Estuaries Ecology and Coastal Marine Waters

A special issue of Diversity (ISSN 1424-2818). This special issue belongs to the section "Marine Diversity".

Deadline for manuscript submissions: closed (29 February 2024) | Viewed by 6869

Special Issue Editors


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Guest Editor
Key Laboratory of Marine Ecosystem Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou 310012, China
Interests: marine biogeochemistry; material cycles; stable isotopes; biomarkers

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Guest Editor
Shirshov Institute of Oceanology, Russian Academy of Sciences, 117997 Moscow, Russia
Interests: carbonate chemistry; ocean acidification; sea-river mixing zone; coastal and shelf biogeochemical processes

Special Issue Information

Dear Colleagues,

Riverbanks, estuarine, and marine coastal areas are the territories that were settled and developed by humans a long time ago. Two-thirds of the most populated cities are concentrated in these areas, and the main economic traffic flows to them. This makes estuarine areas and adjacent shelves very vulnerable to the effects of various types of natural changes and anthropogenic impacts. The study of processes occurring in the mouth areas of rivers has always been considered an essential complex of biological sciences, such as oceanology, hydrology, biology, and geochemistry. During the investigation of estuarine areas, scientists mostly focus on the study of geochemical barrier zones where riverine and marine waters mix. However, water flows are involved in the functioning of geosystems, which are connected in a single transport line (blocks of cascade systems) that carry the substance from the continent to the sea. Any mouth area includes several barrier zones: geochemical, dynamic, and biological. The contribution of individual zones to runoff transformation will depend on many factors determined by climate, water flow, mineralization, and the state of the aquatic ecosystem.

In this Special Issue, we want to collect high-quality scientific papers aimed at the comprehensive study of estuarine areas of rivers in different climate zones. We would like to consider the problems related to the transformation of organic matter in the water and sediment layers, the spatial and temporal variability of the abiotic characteristics of estuarine ecosystems under the influence of climate change, and the response of biological environmental parameters to these changes. We are very interested in scientific results that describe chemical and biological processes not only in the mixing zone of sea and river waters, but also on the adjacent shelf. The variability of habitats of flora and fauna in these heterogeneous environments also attracts our attention. We will be glad to consider the results of studies related to the chemistry and biology of the waters of the estuarine regions of the World Ocean, from the cold Arctic to warm equatorial latitudes.

Dr. Zhongqiao Li
Dr. Alexander Polukhin
Guest Editors

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Keywords

  • estuary
  • coast
  • chemical and biological processes
  • biodiversity, from the Arctic to warm equatorial zones

Published Papers (6 papers)

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Research

15 pages, 3079 KiB  
Article
Picocyanobacteria in Estuaries of Three Siberian Rivers and Adjacent Shelves of Russian Arctic Seas: Genetic Diversity and Distribution
by Tatiana A. Belevich, Irina A. Milyutina and Aleksey V. Troitsky
Diversity 2023, 15(10), 1049; https://doi.org/10.3390/d15101049 - 28 Sep 2023
Viewed by 833
Abstract
Single-cell cyanobacteria, being an integral part of picoplankton in marine ecosystems, have been suggested to be important contributors to primary production and carbon cycles in the global ocean. The spatial distribution, abundance and diversity of natural communities of picocyanobacteria (PC) in estuaries of [...] Read more.
Single-cell cyanobacteria, being an integral part of picoplankton in marine ecosystems, have been suggested to be important contributors to primary production and carbon cycles in the global ocean. The spatial distribution, abundance and diversity of natural communities of picocyanobacteria (PC) in estuaries of Khatanga, Indigirka and Kolyma rivers and adjacent shelves of the Laptev and East Siberian seas were studied in September 2017. The PC concentrations were higher in the estuaries than in the shelf stations of the seas. The abundance of PC was 1.25 × 106 cells/L, 0.42 × 106 cells/L and 1.58 × 106 cells/L in the surface layer of Khatanga, Indigirka and Kolyma estuaries, respectively. The contribution of PC to total autumn picophytoplankton abundance averaged 6% and 3% in the Khatanga and Indigirka estuaries and reached 5% in the Kolyma estuary. Phylogenetic analysis of the 16S rRNA gene and ITS region clone libraries revealed picocyanobacterial sequences related to marine Synechococcus subclusters 5.1-I, 5.2 and 5.3. Of the phylotypes from Synechococcus S5.1-I and S5.2 that were found, only several were discovered earlier, while the remaining clones were unique. Two groups of phylotypes (clades A and E) were found that were not closely similar to those previously described in both marine and freshwater habitats. It can be expected that a more detailed study of the phytoplankton of the Arctic seas will further expand our understanding of the diversity of these key components of the food chains of oceanic biocenoses. Full article
(This article belongs to the Special Issue Estuaries Ecology and Coastal Marine Waters)
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28 pages, 3977 KiB  
Article
Annual Dynamics of a Layered Phytoplankton Structure in a Meromictic Lagoon Partially Isolated from the White Sea
by Irina G. Radchenko, Vasilisa A. Aksenova, Dmitry A. Voronov, Dmitry Viktorovich Rostanets and Elena Dmitrievna Krasnova
Diversity 2023, 15(9), 1009; https://doi.org/10.3390/d15091009 - 11 Sep 2023
Cited by 1 | Viewed by 696
Abstract
In a saline semi-isolated lagoon on Cape Zeleny (White Sea), the annual dynamics of the vertical hydrological structure and the seasonal dynamics of phytoplankton were traced. Species composition, vertical distribution, abundance, nutrition type, and biomass were analyzed. In total, 293 species and supraspecific [...] Read more.
In a saline semi-isolated lagoon on Cape Zeleny (White Sea), the annual dynamics of the vertical hydrological structure and the seasonal dynamics of phytoplankton were traced. Species composition, vertical distribution, abundance, nutrition type, and biomass were analyzed. In total, 293 species and supraspecific taxa of algae and cyanobacteria were found. Most of the identified species are marine, and 38 species are freshwater. Taxonomic composition changed in the lagoon throughout the year. Dinoflagellates dominated in winter and early June; unidentified cocci and flagellates in July; diatoms, dinoflagellates, and unidentified cells in August; dinoflagellates in September; and unidentified cocci and flagellates in October–November. The abundance of algae also changed in the lagoon throughout the year. The integrated biomass in the water column varied from 0.01 g C/m2 in January to 0.78 g C/m2 in early September. According to the environmental parameters, the water column of the lagoon was subdivided into several zones with different environmental conditions and corresponding phytoplankton communities. The similarity between the communities of different horizons was 32–46% in summer and 7% in winter. The chemocline layer was the most populous. It contained a maximum of phytoplankton biomass, 1–2 orders of magnitude higher than that in the overlying horizons. Despite the connection to the sea, the phytoplankton structure in the surface water layer in the lagoon and in the sea differed significantly in composition, quantitative parameters, and seasonal dynamics. The similarity between the communities never exceeded 50%. In terms of biomass dynamics, the lagoon lagged behind the sea until mid-summer, but, starting from August, it outnumbered it, and the phytoplankton development in the lagoon lasted longer, until late autumn. According to sequential tests DistLM, the phytoplankton structure and dynamics in the lagoon and in the sea were related to the daylength, water salinity, oxygen content, and pH by 24.5%. At the same time, the PhP structure did not depend on water temperature, underwater illuminance, or depth. Oxygen content and pH were defined by PhP activity. Salinity serves as a vector of the vertical sequence of ecological niches. The day length seems to be the crucial factor of the seasonal PhP dynamics in the semi-isolated coastal stratified lakes and lagoons. Full article
(This article belongs to the Special Issue Estuaries Ecology and Coastal Marine Waters)
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23 pages, 4811 KiB  
Article
Seagrass Blue Carbon Stock and Air–Sea CO2 Fluxes in the Karimunjawa Islands, Indonesia during Southeast Monsoon Season
by Nurul Latifah, Nining Sari Ningsih, Aditya Rakhmat Kartadikaria, Anindya Wirasatriya, Sigit Febrianto, Novi Susetyo Adi and Faisal Hamzah
Diversity 2023, 15(9), 978; https://doi.org/10.3390/d15090978 - 29 Aug 2023
Viewed by 1472
Abstract
Research focusing on seagrass ecosystems as carbon storage has been conducted in various Indonesian waters. However, an essential aspect that remains unexplored is the simultaneous analysis of blue carbon storage in seagrass alongside carbon dioxide (CO2) flux values, particularly within Karimunjawa [...] Read more.
Research focusing on seagrass ecosystems as carbon storage has been conducted in various Indonesian waters. However, an essential aspect that remains unexplored is the simultaneous analysis of blue carbon storage in seagrass alongside carbon dioxide (CO2) flux values, particularly within Karimunjawa waters. This study aims to assess the organic carbon stock and sea–air CO2 flux in seagrass ecosystems in Karimunjawa. Our hypothesis posits that although seagrass ecosystems release CO2 into the water, their role as blue carbon ecosystems enables them to absorb and accumulate organic carbon within seagrass biomass and sediments. This investigation took place in Karimunjawa waters, encompassing both vegetated (seagrass meadows) and unvegetated (non-seagrass meadows) areas during August 2019, 2020, and 2022. Over this period, the organic carbon stock in seagrass and sediment displayed an increase, rising from 28.90 to 35.70 gCorg m−2 in 2019 and from 37.80 to 45.25 gCorg m−2 in 2022. Notably, the expanse of seagrass meadows in Karimunjawa dwindled by 328.33 ha from 2019 to 2022, resulting in a total carbon stock reduction of the seagrass meadows of 452.39 tC to 218.78 tC. Sediment emerges as a pivotal element in the storage of blue carbon in seagrass, with sedimentary organic carbon outweighing seagrass biomass in storage capacity. The conditions in Karimunjawa, including a high A:B ratio, low dry bulk density, and elevated water content, foster a favorable environment for sediment carbon absorption and storage, facilitated by the waters’ CO2 emission during the southeast monsoon season. Notably, our findings reveal that CO2 release within vegetated areas is lower compared to unvegetated areas. This outcome underscores how seagrass ecosystems can mitigate CO2 release through their adeptness at storing organic carbon within biomass and sediment. However, the presence of inorganic carbon in the form of calcium carbonate introduces a nuanced dynamic. This external source, stemming from allochthonous origins like mangroves, brown algae like Padina pavonica, and calcareous epiphytes, leads to an increase in sedimentary organic carbon stock of 53.2 ± 6.82 gCorg m−2. Moreover, it triggers the release of CO2 into the atmosphere, quantified at 83.4 ± 18.26 mmol CO2 m−2 d−1. Full article
(This article belongs to the Special Issue Estuaries Ecology and Coastal Marine Waters)
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22 pages, 10238 KiB  
Article
Response of the Coastal Phytoplankton Community to the Runoff from Small Rivers in the Northeastern Black Sea
by Valentina M. Sergeeva, Sergey A. Mosharov, Natalia A. Shulga, Viacheslav V. Kremenetskiy, Pavel V. Khlebopashev and Dmitry N. Matorin
Diversity 2023, 15(7), 857; https://doi.org/10.3390/d15070857 - 15 Jul 2023
Viewed by 813
Abstract
River runoff is an important source of nutrients as well as suspended and dissolved organic matter that in coastal zones and on the shelf are transformed due to local production cycles. River runoff affects the hydrological regime, salinity, temperature, and irradiance in river–seawater [...] Read more.
River runoff is an important source of nutrients as well as suspended and dissolved organic matter that in coastal zones and on the shelf are transformed due to local production cycles. River runoff affects the hydrological regime, salinity, temperature, and irradiance in river–seawater mixing zone. Our study focuses on the response of phytoplankton to the impact of small Caucasian rivers in the Northeastern (NE) Black Sea, as one of the most sensitive components of marine ecosystems with respect to the changes in abiotic factors. The leading role of marine species of diatoms, dinoflagellates, and coccolithophores in the structure and functioning when impacted by runoff from small rivers is demonstrated in comparison to the freshwater community. Variability of the taxonomic composition and quantitative and productive characteristics of marine phytoplankton communities impacted by small rivers were comparable to or exceed the seasonal and interannual variability on the NE Black Sea shelf. This indicates the significant role of runoff from small Caucasian rivers in maintaining of a high production level of phytoplankton overall and of the coccolithophore Emiliania huxleyi in particular in the coastal zone. Full article
(This article belongs to the Special Issue Estuaries Ecology and Coastal Marine Waters)
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17 pages, 3283 KiB  
Article
Decadal Stability of Macrobenthic Zonation along the Estuarine Gradient in the Ob Bay, the Largest Siberian Estuary
by Margarita Chikina, Valentin Kokarev, Alexander Basin, Alexander Polukhin, Sergey Shchuka, Miloslav Simakov and Alexey Udalov
Diversity 2023, 15(6), 754; https://doi.org/10.3390/d15060754 - 08 Jun 2023
Viewed by 885
Abstract
The Siberian Arctic Shelf is an area of increasing anthropogenic activity and is predicted to be significantly impacted by climate change. Accordingly, there is an increased demand for baseline knowledge on the scales of natural spatiotemporal variation of different ecosystem components. The study [...] Read more.
The Siberian Arctic Shelf is an area of increasing anthropogenic activity and is predicted to be significantly impacted by climate change. Accordingly, there is an increased demand for baseline knowledge on the scales of natural spatiotemporal variation of different ecosystem components. The study aimed to investigate the spatial variability of macrobenthic communities and associated abiotic forcing in the Ob Bay, a major Arctic estuary. Four main zones of macrobenthic communities were identified: a brackish-water zone in the upper part of the estuary, which was divided into two subzones according to the dominant species; a transition zone at the mouth of the Ob Bay; and a marine zone. This zonation remained stable during the study period (2013–2019) and corresponded well with previous studies in the area. The large-scale variation in macrobenthic communities was related mainly to two independent drivers: salinity and sediment type. The within-zone variation increased with the number of coexisting species, but no temporal trends could be assessed. The study highlights the need to account for the small-scale heterogeneity of benthic communities to understand ecosystem functioning and long-term dynamics, particularly in areas where environmental conditions vary markedly. Full article
(This article belongs to the Special Issue Estuaries Ecology and Coastal Marine Waters)
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20 pages, 4363 KiB  
Article
Timing of Ice Retreat Determines Summer State of Zooplankton Community in the Ob Estuary (the Kara Sea, Siberian Arctic)
by Alexander Drits, Anna Pasternak, Elena Arashkevich, Anastasia Amelina and Mikhail Flint
Diversity 2023, 15(5), 674; https://doi.org/10.3390/d15050674 - 16 May 2023
Viewed by 985
Abstract
In the estuaries of large Siberian rivers, ice coverage and the timing of ice retreat have varied in recent decades under the ongoing climate change. The seasonal development and functioning of the mesozooplankton community depend to a great extent on the timing of [...] Read more.
In the estuaries of large Siberian rivers, ice coverage and the timing of ice retreat have varied in recent decades under the ongoing climate change. The seasonal development and functioning of the mesozooplankton community depend to a great extent on the timing of ice retreat. In the Arctic estuaries, the response of zooplankton to the timing of ice melt remains unclear. An earlier ice retreat was suggested to result in an advanced seasonal development of zooplankton, and higher biomass and feeding rates. Zooplankton composition, biomass, demography and grazing (assessed with the gut fluorescent approach) were studied in the Ob Estuary in July 2019 (“typical” ice retreat time). The obtained results were compared with the published data for July 2016 (ice retreat three weeks earlier). Zooplankton biomass in 2019 was considerably lower than in 2016, while species composition was similar; dominant populations were at an earlier stage of development. Herbivorous feeding of the dominant copepod, Limnocalanus macrurus, was also lower in 2019. The consequences of an earlier ice melt and increased temperature on seasonal population dynamics of the dominant brackish-water species are discussed. Our findings demonstrate that zooplankton communities in the Arctic estuaries are highly sensitive to the environmental changes associated with early sea-ice reduction. Full article
(This article belongs to the Special Issue Estuaries Ecology and Coastal Marine Waters)
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