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PresentationsThe ecosystem model of the Lake Teletskoye: the cycle of nutrients and their assimilationInstitute for Water and Environmental Problems, Siberian Branch of Russian Academy of Sciences, 1Molodezhnaya st. 1, Barnaul 656038 Russia, tskhai@iwep.ru 2Polzunov Altai State Technical University, Lenin av. 46, Barnaul 656038 Russia, taa1956@mail.ru The purpose of the work is to assess the permissible biogenic load on the Lake Teletskoye (TL) by modeling of the cycle for nitrogen and phosphorus compounds to preserve the sustainable state for the ecosystem of the TL. A violation of sustainability is further understood here as a change in the geochemical class of waters (Lozovik, 2006 ), which may entail effects not previously observed in the ecosystem of the reservoir, including undesirable ones. The most significant features of modeling the cycle of compounds of biogenic elements (N and P) and the dynamics of dissolved oxygen (for example, Tskhai and Leonov, 1995 ) in the ecosystem are considered. The model was calibrated taking into account data from long-term observations of water quality in 1985-2003, expeditions, as well as a scenario version of the hydrological regime in 2016. An analysis of the intra-annual variability of state variables, external and internal fluxes of nitrogen and phosphorus compounds in the water of the TL showed that the developed simulation model of the nutrient cycle reproduces the main trends of the ecosystem under consideration. The characteristics of the assimilation potential of the TL are compared with the lakes of the North-West of the Russian Federation. The permissible nitrogen and phosphorus load calculated in this study indicates that the lake's assimilation potential with respect to phosphorus compounds is insignificant, practically absent. In relation to nitrogen compounds, there is still some self-purification reserve. The water is clean not due to sufficient assimilation, but due to the fact that there has been a low anthropogenic load so far. A relatively small increase in anthropogenic phosphorus pollution can lead to a violation for the sustainability of the lake ecosystem. There is an urgent need to bring the monitoring system of the TL to a modern level, both in terms of the number of observation points of the control network in characteristic zones, increasing the list of observed indicators and the frequency of checking, and improving the quality of the instrumental and methodological base. The study was carried out within the framework of the state assignment of the IWEP SB RAS. References Lozovik P.A. Hydrogeochemical criteria of the state for surface waters of the humid zone and their resistance to anthropogenic impact: dissertation of the Doctor of Chemical Sciences. 25.00.36. Moscow: V.I. Vernadsky Geo- and Analitical Chemistry Insituite RAS, 2006. 481 p. Tskhai A.A., Leonov A.V. Forecast of water quality of the projected reservoir based on the model of transformation of nitrogen and phosphorus compounds // Water Resources, volume 22, number 3. 1995. pp. 261-272.
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