Ecological factors and denitrifying bacteria of the Baikal lake epilithon
A. S. GORSHKOVA, G. V. PODLESNAYA, N. A. ZHUCHENKO, I. V. TIKHONOVA, M. Yu. SUSLOVA, Yu. R. NEBESNYKH, E. A. ZIMENS, O. I. BELYKH
Limnological institute SB RAS, Irkutsk, Russia
Keywords: cultivated heterotrophic denitrifying bacteria, epilithon, denitrification factors, ecological stoichiometry
Abstract
Participating in the circulation of nutrients epilithic biofilms play an important role in water bodies. Denitrification actively proceeds in the epilithon of water bodies. However, the information on environmental factors that affect the process in biofilms is still limited. The object of study in this article involves the number of cultivated denitrifying bacteria in biofilms formed on the stony substrates in different parts of Lake Baikal littoral zone. It has been found out that the main factors explaining the differences in the number of cultivated bacteria who perform complete denitrification were the temperature and the concentration of total nitrogen in shallow water. The article shows that lower amount of denitrifiers is a typical for biofilms experiencing nitrogen deficiency as indicated by the low stoichiometric N: P ratio in biofilms. An uneven distribution of heavy metals in the biomass of epilithic biofilms has been determined. It also may potentially impact denitrification in the epilithon of Lake Baikal.
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