MOSCOW, March 11 Scientists from the Institute of Atmospheric Physics (IAP) named after A.M. Obukhov RAS studied how swamps release methane into the atmosphere, which will help assess their contribution to climate warming. The results of the study, supported by a grant from the Russian Science Foundation (RSF), were published in the journal Forests, the RSF reported.
Significant areas of Western Siberia are occupied by swamps, which are considered one of the main carbon storage facilities on Earth. This is because carbon has accumulated here over millennia in the form of peat deposits. Thanks to this, swamps actively participate in the carbon cycle, absorbing and releasing greenhouse gases. In particular, they absorb carbon dioxide and emit methane.
According to IAP RAS scientists, the intensity of such processes depends on the temperature at the surface of the swamp, its microrelief (for example, the presence of hummocks, ridges, vegetation) and soil moisture. Because these characteristics tend to vary greatly, even within a single wetland, it is difficult for researchers to calculate how much greenhouse gases an area emits and absorbs.
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Employees from the IAP RAS studied in detail a raised bog typical of Western Siberia, that is, fed by precipitation, using the example of the Mukhrinsky peat bog, an international field station on the territory of the Khanty-Mansiysk Autonomous Okrug.
During the expedition, scientists described the topography and surface temperature of the swamp by observing the area using a drone. They also made the most detailed measurements to date of heat and moisture fluxes, as well as the amount of methane released per unit area by different microlandscapes of the swamp.
Observations have shown that the structure of the raised bog is extremely heterogeneous: within the Mukhrinsky peat bog, researchers have identified significantly different microlandscapes, such as “ryams” — elevated areas covered with shrubs or low trees, “ridges” — hummocks overgrown with moss, swamps and “hollows” » — low-lying, waterlogged places. Daytime and nighttime surface temperatures in different parts of the swamp varied greatly: the difference between the cold low-lying, water-flooded areas and the elevated areas was about 10°C during the daytime. This is because water heats up more slowly than air, and therefore moist soils usually have a lower temperature.
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“Model development requires detailed and comprehensive observational data. For each type of microlandscape (for elevated areas — ridges and hummocks, and for low areas — hollows, swamps), and for the entire swamp landscape as a whole, many parameters need to be measured simultaneously — this is the kind of data we collect in the swamp,” said senior researcher at IFA RAS Dmitry Chechin.
According to him, detailed observational data makes it possible to develop and verify models of swamps and greenhouse gas emissions.
«Taking into account swamp microlandscapes in models can lead to an increase in simulated methane emissions by almost two times (by 100%). The same can be said and about estimates of regional methane emissions, which are characterized by great uncertainty — the use of detailed maps of swamp microlandscapes in compiling such estimates can lead to a doubling of the estimate of methane emissions from swamps,” the scientist said.
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During the experiment at the Mukhrino test site, the most detailed observation network that has ever existed among all the West Siberian swamps was deployed, Chechin noted.
“This is primarily due to the staff of Ugra State University, who organized a world-class system of constant comprehensive monitoring in Mukhrino, and we supplemented and strengthened it with our equipment for the duration of the experiment. As a result, together we managed to collect a unique array of data that allows us to set and solve «qualitatively new tasks. Such field experiments correspond to the most modern world level,» he emphasized.
Scientists believe that the research will be useful in constructing correct models of the release and absorption of greenhouse gases by swamps, as well as in predicting these processes in conditions of climate change . In addition, understanding the processes of moisture, heat and gas exchange between swamps and the atmosphere, in their opinion, is important when draining or restoring disturbed swamps.
In the future, the researchers plan to study in more detail how different swamp microlandscapes, for example, waterlogged swamps and overgrown shrubs ryams, affect the turbulent transfer of heat, moisture and greenhouse gases in the atmosphere.