Цвет: C C C
Изображения Вкл. Выкл.
Обычная версия сайта

Federal Research Center 
"Krasnoyarsk Science Center of the Siberian
Branch of the Russian Academy of Sciences"

 Федеральный исследовательский центр «Красноярский научный центр Сибирского отделения Российской академии наук»

Federal Research Center 
"Krasnoyarsk Science Center of the Siberian
Branch of the Russian Academy of Sciences"

Ecosystems in the Arctic need to be restored after decades of anthropogenic impact

21 December 2021 г. FRC KSC SB RAS

Восстанавливать экосистемы в Арктике нужно после десятилетий антропогенного воздействия
In May 2020, as a result of the depressurization of the fuel tank, about 20 thousand tons of fuel got into the Arctic ecosystems in the north of the Krasnoyarsk Region. The liquid spilled over a large area, and got to the ground and water bodies in the area and to the north of Norilsk, in particular, into the Arctic lake Pyasino. To assess the scale of pollution and ways to eliminate its consequences, the “Big Norilsk Expedition” was organized, which included scientists from more than ten institutes of the Siberian Branch of the Russian Academy of Sciences. For several months, the expedition members took samples and studied the state of water bodies, soil and biodiversity in the area of the accident, and based on the analysis of the data, they made recommendations for the restoration of the Arctic ecosystem. Scientists came to a conclusion that the main task is not to eliminate the relatively insignificant consequences of the accident, but to restore the lake ecosystem from anthropogenic pollution accumulated over the past decades. The results of many months of scientific work were published in a special issue of the Siberian Ecological Journal.

Large spills of oil and oil products are extremely dangerous for the environment. Water-oil emulsion decomposes very slowly, remaining in water for months. Heavy oil elements settle down, being accumulated in bottom sediments and on the shores. At the same time, in cold Arctic ecosystems, the degradation of spilled oil proceeds slowly, and therefore, accidental spills in this area can have more severe consequences for aquatic ecosystems.

The mission of the Big Norilsk Expedition was to solve environmental problems. One of these concerns pollution of the environment with oil products due to industrial activities, or accidents, as it happened in May 2020. Researchers from the Federal Research Center KSC SB RAS, as part of the Big Norilsk Expedition, studied the ecological environment of the Arctic area and assessed the consequences of the accidental spill, as well as the scale of changes which occurred in the region over the past decades. Based on the collected materials, scientists published a review in a special issue of the Siberian Ecological Journal on the impact of oil on aquatic ecosystems, in which, in particular, they considered how the long-term anthropogenic impact affected the Arctic Lake Pyasino. Based on the data obtained, scientists, among other things, gave recommendations on how to purify the lake and restore its ecosystem to its natural state.

The composition of oil includes hydrocarbons and compounds containing, in particular, carbon, oxygen, sulfur and nitrogen. These are biogenic substances, meaning that they are produced by living organisms and thus, they are natural components of their habitat. Consequently, the negative effect of pollution with oil and oil products is largely associated with the concentration of these substances rather than with the chemical nature. The toxic effects of oil are manifested only when its amount is large.

Oil, especially with a high content of polycyclic aromatic hydrocarbons, can be toxic to aquatic life, such as crustaceans in the water column or insect larvae at the bottom, and it can damage the cell membranes of microalgae. The most typical consequence of oil pollution is a change in the species composition, death of more sensitive and susceptible species, increase in the number of organisms resistant to oil pollution. Pestilence of fish is observed during rare volumetric oil spills. Some oil products and their components cause changes in heart rate and respiration rate, liver enlargement, growth retardation, erosion of fins, various changes at the biochemical and cellular level, as well as deviations in fish behavior. Oil spills can destroy eggs, larvae and fry, especially in shallow waters. In addition to fish, oil spills can affect other aquatic and near-aquatic vertebrates such as amphibians, birds, beavers or otters due to direct contact with pollution, or due to the deterioration of habitat and food supply.

After the diesel fuel spill on the Pyasino River, measures were immediately taken to eliminate the consequences and prevent its further spread along the tributaries. In addition, as experts clarify, oil and oil products undergo natural degradation, for example, it is decomposed into components by individual aquatic microorganisms, bacteria, fungi and yeast. Some animals, such as bivalve mollusks, crustaceans, and worms, swallow oil particles in the process of feeding and, thus, they are also able to partially utilize some hydrocarbons from it. As a result, water ecosystems subjected to oil pollution are gradually being restored.

However, it is not enough to “clean up” the consequences of the spill. Lake Pyasino needs to recover from decades of industrial impact. Scientists working in the area of the accident note that the ecosystem of Lake Pyasino had already been in a disastrous state before the accident in 2020. In the 1980s and 1990s, as a result of industrial and domestic wastewater entering the lake, the water quality deteriorated. At that time, Pyasino was polluted with anthropogenic oil products and heavy metals, namely, compounds of copper, nickel, zinc, iron, nitrates, and phenols. Thus, long before the accident, the lake and the adjacent rivers had been characterized by an extremely high level of pollution, and the water did not meet regulatory requirements in many respects. For more than thirty years, the lake has been almost completely devoid of fish, thus, having no commercial value. Although before that there were quite a lot of valuable fish in it, for example, northern whitefish and broads.

Scientists conclude that before restoring the lake to its commercial value and stocking it with valuable fish species, it is necessary to restore its natural water quality. According to the experts, the primary remedial measure for the Daldykan and Ambarnaya rivers, of course, should be cleaning from residual pollution with diesel fuel. However, this is not enough for the rehabilitation of the ecosystem of rivers and lake Pyasino, subjected to intense industrial and domestic pollution for almost seventy years. It is necessary to restore the natural quality of the water.

The Krasnoyarsk researchers suggested that the process of "guanotrophication" reproduced in artificial conditions could be used as a possible ecotechnology for restoring water quality. It consists in the enrichment of natural reservoirs with mineral and organic substances contained in natural fertilization of the vital secretions (guano) of near-water birds, which lead to an increase in the productivity of natural waters. Scientists note that in order to restore the health of the ecosystem, it is important not only to take measures to restore it, but also to reduce the anthropogenic load on it. Only a well-thought-out integrated approach including the use of natural ecological processes will help to revive the ecosystem of the lake and return valuable inhabitants to it.

“Even after the restoration of the water quality in Lake Pyasino and an increase in its productivity within the natural values characteristic of Arctic lakes, commercial fishing in it is expedient only in the framework of traditional activities of indigenous peoples. Using the resources of the Arctic lakes to supply fish products to the entire population of the Krasnoyarsk Region, not to mention the whole country, is obviously unrealistic. Commercial aquaculture is suitable for these purposes. The development of aquaculture of valuable species of Arctic fish, which will relieve the potential burden of fishing from the northern lakes, is worth pursuing,” says Corresponding Member of the Russian Academy of Sciences Mikhail Gladyshev, curator of the hydrobiological team of the Big Norilsk Expedition, head of the laboratory at the Institute of Biophysics FRC KSC SB RAS.