Ecosystem of blue lake: example of karst sulfur pool with isolated biota

The review presents combined geographical, geological and hydrochemical data as well as the description of biocenosis of Blue Lake: the isolated karst sulfur pool located in the Sergievsk area of Samara region. The underwater landscape mapping using scuba equipment resulted in accurate specification of lake's biota and in compilation of topographic map of the lake's bottom. It is suggested to include this lake into the list of objects having the status of federal nature park.