Gamma-IR Resistance of Bacteria in Soil and Permafrost

Abstract

Ionizing radiation is among the most important planetary factors that regulate the intensity and dynamics of biospheric processes. At the early stages of life on the Earth, short-wave radiation permeated the Earth surface. The evolution of the planet, corrected by fluctuations of cosmophysical factors, contributed to the development of the adaptation processes in the emerging biosystems, including resistance to a wide range of ionizing effects. Studies of microorganisms from extreme habitats have changed the scientific paradigm of cell viability and adaptive potential. The taxonomic spectrum of bacteria and archaea, isolated from extreme biotopes and resistant to ionizing radiation, is constantly enlarged. However, it is also necessary to develop in situ studies at the system level, as well as to assess the ecosystem stability and prospects for its restoration as the basic unit of the biosphere during prolonged exposure to radiation and accumulation of significant doses. The goal of this research was to study the effects of high doses (60‒250 kGy) of ionizing gamma radiation on the viability of bacterial communities in frozen sedimentary rocks and modern soils, as well as to assess the aftereffect of high doses on natural samples.