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11 pages, 2791 KiB

Open AccessArticle

Drainage Ratio Controls Phytoplankton Abundance in Urban Lakes

by Weijie Guo, Ziqian Li, Cai Li, Boyi Liu and Wenqing Shi

Water 2023, 15(4), 683; https://doi.org/10.3390/w15040683 - 09 Feb 2023

Viewed by 1416

Abstract

Urban lakes located in densely populated regions are highly vulnerable freshwater ecosystems compared to lakes in rural areas due to intense anthropogenic activities. However, the impacts of intrinsic lake morphometry on the water quality of urban lakes remain unclear. In the present study, [...] Read more.

Urban lakes located in densely populated regions are highly vulnerable freshwater ecosystems compared to lakes in rural areas due to intense anthropogenic activities. However, the impacts of intrinsic lake morphometry on the water quality of urban lakes remain unclear. In the present study, the water quality of 14 lakes and the underlying factors associated with such quality were explored in Wuhan City, China. Of these surveyed urban lakes, 92.9% were eutrophic or hypereutrophic; phytoplankton biomass ranged between 3.2 and 62.0 mg/L and was positively correlated with drainage ratio values (catchment area/lake area) during the phytoplankton bloom season. These results are consistent with the fact that small lakes associated with a large watershed area generally exhibit high levels of areal nutrient accumulation that rise with the drainage ratio, supporting phytoplankton growth. There were no significant differences in phytoplankton diversity among lakes (p > 0.05), remaining stable at the low Shannon index of 1.9–2.9, which is possibly due to high eutrophication pressure and similar local climatic conditions across the relatively limited study area. Overall, the results of this study will provide a valuable foundation for future efforts to improve water quality management efforts for urban lakes. Full article

(This article belongs to the Special Issue Nutrient Biogeochemical Cycles in Eutrophic Inland Waters and Eutrophication Control)

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15 pages, 3500 KiB

Open AccessArticle

What Is the Suitable Sampling Frequency for Water Quality Monitoring in Full-Scale Constructed Wetlands Treating Tail Water?

by Siyuan Song, Sheng Sheng, Jianqiang Xu and Dehua Zhao

Water 2022, 14(15), 2431; https://doi.org/10.3390/w14152431 - 05 Aug 2022

Cited by 2 | Viewed by 1705

Abstract

Three years of hourly COD and NH₄⁺-N measurements for two full-scale integrated constructed wetlands (CWs) treating secondary effluents from sewage treatment plants (STPs) were used to quantify the proper sampling frequency (SF). The modified coefficient of variation (CV_m) [...] Read more.

Three years of hourly COD and NH₄⁺-N measurements for two full-scale integrated constructed wetlands (CWs) treating secondary effluents from sewage treatment plants (STPs) were used to quantify the proper sampling frequency (SF). The modified coefficient of variation (CV_m) and average variation rate (VR_a) were calculated to monitor the dynamics and annual average performance, respectively. It was found that (1) under CV_m 5%, VR_a 5%, and VR_m 5%, the sampling intervals (SI) of COD can be set as 1.19 h, 526.5 h, and 110.1 h, respectively, and the SI of NH₄⁺-N should be 4.51 h, 66.3 h, and 26.8 h, respectively; (2) under CV_m 10%, VR_a 10%, and VR_m 10%, the monitoring intervals of COD can be set as 11.92 h, 1401.7 h, and 233.5 h, respectively, and the monitoring intervals of NH₄⁺-N should be 30.73 h, 139.3 h, and 50.5 h, respectively. Therefore, to meet the need of monitoring the dynamic changes in data, hourly and 4 h SIs were recommended for COD and NH₄⁺-N evaluation, respectively, when it is necessary to consider the operation and maintenance costs at the same time, 11 h and 30 h SIs were proper for COD and NH₄⁺-N evaluation, respectively. The methods proposed in this study could provide reference to improve the management and evaluation level of full-scale CWs. Full article

(This article belongs to the Special Issue Nutrient Biogeochemical Cycles in Eutrophic Inland Waters and Eutrophication Control)

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12 pages, 8419 KiB

Open AccessArticle

Determination of Glufosinate-P-Ammonium in Soil Using Precolumn Derivation and Reversed-Phase High-Performance Liquid Chromatography

by Lin Chen, Shun Kong, Guodong Wang, Xiaoju Yan, Xuemei Zhang, Xiangji Kong and Yuanqing Bu

Water 2022, 14(11), 1816; https://doi.org/10.3390/w14111816 - 06 Jun 2022

Viewed by 3191

Abstract

This study developed an analytical method to quantify glufosinate-P-ammonium (GLUF-P) in farmland soil using a reversed-phase high-performance liquid chromatography (HPLC) system with a fluorescence detector after derivatization. GLUF-P in farmland soil was extracted with a mixed alkaline solution and was further derivatized with [...] Read more.

This study developed an analytical method to quantify glufosinate-P-ammonium (GLUF-P) in farmland soil using a reversed-phase high-performance liquid chromatography (HPLC) system with a fluorescence detector after derivatization. GLUF-P in farmland soil was extracted with a mixed alkaline solution and was further derivatized with 9-fluorenyl methyl chloroformate (FMOC) at 25 °C for 1 h. The derivatives were separated with an ACE-C18 column, gradient eluted with a mobile phase A of acetonitrile and a mobile phase B of 0.2% phosphoric acid solution, and finally determined by high-performance liquid chromatography (HPLC) with fluorescence detection at an excitation wavelength of 254 nm and an emission wavelength of 279.8 nm. The limits of detection (LODs) in the four types of soil ranged from 0.004 to 0.015 mg/kg, and the limits of quantification (LOQs) ranged from 0.0125 to 0.05 mg/kg. The mean recoveries of GLUF-P ranged from 94% to 119.8%, and the relative standard deviations (RSDs) varied between 2.8% and 9.0% when the spiked concentrations of GLUF-P were 0.1 mg/kg and 1.0 mg/kg, respectively. The coefficients of regression for the linearity equation were more than 0.99. The proposed method had high sensitivity and could be used for the determination of GLUF-P residues in farmland soil. Full article

(This article belongs to the Special Issue Nutrient Biogeochemical Cycles in Eutrophic Inland Waters and Eutrophication Control)

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15 pages, 3633 KiB

Open AccessArticle

Evaluation of the Potential Release Risk of Internal N and P from Sediments—A Preliminary Study in Two Freshwater Reservoirs in South China

by Peng Cheng, Xu Bao, Yang Jiao, Xuezhi Zhang, Qingman Li and Sen Gu

Water 2022, 14(4), 664; https://doi.org/10.3390/w14040664 - 21 Feb 2022

Cited by 3 | Viewed by 1674

Abstract

Growing evidence has demonstrated the influence of internal nitrogen (N) and phosphorus (P) on harmful algae blooms in eutrophic freshwater ecosystems. However, the main controlling factors for internal N and P release risks, and whether these factors vary as environmental conditions change, remains [...] Read more.

Growing evidence has demonstrated the influence of internal nitrogen (N) and phosphorus (P) on harmful algae blooms in eutrophic freshwater ecosystems. However, the main controlling factors for internal N and P release risks, and whether these factors vary as environmental conditions change, remains poorly understood. We evaluated potential release risks of N and P from sediments in two freshwater reservoirs in Beihai City, southern China, by evaluating apparent nutrient fluxes during simulated static incubation experiments at two temperatures (15 °C and 25 °C). Sediments were analyzed to determine their basic properties as well as N and P fractions. Results showed that the main controlling factors of the apparent fluxes in dissolved total P, soluble reactive P, total N, and ammonium were related to sediment adsorption properties, redox properties, and microbial-mediated properties (e.g., water-extractable P, total inorganic N, redox-sensitive P, total organic carbon, organic P). The primary controlling factors for apparent N and P fluxes were dependent on the form of N and P and changed with temperature. The results suggest that care should be taken when simply using total N and P contents in sediments to evaluate their internal nutrient release risks. Full article

(This article belongs to the Special Issue Nutrient Biogeochemical Cycles in Eutrophic Inland Waters and Eutrophication Control)

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12 pages, 2919 KiB

Open AccessArticle

Metacommunity Concepts Provide New Insights in Explaining Zooplankton Spatial Patterns within Large Floodplain Systems

by Baogui Liu, Chuanqiao Zhou, Lilin Zheng, Haixin Duan, Ying Chen and Guoxiang Wang

Water 2022, 14(1), 93; https://doi.org/10.3390/w14010093 - 04 Jan 2022

Cited by 1 | Viewed by 1794

Abstract

Flood pulse related physical variables (FLOOD) can affect zooplankton community structure through local factors directly and can also influence through regional dispersal factors of metacommunity concepts indirectly. Therefore, we infer that spatial patterns of zooplankton communities could be related to metacommunity concepts and [...] Read more.

Flood pulse related physical variables (FLOOD) can affect zooplankton community structure through local factors directly and can also influence through regional dispersal factors of metacommunity concepts indirectly. Therefore, we infer that spatial patterns of zooplankton communities could be related to metacommunity concepts and their importance may depend on the size of the aquatic/terrestrial transition zone (ATTZ). Herein, we explored the relative importance of limnological (LIMNO) and FLOOD variables in zooplankton community by analyzing data from 272 sites across three floodplain lakes in the middle reaches of the Yangtze River. Our results showed that the variation in the zooplankton community can be well explained by the LIMNO and FLOOD variables in all of the lakes under the low water level season. However, during the high water level season, neither LIMNO nor FLOOD can explain the spatial variances of zooplankton. Therefore, our results indicated that testing biogeographical theories and macroecological laws using zooplankton should consider temporal aspects of flood pulse. Furthermore, we noted that the number of explained variance by local variables is negatively correlated with the size of the ATTZ. Metacommunity concepts provide complementary insights in explaining zooplankton spatial patterns within large floodplain systems, which also provide a theoretical basis for ATTZ protection in floodplain management. Full article

(This article belongs to the Special Issue Nutrient Biogeochemical Cycles in Eutrophic Inland Waters and Eutrophication Control)

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10 pages, 2098 KiB

Open AccessFeature PaperArticle

Enhanced Sediment Denitrification for Nitrogen Removal by Manipulating Water Level in the Lakeshore Zone

by Yangfang Gao, Mingming Wang, Jun Wei, Lingwei Kong, Hui Xu, Wenqing Shi and Lin Zhu

Water 2021, 13(23), 3323; https://doi.org/10.3390/w13233323 - 23 Nov 2021

Cited by 4 | Viewed by 1822

Abstract

Denitrification of sediments is an important way to remove reactive nitrogen in lakeshore zones. In this work, we analyzed sediment denitrification patterns across the shore zone of Lake Taihu and explored their underlying mechanisms using flooding simulation experiments. The results showed that denitrification [...] Read more.

Denitrification of sediments is an important way to remove reactive nitrogen in lakeshore zones. In this work, we analyzed sediment denitrification patterns across the shore zone of Lake Taihu and explored their underlying mechanisms using flooding simulation experiments. The results showed that denitrification mainly occurred in the upper sediment layer (0–10 cm) and the denitrification rate was highest at the land–water interface (6.2 mg N/m²h), where there was a frequent rise and fall in the water level. Denitrification was weaker in the lakebed sediments (4.6 mg N/m²h), which were inundated long-term, and in the sediments of the near-shore zone (2.3 mg N/m²h), which were dried out for extended periods. Flooding simulation experiments further indicated a strong positive relationship between sediment denitrification rate and flooding frequency. When the flooding occurred once every 3, 6, 9, 12, or 15 days, the denitrification rate reached 7.6, 5.7, 2.8, 0.9, and 0.6 mg N/m²h, respectively. Frequent flooding caused alternating anoxic and aerobic conditions in sediments, accelerating nitrogen substrate supply and promoting the growth and activity of denitrifying bacteria. Based on these findings, we propose a possible strategy for enhancing sediment denitrification by manipulating the water level, which can help guide nitrogen removal in lakeshore zones. Full article

(This article belongs to the Special Issue Nutrient Biogeochemical Cycles in Eutrophic Inland Waters and Eutrophication Control)

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11 pages, 1259 KiB

Open AccessArticle

Effects of Escherichia coli Alkaline Phosphatase PhoA on the Mineralization of Dissolved Organic Phosphorus

by Yanwen Zhou, Tingxi Zhang, Shengyan Jin, Siyu Chen and Yinlong Zhang

Water 2021, 13(23), 3315; https://doi.org/10.3390/w13233315 - 23 Nov 2021

Cited by 5 | Viewed by 2231

Abstract

Alkaline phosphatases, which play the key role in the mineralization of organic phosphorus, have been grouped into three distinct families, PhoA, PhoX, and PhoD. PhoA is still an important component of the Pho regulon for many microbes although its distribution is not as [...] Read more.

Alkaline phosphatases, which play the key role in the mineralization of organic phosphorus, have been grouped into three distinct families, PhoA, PhoX, and PhoD. PhoA is still an important component of the Pho regulon for many microbes although its distribution is not as wide as that of PhoX and PhoD. However, several questions remain unclear about the effect of PhoA mineralization of dissolved organic phosphorus. In this study, the role of Escherichia coli alkaline phosphatase PhoA (hereinafter referred to as PhoA) in the mineralization of different organic phosphorus including phosphate monoesters, phosphate diesters, and phytic acids was investigated. The influence of the reaction time, organic phosphorus concentration, and L-amino acid on PhoA mineralization was examined. The results show that PhoA specifically hydrolyzes phosphate monoesters except for phytic acid and the optimal reaction time is around 12 h. The PhoA mineralization rate of glucose 6-phosphate disodium (G6P), 5′-adenosine monophosphate (AMP), and sodium glycerophosphate (BGP) significantly decreased by 38.01%, 55.31%, and 57.08%, respectively (p < 0.01), while the concentration of organic phosphorus increased from 0.50 to 5.00 mg/L. Overall, L-amino acids inhibited PhoA mineralization in a concentration-independent manner. The inhibitory effect of neutral amino acids serine (L-Ser) and tyrosine (L-Tyr) was significantly higher than that of basic amino acids arginine (L-Arg), lysine (L-Lys), and histidine (L-His). All the five amino acids can inhibit PhoA mineralization of AMP, with the highest inhibition rate observed for L-Tyr (23.77%), the lowest—for L-Arg (1.54%). Compared with other L-amino acids, L-Tyr has the highest G6P and BGP mineralization inhibition rate, with the average inhibition rates of 12.89% and 11.65%, respectively. This study provides meaningful information to better understand PhoA mineralization. Full article

(This article belongs to the Special Issue Nutrient Biogeochemical Cycles in Eutrophic Inland Waters and Eutrophication Control)

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Review

Jump to: Research

17 pages, 5628 KiB

Open AccessReview

Research Development, Current Hotspots, and Future Directions of Blue Carbon: A Bibliometric Analysis

by Qiuying Lai, Jie Ma, Fei He, Aiguo Zhang, Dongyan Pei, Geng Wei and Xiaolin Zhu

Water 2022, 14(8), 1193; https://doi.org/10.3390/w14081193 - 08 Apr 2022

Cited by 9 | Viewed by 4028

Abstract

The blue carbon ecosystem has a strong capacity for carbon sequestration, but its research progress and development are still unclear. This study used CiteSpace to conduct a visual analysis, based on the analysis of 908 articles retrieved from the Web of Science Core [...] Read more.

The blue carbon ecosystem has a strong capacity for carbon sequestration, but its research progress and development are still unclear. This study used CiteSpace to conduct a visual analysis, based on the analysis of 908 articles retrieved from the Web of Science Core Collection. The results showed that blue carbon research has gone through an early exploratory stage based on the scientific concept research, a research stage on the carbon sequestration process of the diverse blue carbon ecosystems, and a blue carbon protection and restoration stage based on climate change and human activities. The blue carbon theoretical framework has been continuously improved and the subject is currently more focused. The hot research topics are different at different stages. In the early stage, they focused on the types of blue carbon ecosystems and the process of carbon sequestration. Blue carbon research has developed from a single ecosystem type to multiple ecosystem types, and from concept recognition to system assessment research. Recently, research on the response, restoration and protection of blue carbon ecosystems has become a hotspot under the combined effect of human activities and climate change. In the future, it is necessary to strengthen the scientific research on blue carbon, to protect the integrity of the ecosystem structure and service functions, and to make a greater contribution to the global carbon neutrality strategy. Full article

(This article belongs to the Special Issue Nutrient Biogeochemical Cycles in Eutrophic Inland Waters and Eutrophication Control)

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