How much methane and CO2 do Siberian lakes gather during winter?

The study of carbon cycle is one of the major global research trends, as carbon is a part of active greenhouse gasses. In Russia, the field season is limited by weather conditions; few research groups analyze carbon balance during winter. For several years, TSU scientists have been monitoring the carbon level in water ecosystems. Recently, they have collected winter samples of the Ob River floodplain using new devices that can quickly and accurately determine the ecological properties of bodies of water.

“Lakes of the Ob floodplain are rich in organic matter and play an important role in the global carbon cycle, but it is still unclear what processes occur in lakes during winter,” says Lyudmila Borilo, executive director of the strategic academic unit Siberian Institute of the Future. “We organized a comprehensive winter expedition to the Kaibasovo research station to assess the main factors influencing biogeochemical cycles. We have determined the amount of CO2 gathered during the winter. The level is higher than in spring or summer. Now, we need to understand the sources of carbon in the water.”

The expedition used new equipment bought from the grant of the Ministry of Science and Higher Education to provide the unique TSU research infrastructure Megafacility with new devices. In particular, to construct bottom profiles, the expedition used thermo-oximeters and a multiparameter water quality probe YSI EXO2 that allows assessing measurements on the spot. It is one of the best devices in its league for measuring temperature, dissolved oxygen level, fluorescent organic carbon concentration, electrical conductivity, pH, and redox potential.

“YSI EXO2 is able to take complex measurements, is simple and mobile. It can also store a large amount of data in its memory,” explains Larisa Kolesnichenko, assistant professor at the Siberian Institute of the Future. “Later, we will determine the concentration of distilled organic and inorganic carbon using Shimadzu TOC-LCSN analyzer.”

The project team collected air samples to assess carbon dioxide and methane emission flows from the water surface, as well as to determine isotopic composition of these gasses (d13C-CO2 and d13C-CH4) using Picarro 2201-I laser analyzer. It will help understand whether CO2 in the water is the result of phytoplankton activity, or entered the lake with groundwater.

Assessment of emission fluxes of carbon dioxide and methane and their composition of stable isotopes will be carried out in Sukachev Institute of Forest, Siberian Branch of the Russian Academy of Sciences, a TSU partner in the consortium Global Earth Changes: Climate, Ecology, Quality of Life.

“TSU’s strategic project of the same name is implemented with the support of the Priority 2030 federal project,” sums up Ludmila Borilo. “The main task is to study carbon cycle and its influence on global climate transformation, to develop ways to adapt humanity to these changes, and to create technologies to mitigate them.”

The project “Mechanisms of hydrochemical runoff of the Ob River: Regulatory role of the floodplain” is supported by the Russian Science Foundation