The expanded survey became especially urgent after the brief flood of the previous year, when only half of the floodplain was flooded.
Low water levels increase the risk of freezing of shallow water bodies such as lakes, channels, and eriks, which can lead to mass mortality of aquatic organisms.
During the survey, water samples were collected from 14 water bodies for operational monitoring of hydrogen sulfide levels and determination of acute toxicity. Hydrobiological data were also collected.
In most water bodies, hydrochemical and physical parameters corresponded to typical winter conditions: water temperatures ranged from 0.6 to 2.44°C, dissolved oxygen concentrations ranged from 7.03 to 9.91 mg/L, ice thickness was 25-40 cm, and snow cover was 5-10 cm. However, two shallow lakes, Dubok and Kudayevskoye, recorded low dissolved oxygen levels of 2.49 and 3.5 mg/L, respectively, while hydrogen sulfide levels reached 12 μg/L, exceeding permissible limits.
Preliminary results indicate unfavorable wintering conditions for aquatic biological resources in the Volga-Akhtuba floodplain. The collected material has been delivered to the branch laboratory, where it will be fully analyzed. No fish kills were detected at the time of the survey.
VNIRO Press Service