Abstract
Based on satellite data from the SeaWiFS, MODIS-Aqua, and MODIS-Terra scanners, the long-term dynamics of coccolithophores in the Black Sea and their large-scale heterogeneity have been studied. During the twenty years in May and June, mass development of coccolithophores population of different intensities was recorded annually. Summer blooms of coccolithophores reached peak levels in 2006, 2012, and 2017, after abnormally cold winters. It was noted that in conditions of low summer temperatures, the blooming of coccolithophores could be significantly reduced or acquire a local character (2004). In the anomalous cold summer of 2001, coccolithophore blooms was replaced by the mass growth of diatoms. Over twenty years, numerous signs of coccolithophores mass development in the cold season have been revealed. Winter blooms develop mainly in warm winters with periods of low wind activity. The formation of a thermocline and the surface layer’s stability are essential factors for initiating winter blooms of coccolithophores. It was noted that after the winter blooms of coccolithophores, their summer growth was poorly expressed. It is shown that during periods of rapid growth, the bulk of coccolithophores is concentrated in the upper mixed layer and thermocline. During the blooming period, the share of coccolithophores in phytoplankton biomass constituted 70–85%. The intensity of coccolithophore’s blooms is associated with the previous diatoms’ growth level. The effect of eddies circulation on the distribution and growth of coccolithophores is considered.
Highlights
As the primary productive link of the marine ecosystem, phytoplankton affects the fundamental biogeochemical processes in the ocean [1,2]
The objectives of this work are to consider the main features of coccolithophores dynamics over twenty years based on remotely sensed data, to record the most significant regular and abnormal events in seasonal and long-term cycles of algae growth with a view to their further in-depth study, to fill in the existing gaps in the study of coccolithophores in the Black Sea based on new data from field and satellite observations
The long-term dynamics of coccolithophores expressed as PIC concentrations show that every year from May to July, there are periods of mass coccolithophores growth of different intensities (Figure 3a,b), reaching the level of blooms with about a two-four-year periodicity
Summary
As the primary productive link of the marine ecosystem, phytoplankton affects the fundamental biogeochemical processes in the ocean [1,2]. The mass growth of coccolithophores is accompanied by the assimilation of vast amounts of dissolved carbonates and CO2 , followed by the transition of carbon compounds into a suspended form. This process affects the parameters of CO2 exchange between the ocean and the atmosphere [3]. The particular importance of coccolithophores for the Black Sea ecosystem is defined by the drastic changes in the phytoplankton structure taking place over recent decades. During the summer growing season, the coccolithophores abundance reaches 10 million cells/L and more, while their share in phytoplankton biomass exceeds 90% This process directly impacts functioning of the food chains of the Black Sea ecosystem. Due to the low nutritional value of coccolithophores for zooplankton [5], the expansion of their dominance in the primary link of the food
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
