flows into the river in the Lower Tapi Basin. To achieve this objective, daily discharge data from three sites, Ukai (period 1975–2020), Motinaroli (period 1990–2021), and Ghala (period 1995–2005) were collected and analyzed using the Tennant, Tessman, variable monthly flow (VMF), and Smakhtin methodologies. A comparative analysis was carried out on all three sites using the four methodologies. The Tessman and VMF approaches have a strong connection with the computed environmental flow requirements (EFR), according to the results. The calculated EFR was found to be in the range of 30–35% of mean annual flows (MAF). The maximum EFR found at station Ghala is about 54.5% of MAF according to the Tessman method. Such research will help to prevent future degradation of the river by supplying flow in accordance with the EFR, and it will also be used by stakeholders and policymakers to allocate water to preserve the ecosystem.
]]>Earth doi: 10.3390/earth4030029
Authors: Brice B. Hanberry
Climate classifications supply climate visualization with inference about general vegetation types. The Köppen classification system of thermal classes and an arid class is widely used, but options are available to strengthen climate change detection. For this study, I incorporated temperature and aridity information into all climate classes to isolate climate change, added a hypertropical class to better detect warming and drying in tropical zones, and developed a consistent ruleset of thermal classes with one temperature variable for streamlined application, yet maintained primary Köppen thermal classes. I compared climate currently to 6000 years ago (ka; Mid-Holocene) and 22 ka (Last Glacial Maximum) worldwide. Growing degree days > 0 °C was the most efficient variable for modeling thermal classes. Climate classes based on growing degree days matched 86% of Köppen thermal classes. Current climate shared 80% and 23% of class assignments with the Mid-Holocene and Last Glacial Maximum, respectively, with dry conditions shifting to the tropical and hypertropical classes under current climate. Contributing to our understanding of global environmental change, this classification demonstrated that the hypertropical class experienced the greatest change in area since 6 ka and the second greatest change in area since 22 ka, and the greatest increase in percentage arid classes during both intervals. The added hypertropical class with aridity information delivered sensitive detection of warming and drying for relevant climate classes under climate change.
]]>Earth doi: 10.3390/earth4030028
Authors: Amin R. Kazoka Jilisa Mwalilino Paul Mtoni
Consumption of fish containing elevated levels of radionuclides can lead to undesirable health effects for consumers. People in the Singida Municipality harvest fish from lakes and ponds of granite rocks which are linked with hazardous radioisotopes that may be bio-concentrated by fishes they consume. Currently, no study has ascertained the levels of radioisotopes in fish from these environments. This study was carried out to analyse the radioactivity levels of 226Ra, 228Ra and 40K isotopes in order to assess the radiological risk associated with Tilapia fish consumption and its environment in Singida Municipality. Some 51 samples, which included water (20), sediment (20), Nile tilapia (8) and Manyara tilapia (3), were randomly sampled and composited; then, they were analysed using a high-purity germanium (HPGe) detector, between May and June 2022. The results revealed that (i) the activity levels of 228Ra were below the detection limit for fish and water samples, while in sediment, the combined activity of 228Ra was within the acceptable international levels; (ii) the mean activity concentrations of 226Ra and 40K in all other samples were within the recommended levels; (iii) the activities of radionuclides in the samples analysed were high in sediments, followed by fish, and lastly water; (iv) the bioaccumulation results show that only 40K was bio-accumulated (with 1.26 in Nile tilapia), while other radionuclides (226Ra, 228Ra) were not bio-accumulated; (vi) the radionuclide transfer from water to fish was higher compared to the radionuclide transfer from sediment to fish; (vii) the human effective doses due to consumption of Nile tilapia and Manyara tilapia were 0.00973 and 0.005 mSv/y, respectively, which is below the 1 mSv/y international limit. These findings therefore show that the current levels of radioactivity in fish in the study area do not pose a significant radiological risk to fish consumers. However, more studies on other types of fish are recommended.
]]>Earth doi: 10.3390/earth4030027
Authors: Jason Giovannettone
In order to better understand the extent to which global climate variability is linked to the frequency and intensity of heat waves and overall changes in temperature throughout the United States (US), correlations between long-term monthly mean, minimum, and maximum temperatures throughout the contiguous US on the one hand and low-frequency variability of multiple climate indices (CIs) on the other hand are analyzed for the period from 1948 to 2018. The Pearson’s correlation coefficient is used to assess correlation strength, while leave-one-out cross-validation and a bootstrapping technique (p-value) are used to address potential serial and spurious correlations and assess the significance of each correlation. Three parameters defined the sliding windows over which surface temperature and CI values were averaged: window size, lag time between the temperature and CI windows, and the beginning month of the temperature window. A 60-month sliding window size and 0 lag time resulted in the highest correlations overall; beginning months were optimized on an individual site basis. High (r ≥ 0.60) and significant (p-value ≤ 0.05) correlations were identified. The Western Hemisphere Warm Pool (WHWP) and El Niño/Southern Oscillation (ENSO) exhibited the strongest links to temperatures in the western US, tropical Atlantic sea surface temperatures to temperatures in the central US, the WHWP to temperatures throughout much of the eastern US, and atmospheric patterns over the northern Atlantic to temperatures in the Northeast and Southeast. The final results were compared to results from previous studies focused on precipitation and coastal sea levels. Regional consistency was found regarding links between the northern Atlantic and overall weather and coastal sea levels in the Northeast and Southeast as well as on weather in the upper Midwest. Though the MJO and WHWP revealed dominant links with precipitation and temperature, respectively, throughout the West, ENSO revealed consistent links to sea levels and surface temperatures along the West Coast. These results help to focus future research on specific mechanisms of large-scale climate variability linked to US regional climate variability and prediction potential.
]]>Earth doi: 10.3390/earth4030026
Authors: Upasana Choudhury Suraj Kumar Singh Anand Kumar Gowhar Meraj Pankaj Kumar Shruti Kanga
Amid global concerns regarding climate change and urbanization, understanding the interplay between land use/land cover (LULC) changes, the urban heat island (UHI) effect, and land surface temperatures (LST) is paramount. This study provides an in-depth exploration of these relationships in the context of the Kamrup Metropolitan District, Northeast India, over a period of 22 years (2000–2022) and forecasts the potential implications up to 2032. Employing a high-accuracy supervised machine learning algorithm for LULC analysis, significant transformations are revealed, including the considerable growth in urban built-up areas and the corresponding decline in cultivated land. Concurrently, a progressive rise in LST is observed, underlining the escalating UHI effect. This association is further substantiated through correlation studies involving the normalized difference built-up index (NDBI) and the normalized difference vegetation index (NDVI). The study further leverages the cellular automata–artificial neural network (CA-ANN) model to project the potential scenario in 2032, indicating a predicted intensification in LST, especially in regions undergoing rapid urban expansion. The findings underscore the environmental implications of unchecked urban growth, such as rising temperatures and the intensification of UHI effects. Consequently, this research stresses the critical need for sustainable land management and urban planning strategies, as well as proactive measures to mitigate adverse environmental changes. The results serve as a vital resource for policymakers, urban planners, and environmental scientists working towards harmonizing urban growth with environmental sustainability in the face of escalating global climate change.
]]>Earth doi: 10.3390/earth4030025
Authors: Godson Ebenezer Adjovu Haroon Stephen Sajjad Ahmad
Lake Mead located in the Arizona–Nevada region of the Mohave Dessert is a unique and complex water system whose flow follows that of a warm monomictic lake. Although monomictic lakes experience thermal stratification for almost the entire year with a period of complete mixing, the lake on occasion deviates from this phenomenon, undergoing incomplete turnovers categorized with light stratifications every other year. The prolonged drought and growing anthropogenic activities have the potential to considerably impact the quality of the lake. Lake Mead and by extension the Boulder Basin receive cooler flow from the Colorado River and flow with varying temperatures from the Las Vegas Wash (LVW), which impacts its stratification and complete turnovers. This study analyzes four key water quality parameters (WQPs), namely, total dissolved solids (TDS), total suspended solids (TSS), temperature, and dissolved oxygen (DO), using statistical and spatial analyses to understand their variations in light of the lake stratifications and turnovers to further maintain its overall quality and sustainability. The study also evaluates the impacts of hydrological variables including in and out flows, storage, evaporation, and water surface elevation on the WQPs. The results produced from the analysis show significant levels of TDS, TSS, and temperature from the LVW and Las Vegas Bay regions compared with the Boulder Basin. LVW is the main channel for conveying effluents from several wastewater treatment facilities into the lake. We observed an increase in the levels of TDS, TSS, and temperature water quality in the epilimnion compared with the other layers of the lake. The metalimnion and the hypolimnion layer, however, showed reduced DO due to depletion by algal blooms. We observed statistically significant differences in the WQPs throughout various months, but not in the case for season and year, an indication of relatively consistent variability throughout each season and year. We also observed a no clear trend of influence of outflows and inflows on TDS, temperature, and DO. TSS concentrations in the lake, however, remained constant, irrespective of the inflows and outflows, possibly due to the settling of the sediments and the reservoir capacity.
]]>Earth doi: 10.3390/earth4030024
Authors: Monera Mostafa Wan Luo Jiarong Zou Ali Salem
The AquaCrop model is used to predict rice yield in response to different irrigation management in the Yanyun irrigation area in Yangzhou, China, and the constraints to rice production were identified to maximize water productivity based on model simulations. The model was calibrated by comparing measured and predicted canopy cover (CC), yield, and soil water content during the growing season in 2018. The results showed that, for CC simulations, R2 was 0.99, RMSE was 3.6%, and NRMSE was 5.3%; for Biomass simulation, RMSE was 0.50 t/ha, and NRMSE was 5.3%. Different irrigation strategies were analyzed for a long-term simulation period from 1955 to 2014. The simulated rice yield increased rapidly as irrigation demand increased initially, and then gradually stabilized. The simulated rice yield fluctuated in the different years. The Pearson type-III model method was used to identify different hydrological years of wet, normal, and dry years. The analysis identified the wet year as 1991, normal year as 1981, and dry year as 1966. In the different rainfall years (1991, 1981, and 1966) water use efficiency (WUE), water productivity (WPet), and irrigation water productivity (IWP) were utilized to determine the irrigation strategy. The predicted highest WPet in the wet year was 1.77kg m−3, while the lowest WPet in the dry year was 1.13 kg m−3. The highest IWP was 19.78 kg m−3 in the wet year, and 9.32 kg m−3 in the normal year; while the lowest IWP in the dry year was 1.90 kg m−3. IWP was significantly higher in the rainy year, while WUE was significantly lower. On the other hand, WPet was more extensive in the wet year because the yield was higher, and the Evapotranspiration (ET) was smaller in comparison to the dry year.
]]>Earth doi: 10.3390/earth4020023
Authors: Dmitry A. Ruban
Mineral resources remain essential to contemporary society and determine the important patterns of its sustainable development [...]
]]>Earth doi: 10.3390/earth4020022
Authors: Ronny G. Matenge Bhagabat P. Parida Moatlhodi W. Letshwenyo Gofetamang Ditalelo
Futuristic rainfall projections are used in scale and various climate impact assessments. However, the influence of climate variability on spatial distribution patterns and characteristics of rainfall at the local level, especially in semi-arid catchments that are highly variable and are not well explored. In this study, we explore the influence of climate variability on the spatial distribution and rainfall characteristics at a local scale in the semi-arid Shashe catchment, Northeastern Botswana. The LARS-WG, Long Ashton Research Station Weather Generator downscaling method, three representative scenarios (RCP 2.6, RCP 4.5, and RCP 4.5), three trend detection methods (Mann-Kendall, Sen’s slope, and innovative trend analysis) and L-moment method were used to assess climate change impacts on rainfall. Two data sets were used; one with 40 years of observed data from 1981–2020 and the other with 70 years from 1981–2050 (40 years of observed and 30 years of projected data from 2021–2050). Generally, the study found trend inconsistencies for all the trend detection methods. In most cases, Sen’s Slope has a high estimate of observed and RCP 2.6, while ITA overestimates rainfall totals under RCP 4.5 and RCP 8.5. The trend is increasing for annual total rainfall in most gauging stations while decreasing for annual maximum rainfall. The catchment is homogeneous, and Generalized Logistic distribution is the dataset’s best-fit distribution. Spatial coverage of a 100-year rainfall between 151–180 mm will be 81% based on observed data and 87% based on projected data under RCP 2.6 scenario when it happens. A 200-year rainfall between 196–240 mm under RCP 4.5 and 8.5 has high spatial areal coverage, at least 90% of the total catchment. The outcomes of this study will provide insightful information for water resource management and flood risk assessment under climate change. There is a need, however, to assess the transferability of this approach to other catchments in the country and assess the performance of other advanced modelling systems, such as machine learning, in this region.
]]>Earth doi: 10.3390/earth4020021
Authors: Nail G. Nazarov Vadim E. Prokhorov Aidar G. Sharifullin Artyom V. Gusarov Fedor N. Lisetskii
The reintroduction of Eurasian beaver (Castor fiber L.) results in significant changes in ecosystems. The purpose of this study is to assess the impact of the environment-forming activity of C. fiber on the riparian phytocoenoses of the Raifa forest sector of the Volga-Kama State Nature Biosphere Reserve (Middle Volga region, European Russia) after the reintroduction. Phytoindication methods of ecological–coenotic groups and indicator values were used to assess changes in environmental conditions under the influence of beaver activity. The influence of the beaver reintroduction factor on the increase in the moisture regime (by three points according to the Tsyganov indicator values) and the illumination of habitats, the richness of soils in nitrogen, and the acidity and salt regime of soils (by one point) was revealed. Under the conditions of fodder and construction activities of the beaver, an increase in the proportion of aquatic and wetland groups from 10.2% to 28.2% and boreal plant species from 15.0% to 27.6% was detected. An expansive nature of the change in the degree of landscape occupancy with wetland plants was noted. A decrease in the degree of landscape occupancy (3 to 2 points) of the distribution of ruderal species in the riparian zones of the waterbodies of the reserve due to the activity of the beaver was revealed. Based on phytoindication and ecological–coenotic analyses, it was shown that the reintroduction of C. fiber into the waterbodies of the Raifa forest sector of the reserve is responsible for maintaining the necessary microclimatic conditions for the preservation of natural southern boreal communities. The results obtained can be used for predictive assessment of the influence of the beaver on riparian (small rivers and lakes) plant communities of forest ecosystems in the Middle Volga region of European Russia and other regions of the planet with similar environmental conditions.
]]>Earth doi: 10.3390/earth4020020
Authors: Renatus James Shinhu Aloyce I. Amasi Maarten Wynants Joel Nobert Kelvin M. Mtei Karoli N. Njau
The Lake Victoria basin’s expanding population is heavily reliant on rainfall and river flow to meet their water needs, making them extremely vulnerable to changes in climate and land use. To develop adaptation and mitigation strategies to climate changes it is urgently necessary to evaluate the impacts of climate change on the quantity of water in the rivers that drain into Lake Victoria. In this study, the semi-distributed hydrological SWAT model was used to evaluate the impact of current land use and climate changes for the period of 1990–2019 and assess the probable future impacts of climate changes in the near future (2030–2060) on the Simiyu river discharge draining into Lake Victoria, Northern Tanzania. The General Circulation Model under RCPs 4.5, 6.0 and 8.5 predicted an increase in the annual average temperature of 1.4 °C in 2030 to 2 °C in 2060 and an average of 7.8% reduction in rainfall in the catchment. The simulated river discharge from the hydrological model under RCPs 4.5, 6.0 and 8.5 revealed a decreasing trend in annual average discharge by 1.6 m3/s from 5.66 m3/s in 2019 to 4.0 m3/s in 2060. The increase in evapotranspiration caused by the temperature increase is primarily responsible for the decrease in river discharge. The model also forecasts an increase in extreme discharge events, from a range between 32.1 and 232.8 m3/s in 1990–2019 to a range between 10.9 and 451.3 m3/s in the 2030–2060 period. The present combined impacts of climate and land use changes showed higher effects on peak discharge at different return periods (Q5 to Q100) with values of 213.7 m3/s (Q5), 310.2 m3/s (Q25) and 400.4 m3/s (Q100) compared to the contributions of climate-change-only scenario with peak discharges of 212.1 m3/s (Q5), 300.2 m3/s (Q25) and 390.2 m3/s (Q100), and land use change only with peak discharges of 295.5 m3/s (Q5), 207.1 m3/s Q25) and 367.3 m3/s (Q100). However, the contribution ratio of climate change was larger than for land use change. The SWAT model proved to be a useful tool for forecasting river discharge in complex semi-arid catchments draining towards Lake Victoria. These findings highlight the need for catchment-wide water management plans in the Lake Victoria Basin.
]]>Earth doi: 10.3390/earth4020019
Authors: Daneisha Blair Yangxing Zheng Mark A. Bourassa
This study provides, to the best of our knowledge, the first detailed analysis of how surface oil modifies air–sea interactions in a two-way coupled model, i.e., the coupled–ocean–atmosphere–wave–sediment–transport (COAWST) model, modified to account for oil-related changes in air–sea fluxes. This study investigates the effects of oil on surface roughness, surface wind, surface and near-surface temperature differences, and boundary-layer stability and how those conditions ultimately affect surface stress. We first conducted twin-coupled modeling simulations with and without the influence of oil over the Deepwater Horizon (DWH) oil spill period (20 April to 5 May 2010) in the Gulf of Mexico. Then, we compared the results by using a modularized flux model with parameterizations selected to match those selected in the coupled model adapted to either ignore or account for different atmospheric/oceanic processes in calculating surface stress. When non-oil inputs to the bulk formula were treated as being unchanged by oil, the surface stress changes were always negative because of oil-related dampening of the surface roughness alone. However, the oil-related changes to 10 m wind speeds and boundary-layer stability were found to play a dominant role in surface stress changes relative to those due to the oil-related surface roughness changes, highlighting that most of the changes in surface stress were due to oil-related changes in wind speed and boundary-layer stability. Finally, the oil-related changes in surface stress due to the combined oil-related changes in surface roughness, surface wind, and boundary-layer stability were not large enough to have a major impact on the surface current and surface oil transport, indicating that the feedback from the surface oil to the surface oil movement itself is insignificant in forecasting surface oil transport unless the fractional oil coverage is much larger than the value found in this study.
]]>Earth doi: 10.3390/earth4020018
Authors: Josip Janjić Lidija Tadić
Soil and Water Assessment Tool (SWAT) is a widely used model for runoff, non-point source pollution, and other complex hydrological processes under changing environments (groundwater flow, evapotranspiration, snow melting, etc.). This paper reviews the key characteristics and applications of SWAT. Since its inception in the 1990s, there has been a significant increase in the number of articles related to the SWAT model. In the last 10 years, the number of articles almost reached 4000. The range of applications varies between small and large scales; however, large watershed modelling dominates in North America and Asia. Moreover, the prevailing modelling is related to hydrological impacts in a changing environment, which is a global problem. The significant shortcoming of the SWAT model is the vast quantity of data necessary to run the model to generate accurate and reliable results, which is not accessible in some regions of the world. Apart from its accessibility, it has several advantages, including continuous development, which results in a slew of new interfaces and tools supporting the model. Additionally, it can simulate human activity and agricultural measures and adapt to new circumstances and situations. This article emphasizes weaknesses and strengths of SWAT model application on modelling of hydrological processes in changing climate and environment.
]]>Earth doi: 10.3390/earth4020017
Authors: Habtamu Dagne Engdawork Assefa Ermias Teferi
For the past forty years, Ethiopia has been promoting sustainable land management activities to enhance agricultural productivity. This study was intended to identify the factors determining farmers’ adoption and continued use of soil bund measures in the Handosha watershed, Omo-Gibe river basin. A multistage sampling technique was used to select 340 households using the Heckman sample selection model. A total of 235 (69.12%) households adopted soil bunds, but only 89 (37.87%) of them were sustainably practicing soil bunds on their farm plots. Most adopters widely practiced soil bunds (49.42%), followed by stone bund (15.9%), and Fanyajuu (10%). The empirical results of the Heckman sample selection model showed that the farming experience, land tenure security, and perception of profitability of conservation measures were significantly positively affected the adoption of soil bund. Whereas, farm plot size and participation in off farm activities significantly negatively influenced the adoption of soil bund. Sustainable use of soil bund measures were significantly positively influenced by land tenure security, family size, and frequency of extension contact, whereas the distance between farm plots and home, and farm plot size were negatively affected. As a result, a design of agro-ecological-based soil and water conservation (SWC) measures was essential in reducing farmland vulnerability to soil erosion and food insecurity. It has been concluded that conservation practices should not only focus on the implementation and biophysical factors but also consider the socioeconomic interests of the farmers to improve the sustainable use of conservation technologies.
]]>Earth doi: 10.3390/earth4020016
Authors: Linda Theres Selvakumar Radhakrishnan Abdul Rahman
Urbanization is one of the biggest challenges for developing countries, and predicting urban growth can help planners and policymakers understand how spatial growth patterns interact. A study was conducted to investigate the spatiotemporal dynamics of land use/land cover changes in Salem and its surrounding communities from 2001 to 2020 and to simulate urban expansion in 2030 using cellular automata (CA)–Markov and geospatial techniques. The findings showed a decrease in aerial vegetation cover and an increase in barren and built-up land, with a rapid transition from vegetation cover to bare land. The transformed barren land is expected to be converted into built-up land in the near future. Urban growth in the area is estimated to be 179.6 sq km in 2030, up from 59.6 sq km in 2001, 76 sq km in 2011, and 133.3 sq km in 2020. Urban sprawl is steadily increasing in Salem and the surrounding towns of Omalur, Rasipuram, Sankari, and Vazhapadi, with sprawl in the neighboring towns surpassing that in directions aligned toward Salem. The city is being developed as a smart city, which will result in significant expansion and intensification of the built-up area in the coming years. The study’s outcomes can serve as spatial guidelines for growth regulation and monitoring.
]]>Earth doi: 10.3390/earth4020015
Authors: Nisha Vaghmaria James ME Alok Sagar Gautam Sneha Gautam
Changes in vertical column concentration, size distribution, and surface concentration of aerosol associated with the lockdown imposed by the COVID-19 pandemic in 2020 over the Ahmedabad region in Gujarat State, India, were analyzed. The results are compared with changes over selected Indo-Gangetic Plain (IGP) regions. On 25 March 2020, the prime minister of India declared a complete lockdown throughout the country and later lifted restrictions in a phased manner. Aerosol optical depth (AOD) over the Ahmedabad region on 29 March dropped to as low as 0.11, and in the first two weeks of lockdown, the weekly average AOD was only 0.18. On almost all days of the lockdown period, AOD over the Ahmedabad region was lower than the decadal mean. It was found that the Ahmedabad region responded differently to lockdown conditions compared to the IGP regions. During the first lockdown phase, AOD decreased by about 29% compared to the pre-lockdown period over the Ahmedabad region. However, the average reduction over the IGP was much more, about 50%. The average Angstrom exponent (AE) of 0.96 during the pre-lockdown period over the Ahmedabad region increased phase-wise to 1.36 during the L3 lockdown phase, indicating dominance of fine-mode particles during the lockdown period. It suggests a reduction in anthropogenically produced coarse-mode particles, typically dust produced by vehicular movement, construction, and industrial activities. However, on the other hand, over the IGP region, the high dominance of fine-mode particles during the pre-lockdown period had changed to a high dominance of coarse-mode particles, especially over the Delhi region. This indicates a reduction in anthropogenically produced fine-mode particles, which are mainly generated by fossil and biofuels/biomass combustion, over the IGP region by lockdown conditions. Within a few days of lockdown, PM2.5 was reduced by 64% and 76% over the Ahmedabad and Delhi regions, respectively. The lockdown imposed by the pandemic provided an excellent opportunity to ascertain background aerosol conditions in the atmosphere.
]]>Earth doi: 10.3390/earth4020014
Authors: Marko Šrajbek Bojan Đurin Petra Sušilović Suraj Kumar Singh
Protecting groundwater from contamination is today’s most current environmental protection topic. What can man do in his environment to reduce the harmful impact of contamination on the environment, and thus the immediate effect on groundwater? Agricultural production is an ongoing source of groundwater contamination due to the increasingly frequent use of nitrates in fertilizers, which are washed out from the soil into groundwater due to precipitation. This paper investigates three wellfields in the north of the Republic of Croatia near the town of Varaždin. With the application of the RAPS method, the dependence of nitrate concentration in groundwater on the amount of precipitation was established. The analysis results show the connection of the observed parameters, especially in the upper aquifer layer. In this layer, the coefficients of correlation are greater than 0.80 at all locations, which shows a strong positive connection between the parameters. In the lower aquifer, the values of the coefficients of correlation are lower, and the results mostly indicate a weak correlation. The obtained results will serve as a starting point for future studies, which will aim to precisely determine the factors that influence groundwater quality in the observed area.
]]>Earth doi: 10.3390/earth4020013
Authors: Juma N. Kubingwa Edikafubeni E. Makoba Kassim Ramadhani Mussa
The rapid growth of civil societies coupled with population influx due to the artisanal mining industry in the Bukombe district (BD) has triggered a high demand for water resources. The daily consumption of water resources in the district surpasses the supply from available surface water sources. Thus, the situation has raised the demand for groundwater resources as an alternative. Despite the importance of groundwater resources, no current studies have spatially assessed groundwater potential to locate optimal points for borehole development. This study intended to investigate and map the groundwater potential areas (GWPAs) in the semi-arid BD using remote sensing (RS), the geographic information system (GIS), and the analytic hierarchy process (AHP) to help local communities access clean and safe water. Rainfall, geology, slope, drainage density, land use/land cover and lineament density were prepared to delineate the map of GWPAs. The map was categorized into poor (0.21%), moderate good (51.39%), good (45.70%) and very good (2.70%). Finally, the GWPA map was validated using Vertical Electrical Sounding (VES), 2-D sections and a drilled borehole. The validation results confirmed that the applied approach provides significant results that can help in planning the sustainable utilization of groundwater resources.
]]>Earth doi: 10.3390/earth4020012
Authors: Marufa Khondoker Sujata Mandal Ranjit Gurav Sangchul Hwang
Climate-change-induced freshwater shortage and saline intrusion have been posing significant risks to agricultural sectors in arid and semi-arid regions, negatively impacting irrigation, crop yield, and food production. Climate-smart sustainable solutions are the requirement to combat these major concerns. To overcome freshwater scarcity, pressure-driven desalination techniques are used that require advanced operational systems and electricity, which creates an additional economic burden when applied in the agriculture sector. Therefore, more sustainable methods for soil and water desalination using plant-, microbial-, algal-, biomass-, and carbon-based systems are needed. This scoping review addresses the effects of climate change on freshwater shortage and global food production, the influence of salinity and sodicity on agriculture, and sustainable desalination technologies.
]]>Earth doi: 10.3390/earth4020011
Authors: Alfiya I. Fazlutdinova Rezeda Z. Allaguvatova Lira A. Gaysina
Data about the ecotonic diatom communities of the Kamchatka Peninsula, a unique territory with strong volcanic activity, are very limited. We aimed to investigate diatom algae of the ecotones in the southeastern part of Kamchatka, including the Paratunka river valley, at the foot of the Vachkazhets volcano, and the bank of the Bystraya river. In total, 55 taxa were identified. The most diverse were the flora of the Paratunka river, with 31 taxa. Near the Bystraya river, 26 taxa were identified. Near the Vachkazhets volcano, 18 taxa were identified. Fragilariforma virescens, Planothidium lanceolatum, Pinnularia cf. subcapitata, Halamphora normanii, Nitzschia palea, and Eunotia exigua were the dominant species in the studied ecosystems, with the maximum abundance score. Pinnularia cf. subcapitata and Planothidium lanceolatum were found in all ecotones. In the studied habitats, small indifferent alkaliphilic cosmopolitan species prevailed. Our study revealed that the diatom species composition of the Kamchatka ecotones reflects their adaptability to survive in the extreme conditions of volcanic substrates. The results contribute to our knowledge of the ecology and biogeography of a number of diatom taxa.
]]>Earth doi: 10.3390/earth4020010
Authors: Raphael Mongare Elfatih M. Abdel-Rahman Bester Tawona Mudereri Emily Kimathi Simon Onywere Henri E. Z. Tonnang
In the recent past, the Horn of Africa witnessed an upsurge in the desert locust (Schistocerca gregaria) invasion. This has raised major concerns over the massive food insecurity, socioeconomic impacts, and livelihood losses caused by these recurring invasions. This study determined the potential vegetation damage due to desert locusts (DLs) and predicted the suitable habitat at high risk of invasion by the DLs using current and future climate change scenarios in Kenya. The normalized difference vegetation index (NDVI) for the period 2018–2020 was computed using multi-date Sentinel-2 imagery in the Google Earth Engine platform. This was performed to assess the vegetation changes that occurred between May and July of the year 2020 when northern Kenya was the hotspot of the DL upsurge. The maximum entropy (MaxEnt) algorithm was used together with 646 DL occurrence records and six bioclimatic variables to predict DL habitat suitability. The current (2020) and two future climatic scenarios for the shared socioeconomic pathways SSP2-4.5 and SSP5-8.5 from the model for interdisciplinary research on climate (MIROC6) were utilized to predict the future potential distribution of DLs for the year 2030 (average for 2021–2040). Using Turkana County as a case, the NDVI analysis indicated the highest vegetation damage between May and July 2020. The MaxEnt model produced an area under the curve (AUC) value of 0.87 and a true skill statistic (TSS) of 0.61, while temperature seasonality (Bio4), mean diurnal range (Bio2), and precipitation of the warmest quarter (Bio18) were the most important bioclimatic variables in predicting the DL invasion suitability. Further analysis demonstrated that currently 27% of the total area in Turkana County is highly suitable for DL invasion, and the habitat coverage is predicted to potentially decrease to 20% in the future using the worst-case climate change scenario (SSP5-8.5). These results have demonstrated the potential of remotely sensed data to pinpoint the magnitude and location of vegetation damage caused by the DLs and the potential future risk of invasion in the region due to the available favorable vegetational and climatic conditions. This study provides a scalable approach as well as baseline information useful for surveillance, development of control programs, and monitoring of DL invasions at local and regional scales.
]]>Earth doi: 10.3390/earth4010009
Authors: Amit U. Raysoni Sai Deepak Pinakana Esmeralda Mendez Dawid Wladyka Katarzyna Sepielak Owen Temby
With advances in technological sciences, individuals can utilize low-cost air monitoring sensors to record air quality at homes, schools, and businesses. Air quality data collected from LCSs are publicly accessible, informing the community of the air quality around them. It is important to measure local and regional particulate matter (PM) concentrations to keep the public involved, especially those with specific health concerns, such as asthma, wheezing, and seasonal allergies. The number of studies involving the use of LCSs to evaluate PM levels is increasing with more manufacturers producing ‘easy to use’ LCSs targeting the public. The goal of this review is to understand and incorporate the findings from studies using LCSs to analyze PM of various sizes, i.e., PM1, PM2.5, PM4, and PM10. This review integrates analyses from 51 different studies in 14 countries, including the U.S. The findings indicate spatial heterogeneity in the PM concentrations across a region. Some of the low-cost sensor manufacturers mentioned in these studies include Plantower, AQMesh, Alpha-sense, PurpleAir, E-MOTEs, and Shinyei. This review emphasizes the importance of LCSs in the field of PM monitoring and its potential to inform the public about their exposure burden, and to aid state and federal decision makers in formulating policies for mitigating the effects of PM pollution in any urban or rural setting.
]]>Earth doi: 10.3390/earth4010008
Authors: Thomas Plocoste Adarsh Sankaran
In this paper, the wind direction (WD) behaviour with respect to the variability of other meteorological parameters (i.e., rainfall (R), temperature (T), relative humidity (Rh), solar radiation (SR) and wind speed (U)) was studied in a multi-scale way. To carry out this study, the Hilbert–Huang transform (HHT) framework was applied to a Guadeloupe archipelago dataset from 2016 to 2021. Thus, the time-dependent intrinsic correlation (TDIC) analysis based on multivariate empirical mode decomposition (MEMD) was performed. For time scales between ∼3 days and ∼7 months, the localized positive and negative correlations between WD and the meteorological parameters have been identified. The alternation between these correlations was more significant for T and Rh. With regard to SR and U, there was a dominance of a negative correlation with WD. We assumed that the micro-climate previously identified in the literature for the study area plays a key role in these behaviours. A strong positive correlation between WD and R was found from ∼7 months to ∼2.5 years. At the annual scale, the relationships between WD and all meteorological parameters were long range and no significant transition in correlation was observed showing the impact of the Earth’s annual cycle on climatic variables. All these results clearly show the influence of R-T-Rh-SR-U on WD over different time scales.
]]>Earth doi: 10.3390/earth4010007
Authors: Sandra Lizbeth Medina-Fernández Juan Manuel Núñez Itzia Barrera-Alarcón Daniel. A. Perez-DeLaMora
The Surface Urban Heat Island (SUHI) effect refers to the difference in Land Surface Temperature (LST) between an urban area and its surrounding non-urban area. LST can provide detailed information on the variations in different types of land cover. This study, therefore, analyzes the behavior of LST and SUHIs in fourteen cities in the El Bajío Industrial Corridor, Mexico, using Landsat satellite images from 2020, with QGIS software. It utilizes thermal profiles to identify the land uses that intensify LST, which are essentially those that are anthropologically altered. The results show that the increases in LST and SUHI are more pronounced in cities with greater urban conglomeration, as well as those where there are few green areas and a sizeable industrial or mixed area, with few or no bodies of water. In addition, the increase in temperature in the SUHI is due to certain crops such as vegetables, red fruits, and basic grains such as corn, wheat, and sorghum that use fallow as part of agricultural practices, located around urban areas, which minimizes natural areas with arboreal vegetation.
]]>Earth doi: 10.3390/earth4010006
Authors: Casper Boongaling Agaton Patricia Marie Caparas Guila
Constructed wetlands (CWs) are nature-based solutions that utilize natural vegetation, soils, and microbes to treat domestic wastewater and industrial effluents. They are engineered treatment systems that mimic the functions of natural wetlands to capture stormwater, reduce nutrient loads, and create diverse wildlife habitats. Providing these monetary and non-monetary benefits, its implementation has grown in several applications and geographical spread. Recent studies integrate the ecosystem services of CWs in project valuation, and the critical analysis of research hotspots has not been made yet. This study employs a systematic review to analyze the literature on ecosystem services provided by CWs and how they are incorporated into the valuation of CW projects. Among the ecosystem services that have been identified are provisioning (biomass and water supply), regulating (wastewater treatment and purification, climate regulation, flood prevention, and erosion control), cultural (recreation and aesthetic, biodiversity, education, and research), and supporting (habitat formation, nutrient cycling, and hydrological cycle). In terms of valuation methods and techniques, the results identified contingent valuation, shadow pricing, cost–benefit analysis, benefits transfer, habitat evaluation procedures, replacement cost, and travel cost. The analysis results provide researchers with a concrete basis for future studies and directions for further development. This also provides policymakers and CW project planners with valuable insights on various aspects of policy support for CW adoption and project valuation.
]]>Earth doi: 10.3390/earth4010005
Authors: Davor Kržišnik José Gonçalves
Fungi are a diverse and fascinating group of organisms that play an important role in various ecosystems, e.g., in the decomposition of organic matter and nutrient cycling. However, climate change poses a significant threat to these ecosystems and the organisms that inhabit them. Fluctuations in temperature and humidity can cause shifts in the distribution of fungi and negatively impact the ecosystems they inhabit. Yet fungi have the potential to play a role in mitigating the effects of climate change. With the use of biotechnology, fungi can help meet the United Nations Sustainable Development Goals, and their properties make them useful organisms in addressing the urgent challenges that humanity faces. For example, industrial biotechnology using fungi can lead to the production of goods that are more biodegradable, use less energy and produce less waste. Fungi have long been used in the production of enzymes, alkaloids, detergents, acids, and biosurfactants on an industrial scale. Recent research in the field of white biotechnology has made significant progress, and further advances are expected in the near future, especially in agricultural and environmental biotechnology. With this in mind, it is crucial to explore the use of fungi in novel and environmentally conscious technologies, as well as in mitigating the effects of climate change.
]]>Earth doi: 10.3390/earth4010004
Authors: Earth Editorial Office Earth Editorial Office
High-quality academic publishing is built on rigorous peer review [...]
]]>Earth doi: 10.3390/earth4010003
Authors: Dat Tran Tatiana Borisova Kate Beggs
Sea-level rise, population growth, and changing land-use patterns will further constrain Florida’s already scarce groundwater and surface water supplies in the coming decades. Significant investments in water supply and water demand management are needed to ensure sufficient water availability for human and natural systems. Section 403.928 (1) (b) of the Florida Statutes requires estimating the expenditures needed to meet the future water demand and avoid the adverse effects of competition for water supplies to 2040. This study considers the 2020–2040 planning period and projects (1) future water demand and supplies; and (2) the total expenditures (capital costs) necessary to meet the future water demand in Florida, USA. The uniqueness of this study compared with the previous studies is the introduction of a probabilistic-based approach to quantify the uncertainty of the investment costs to meet future water demand. We compile data from the U.S. Geological Survey, Florida’s Department of Agriculture & Consumer Services, Florida’s Water Management Districts, and the Florida Department of Environmental Protection to project the future water demand and supplies, and the expenditures needed to meet the demand considering uncertainty in the costs of alternative water supply options. The results show that the total annual water demand is projected to increase by 1405 million cubic meters (+15.9%) by 2040, driven primarily by urbanization. Using the median capital costs of alternative water supply projects, cumulative expenditures for the additional water supplies are estimated between USD 1.11–1.87 billion. However, when uncertainty in the project costs is accounted for, the projected expenditure range shifts to USD 1.65 and USD 3.21 billion. In addition, we illustrate how using Modern Portfolio Theory (MPT) can increase the efficacy of investment planning to develop alternative water supply options. The results indicate that using MPT in selecting the share of each project type in developing water supply options can reduce the standard deviation of capital costs per one unit of capacity by 74% compared to the equal share allocation. This study highlights the need for developing more flexible funding strategies on local, regional, and state levels to finance additional water supply infrastructure, and more cost-effective combinations of demand management strategies and alternative water supply options to meet the water needed for the state in the future.
]]>Earth doi: 10.3390/earth4010002
Authors: Monique Makuate Tagne Merlin Simo-Tagne Nnaemeka R. Nwakuba Estelle Ndome Effoudou-Priso Jules Rémy Ndam Ngoupayou Michel Mbessa Ablain Tagne Tagne Razika Kharchi
Due to the limited reach of the drinking-water delivery network, Yaoundé’s surrounding communities (such as Nkoabang) rely on well water, boreholes, and springs. This study conducted a Thornthwaite water-balance analysis in the watershed in order to understand its hydrology capability and investigated the influence of the flows and infiltrations on the recharge of the aquifer of Nkoabang (Centre Region, Cameroon). The methodology of this work consisted of updating the rainfall and temperature data of the Mvan meteorological station in Yaoundé to carry out the hydrological and water balances of the Nkoabang aquifer and performing the piezometric monitoring of seven wells and one spring in the dry season and the rainy season. The average rainfall height for the period between 1951–2017 was 1577 ± 222 mm, while the monthly temperatures ranged from 22.8 (July) to 25.4 °C (February) for an average of 24.1 °C ± 0.8 °C. The average interannual infiltration was 137 mm, corresponding to an infiltration coefficient of 8.68%. The value of the piezometric levering varies between 706 and 718 m for an average of 711.76 m during the dry season. It fluctuates between 706 and 719 m during the rainy season for an average of 712.95 ± 4.09 m. Irrespective of the season, the highest and lowest values are those of P6 and P3, respectively. Piezometric level values vary little from one season to another but are higher in the rainy season than in the dry season. Wells in the study area generally show small variations in piezometric level amplitude, ranging from 0.4 to 3.3 m with an average of 1.19 ± 1 m. The analysis of the piezometric map of the Nkoabang aquifer shows a flow in the NE-SW direction; storage areas south of the study areas and the water supply area in the peaks and NE of Nkoabang. The daily indicative flow rates of the spring (S) are 0.15 m3 (dry season), which can supply in the dry and rainy seasons 36 to 46 people, respectively, based on a ratio of 0.1 m3 per day per habitant.
]]>Earth doi: 10.3390/earth4010001
Authors: Sebastian Roessler Andreas Jürgen Dietz
Globally, the seasonal snow cover is the areal largest, the most short-lived and the most variable part of the cryosphere. Remote sensing proved to be a reliable tool to investigate their short-term variations worldwide. The medium-resolution sensor MODIS sensor has been delivering daily snow products since the year 2000. Remaining data gaps due to cloud coverage or polar night are interpolated using the DLR’s Global SnowPack (GSP) processor which produces daily global cloud-free snow cover. With the conclusion of the hydrological year 2022 in the northern hemisphere, the snow cover dynamics of the last 23 hydrological years can now be examined. Trends in snow cover development over different time periods (months, seasons, snow seasons) were examined using the Mann–Kendall test and the Theil–Sen slope. This took place as both pixel based and being averaged over selected hydrological catchment areas. The 23-year time series proved to be sufficient to identify significant developments for large areas. Globally, an average decrease in snow cover duration of −0.44 days/year was recorded for the full hydrological year, even if slight increases in individual months such as November were also found. Likewise, a large proportion of significant trends could also be determined globally at the catchment area level for individual periods. Most drastic developments occurred in March, with an average decrease in snow cover duration by −0.16 days/year. In the catchment area of the river Neman, which drains into the Baltic Sea, there is even a decrease of −0.82 days/year.
]]>Earth doi: 10.3390/earth3040073
Authors: Erico Fernando Lopes Pereira-Silva Carlos Joly Ladaslav Sodek Elisa Hardt Marcos Aidar
We hypothesized that neotropical Myrtaceae could be organized into groups that are naturally less or non-responsive to NO3−, and that use other N forms, such as amino acids, for internal N transport. Ecophysiological tests were conducted to measure nitrate reductase activity (NRA), NO3− content, total N, δ15N natural abundance, the C:N ratio in leaves, free amino acid, and NO3− transport via xylem sap. We showed that Myrtaceae tree species have a relatively low NRA, in addition to little NO3− in leaves and free NO3− in the xylem sap during the wet and dry seasons. We suggested a possible compartmentalization of N use, wherein plants derive their internal N from and use their transport mechanism to move N between below-ground and above-ground parts, assimilating and transporting more N and C through amino acids such as glutamine, arginine, and citrulline. Evidence of low NO3− availability in tropical soils is important when trying to understand forest species’ N-use strategies, given their importance to plant nutrition. Differences in the responses of some Myrtaceae species to the seasonality of environmental factors suggest the need for further studies concerning N in natural forests, for example, to help understand the problem of N deposition ecosystems.
]]>Earth doi: 10.3390/earth3040072
Authors: Haile Belay Assefa M. Melesse Getachew Tegegne
Improving the quality of atmospheric precipitation measurements is crucial in the view of minimizing the uncertainty in weather forecasting, climate change impact assessment, water resource assessment and management, and drought and flood prediction. Remote sensing technology has considerably improved the spatio-temporal assessment of precipitation. Despite the advancement in the remote sensing technology, there is a need to investigate the robust approach towards integrating ground-based-measured and satellite-product precipitation to better understand the hydrologic process of any basin. Several data-merging methods have been proposed; however, the application of merged precipitation products for hydrological simulation has rarely been investigated. Thus, in this review, technical characteristics including basic assumptions, along with their procedures, are discussed. Moreover, the limitations of eight commonly used merging approaches, (1) Multiple Linear Regression, (2) Residual Inverse Distance Weighting, (3) Linearized Weighting, (4) Inverse Root-Mean-Square Error Weighting, (5) Optimal Interpolation, (6) Random-Forest-Based Merging Procedure, (7) Bayesian Model Averaging, and (8) the Kriging Method, and their advances with respect to hydrological simulation are discussed. Finally, future research directions towards improving data merging approaches are recommended.
]]>Earth doi: 10.3390/earth3040071
Authors: Alessandra Francini Daniela Romano Stefania Toscano Antonio Ferrante
Urban areas can be differently anthropized; often, high-density populations lead to higher amounts of pollution. Nowadays, ornamental plants can represent important living components of urban areas, and if appropriate species are used, they can provide important ecosystem services. The relationships between green infrastructures and ecosystem services have been recognized for a long time, but the role of ornamental plant species has not been studied as much. In this frame, the different ecosystem services of ornamental plants, i.e., provisioning (e.g., food, air, and water cleaning), regulating (e.g., rain water, climate, nutrient recycling, pollination, and the formation of fertile soils), and cultural (e.g., recreation opportunities or the inspiration we draw from nature) will be critically analyzed to select the most suitable ornamental plant species able to assure the better performance. The action mechanisms will also be analyzed and discussed to individuate the best ideotypes of plant species able to better assure water purification, air quality, space for recreation, climate mitigation and adaptation, human wellbeing, and health. This information is suitable to ensure that the protection, restoration, creation, and enhancement of green infrastructure become integral parts of urban spatial planning and territorial development.
]]>Earth doi: 10.3390/earth3040070
Authors: Leonid Petrov Elena Bukvareva Alexey Aleinikov
Water-regulating ecosystem services (ESs) are a key factor in water supply for the population and the economy. In recent years, these ESs have been intensively included in regional and global assessments. However, the degree of knowledge of various water-regulating ESs and the availability of models for their estimation and mapping vary greatly. For example, most regional assessments currently do not take into account the ESs of moisture and precipitation recycling by forests which can lead to erroneous decisions on land use and forest management. To what extent is it possible to make adequate decisions on the basis of a partial assessment of the ESs? In this article, we discuss this problem using the example of boreal forests in the catchment of the Lake Kenozero in the north of the European part of Russia. Using the InVEST model, two ESs were quantified and mapped: water yield regulation due to evapotranspiration and water quality assurance due to prevention of soil erosion. The reduction in water yield due to evapotranspiration was estimated at 125 mm/year, and the prevention of soil erosion was estimated at 9.56 t/ha/year. Forest felling in the study area from 2007 to 2021 led to an increase in runoff and soil erosion by 6 mm/year and 0.03 t/ha/year, respectively. The hypothetical total instantaneous forest loss could lead to an increase in runoff and soil erosion by 71 mm/year and 2.44 t/ha/year, respectively. A tradeoff between these ESs was predictably identified as deforestation led to an increase in water yield and a deterioration in water quality due to soil erosion. The significance of a number of other water-regulating ESs for making regional decisions was expertly assessed. In particular, the importance of the ESs of precipitation recycling of sludge under climate change was discussed. Expanding the range of ESs under consideration increases the likelihood of choosing a protection strategy instead of a harvesting one in forest management.
]]>Earth doi: 10.3390/earth3040069
Authors: Kimendren Gounden Festus Maina Mwangi Turup Pandurangan Mohan
Plastics are a precious, versatile set of materials. The accumulation of plastic waste threatens the environment. Recycling plastic waste can produce many new products. The many opportunities for using plastic waste create pressure for a strategy to develop or improve current waste management systems to reduce the negative impact on humans, fauna and flora. The objective of this review paper is to consider an opportunity to recycle plastic; to convert plastic waste into plastic sand bricks. This would reduce the impact of the four emerging crises (plastic pollution, unemployment, the shortage of affordable housing and climate change) identified in South Africa as a threat to sustainability. This paper reviews studies utilising plastic waste to manufacture materials for the construction industry. The feasibility of using plastic waste to manufacture bricks revealed high compressive strength, low water absorption and weighed considerably lower compared to traditional bricks. Plastic sand bricks, therefore, can provide a solution that can be used to curb the four emerging crises and contribute to sustainability.
]]>Earth doi: 10.3390/earth3040068
Authors: Agho Oliver Bamenju Xiaoyue Liu Jeongsoo Yu Kazuaki Okubo
In this era of globalization, with social problems extending across social and geographical boundaries, partnerships between governments and international organizations are key to achieving the Sustainable Development Goals (SDGs). Agriculture is essential to reducing poverty in Cameroon. Since 2002, the Japan International Cooperation Agency (JICA) has contributed to agricultural development through various projects in Cameroon. However, research has not been conducted to determine the contributions of agricultural development to poverty reduction. The aim of this study is to outline current agricultural problems and international cooperation projects in Cameroon. A social inquiry involving the collection of qualitative and quantitative data was conducted to assess whether agricultural projects have contributed to increasing income and alleviating other multidimensional indicators of poverty amongst the beneficiaries. In this paper, we provide useful recommendations with respect to solving the problem of poverty and achieving the SDGs. The analysis revealed that agriculture projects have significantly contributed to an increase in income, wellbeing and standard of living of the project beneficiaries. African countries, such as Cameroon, need to address poverty by improving the agricultural sector because these nations cannot currently maintain a stable crop production. International cooperation in the agricultural sector can help to increase crop yields, incomes and quality of life.
]]>Earth doi: 10.3390/earth3040067
Authors: Neema J. Mkumbo Kassim R. Mussa Eliapenda E. Mariki Ibrahimu C. Mjemah
Groundwater is a useful source of water for various uses in different places. The major challenge in the use of this resource is how to manage and protect it from contamination. The current study was conducted in Morogoro Municipality to identify vulnerable groundwater areas by using DRASTIC-LU/LC model. The study applied eight input parameters, i.e., depth to water table, net recharge, aquifer media, soil media, topography, impact of vadose zone, hydraulic conductivity and land use/land cover patterns, which were overlaid in GIS to generate groundwater vulnerable map. The model used rating (R = 1–10) and weighting (W = 1–5) techniques to assess the effect of each parameter on groundwater contamination. The DRASTIC-LU/LC Vulnerability Index map was classified into low- (area = 29.2 km2), moderate- (area = 120.4 km2) and high-vulnerability zones (area = 124.4 km2). Nitrate analysis was conducted using the cadmium reduction method (DR 890) to assess the validity of the model and it was observed that 55%, 15% and 50% of the samples with unacceptable (>50 mg/L), high (29–50 mg/L) and moderate (14–28 mg/L) nitrate concentrations, respectively, fall into the high-vulnerability zone. Furthermore, 45%, 70% and 50% of the samples with unacceptable, high and moderate nitrate concentrations, respectively, fall into the moderate-vulnerability zone. In the low-vulnerability zone, only 15% of samples were found with a high nitrate concentration.
]]>Earth doi: 10.3390/earth3040066
Authors: Roman Croitor
The article describes the paleobiogeographic history of the modern subfamilies so-called “crown deer” of the family Cervidae (Artiodactyla, Mammalia) in the world from the late Miocene to the late Pleistocene. The study overviews the taxonomic diversity and evolutionary radiation of Cervidae from all zoogeographic realms where this systematic group is present in the paleontological record. The evolutionary diversification of the fossil Cervidae is based on the estimations of species body masses that are regarded here as a proxy of occupied ecological niches. The study reveals two important evolutionary radiations of Cervidae during the late Miocene of Eurasia that gave the origin of the modern subfamilies Cervinae and Capreolinae. The evolutionary radiation of Capreolinae during the Pleistocene in South America shows a range of diversity comparable to the late Miocene radiations of Old World deer and provides multiple examples of evolutionary convergences with Eurasian Pleistocene cervids. The article discusses factors that shaped the modern biogeographic distribution of representatives of the subfamilies Cervinae and Capreolinae.
]]>Earth doi: 10.3390/earth3040065
Authors: Nima Karimi Kelvin Tsun Wai Ng
Due to rapid urbanization and population growth, identification and management of illegal dump sites has been a global challenge. In this study, satellite imagery and geographic information system were used to map potential illegal dump sites (PIDS). An original analytical approach was developed to identify PIDS using a set of remote sensing indices and vector files. The Network Analysis tool was used to prioritize PIDS considering driving distance between PIDS and neighboring populated points. A total of five variables (Landfills, LST, HCHO, Highways, and EVI) were considered. A study area in Saskatchewan, Canada, was selected, and the identified PIDS account for about 37.3% of the total area. Road network intensity and accessibility appear important to the occurrence of PIDS. Overall road densities in identified PIDS ranged from 0.098 to 0.251 km/km2. All five variables have observable effects on the occurrence of PIDS; however, LST and highways are recommended for future studies due to their higher membership grade and spatial sensitivity. The combination of multiple remote sensing indices and network analysis on PIDS prioritization is advantageous. The proposed PIDS mapping and prioritization method can be easily employed elsewhere.
]]>Earth doi: 10.3390/earth3040064
Authors: Laura Onofri
Ecosystem services, like water provision or pollination, may increase both agricultural productivity (that is, the capability of the sector to increase the output in volume and value) and alleviate poverty (for instance, through food provision). In addition, increased agricultural productivity can help alleviate poverty by increasing the profitability of the sector, the income of the farmers, and the rates of return on (natural and other) capital investments. However, those beneficial effects come at the cost of (possible) deterioration of existing ESs, that, prima facie, represented the main driver for the generation of benefits. This paper, therefore, identifies and discusses the implications (and possible remedies) of a critical issue that, to our knowledge, is under-studied in an integrated context and methodological approach.
]]>Earth doi: 10.3390/earth3040063
Authors: Sydney Moyo
Globally, wildfires and prescribed fires are becoming more prevalent and are known to affect plant and animals in diverse ecosystems. Understanding the responses of animal communities to fire is a central issue in conservation and a panacea to predicting how fire regimes may affect communities and food webs. Here, a global meta-analysis of 2581 observations extracted from 208 empirical studies were used to investigate the effect of fire on aboveground and belowground fauna (e.g., bacteria, fungi, small mammals, arthropods). Overall, results revealed that fire had a negative effect on biomass, abundance, richness, evenness, and diversity of all faunas. Similarly, when considering wildfires and prescribed fires the data revealed that both fire regimes have negative effects on fauna. Similarly, fire had negative impacts on aboveground and aboveground fauna across most biomes and continents of the world. Moreover, there was little evidence of changes in pH, moisture and soil depth on soil organisms suggesting that other factors may drive community changes following a fire disturbance. Future research in fire ecology should consider the effects of fire across several species and across larger geospatial scales. In addition, fire effects on faunal community structure must be studied under contrasting global fire regimes and in light of the effects of climate change.
]]>Earth doi: 10.3390/earth3040062
Authors: Najla Sayari Giuseppe Brundu Zayneb Soilhi Mounir Mekki
Solanum elaeagnifolium, one of the world’s most widespread invasive weeds, thrives in the regions of Tunisia with a semi-arid climate. An enhanced understanding of its biological traits could be useful for its management. For this purpose, S. elaeagnifolium vegetative propagation, flowering, fruiting, and spread patterns were assessed under semi-arid environmental conditions at Chott Mariem (Tunisia) over three years (2013–2015). Our results revealed that S. elaeagnifolium showed an active vegetative growth phase during the spring (March–May). Thereafter, the plant stopped its vegetative growth in June–August in favor of flowering and fruiting. The vegetative growth resumed during September–October and declined in November, announcing its dormant period. Thanks to its vigorous rhizomatous system, S. elaeagnifolium was able to emit offshoots within a radius of 1.5 m from parent shoots by 30 months after its establishment. These findings could inform and improve dedicated management control options for S. elaeagnifolium. Silverleaf nightshade should be controlled before the full-flowering stage in spring and following the first autumnal rainfall to prevent vegetative propagation and fruiting.
]]>Earth doi: 10.3390/earth3040061
Authors: Zbigniew Sierota Stanisław Miścicki
A variety of elements in nature, from a pine cone’s bracts to a spiral galaxy, are described by a unique mathematical relationship described by Fibonacci as adhering to the “golden ratio”. In forest management, various models are used to achieve a balance between forest use and conservation that meets societal expectations in both ecological and economic terms. In Central European countries, where forest management has been subordinated to the timber industry, such a transition is still in progress, and people continue to look for an acceptable balance between forest conservation and management. The main objective of this paper is to review approaches to forest management in Central Europe with the aim of contributing to current discussions on forest management models in Europe. We anticipate that the new EU Biodiversity Strategy for 2030 will implement the billion-tree afforestation program with appropriate consideration of forest potential based on the tenets of sustainable management and that the future climate will be neutral. We hope that the forestry aspects of the strategy will provide a positive impetus to forest management by finding effective compromises between forest conservation and forest use in furthering the aims of sustainable development.
]]>Earth doi: 10.3390/earth3040060
Authors: Cailing Zhao Chongshui Gong Haixia Duan Pengcheng Yan Yuanpu Liu Ganlin Zhou
Soil temperature is a crucial parameter in surface emissions of carbon, water, and energy exchanges. This study utilized the soil temperature of 836 national basic meteorological observing stations over China to evaluate three soil temperature products. Soil temperature data from the China Meteorology Administration Land Data Assimilation System (CLDAS), European Centre for Medium-Range Weather Forecasts (ERA-Interim), and Global Land Data Assimilation System (GLDAS) during 2017 are evaluated. The results showed that soil temperature reanalysis datasets display a significant north-to-south difference over eastern China with generally underestimated magnitudes. CLDAS data perform soil temperature assessment best at different depths and can be reproduced well in most areas of China. CLDAS slightly overestimates soil temperature in summer. The most significant deviation of ERA-Interim (GLDAS) appears in summer (summer and autumn). As soil depth increases, the soil temperature errors of all three datasets increase. The CLDAS represents the soil temperature over China but owns a more considerable bias in barren or sparsely vegetated croplands. ERA-Interim performs poorest in urban and built-up and barren or sparsely vegetated areas. GLDAS overall owns an enormous bias at the mixed forest, grassland, and croplands areas, which should be improved, especially in summer. However, it performs better in open shrublands and barren or sparsely vegetated areas. The ST of mixed forests shows better results in the south region than the north region. For grasslands, smaller MEs are located in the north and northwest regions. The ST of croplands shows the poorest performance over the northwest region.
]]>Earth doi: 10.3390/earth3030059
Authors: Aristotelis Koskinas Eleni Zaharopoulou George Pouliasis Ilias Deligiannis Panayiotis Dimitriadis Theano Iliopoulou Nikos Mamassis Demetris Koutsoyiannis
Hydroclimatic processes such as precipitation, temperature, wind speed and dew point are usually considered to be independent of each other. In this study, the cross–correlations between key hydrological-cycle processes are examined, initially by conducting statistical tests, then adding the impact of long-range dependence, which is shown to govern all these processes. Subsequently, an innovative stochastic test that can validate the significance of the cross–correlation among these processes is introduced based on Monte-Carlo simulations. The test works as follows: observations obtained from numerous global-scale timeseries were used for application to, and a comparison of, the traditional methods of validation of statistical significance, such as the t-test, after filtering the data based on length and quality, and then by estimating the cross–correlations on an annual-scale. The proposed method has two main benefits: it negates the need of the pre-whitening data series which could disrupt the stochastic properties of hydroclimatic processes, and indicates tighter limits for upper and lower boundaries of statistical significance when analyzing cross–correlations of processes that exhibit long-range dependence, compared to classical statistical tests. The results of this analysis highlight the need to acquire cross–correlations between processes, which may be significant in the case of long-range dependence behavior.
]]>Earth doi: 10.3390/earth3030058
Authors: Holly Atkinson Bogdan Cristescu Laurie Marker Nicola Rooney
Bush encroachment is a habitat change phenomenon that threatens savanna and grassland ecosystems worldwide. In Africa, large carnivores in bush encroached landscapes must adjust to increasing woody plant cover and biomass, which could affect predation success at multiple stages through complex and context-dependent pathways. We highlight, interpret, and compare studies that assessed how bush encroachment or related habitat parameters affect the predation stages of large African carnivores. Bush encroachment may directly or indirectly affect predation success in various ways, including by: (1) altering habitat structure, which may affect hunting efficiency and prey accessibility; (2) changing prey abundance/distribution, with smaller species and browsers being potentially favoured; (3) influencing interference competition within the carnivore guild. For habitat or dietary specialists, and subordinate predators that are vulnerable to both top-down and bottom-up ecosystem effects, these alterations may be detrimental and eventually incur population fitness costs. As the threat of bush encroachment continues, future studies are required to assess indirect effects on competitive interactions within the large African carnivore guild to ensure that conservation efforts are focused. Additionally, to better understand the effects of bush encroachment across Africa, further research is necessary in affected areas as overall little attention has been devoted to the topic.
]]>Earth doi: 10.3390/earth3030057
Authors: Martin A. Spetich Michael A. Jenkins Stephen R. Shifley Robert F. Wittwer David L. Graney
Dry-mesic old-growth oak forests are widely distributed remnants across the eastern U.S. and are expected to increase in number and extent as second-growth forests mature. In this study, we synthesize published and unpublished information to better define the species, structure and extent of these forests. Mean site tree density for trees ≥10 cm dbh ranged from 341–620 trees ha−1. In the eastern part of the region, most stand basal areas were >23 m2 ha−1, compared to ≤23 m2 ha−1 in the westernmost stands. Overall, woody species diversity was relatively low compared to old-growth oak forests on moister sites, with tree species per forest ranging from 5–18. The most common species among the stands were white oak (Quercus alba), northern red oak (Quercus rubra), and black oak (Quercus velutina). Shrub and vine species per forest ranged from 1–10, with common species or genera including Virginia creeper (Parthenocissus quinquefolia), poison ivy (Toxicodendron radicans), Vaccinium spp., and grapevines (Vitis spp.). Within the southern Appalachian Mountains, rosebay rhododendron (Rhododendron maximum) and mountain laurel (Kalmia latifolia L.) were common. Herbaceous species per stand ranged from 4–51, with the highest richness occurring in a southern Appalachian oak-hickory forest. The maximum within-stand age of the large trees ranged from 170 to over 365 years. The mean density of standing dead trees ≥10 cm dbh ranged from 31–78 ha−1 and the volume of coarse woody debris ≥10 cm in diameter averaged 52 m3 ha−1. We more fully describe the characteristics of these forests and fill gaps in the collective knowledge of this increasingly important forest type. However, over the past 20 years, there has been scant research on these forests, and older research studies have used a variety of research plots and methods. A uniform approach to surveying these sites is needed to gain a better understanding of these forests before we are faced with caring for an increase in old-growth forest areas.
]]>Earth doi: 10.3390/earth3030056
Authors: James Acker Alexis Hunzinger Norman Kuring
On the first several days of October 2013, daily chlorophyll a (chl a) data acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard the National Aeronautics and Space Administration (NASA) Aqua satellite detected a marked increase in chlorophyll a concentrations (chl a) in the vicinity of Chuuk Lagoon and the Federated States of Micronesia. Such an increase, likely indicative of a phytoplankton bloom, has not been observed in this location at any other time during the MODIS-Aqua mission, which commenced in 2002 and continues to present. Examination of sea surface wind data from the Modern Era Retrospective analysis for Research and Applications Version 2 (MERRA-2) reanalysis dataset indicated that the region experienced a sequence of alternating elevated and very low wind speed events prior to the observation of the bloom. The influence of the winds can be seen in MERRA-2 sea surface skin temperature data. Elevated windspeeds for several days likely induced a mixing of deeper waters with higher nutrient levels to the surface, which was followed by stratification and phytoplankton growth during low wind intervals and finally transport induced by a brief high windspeed event. Analysis of hourly MERRA-2 maximum windspeed data over a 40-year period indicated that this sequence was climatologically rare.
]]>Earth doi: 10.3390/earth3030055
Authors: Maria Minioti Aggelos Tsaligopoulos Yiannis G. Matsinos Gerasimos Pavlogeorgatos
Drystone terraces offer a series of ecosystem services including both biological and cultural benefits. The aesthetic contribution towards the landscape and the increase in biodiversity levels, constitute drystone terraces and other similar constructions, as important biocultural assets. The low maintenance and the eventual abandonment of drystone terraces cause a series of drawbacks regarding the sustainability of agricultural environments. The main goal of this research was to assess the effect of drystone terrace maintenance level on biodiversity. For that reason, two closely distant agricultural areas of Lesbos Island (North Aegean, Greece) in which olive grove drystone terraces dominate were compared. The non-intrusive method of ecoacoustics was selected, and the levels of the acoustic complexity and acoustic diversity were statistically analyzed for areas that included highly maintained and poorly maintained olive grove drystone terraces. The results indicated an increase in acoustic biodiversity levels in the poorly maintained drystone terraces area. At this early stage, the results highlighted the fact that the increased resources in the poorly maintained drystone terraces, in terms of nesting and feeding opportunities, increased the biodiversity levels. Nevertheless, the spatiotemporal expansion of this research is undeniably important.
]]>Earth doi: 10.3390/earth3030054
Authors: Giuliana Vinci Sabrina Antonia Prencipe Luca Masiello Mary Giò Zaki
Animal based-food products represent an essential source of protein supply in overall diets, and livestock provide 25% of the total protein content consumed by humans as food. Concurrently, livestock significantly impacts the environment, being responsible for 10–12% of total anthropogenic CO2 emissions. Among livestock, pork is considered one that accounts for the greatest impact in terms of emissions, about 4.62 kg CO2 eq/kg. Furthermore, the growing global demand for protein sources has led to a widespread need to find agri-food solutions that meet the demand for food through sustainable production systems. The high nutritional quality of edible insects, in terms of amino acids, fats, minerals, and vitamins, is comparable with meat products. This study aims to compare protein production from pork and mealworm, assessing the degree of substitution and environmental impacts of the two production systems. To assess the impacts of protein production from mealworms and pork on the ecosystem, resources, and human health, an LCA was conducted using the ReCiPe 2016 Endpoint method, with a 100-year hierarchical perspective (H) V1.05. It emerged that pork production is characterized by high impacts on the ecosystem, land use, climate-altering emissions, and fossil resources, in contrast with mealworm protein production. The low impact of insect protein production and the high nutritional values make edible insects a sustainable solution to growing food demand and economic benefits render edible insects globally a major potential future food.
]]>Earth doi: 10.3390/earth3030053
Authors: Yaya Fodoué Ahmadou Ismaila Mero Yannah Mengnjo Jude Wirmvem Christian Bouba Mana
Pawara area is a mining district in the eastern region of Cameroon. Mining in the area is generally artisanal and semi-mechanized, practiced by the local miners and immigrants from neighboring African countries and China. The lack of strict regulations and control of mining activities permits the miners to use illegal substances, especially Hg in gold separation. These expose the area to toxic and heavy metals pollution. This study highlights the source of heavy metals concentration in the Pawara soils and the potential adverse effects of Hg on gold separation to the environment and health. Three mining sites and one control site were investigated, namely Site A, Site B and Site C. The control Site 0 (background) is an area where no mining and agricultural activities have taken place. Soil samples were collected at depth of 20 cm, with six from each site (24 samples). Samples were analyzed for Al, Cd, Cr, Cu, Fe, Hg, Pb, Cd and Zn content using atomic absorption spectrophotometry in a graphite furnace. The metals, except for Fe, show high values for all three sites exceeding the background levels in the soils. Hg shows the highest concentration on Site A with a value of 1590 mg kg−1. Pb is highest on Site B with a concentration of 12,274 mg kg−1. The contamination degree was assessed with the help of contamination indices (Igeo—index of geo-accumulation; PLI—pollution load index; RI—potential ecological risk; Eri—ecological risk; Pi—single pollution index; CF—contamination factor) and all parameters show a high degree of contamination on all three sites compared to the control site. Hg, Pb, Cd, Cr and Cu as single pollutants show the highest ecological risk on Site A and Site B where intense mining is taking place. The absence of industrial and large-scale agricultural activities in the Pawara area, the nonexistence of contaminants on the control site and the presence of contaminants on Site C where farming is high and mining is low jointly show that the discharge of mine wastes onto the soils and stream channels are the main source of contaminants and potential pollutants of the Pawara ecological environment.
]]>Earth doi: 10.3390/earth3030052
Authors: Toni Trickett Douglas James Warner
Regenerative agriculture is a potential alternative to conventional agricultural systems. It integrates the components of zero-tillage, permanent soil cover, diverse crop rotations and rotational or mob-grazing by ruminant livestock. Earthworms are beneficial soil macrofauna and function as indicators of soil health. A need exists to identify how earthworm populations are affected when all four regenerative agriculture components are implemented simultaneously. This study investigates earthworm abundance in three split-plot treatments located on adjacent land within the same farm: (1) ungrazed permanent grassland, (2) a three-year grass-clover ley within an arable zero tillage system without grazing and (3) identical to treatment 2 but with mob-grazing. Earthworms were sampled using soil pits and classified into four functional groups: epigeic (surface dwellers), endogeic (sub-surface), anecic (deep soil) and juveniles. The total earthworm count, epigeic and juvenile functional groups were significantly (p ≤ 0.05) higher in treatment (3), the arable zero tillage system with mob-grazing. Mob-grazing increases the diversity of carbon sources available to earthworms and has a positive impact on earthworm abundance and functional group diversity within the arable rotation under evaluation.
]]>Earth doi: 10.3390/earth3030051
Authors: Yukako Inamura Pankaj Kumar
Although environmental sustainability provides a foundation for maintaining economic and social sustainability, it is often neglected in favor of economic sustainability. Ameliorating water impairment is costly, and policymakers do not always prioritize this problem because its economic benefits are often intangible. This study explored the potential economic value for Tokyo’s regional economy of past improvements in the water quality of its rivers. Transitioning the rivers from their previous role as sewage drainage pipes to venues for spending leisure time created economic incentives in the local economy. An input-output analysis showed that in 1985, the inland navigation sector in the Sumida River generated 1.5 times the economic output by increasing demand. While this impact decreased to 1.3 times in 2005, the results clearly indicate that the regional economy can generate amenity values by improving the environmental quality. This study provides useful information to guide policymakers in allocating the budget for environmental management. In particular, it allows them to envision possible development plans to promote the livelihood of urban residents as well as understand the linkage between the environment and the economy.
]]>Earth doi: 10.3390/earth3030050
Authors: Huynh Vuong Thu Minh Kim Lavane Le Thi Lanh Lam Van Thinh Nguyen Phuoc Cong Tran Van Ty Nigel K. Downes Pankaj Kumar
Information on the relationship between rainfall intensity, duration and accumulation frequency or return period (IDF) is commonly utilized in the design and management of urban drainage systems. Can Tho City, located in the Vietnamese Mekong Delta, is a city which has recently invested heavily in upgrading its stormwater drainage systems in the hope of preventing reoccurring flood events. Yet, much of these works were designed based on obsolete and outdated IDF rainfall curves. This paper presents an updated IDF curve for design rainfall for Can Tho City. For each duration and designated return period, a cumulative distribution function (CDF) was developed using the Pearson III, Log-Pearson III, and Log-Normal distribution functions. In order to choose the best IDF rainfall curve for Can Tho City, the CDF rainfall curve and empirical formulas used in Vietnam and Asia (Vietnamese standard 7957:2008, Department of Hydrology, Ministry of Transportation, Talbot, Kimijima, and Bermard) were compared. The goodness of fit between the IDF relationship generated by the frequency analysis (CDF curve), and that predicted by the IDF empirical formulas was assessed using the efficiency index (EI), and the root mean squared error (RMSE). The IDF built from Vietnam’s standard TCVN 7957:2008 with new parameters (A = 9594, C = 0.5, b = 26, n = 0.96) showed the best performance, with the highest values of EI (0.84 ≤EI≤ 0.93) and the lowest values of RMSE (2.5 ≤RMSE≤ 3.2), when compared to the other remnants.
]]>Earth doi: 10.3390/earth3030049
Authors: Sophie Manson K. A. I. Nekaris Andrew Rendell Budiadi Budiadi Muhammad Ali Imron Marco Campera
Soil quality can directly influence the health, yield, and quality of a particular crop species, and agrochemicals are often used to boost soil micro- and macro-nutrients. The excessive application of agrochemicals, however, is often the cause of imbalances in acidity and nutrient concentration and can cause soil to deteriorate. The presence of multiple shade trees in farmland can positively influence soil quality. Here, we evaluate the effect of agrochemical use (i.e., organic, mixed, and intensive) and shade tree complexity (i.e., sun, low, and high) on soil quality (i.e., pH, macronutrients, and micronutrients) in 56 coffee home gardens in Indonesia. We found that Al, Fe, K, and Mn were significantly higher in farms that used agrochemicals, and pH was more acidic in fields with intensive use of agrochemicals. C:N ratio and Mn were higher in soils with high shade complexity than in sun-exposed soils. The use of agrochemicals, however, is not sustainable as it increases the Al concentration and decreases pH, both of which are associated with poor coffee growth and reduced soil quality. Shade tree removal and the use of invasive, non-native species, such as eucalyptus, can also negatively influence soil quality, and thus the maintenance of complex shade cover with native trees should be prioritised.
]]>Earth doi: 10.3390/earth3030048
Authors: Manuel Rodríguez-Rastrero Almudena Ortega-Martos
With the aim of contributing to the knowledge of soil organic carbon stocks in dry areas, this work is based on a quantification of SOC stocks in gypsum-bearing soils whose vertical and spatial heterogeneity greatly limits inferring the total SOC stocks solely from soil surface information. Public databases of soil profiles were key to this quantification, through which it was estimated which amounts of organic carbon can potentially be excluded from calculations associated with soil C cycle models in the absence of information regarding deep soil horizons. These databases include two key factors in the quantification of SOC stocks, which are often excluded: the volume of coarse fragments and the thickness of all sampled soil horizons where SOC concentration was determined. The observed average value of SOC stocks in the studied subsurface horizons reaches 73% of the whole soil. Climate, relief, and land use influence the quantity and heterogeneity of SOC stocks in these soils. Information based on the mere surface of the soil is not relevant to quantify the total SOC; however, the calculation of stocks through soil pits of medium depth (30 cm) has proven to be potentially useful as a complementary approach to these stocks.
]]>Earth doi: 10.3390/earth3030047
Authors: Carolina Herrera Pablo Cabrera-Barona
With a growing interest in the study of urban life and health, evidence indicates that the quality of the environment in which we live can have implications for our subjective well-being and health. This study assesses the potential impacts of perceptions of visual air pollution, olfactory air pollution, and noise pollution on self-perceived health, self-perceived happiness, and satisfaction with life, through the calculation of ordinal logistic regressions, using the information of an online survey carried out in Quito, Ecuador. We found that perceptions of unpleasant odors and noise pollution influence self-perceived health, self-perceived happiness, and satisfaction with life. The obtained results may support the incorporation of citizens’ perspectives to better understand environmental pollution and to enrich local planning for urban sustainability.
]]>Earth doi: 10.3390/earth3030046
Authors: Masoud Taheriyoun Hossein Marzban Mohammadali Geranmehr Mohammad Nazari-Sharabian
Water quality management of rivers is one of the challenges in the analysis of water resource systems. The optimal operation of the pollutant carrying capacity of these systems provides significant economic value and could reduce treatment costs. In this study, the application of the trading ratio system is investigated to control the cost of pollutants in a river and make a fair deal. In this regard, transfer coefficients between pollution sources, along with the trade coefficients, are determined, considering the system limitations and each pollutant’s contaminant impact. To provide allowable limits of river water quality concentrations, the total cost of all sources and the system is minimized, using the linear programming method. Finally, the new trading discharge permits are calculated for each source. The proposed method is successfully applied to Dez River as a case study. Results show that using a trading ratio system could maintain water quality at a standard level containing economic benefits for the participants of this program.
]]>Earth doi: 10.3390/earth3030045
Authors: Teresa Mouga Isabel Barreto Fernandes
Gelidium corneum (Giant Gelidium or Atlantic agar) is a well-known red seaweed harvested for its high-quality agar content. Agar is a mixture of the polysaccharides used in the food industry as a gelling, thickener, clarifying, and stabilizer agent. The best agar quality is also used in the laboratory as bacteriological agar. Yet, in recent years, the species has been studied for many other applications. Examples of uses are pharmaceuticals, cosmetics, food supplements, bioremediation, biofuels, biofertilizers and biostimulants, biomaterials, and nanocrystals, among others. The use of this biomass, though, raises concerns about the sustainability of the resource, since this is not a cultivated species, being harvested in the wild. Thus, other uses of G. corneum biomass increase pressure on wild stocks already stressed due to climate change. However, in a biorefinery approach, a new trend is emerging, using waste biomass rather than harvested biomass to produce new bio-based materials. These are smart solutions that transform waste into innovative products, useful for various sectors of society while reducing the impact of biomass exploitation. The aim of this review paper, thus, is to address the current state of G. corneum biology, ecology, threats, its current uses and market, and the ongoing research on innovative proposals in a circular economy framework.
]]>Earth doi: 10.3390/earth3030044
Authors: Lazaro J. Mangewa Patrick A. Ndakidemi Richard D. Alward Hamza K. Kija John K. Bukombe Emmanuel R. Nasolwa Linus K. Munishi
Habitat condition is a vital ecological attribute in wildlife conservation and management in protected areas, including the Burunge wildlife management areas in Tanzania. Traditional techniques, including satellite remote sensing and ground-based techniques used to assess habitat condition, have limitations in terms of costs and low resolution of satellite platforms. The Normalized Difference Vegetation Index (NDVI) and Green NDVI (GNDVI) have potential for assessing habitat condition, e.g., forage quantity and quality, vegetation cover and degradation, soil erosion and salinization, fire, and pollution of vegetation cover. We, therefore, examined how the recently emerged Unmanned Aerial Vehicle (UAV) platform and the traditional Sentinel-2 differs in indications of habitat condition using NDVI and GNDVI. We assigned 13 survey plots to random locations in the major land cover types: three survey plots in grasslands, shrublands, and woodlands, and two in riverine and mosaics cover types. We used a UAV-mounted, multi-spectral sensor and obtained Sentinel-2 imagery between February and March 2020. We categorized NDVI and GNDVI values into habitat condition classes (very good, good, poor, and very poor). We analyzed data using descriptive statistics and linear regression model in R-software. The results revealed higher sensitivity and ability of UAV to provide the necessary preliminary diagnostic indications of habitat condition. The UAV-based NDVI and GNDVI maps showed more details of all classes of habitat conditions than the Sentinel-2 maps. The linear regressions results showed strong positive correlations between the two platforms (p < 0.001). The differences were attributed primarily to spatial resolution and minor atmospheric effects. We recommend further studies to test other vegetation indices.
]]>Earth doi: 10.3390/earth3030043
Authors: Yangxing Zheng Mark A. Bourassa Dmitry Dukhovskoy M. M. Ali
Dmitry Dukhovskoy was not included as an author in the original publication [...]
]]>Earth doi: 10.3390/earth3030042
Authors: Letícia de Freitas Jener de Moraes Adriana da Costa Letícia Martins Bruno Silva Junior Avanzi Alexandre Uezu
Water resources are paramount for the maintenance of the Earth’s system equilibrium; however, they face various threats and need increased conservation and better management. To restore water resources, nature-based solutions can be applied. Nevertheless, it is unclear which solution promotes greater water supply resilience: restoring riparian vegetation, improving management practices in key areas for water recharge, or both? In addition, how significant are these results in the face of climate change effects? To answer this, we used the SWAT (Soil and Water Assessment Tool) model to simulate and compare four different land use scenarios under three climate conditions (i.e., observed climate and two of the IPCC’s future climate projections). Focusing on key areas contributed more to increasing water supply resilience than forest restoration. Applying both solutions, however, yielded the greatest increases in resilience and groundwater recharge and the greatest decreases in surface runoff and sediment loads. None of the solutions caused a significant difference in streamflow and water yield. Furthermore, according to both of the IPCC climate projections evaluated, by the end of this century, the average annual streamflow will be lower than the historical mean for the region. Climate adaptation strategies alone will be insufficient to ensure future water access, highlighting the need for implementing drastic mitigation actions.
]]>Earth doi: 10.3390/earth3020041
Authors: I-Shian Suen
This study aims to assess urban heat islands and land cover types in relation to vulnerable populations. The city of Richmond, Virginia was selected as the study area using the Census Block Group as the geographic unit of analysis. Regression analysis was carried out to examine the impacts of land cover types on ambient temperatures, while correlation analysis was used to assess the relationship between ambient temperature and vulnerable populations. Lastly, multivariate clustering analysis was performed to identify areas vulnerable to urban heat in the city. Findings suggest that: (1) impervious surfaces lead to higher ambient temperatures, while tree coverage has a cooling effect on urban heat; (2) vulnerable populations, except for older adults, tend to live in areas with higher ambient temperatures; and (3) vulnerable populations are spatially clustered in specific locations in the city. This study concludes with recommendations of mitigation measures to reduce the adverse effect of urban heat islands by applying high-albedo materials to urban surfaces and expanding tree coverage and green space.
]]>Earth doi: 10.3390/earth3020040
Authors: Sadeq Khaleefah Hanoon Ahmad Fikri Abdullah Helmi Z. M. Shafri Aimrun Wayayok
Globally, urbanisation has been the most significant factor causing land use and land cover changes due to accelerated population growth and limited governmental regulation. Urban communities worldwide, particularly in Iraq, are on the frontline for dealing with threats associated with environmental degradation, climate change and social inequality. However, with respect to the effects of urbanization, most previous studies have overlooked ecological problems, and have disregarded strategic environmental assessment, which is an effective tool for ensuring sustainable development. This study aims to provide a comprehensive vulnerability assessment model for urban areas experiencing environmental degradation, rapid urbanisation and high population growth, to help formulate policies for urban communities and to support sustainable livelihoods in Iraq and other developing countries. The proposed model was developed by integrating three functions of fuzzy logic: the fuzzy analytic hierarchy process, fuzzy linear membership and fuzzy overlay gamma. Application of the model showed that 11 neighbourhoods in the study area, and more than 175,000 individuals, or 25% of the total population, were located in very high vulnerability regions. The proposed model offers a decision support system for allocating required financial resources and efficiently implementing mitigation processes for the most vulnerable urban areas.
]]>Earth doi: 10.3390/earth3020039
Authors: Charles P. Humphrey
Excess phosphate (P) loading to surface waters increases productivity sometimes causing an imbalance leading to eutrophication and water quality degradation. Wastewater contains elevated concentrations of P and other contaminants that pose threats to environmental health. Onsite wastewater systems (OWS) are used in many rural areas, but most are not monitored for P removal effectiveness. The goal of this research was to gain a better understanding of the P treatment efficiency of OWS in a nutrient-sensitive watershed. Groundwater monitoring infrastructure, including networks of wells and piezometers, was installed at five sites with OWS in coastal North Carolina. Groundwater samples from the piezometers and wastewater samples from the septic tanks were collected and analyzed for phosphate and physicochemical parameters. Results suggest that significant reductions in P concentrations (79.7 to 99.1%) were occurring in the soil immediately beneath the drainfield trenches, but P concentrations in groundwater near the OWS and more than 35 downgradient were alike and significantly elevated relative to background concentrations. OWS in areas with sandy soils such as the Hoods Creek watershed may be sources of P to groundwater and surface water. Nutrient management policies in watersheds with sandy soils should include provisions for assessing and reducing P contributions from OWS to surface waters.
]]>Earth doi: 10.3390/earth3020038
Authors: Paola Varela Pérez Beatrice E. Greiner Moritz von Cossel
Africa has been a hotspot for the development of food and bioenergy crop cultivation since the 2000s, leading to systematic challenges towards its ability to become a bioeconomy. To reduce land-use conflicts with food crop cultivation, marginal African drylands (MADs) are proposed for sustainable bioenergy cropping systems (BCSs). This study reviews the foremost socio-economic and environmental challenges for BCSs on MADs, and the development of key principles for minimizing adverse outcomes towards a sustainable bioeconomy. Socio-economic prosperity in Africa depends on several systematic solutions, and BCSs that are based on perennial bioenergy crops are promising strategies as they provide a renewable and sustainable energy source for rural areas. However, critical multidimensional challenges such as poverty, food security, gender equality, access to energy, and environmental impact must also be considered to ensure long-term sustainability. This review argues for more transparent land sales/usage (considering the agricultural work of women) and more perennial bioenergy crops. In this context, key principles were derived for a people-centered bottom-up approach that is considered fundamental to ensure the sustainable development of BCSs on MADs in the future.
]]>Earth doi: 10.3390/earth3020037
Authors: Irina-Adriana Chiurciu Daniela Dana Aurelia-Ioana Chereji Ioan Chereji Valentina Voicu Andreea-Roxana Firățoiu
The current paper presents the monitoring of soil and nutrient losses through runoff as the result of the climate change. The experimental results were recorded on the standard plots for runoff and erosion control. The results of the studies carried out highlight that total nitrogen losses range from 0.05 kg/ha to 12.60 kg/ha, potassium displaced from the plots has values between 0.02 and 1.35 kg/ha, the humus associated with the eroded soil includes values between 0.51 and 176.5 kg/ha, phosphorus is recorded with maximum values of 0.39 kg/ha, the total iron losses have values between 3.14 and 431.16 g/ha, manganese has losses from 1.69 to 290.82 g/ha, copper losses range from 0.15 to 7.62 g/ha, and, regarding zinc, the values are within the limits of 0.25–57.22 g/ha. The maximum values of the displacement of fertilizing elements from the sloping agricultural lands, by means of liquid and solid leaks, are registered at the plots left as permanent black fields, the plots practically unprotected against the rain erosion. The experiments were performed at the Soil Erosion Research and Development Station “Mircea Moțoc”, Perieni/Staţiunea de Cercetare Dezvoltare pentru Combaterea Eroziunii Solului “Mircea Moţoc”, Perieni (SCDCES—MM, Perieni), Vaslui County, an institution strategically located in an area subject to erosion soil. Additionally, the paper envisages how the National Rural Development Programme (NRDP) and the Common Agricultural Policy (CAP) can be of use in this area by analysing past lessons and providing an overview of what was done.
]]>Earth doi: 10.3390/earth3020036
Authors: Mohamed Shamsudeen Rajchandar Padmanaban Pedro Cabral Paulo Morgado
Land-use changes adversely may impact ecological entities and humans by affecting the water cycle, environmental changes, and energy balance at global and regional scales. Like many megaregions in fast emerging countries, Tamil Nadu, one of the largest states and most urbanized (49%) and industrial hubs in India, has experienced extensive landuse and landcover change (LULC). However, the extent and level of landscape changes associated with vegetation health, surface permeability, and Land Surface Temperature (LST) has not yet been quantified. In this study, we employed Random Forest (RF) classification on Landsat imageries from 2000 and 2020. We also computed vegetation health, soil moisture, and LST metrics for two decades from Landsat imageries to delineate the impact of landscape changes in Tamil Nadu using Google Earth Engine (GEE). The level of vegetation health and drought for 2020 was more accurately assessed by combining the Temperature Condition Index (TCI) and Vegetation Condition Index (VCI). A Soil moisture index was subsequently used to identify surface permeability. A 75% expansion in urban areas of Tamil Nadu was detected mainly towards the suburban periphery of major cities between 2000 and 2020. We observed an overall increase in the coverage of urban areas (built-up), while a decrease for vegetated (cropland and forest) areas was observed in Tamil Nadu between 2000 and 2020. The Soil-Adjusted Vegetation Index (SAVI) values showed an extensive decline in surface permeability and the LST values showed an overall increase (from a maximum of 41 °C to 43 °C) of surface temperature in Tamil Nadu’s major cities with the highest upsurge for urban built-up areas between 2000 and 2020. Major cities built-up and non-vegetation areas in Tamil Nadu were depicted as potential drought hotspots. Our results deliver significant metrics for surface permeability, vegetation condition, surface temperature, and drought monitoring and urges the regional planning authorities to address the current status and social-ecological impact of landscape changes and to preserve ecosystem services.
]]>Earth doi: 10.3390/earth3020035
Authors: Tapio S. Katko Petri S. Juuti Riikka P. Juuti Eric J. Nealer
Water and wastewater services are invaluable for communities. The aim of this article is to understand and explain the overall long-term development of water services in Finland in the wider PESTEL framework with policy implications for the future. The original megastudy was based on an extensive literature review. The article first covers the birth and development of urban and rural water systems in Finland. This is followed by analysing selected decisions with long-term impacts, institutional issues, discussion and lessons learnt, and conclusions. The development of water services in Finland has largely been based on trust. In socio-institutional factors, institutional diversity is fundamental. Gradual expansion of water supply and wastewater systems has brought technical, economic and social benefits in a country with quite a dispersed population. Efficient water pollution control in communities was implemented within two decades through developing technology and applying proper legislation and control. Continuous and dynamic development has been a key principle. Nature-based solutions include raw water source selection, treatment processes such as managed aquifer recharge, sites for final effluents disposal, and water related land use planning. Aging infrastructure is the most pressing future challenge in Finland and worldwide and will need new requirements and innovations.
]]>Earth doi: 10.3390/earth3020034
Authors: Sören Köpke
There is a vivid scientific debate on how climate change affects stability, resilience, and conflict dynamics of human societies. Environmental security and collapse theory are theoretical approaches that claim severe negative impacts of climatic disasters on political stability, allegedly through the vector of food insecurity. Yet there is a disconnect between this work and the rich body of knowledge on food insecurity and society. The literature is fairly unanimous that (a) drought does not necessarily lead to famines, since (b) famines have a political context that is often more important than other factors; in addition, (c) famines and the distribution of suffering reflect social hierarchies within afflicted societies, and (d) even large-scale famines do not necessarily cause collapse of a polity’s functioning, as (e) food systems are highly interconnected and complex. As an illustrative case, the paper offers a longitudinal study of Malawi. By combining environmental history and analysis of Malawi’s idiosyncratic (post-)colonial politics, it discusses the possible connections between droughts, food insecurity, and political crises in the African country. The single-case study represents a puzzle for adherents of the “collapse” theory but highlights the complex political ecology of food crises in vulnerable societies. This has implications for a formulation of climate justice claims beyond catastrophism.
]]>Earth doi: 10.3390/earth3020033
Authors: Chao Xu Weibo Liu
Tidal flats are widely recognized as sentinels of coastal environment change, and are also the guardians for beachfront communities. As a result of urban expansion, tidal flats have increasingly received environmental pressures and the surrounding ecosystem has been functionally downgraded. However, the existing studies could not provide an effective method to identify and quantify the interactions between urban areas and tidal flats, which is essential work particularly for the coastal preservations in the United States. Aiming at this environmental crisis, we proposed an approach which quantifies the change patterns from a spatiotemporal perspective. To justify the rationality and feasibility of this approach, this study selected three highly urbanized coastal counties in the southeastern United States as the study area. We analyzed the annual dynamics during 1985~2015, and the generated spatiotemporal regularities were used to identify and quantify the correlations between urban expansion and tidal flat dynamics. This study not only justified that the coastal urban expansion could considerably damage the environment of tidal flats, but also verified an effective approach to investigate the correlations between urban expansion and tidal flat loss on a large spatiotemporal scale.
]]>Earth doi: 10.3390/earth3020032
Authors: Anastasia-Alkmini Agapitidou Sofia Skroufouta Evangelos Baltas
The non-interconnected islands of Greece can benefit from the comprehensive use of RES to avoid water droughts and ensure energy autonomy. The present paper analyzes an HRES with two possible operating scenarios. Both of them include a wind park of 27.5 MW capacity, an 1175 m3/day desalination plant, and a 490,000 m3/day water tank in Lemnos, Greece. Regarding the wind power, 70% is used in the HRES, while the rest is channeled directly to the grid. The main difference comes down to how the wind energy is stored, either in the form of hydraulic energy or in the form of hydrogen. The lifespan of the system is 25 years, such as the produced stochastic series of rainfall, temperature, and wind of the area. Through the comparison of the operating scenarios, the following results arise: (i) the water needs of the island are fully covered and the irrigation needs have a reliability of 66%, in both scenarios. (ii) Considering the energy needs, the pumping storage seems to be the most reliable solution. (iii) However, depending on the amount of wind energy surplus, the use of hydrogen could produce more energy than the hydroelectric plant.
]]>Earth doi: 10.3390/earth3020031
Authors: Nicolas Marine
The implementation of the European Landscape Convention (ELC) at national and regional scales has brought with it the need to rethink landscape governance policies. In view of the disparity of possible methods for approaching landscape knowledge derived from the ELC, this article proposes the study of the three most ambitious landscape assessment methods developed in Spain at present. Specifically, those of Valencia, Galicia and Catalonia. Their study and comparative reading allow us to conclude that they have a similar structure imposed in part by the requirements of the Convention. Despite this, all three demonstrate a wide operational flexibility depending on the purpose of each one. As a derivative of the study, it is argued that a method seeking to fulfill both a sustainability and a public participation agenda would have to combine quantitative forms of socio-ecological assessment with a qualitative measurement of cultural appreciation of landscapes.
]]>Earth doi: 10.3390/earth3020030
Authors: Yangxing Zheng Mark Bourassa Dmitry Dukhovskoy M. Ali
The upper-ocean processes controlling the near-surface layer temperature in the western Gulf of Mexico (GOM) are examined by estimating the contributing terms in the heat equation based on a 54-year simulation of an eddy-resolving HYbrid Coordinate Ocean Model (HYCOM). An eddy-active region defined by large surface eddy kinetic energy, representing the Loop Current eddies (LCEs) primary trajectory region, is selected for analysis. Both observations and the simulation reveal that the mean net surface heat flux cools the northern GOM and warms the southern GOM. Mean horizontal heat advection contributes to an overall cooling in the eddy-active region. Mean vertical heat advection has a strong seasonal variability associated with the strong seasonal cycle of the mixed layer process: winters tend to have a strong downward heat advection in the eddy-active region and a strong upward heat advection in the rest of the western GOM, while summers tend to have a weak advective heat flux. The downwelling (upwelling) is primarily due to the dominant anticyclonic (cyclonic) wind stress curl. Mean eddy heat flux convergence contributes to the overall warming in the upper ocean of the western GOM. Diffusive flux is not small across the thermocline, and it is expected to have an insignificant influence on the near-surface temperature.
]]>Earth doi: 10.3390/earth3010029
Authors: Samuele De Petris Filippo Sarvia Enrico Borgogno-Mondino
Forest height is a key parameter in forestry. SAR interferometry (InSAR) techniques have been extensively adopted to retrieve digital elevation models (DEM) to give a representation of the continuous variation of the Earth’s topography, including forests. Unfortunately, InSAR has been proven to fail over vegetation due to low coherence values; therefore, all phase unwrapping algorithms tend to avoid these areas, making InSAR-derived DEM over vegetation unreliable. In this work, a sensitivity analysis was performed with the aim of properly initializing the relevant operational parameters (baseline and multilooking factor) to maximize the theoretical accuracy of the height difference between the forest and reference point. Some scenarios were proposed to test the resulting “optimal values”, as estimated at the previous step. A simple model was additionally proposed and calibrated, aimed at predicting the optimal baseline value (and therefore image pair selection) for height uncertainty minimization. All our analyses were conducted using free available data from the Copernicus Sentinel-1 mission to support the operational transfer into the forest sector. Finally, the potential uncertainty affecting resulting height measures was quantified, showing that a value lower than 5 m can be expected once all user-dependent parameters (i.e., baseline, multilooking factor, temporal baseline) are properly tuned.
]]>Earth doi: 10.3390/earth3010028
Authors: Alexander N. Fedorov
The results of permafrost landscape studies on northeastern Eurasia are presented in this review. The assessment of permafrost vulnerability to disturbances and global warming was the basis for the development of these studies. The permafrost landscape, considering the morphological features of the landscape and the permafrost together, is a timely object of study. The theoretical developments of Soviet physical geographers and landscape scientists are the basis for permafrost landscape studies. Over the past four decades, numerous permafrost landscape studies have been carried out on northeastern Eurasia (and Russia). Considering the results of these studies is the main objective of this article. The analysis of the problems of permafrost landscape identification, classification, and mapping and the study of their dynamics and evolution after disturbances and long-term development were carried out. Permafrost landscape studies employ the research methods of landscape science and geocryology. Environmental protection and adaptation of socioeconomic conditions to modern climate warming will determine the prospects for studying permafrost landscapes.
]]>Earth doi: 10.3390/earth3010027
Authors: Geminn Louis C. Apostol Sary Valenzuela Xerxes Seposo
Arsenic (As) is a highly toxic, carcinogenic trace metal that can potentially contaminate groundwater sources in volcanic regions. This study provides the first comparative documentation of As concentrations in groundwater in a volcano-sedimentary region in the Philippines. Matched, repeated As measurements and physico-chemical analyses were performed in 26 individual wells from 11 municipalities and city in Batangas province from July 2020 to November 2021. Using the electrothermal atomic absorption spectrometric method, analysis of the wells revealed that in 2020, 23 out of 26 (88.46%) had As levels above the WHO limit of >10 ppb while 20 out of 26 wells (76.92%) had persistently high As levels a year later. Using a Wilcoxon signed-rank test, levels of As were found to be statistically elevated compared to the national safe limit of 10 pbb in the 26 matched sampling sites in both 2020 (p-value < 0.001) and 2021 (p-value = 0.013). Additionally, a two-paired Wilcoxon signed-rank test revealed that As levels were statistically higher in 2020 than in 2021 (p-value = 0.003), suggesting that As levels may be higher in years when there is more volcanic activity; however, this remains to be further elucidated with suitable longitudinal data, as this study is still in its preliminary stages. The data was also analyzed using a bivariable regression, which showed no evidence of a significant relationship between As levels and distance from the danger zone (Taal volcano crater); however, results showed an inverse but statistically insignificant relationship between As levels and elevation. Due to the toxic profile and persistence of As in groundwater in Batangas Province, continuous groundwater As monitoring, timely public health risk communication, and the provision of alternative water sources to affected populations are recommended.
]]>Earth doi: 10.3390/earth3010026
Authors: Egidijus Jurkus Ramūnas Povilanskas Artūras Razinkovas-Baziukas Julius Taminskas
The background of this feature article is a necessity to systematize a vast array of issues pertinent to the latest applications of remote sensing in coastal and marine conservation. Hence the purpose of this study: stocktaking of cutting-edge research articles in this field and eliciting the essential trends and issues shaping the knowledge and future research and technical development perspectives in coastal and marine nature conservation, which is pivotal for meeting the United Nations Sustainable Development Goals till 2030. A hierarchical cluster analysis was undertaken with the KH Coder 3.0 tool to elicit topical co-occurrence networks for thematic words in academic papers from 2015 to 2021 on the topic quarried from Scholar Google. The article’s main findings are the elicited four main trending themes in applications of remote sensing in coastal and marine conservation: (1) Remote Sensing-Based Classification and Modelling; (2) Conservation of Tropical Coastal and Marine Habitats; (3) Mapping of Habitats and Species Distribution; (4) Ecosystem and Biodiversity Conservation and Resource Management. The main conclusion of the article is that habitat vulnerability is a key factor to take into consideration for the future hybrid applications of remote sensing and “citizen science” inputs.
]]>Earth doi: 10.3390/earth3010025
Authors: Anil Aryal Manisha Maharjan Rocky Talchabhadel Bhesh Raj Thapa
Drought is an environmental disaster related to the extremes (on a drier side) in hydrometeorology. The precipitation amount modulates drought in Nepalese river basins. It is vital for efficient water resources management to quantify and understand drought. This paper aims to characterize the droughts in Nepal based on standard precipitation index (SPI) and rainfall anomaly index (RAI) using daily precipitation data and assess their impacts on annual crop yields. We used 41 years (1975–2015) of daily precipitation data to compute monthly means and then the drought indices, namely, SPI and RAI, at 123 stations across Nepal. Results showed that the northwest and eastern regions experienced drought compared to other regions, although the severity and duration were shorter. For stations 101 and 308, we found extreme drought events after 2005 for SPI-1, SPI-3, and SPI-6. However, for SPI-6, extreme drought was also observed in 1989 and 1994 at both stations. The year 1992 was one of the severest drought years for the western and northwest regions, where the severity crossed more than −2.0 for all SPI months. Similar to SPI, RAI also revealed a similar degree of drought in the country. RAI showed that the eastern region depicted a higher degree of severity of drought compared to other areas beyond 2004. The lesser severity is also seen in the far west part beyond 2005. The results showed that SPI and RAI could equally be used to analyze drought severity. More frequent drought incidents have been observed after 2010 at all the considered precipitation stations. With the increase in the drought severity, the crop yield (such as paddy, maize, barley, millet, and wheat) has been directly impacted. These results might be significant for planning water resource and irrigation water management systems.
]]>Earth doi: 10.3390/earth3010024
Authors: Sebastian Lüning Philipp Lengsfeld
Global mean annual temperature has increased by more than 1 °C during the past 150 years, as documented by thermometer measurements. Such observational data are, unfortunately, not available for the pre-industrial period of the Common Era (CE), for which the climate development is reconstructed using various types of palaeoclimatological proxies. In this analysis, we compared seven prominent hemispheric and global temperature reconstructions for the past 2000 years (T2k) which differed from each other in some segments by more than 0.5 °C. Whilst some T2k show negligible pre-industrial climate variability (“hockey sticks”), others suggest significant temperature fluctuations. We discuss possible sources of error and highlight three criteria that need to be considered to increase the quality and stability of future T2k reconstructions. Temperature proxy series are to be thoroughly validated with regards to (1) reproducibility, (2) seasonal stability, and (3) areal representativeness. The T2k represents key calibration data for climate models. The models need to first reproduce the reconstructed pre-industrial climate history before being validated and cleared for climate projections of the future. Precise attribution of modern warming to anthropogenic and natural causes will not be possible until T2k composites stabilize and are truly representative for a well-defined region and season. The discrepancies between the different T2k reconstructions directly translate into a major challenge with regards to the political interpretation of the climate change risk profile. As a rule of thumb, the larger/smaller the pre-industrial temperature changes, the higher/lower the natural contribution to the current warm period (CWP) will likely be, thus, reducing/increasing the CO2 climate sensitivity and the expected warming until 2100.
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