Analysis of the dynamics of organogenic substance concentrations and ratesof production-destruction processes in the waters of the northern part of Caspian Sea

Dynamics of dissolved organic and mineral fractions of nutrients(C, SI, N a nd P) is simulated for ten regions of the Caspian Sea with the help of an e cological model. The modeling results are analyzed for the most productive northern part of the sea. Assessments of biogenic substance inputs to the s ea with the river run off (Volga, Ural, Terek) as well as the internal flux es of the compound biotransformations in the marine ecosystem are presented and discussed. The values of primary production, calculated from the model ing results, are in good agreement with experimental data available from th e literature.