The photo is sourced from ysia.ru
In the period from 1750 to 2020, average air temperature near the Earth’s surface rose by about 1 degree Celsius, whereas in permafrost areas this indicator went up by about 4 degrees Celsius in the last 70 years alone. This difference is due to the fact that permafrost thawing creates a favourable environment for microbial communities, which turn ancient carbon from permafrost deposits into methane. This results in faster warming compared to other regions of the planet. Methane poses a greater danger to the environmental balance than carbon dioxide because the concentration of CH4 that can cause the average temperature to rise by 1 degree Celsius is 17 times lower than that of CO2.
That aside, how does the diversity of microbes in permafrost affect the warming processes? To answer this question, the authors of the study used the Goody mathematical model, which views the atmosphere as a set of individual cells, in which air circulates. Further down, near the surface of the Earth, the air warms up, after which it rises, cools down and comes back to the Earth. To understand how this system is affected by methane emissions from microorganisms, the authors expanded the Goody model by introducing mathematical functions that describe the flow of greenhouse gas synthesised by bacteria.
The study showed that the rate of permafrost thawing depends on the number of microorganism species. If an environment is inhabited by no more than three species of microorganisms, for which roughly the same soil temperature is optimal, the bacteria start actively growing and releasing large amounts of methane even after a slight warming. If the number of bacteria species is higher than three, the optimal temperature for them varies greatly, which hinders the rapid growth of microorganisms and the accompanying release of methane. In case of high interspecific competition, bacteria suppress one another, preventing the growth of individual populations and, as a consequence, massive methane emissions.
“We’ve managed to prove that the moment, at which temperature near the Earth’s surface might soar depends on microbial diversity. The diversity hinges on humidity, temperature, nutrient content and acidity of the soil. And although we cannot impact microbial diversity, the relationship we have identified should be taken into account when forecasting the warming processes. The existing models do not take into account the activity of permafrost microorganisms, but if we include this factor, it might adjust the temperatures forecast for 2100 by several degrees, which is quite significant,” Elena Savenkova, one of the authors of the study and senior researcher at the Centre for Research and Invention, is quoted as saying by the Russian Science Foundation.
