Environmental factors controlling the Barents Sea spring-summer phytoplankton blooms

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Abstract

[1] We provide an analysis of the seasonal change of the physical forcing factors and their impact on the timing and intensity of phytoplankton blooms in the Barents Sea, with emphasis on the different functional groups that can be distinguished (coccolithophores and other phytoplankton groups) using satellite remote sensing algorithms. Our analyses are based on an integration of satellite derived products and historical hydrographic data. There is a significant phase shift between the peaks of the diatom bloom in May to the coccolithophore bloom in August. Light and nutrient variability, driven by the large seasonal changes of solar irradiance and mixed layer depth in the Barents Sea, are the major environmental factors controlling these phytoplankton blooms. Based on previous field campaigns that identified Emiliana huxleyi as the most predominant species of coccolithophores in the Barents Sea, we conclude that the high concentration of calcite retrieved by ocean color satellites in summer is a result of bloom-forming coccolithophores of this species. A strong correlation between calcite concentration and wind speed squared (r2 = 0.8) was found during the peak of the bloom. We suggest that this correlation is an indication of CO2 fertilization resulting from regionally enhanced uptake of atmospheric CO2.

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