Variability of suspended organic matter in the surface layer of the Black Sea (deep-sea areas)

The peculiarities of the distribution of the components of the suspended organic matter (SOM) and their interannual and seasonal variability have been analysed in the surface water layer and photic water layer of the Black Sea (the deep-sea areas) for the period of 1978–1995. The statistical assessment of the seasonal and monthly dynamics of the SOM components and their ratios was performed. The seasonal dynamics of the concentration of particulate organic carbon have been calculated based on the data on the Chlorophyll “a” (Chl “a”) concentration in the surface water layer based on the regression relationship between these two parameters measured in situ simultaneously. Taking these relationships into account, the interannual dynamics of the Chl “a” concentration have been analysed for the period of 1978–2010. It was found that the concentrations of the SOM components increased significantly in the 1980’s and early 1990’s with the maximum reached in the summer of 1992. It was also found that the seasonal interannual dynamics of the components of the SOM were mainly preconditioned by the interannual dynamics of the phytoplankton biomass, which, in turn, depended on the climatic conditions.