Calculation of flows of autochtonic organic matter on the example of lake Nizhneye Barabinsky district Novosibirsk region

Fluxes of matter, especially biogenic migration of elements, are the basis for the functioning of aquatic ecosystems. Currently, no models have been developed for assessing the processes of accumulation of organic matter in small lakes, whereas they are the main accumulators of organic matter of both allochthonous and autochthonous origin. In the proposed work, the calculation of the contribution of aquatic organisms to the total sedimentation flow in a typical small lake of the forest-steppe zone of the Baraba lowland is given in order to determine the sources of the formation of organic matter in the bottom sapropel. The assessment of the current state of the ecosystem of the water body according to the characteristics of the biocenosis: benthos, phytoplankton, zooplankton, higher aquatic vegetation. The production characteristics of various links of the hydrobiocenosis have been determined. Experiments with sedimentation traps have been set up. It is shown that Lake Nizhneye is characterized by all the signs of a eutrophic lakes: overproduction of primary production with an excess supply of organic matter in bottom sediments; desynchronization in the development of producers and consumers; suppression of the pasture chain and a shift in the flow of substances and energy into the detrital chain. Sapropel in Lake Nizhny has a macrophytic-planktonic genesis, which is typical for actively swamping aging lake ecosystems of the forest-steppe region. The share of autochthonous organic matter is 34%. More than half of the sedimentation flow comes from the catchment area. The accumulation rate of sapropel can fluctuate annually depending on weather conditions and the development of producers and averages 1.25 cm per year. The extraction of sapropel and the cleaning of the lake basin from the accumulated bottom sediments can be in the future to restore the fish productivity of the reservoir.