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Scientists from the Institute of Physico-Chemical and Biological Problems of Soil Science of the Russian Academy of Sciences (IPCBPSS RAS), a separate division of the Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences, summed up the results of a longterm study of the largest thermokarst retrogressive thaw slump in the world, located near the settlement of Batagai in northern Yakutia.
The research was conducted jointly with colleagues from the Research Institute of Applied Ecology of the North of the M.K. Ammosov NEFU and the P.I. Melnikov Permafrost Institute of the Siberian Branch of the Russian Academy of Sciences, as well as in collaboration with colleagues from the UK.
The uniqueness of the Batagai site (alternative names are Batagaika, Batagai crater) is that it reveals a continuous stratigraphic sequence of permafrost deposits accumulated over the past at least 250 thousand years.
"Our laboratory has been working closely with our colleagues from Yakutia for a long time. And the uniqueness of the Batagai site is in the fact that very ancient permafrost layers are being exposed there, which have remained preserved for at least 250 thousand years! And it is possible that the lowermost layers are much more ancient. Some analytical methods show that they may be about 650-700 thousand years old, and now we are verifying the reliability of these estimates. And if these estimates are correct, then this is already the Middle Pleistocene, very ancient strata, the deposition of which preceded the last major interglacial," said Ph.D. Alexey Lupachev, senior researcher at the Department of Cryogenic Soils of the IPCBPSS RAS, project manager.
As a result of the conducted research, scientists have obtained unique data that will allow reconstructing the paleoecological situation of the Late Pleistocene, obtaining information about the climate, soil cover, plant and animal communities, as well as forming a forecast for the further development of the region under study in the context of global climate change and local anthropogenic impacts.
"For example, we are now living in the era of the modern interglacial, which is called the Holocene. And about 120-130 thousand years ago there was a previous warm epoch, comparable in terms of bioclimatic conditions with the modern one. But there is very little direct data, especially from the area of permafrost distribution, specifically on the appearance of layers of this age on the daytime surface! And here you can study them not blindly (from a borehole core), but directly within the frozen wall, in the context of the surrounding landscape, and you can observe the beautiful morphological structure of permafrost, the spatial distribution of ancient soil cover, and generally characterize the natural environment of bygone eras," said Alexey Lupachev.
As a result of the calculations, it was found that during the period of instrumental observations (2014-2023), the flux of mineral material from the slump amounted to about 650 thousand cubic meters, the flow of meltwater over the same period amounted to about 1.5 million cubic meters. According to preliminary estimates, over 150,000 tons of organic carbon have been released into the environment over the entire period of the Batagai thaw slump existence.
A multidisciplinary study of modern soils, as well as buried paleosols from sediments from 130 to 650 thousand years old, revealed traces of deep processing of mineral material by soil processes and pronounced differentiation of horizons. The presence of a highly organized structure of soil profiles indicates the relative duration (tens of thousands of years) of favorable climatic conditions for soil formation, comparable to the modern conditions of the Holocene interglacial.
The research was carried out at the expense of the grant of the Russian Science Foundation No. 23-27-00242, https://rscf.ru/project/23-27-00242/
