Inflow and accumulation of organic matter in the bays at Russian coast of the Japan Sea are evaluated using the data on chemical parameters of seawater and total content of carbon in the bottom sediments. Complex index of organic content in the environment (CIOCE) is proposed. Shannon diversity index (I) and the index of trophic structure disturbance (ITSD) are assessed for macrobenthos of these areas and compared with CIOCE non-linear parabolic dependence is revealed with the 90 % confidence level. The value of CIOCE ecological optimum (when macrobenthos has the highest species diversity and healthy trophic structure) is determined as 1.5–2.5 both higher and lower CIOCE values cause reduction of species diversity and disturbance of trophic structure that means that the organic matter supply is favorable for macrobenthos until a certain threshold.

Предложен комплексный индекс содержания органики в среде (КИСОС). Проведена оценка зависимости индекса разнообразия Шеннона и трофической структуры от КИСОС. Установлен диапазон значений данного индекса, которому соответствуют максимальные показатели разнообразия и благополучия трофической структуры. Предложена градация экологического благополучия акваторий в отношении содержания органического вещества на три уровня.