Microbiological Specificity of Baikal and Khubsugul – Ancient lakes of Eastern Asia

Abstract

A comparative analysis of structure–functional parameters of microbial communities in estuaries of Lake Khubsugul rivers has shown that the level of development of the total number of microorganisms (TNM) is 2.5 times lower than in analogous places in Lake Baikal. Waters of Baikal rivers were, on average, 1.7 times richer in saprophyte bacteria than the Khubsugul river waters. Bacterial production in rivers and their estuaries in Baikal averaged over twice those of Khubsugul. Trophic levels in rivers and estuaries Khubsugul was lower than in Baikal. Structure–functional indices in the estuaries Baikal and Khubsugul rivers are at levels typical of oligotrophic and ultra-oligotrophic waterbodies. Microbial production in bottom sediments of Khubsugul is comparable, in absolute terms, with productivity characteristics of microbioceonoses in Baikal. Conditions governing the bioproductivity of bacterial populations are relatively more homogeneous in the Khubsugul benthic. The functional activity of microbioceonoses in bottom sediments of the lakes studied, determined by 14C-assimilation, dehydrogenase and cellulose activity, depends on lithological and granulometric composition of bottom sediments. Activity increases in the sequence: sands – sandy silts – clay silts – silted sands – detritus silts, reaching maximum in (15 mkg production (P), 444 mkl H2 dehydrogenase activity (DA) and 625 mkg glucose cellulose activity (CA)). Fermentative activities of productivity and metabolism of bottom microbiocoenoses in these two lakes are characterized by closeness of values of energy and matter exchange at levels typical of oligotrophic and ultra-oligotrophic water ecosystems.