May 17, 2023

The scientists of the Krasnoyarsk Scientific Center of the Siberian Branch of the Russian Academy of Sciences have established that fuel spills in permafrost conditions are gradually processed by soil microorganisms. This process reduces pollution, however, at the same time it releases the greenhouse gas carbon dioxide, which can affect climate change. The press service of the Krasnoyarsk Scientific Center SB RAS reports about this research.

Intensive human development of the Arctic has resulted in increased human intervention in the ecosystem and the spread of pollutants, including from refined petroleum products. Arctic ecosystems are vulnerable and contain a large amounts of greenhouse gas sources, so the problem of Arctic pollution is of concern.

In 2020, a man-made disaster occurred in Norilsk area. The spill caused more than twenty thousand tons of diesel fuel rerorting into the environment. To assess the potential damage from such accidents for northern territory soils, the scholars of the FRC "Krasnoyarsk Scientific Center SB RAS" and SFU investigated the effect of different concentrations of the most common brand of diesel fuel on the activity of soil microbes and the amount of carbon released into the atmosphere by these microbes.

Carbon is stored in the soil in the form of organic matter. Here, the release of carbon from the soil can occur both slowly, for decades or even centuries, and very quickly. The rate of carbon release is subject to the type of soil, climatic conditions, vegetation and other factors. The slow release of carbon occurs as a result of biological processes (for instance, the decomposition by bacteria of organic matter that became available during the permafrost thawing). It may occur faster during catastrophic, especially anthropogenic (for example, fires, deforestation) processes.

The results of the study showed that diesel fuel, in most cases, significantly increases the release of slow carbon from the Arctic soil. First of all, spilled fuel impacts the soil as a habitat for microorganisms: fungi and bacteria. The scientists had assumed, and then experimentally confirmed, that soil microorganisms of Arctic biomes, underlain by permafrost, have the ability to use diesel fuel as a nutrient medium. They release carbon as a result of their life activity. Thus, polluted soils potentially generate more carbon compared to unpolluted soils.

The scientists determined the types of microorganisms that dominate in such permafrost soils and most actively process diesel fuel. Among them were rod-shaped bacteria of the species Serratia proteamaculans, S. liquefaciens, S. plymuthica, the bacteria that oxidise carbohydrate - Rhodococcus erythropolis, also pseudomonas of species of Pseudomonas antarctica, P. libanensis, P. brassicacearum and P. chlororaphis. Oil pollution subsequently decreases as a result of the activity of these bacteria.

"We assumed that soil microorganisms of northern ecosystems have the ability to use diesel fuel as a substrate. Decomposition of fuel by microorganisms leads to carbon dioxide emissions. Soil microorganisms can remain metabolically active at temperatures below 0°C and hence contribute to increased carbon dioxide emissions during the cold season. Therefore, permafrost soils contaminated with fuels should be considered in local and regional carbon balance assessments, especially in relation to climate change in high latitudes. The bacteria that we extracted from permafrost soils that are contaminated with diesel fuel are recommended for the development of preparations to eliminate the effects of contamination of permafrost soils with oil and its products," said Oksana Masyagina, researcher at the Forest Institute named after V. N. Sukachev of SB RAS.

The results of the study are published in the Environmental Pollution journal.

Sources:

https://www.sciencedirect.com/science/article/abs/pii/S0269749123002713?dgcid=author/

https://ksc.krasn.ru/news/razlivy_dizelnogo_topliva/

Tranclated be Muhiddin Ganiev