Phytoplankton Dynamics and Biogeochemistry of the Black Sea
The biogeochemistry of waters is an essential regulator of phytoplankton dynamics, determining the level of species bloom and the change in dominants. This paper investigated the seasonal dynamics of phytoplankton and the nutrient concentrations and their ratios in the northeastern Black Sea in 2017...
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| Format: | Article |
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MDPI AG
2023-06-01
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| Series: | Journal of Marine Science and Engineering |
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| Online Access: | https://www.mdpi.com/2077-1312/11/6/1196 |
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| author | Vladimir Silkin Larisa Pautova Oleg Podymov Valeryi Chasovnikov Anna Lifanchuk Alexey Fedorov Agnislava Kluchantseva |
| author_facet | Vladimir Silkin Larisa Pautova Oleg Podymov Valeryi Chasovnikov Anna Lifanchuk Alexey Fedorov Agnislava Kluchantseva |
| author_sort | Vladimir Silkin |
| collection | DOAJ |
| description | The biogeochemistry of waters is an essential regulator of phytoplankton dynamics, determining the level of species bloom and the change in dominants. This paper investigated the seasonal dynamics of phytoplankton and the nutrient concentrations and their ratios in the northeastern Black Sea in 2017–2021. Two taxonomic groups, diatoms and coccolithophores, determine the seasonal dynamics and significantly contribute to the total phytoplankton biomass. Coccolithophores formed blooms in early June annually, except in 2020. Large diatoms dominated in summer with a biomass exceeding 1000 mg m<sup>−3</sup> annually, except in 2019. During the blooms of these taxonomic groups, their contribution to the total phytoplankton biomass exceeded 90%. Each group has characteristic biogeochemical niches in the nitrogen and phosphorus concentration coordinates. The position of the seasonal thermocline regulates the biogeochemistry of the water. With a high-lying and sharp gradient thermocline (the average for five years is 6.87 m), low nitrogen concentrations and a nitrogen-to-phosphorus ratio below the Redfield ratio are created in the upper mixed layer. These conditions are optimal for the dominance of coccolithophores. When the thermocline is deepened (the average for five years is 17.96 m), the phosphorus concentration decreases significantly and the ratio of nitrogen to phosphorus is significantly higher than the Redfield ratio, and these conditions lead to the dominance of large diatoms. The results of experimental studies with nitrogen and phosphorus additives in the natural phytoplankton population confirm the above statements. The addition of phosphorus leads to the increased role of coccolithophores in the total phytoplankton biomass, the addition of nitrogen alone contributes to the growth of large diatoms, and the combined addition of phosphorus and nitrogen in a ratio close to the Redfield ratio leads to the dominance of small diatoms. |
| first_indexed | 2024-03-11T02:17:29Z |
| format | Article |
| id | doaj.art-7fd8750ddc8143ca9cacc970fa2b1753 |
| institution | Directory Open Access Journal |
| issn | 2077-1312 |
| language | English |
| last_indexed | 2024-03-11T02:17:29Z |
| publishDate | 2023-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Journal of Marine Science and Engineering |
| spelling | doaj.art-7fd8750ddc8143ca9cacc970fa2b17532023-11-18T11:07:12ZengMDPI AGJournal of Marine Science and Engineering2077-13122023-06-01116119610.3390/jmse11061196Phytoplankton Dynamics and Biogeochemistry of the Black SeaVladimir Silkin0Larisa Pautova1Oleg Podymov2Valeryi Chasovnikov3Anna Lifanchuk4Alexey Fedorov5Agnislava Kluchantseva6Shirshov Institute of Oceanology, Russian Academy of Sciences, 117977 Moscow, RussiaShirshov Institute of Oceanology, Russian Academy of Sciences, 117977 Moscow, RussiaShirshov Institute of Oceanology, Russian Academy of Sciences, 117977 Moscow, RussiaShirshov Institute of Oceanology, Russian Academy of Sciences, 117977 Moscow, RussiaShirshov Institute of Oceanology, Russian Academy of Sciences, 117977 Moscow, RussiaShirshov Institute of Oceanology, Russian Academy of Sciences, 117977 Moscow, RussiaShirshov Institute of Oceanology, Russian Academy of Sciences, 117977 Moscow, RussiaThe biogeochemistry of waters is an essential regulator of phytoplankton dynamics, determining the level of species bloom and the change in dominants. This paper investigated the seasonal dynamics of phytoplankton and the nutrient concentrations and their ratios in the northeastern Black Sea in 2017–2021. Two taxonomic groups, diatoms and coccolithophores, determine the seasonal dynamics and significantly contribute to the total phytoplankton biomass. Coccolithophores formed blooms in early June annually, except in 2020. Large diatoms dominated in summer with a biomass exceeding 1000 mg m<sup>−3</sup> annually, except in 2019. During the blooms of these taxonomic groups, their contribution to the total phytoplankton biomass exceeded 90%. Each group has characteristic biogeochemical niches in the nitrogen and phosphorus concentration coordinates. The position of the seasonal thermocline regulates the biogeochemistry of the water. With a high-lying and sharp gradient thermocline (the average for five years is 6.87 m), low nitrogen concentrations and a nitrogen-to-phosphorus ratio below the Redfield ratio are created in the upper mixed layer. These conditions are optimal for the dominance of coccolithophores. When the thermocline is deepened (the average for five years is 17.96 m), the phosphorus concentration decreases significantly and the ratio of nitrogen to phosphorus is significantly higher than the Redfield ratio, and these conditions lead to the dominance of large diatoms. The results of experimental studies with nitrogen and phosphorus additives in the natural phytoplankton population confirm the above statements. The addition of phosphorus leads to the increased role of coccolithophores in the total phytoplankton biomass, the addition of nitrogen alone contributes to the growth of large diatoms, and the combined addition of phosphorus and nitrogen in a ratio close to the Redfield ratio leads to the dominance of small diatoms.https://www.mdpi.com/2077-1312/11/6/1196phytoplanktonBlack Seabiogeochemistryspecies compositiondiatomscoccolithophores |
| spellingShingle | Vladimir Silkin Larisa Pautova Oleg Podymov Valeryi Chasovnikov Anna Lifanchuk Alexey Fedorov Agnislava Kluchantseva Phytoplankton Dynamics and Biogeochemistry of the Black Sea Journal of Marine Science and Engineering phytoplankton Black Sea biogeochemistry species composition diatoms coccolithophores |
| title | Phytoplankton Dynamics and Biogeochemistry of the Black Sea |
| title_full | Phytoplankton Dynamics and Biogeochemistry of the Black Sea |
| title_fullStr | Phytoplankton Dynamics and Biogeochemistry of the Black Sea |
| title_full_unstemmed | Phytoplankton Dynamics and Biogeochemistry of the Black Sea |
| title_short | Phytoplankton Dynamics and Biogeochemistry of the Black Sea |
| title_sort | phytoplankton dynamics and biogeochemistry of the black sea |
| topic | phytoplankton Black Sea biogeochemistry species composition diatoms coccolithophores |
| url | https://www.mdpi.com/2077-1312/11/6/1196 |
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