Role of natural and climatic factors in formation of autochthonic organic substance streams in small lakes of the south of Western Siberia

Abstract

The main objectives of this study are to identify the role of external physical and chemical factors in productivity formation of small lakes ecosystems in the south of Western Siberia as well as to assess the impact of these factors on some ecosystem elements (phyto- and zooplankton, macrophytes, benthos) in the light of climate change. The explored lakes are along a 700 km south-north transect latitude from 5115N for 5645N in the territory within Altai Krai and the Novosibirsk region, in four broadly defined vegetation zones: dry-steppe, steppe, forest-steppe and subtaiga. The lakes have different mineralization (from 0.01 to 67.88 g/dm³), pH value (from 6.3 to 9.96), dissolved oxygen content (3 13 mg/dm³), BOD₅ (0.28 8.32 mgO₂/dm³), hydrocarbonates, chlorides, sulphates, nitrates, phosphates and calcium. The determining factors in the formation of total production of aquatic ecosystems in the dry steppe zone (primary phytoplankton production, primary production formation in submerged plants, zooplankton and zoobenthos production) are pH and mineralization (94% of explained dispersion) and in the steppe zone also pH and salinity, but to a lesser degree (65%). In the north, the role of mineralization and strong response of the medium decreases, whereas the sum of temperatures and ion balance of water increases.