Russian scientists have established that glaciations, which occurred repeatedly in the Pleistocene, significantly affected the modern ranges of freshwater daphnia. These crustaceans colonized the waters where they can still be found today from a small number of lakes in Beringia, the land bridge between Eurasia and North America. The data obtained will help in the development of a complete biogeographic zoning of Northern Eurasia.
The results of the study, supported by a grant from the Russian Science Foundation (RSF), are published in the journal Water. Cladocerans of the genus Daphnia are one of the most common planktonic organisms in fresh water. They play an important role in ecosystems, in particular, many species of fish feed on them. Daphnia are widespread in many climatic zones, but due to the harsh climate, their diversity in the Arctic and subarctic regions is significantly reduced.
At the same time, in the course of the historical development of the Earth, there were several periods of freezing, when the temperatures on its surface were much lower than now. This greatly affected the habitats of living organisms, including crustaceans. For example, during the Pleistocene glaciations, many representatives of the Daphnia genus inhabited the Bering region, including Beringia itself, a wide land bridge connecting Eurasia and North America.