Chemical and biological features of the saline Lake Krasnovishnevoye (Baraba,Russia) in comparison with Lake Malinovoe (Kulunda,Russia): a reconnaissance study

The Baraba and Kulunda steppes are located in southwestern Siberia in an area with an arid continental climate. This paper presents results of the first study of the hypersaline Lake Krasnovishnevoye(Baraba steppe, TDS(total dissolved solids)=297 g/L, pH 7.88). The major chemical, mineralogical and biological features of the lake were studied and compared to those of Lake Malinovoe, a typical saline neutral lake of Kulunda steppe(TDS=396 g/L, pH 7.63). The phytoplankton composition and the culturable diversity of anoxygenic phototrophic bacteria from Lake Krasnovishnevoye correspond to the ones in the Kulunda lakes. Nevertheless, the peculiarities of water composition and regime of Lake Krasnovishnevoye reduce the biodiversity to prokaryotes and unicellular algae.     

Climate Change and Geochemistry May Explain the Finding of Marine Cyanobacteria in a Continental Saline Lake

正1 Introduction Alkaline Lake Khilganta located in a steppe zone of South Siberia(N 50°42'535,E 115°06'086)is unique among adjacent lakes because of a development of a thick(up to 3 cm)cyanobacterial mat dominated by     

Microbial Processes in Stratified Lake Doroninskoe(Transbaikal Region)

正In recent decades,meromictic ponds attract the attention of researchers in different directions,because here the character of the physical,chemical and biological processes differ from those of typical mixing waters(Kuznetsov,1970;Hutchinson,1969).In Transbaikalia widely distributed soda and salt lakes with different salinity.Notable among them is Lake Doroninskoye,which has a pronounced stratification for a     

Microbial processes and factors controlling their activities in alkaline lakes of the Mongolian plateau

A striking feature of the Mongolian plateau is the wide range of air temperatures during a year,-30 to 30°C.High summer temperatures,atmospheric weathering and the arid climate lead to formation of numerous alkaline soda lakes that are covered by ice during 6–7 months per year.During the study period,the lakes had p H values between 8.1 to 10.4 and salinity between 1.8 and 360 g/L.According to chemical composition,the lakes belong to sodium carbonate,sodium chloride-carbonate and sodium sulfate-carbonate types.This paper presents the data on the water chemical composition,results of the determination of the rates of microbial processes in microbial mats and sediments in the lakes studied,and the results of a Principal Component Analysis of environmental variables and microbial activity data.Temperature was the most important factor that influenced both chemical composition and microbial activity.p H and salinity are also important factors for the microbial processes.Dark CO 2 fixation is impacted mostly by salinity and the chemical composition of the lake water.Total photosynthesis and sulfate-reduction are impacted mostly by p H.Photosynthesis is the dominant process of primary production,but the highest rate(386 mg C/(L?d)) determined in the lakes studied were 2–3 times lower than in microbial mats of lakes located in tropical zones.This can be explained by the relatively short warm period that lasts only 3–4 months per year.The highest measured rate of dark CO 2 assimilation(59.8 mg C/(L?d)) was much lower than photosynthesis.The highest rate of sulfate reduction was 60 mg S/(L?d),while that of methanogenesis was 75.6 μLСН 4 /(L?d) in the alkaline lakes of Mongolian plateau.The rate of organic matter consumption during sulfate reduction was 3–4 orders of magnitude higher than that associated with methanogenesis.