Extremely strong coccolithophore blooms in the Black Sea: The decisive role of winter vertical entrainment of deep water

Kubryakov, A. A.; Mikaelyan, Alexander S.; Stanichny, S. V.

doi:10.1016/j.dsr.2021.103554

Cited by 10 publications

(8 citation statements)

References 90 publications

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“…Chl‐a fluorescence data serve as a proxy for phytoplankton biomass; bbp can be used as a proxy to detect coccolithophore blooms because coccoliths in the Black Sea induce strong backscattering (Kubryakov et al., 2021). Ricour et al.…”

Section: Discussionmentioning

confidence: 99%

The Synergy of Data From Profiling Floats, Machine Learning and Numerical Modeling: Case of the Black Sea Euphotic Zone

2022

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Several important developments in recent decades have greatly advanced our understanding of the biogeochemistry of the ocean and its evolution. The first is attributable to satellites, which continue to provide data on some surface biogeochemical (BGC) properties. The second advancement is the development of sensors for acquiring in situ measurements, particularly by new observational platforms such as the BGC-Argo network (Claustre et al., 2020) and gliders. The third is the advancement in numerical BGC modeling. Unfortunately, each of these advancements suffers from numerous problems. Satellites observe only the ocean surface, whereas the layers beneath could be much more representative of the BGC system than the thin surface layer. BGC-Argo sensors measure properties over large depth ranges; however, sampling locations cannot be determined in advance, and coverage remains insufficient over most of the world's oceans. In addition, the number of sensors is limited.

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Section: Discussionmentioning

confidence: 99%

The Synergy of Data From Profiling Floats, Machine Learning and Numerical Modeling: Case of the Black Sea Euphotic Zone

2022

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“…However, there is a hypothesis that the intensity of the bloom is associated with the intensity of winter mixing; after cold winters with increased vertical turbulence, the bloom is more intense [87]. Indeed, deeper mixing in cold winters transfers denser waters to the upper layers, which enhances vertical exchange when convective mixing stops [88].…”

Section: The Bloom Of the Coccolithophore Emiliania Huxleyimentioning

confidence: 99%

Phytoplankton Dynamics and Biogeochemistry of the Black Sea

Silkin,

Pautova,

Podymov

et al. 2023

JMSE

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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−3 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.

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“…Coccolithophore blooms are regularly observed in the Black Sea [1][2][3][4] . Coccolithophores are the main contributors to a 'carbonate pump' [5][6][7] .…”

Section: Introductionmentioning

confidence: 99%

Bio-optical model for conditions of intense coccolithophore bloom in the Black Sea

Vazyulya,

Deryagin,

Glukhovets

et al. 2023

29th International Symposium on Atmospheric and Ocean Optics: Atmospheric Physics

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The possibility of creating a bio-optical model for calculating parameters of underwater light fields under conditions of intense coccolithophore bloom in the Black Sea is shown. Hydrolight software is used for bio-optical modeling. The influence of the parameters of the bio-optical model both on the remote sensing reflectance spectrum and on the concentration of coccolithophores is demonstrated. The coccolithophore concentration is calculated using a regional algorithm. The optimal modeling parameters yield the remote sensing reflectance spectrum which nearly coincides with measured one. A decrease in the thickness of the coccolithophore layer relative to the optimal one leads to a comparable decrease in the concentration of coccolithophores, at the same time its increase does not play such a significant role. Estimates of the concentration of coccolithophores change little with variations in the concentration of chlorophyll, but they are more sensitive to changes in the amount of colored dissolved organic matter. The created bio-optical model made it possible to study the accuracy of chlorophyll estimation algorithms under conditions of intensive coccolithophore bloom.

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Extremely strong coccolithophore blooms in the Black Sea: The decisive role of winter vertical entrainment of deep water

Cited by 10 publications

References 90 publications

The Synergy of Data From Profiling Floats, Machine Learning and Numerical Modeling: Case of the Black Sea Euphotic Zone

The Synergy of Data From Profiling Floats, Machine Learning and Numerical Modeling: Case of the Black Sea Euphotic Zone

Phytoplankton Dynamics and Biogeochemistry of the Black Sea

Bio-optical model for conditions of intense coccolithophore bloom in the Black Sea

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