Mercury enters Russian Arctic lakes by atmospheric fallout. This was reported by the Ministry of Education and Science of the Russian Federation.
This conclusion was made on the basis of examination of bottom sediment samples from thermokarst lakes – Longtibeito on Yamal and Goltsovoye on the Gydan Peninsula. Such lakes form in areas of thawed permafrost where the soil has therefore settled. The bottom of the lakes in these regions is practically not affected by human activities, and therefore the columns (cylinders) removed from the sediments work like chronicles of natural history – by analyzing their layers, scientists can restore the state of the environment in different years.
“In the analysis of the columns, we determined that the lowest layers belong to the pre-industrial period (before 1850). The mercury content in the near-surface layers, unlike the other elements, was 7.5-8 times higher than the background values. However, even these concentrations slightly exceed the average mercury content in the earth’s crust (0.045 µg/kg) and are far from critical values. In our opinion, the flow of mercury through the earth’s crust, which sets the background, is fairly constant. “It is much less than the entry of sediments from the atmosphere into the upper layers,” said geologist Yury Tatsiy.
In addition, an increase in mercury content was observed in Lake Goltsovoe at the beginning of the 20th century. This was likely due to local climate warming, which led to a northward retreat of the permafrost boundary.
ancient biologists approvedthat the moths’ “tails” act as decoys for bats.