Current state of lakes in Northern Yakutia (diatom algae and abiotic parameters)

Abstract

The review shows the definition of morphometric characteristics, water chemical parameters and diatom assemblages of lakes located in the Arctic zone of Yakutia, in catchments of Anabar, Olenek, Lena, Indigirka and Kolyma Rivers. Main amount of these lakes has small water areas and low depth. The lakes are ultra fresh and mainly with neutral pH, characterized by moderate transparency (on average 43 % of a maximum water depth) and increased concentrations of total iron, silicon, phosphate and ammonium ions. More than the half of the lakes are characterized by exceed of the fishery limits in total iron and phosphate concentrations. In most cases, the dominant major ions are hydrocarbonates and calcium. 502 species and subspecies of 92 genera of diatoms have been discovered in the studied lakes. The highest number of species are included in such genera as Eunotia (38 taxa), Pinnularia (33), Nitzschia (30), Navicula (29), Gomphonema (20) and Achnanthes (17). The most broadly occurred species Tabellaria flocculosa, T. fenestrata, Staurosirella pinnata, Staurosira venter, S. construens, Achnanthidium minutissimum and Eunotia praerupta. Diatom assemblages of the lakes are characterized by a rather high diversity and evenness. The Pantle-Buck saprobity index, calculated inferred from known values of indicative significance of diatoms, indicates that most of the lakes have clean water. Water of 16.9 % lakes is moderate polluted.