Late permian changes in conditions of the atmosphere and environments caused by halogenated gases

Abstract

There are periods in the Earth’s history when environmental conditions and the climate sharply changed. Some of such changes were accompanied by mass extinction of living organisms and a decrease in the species diversity. At present, there exist numerous hypotheses and conflicting scenarios of terrestrial and extraterrestrial events which led to such consequences. In particular, the most striking such episode belonging to the Late Permian is related to eruption of volcanoes in Siberia, the impact of a large asteroid, and climatic fluctuations caused by a decrease in the ozone concentration in the atmosphere (see for instance, [1]). By the ratio of isotopes in sedimentary rocks, there was revealed a degradation of vegetation in that period, which was accompanied by an appreciable decrease in productivity of photosynthesis [2]. The photosynthesis reduction resulted in a decrease in O 2 and an increase in CO 2 concentrations in the atmosphere and oceans. Volcanic emission of CO 2 in Siberia in the Late Permian also contributed to a general increase in the CO 2 concentration on the Earth. The change in the radiation budget, the warmed-up climate of the Earth, and aridization of some regions on the planet could cause mass extinction of living organisms [1]. The mass extinction of living organisms on the Earth at the boundary between the Permian and Triassic is known to have lasted over a million years (within the interval of 252.3 ± 0.3‐251.4 ± 0.3 Ma ago), i.e., in a very short period of time in terms of geology. Died out during this period were 90% of sea species, 60% of reptile and amphibian families, 30% of insect varieties, and most terrestrial plants [3]. The gradual and continuous changes in the species diversity of living organisms indicate that the mass extinction was caused by a gradual effect rather than a geologically instantaneous event spanning over several years or centuries. This suggests that such global changes began due to terrestrial causes, and later other, probably, extraterrestrial factors came into play. This work discusses a new possible cause of changes in the state of the Earth’s system and mass extinction of living organisms at the boundary between the Permian and Triassic, which was related to an increased emission of volatile phytotoxicological halogenated hydrocarbons (HHCs) from hypersalt lakes and seas. The possibility for HHC to form actively in water and bottom sediments of such water bodies was revealed in recent years in the course of studying aridization processes during climatic warming [4, 5].