NATURAL SCIENCES

Journal of fundamental
and
applied researches

Spatial distribution of organic matter in bottom sedimentsof the Nothern Caspian depending on abiotic and biotic environmental factors

2013. №2, pp. 49-56

Degtyareva Larisa V.  - Research Worker, Caspian Fisheries Research Institute, 1 Savushkin St., Astrakhan, 414056, Russian Federation, dlgru@mail.ru

The accumulation rate of organic substances at bottom sediments determines water body trophicity and toxic substances deposition level. The purpose of the paper is to study spacial distribution of organic substance in the sediments of western part of the Northern Caspian depending on abiotic and biotic ecological factors. The concentration of organic carbon varied from 0.01 to 2.82 %. As a part of the study the direct correlation relationships between the the organic substance content in the soils and the percentage of pellite fraction, depth and indicators of the level of development of production processes (oxygen in the surface layer of the water, pH, the concentration of phytopigments, the content of dissolved forms of organic nutrients). The level of accumulation of organic matter negatively depends on temperature, salinity and oxygen saturation of the bottom water layer. The highest rate of the organic material accumulation is peculiar for finely-dispersed grounds, which are deeply superposed at the areas with high level of organic matter growth. The increase of water temperature at benthic area, the ground salinity increase and oxygenating of bottom waters expedite the destruction of the organic substance in the sediments.

Key words: organic matter,organic carbon,bottom sediments,the Northern Caspian,spatial distribution,grain-size content,oxygen,nutrients,phytopigments,active reaction of environment (pH)