Features of phytoplankton changes in the Sevastopol and Karadag coastal areas (the Black sea) in spring

Abstract

Based on field-monitoring and satellite dataset obtained during spring season, we studied the features of phytoplankton changes under effect of hydrometeorological factors in the coastal areas of Sevastopol in 2000–2021 and Karadag in 1989–2021. For these areas, significant positive correlations were observed between phytoplankton biomass and winds causing coastal upwellings which lift nutrients from deep layers to the surface. On the basis of Principal Component Analysis (PCA) and ANOVA, a positive effect of the north wind speed on phytoplankton biomass in the Sevastopol and Karadag coastal areas was established. Different mechanisms of the north wind effect on the nutrient-rich waters rise for two investigated areas were revealed and it was due to peculiarities of these coastal areas. The north wind also contributes to nutrient supply from the river runoff of the northwestern shelf to the Sevastopol coastal area. High values of phytoplankton biomass and chlorophyll a concentration were mainly observed in cold years.