Study of CO2 and CH4 fluxes from the water surface in the coastal zone of the Ob River
M.Yu. Arshinov, B.D. Belan, G.A. Kolotkov, D.A. Pestunov, A.V. Fofonov
V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, Tomsk, Russia
Keywords: “water - atmosphere” gas flow, chamber method, methane, dioxide gas, greenhouse gas, freshwater carbon cycle
Abstract
River ecosystems are a key component of the global carbon cycle, facilitating the transformation, transport, and emission of carbon. They ensure the movement of organic matter from continents to ocean basins and actively exchange substantial volumes of CO2 and CH4 with the atmosphere, thus significantly contributing to Earth's climate regulation. This work presents results of field measurements of greenhouse gas fluxes (CH4 and CO2) at the “water - air” interface in the coastal zone of the Ob River (Western Siberia) in summer - autumn 2024 using an original mobile chamber system consisting of a floating chamber and a portable laser gas analyzer Picarro G4301. Gas flux calculations at the “water - air” interface for each measurement used the open-source FluxCalR package in RStudio. The river ecosystem in the area under study acts as a constant source of methane emission into the atmosphere, with the intensity ranging from 0.12 to 15.81 mg × m-2 × h-1 (median values). For carbon dioxide, a transition was observed from emission at the beginning of the season (maximal intensity of up to 217.31 mg × m-2 × h-1 in July) to sink in August-October. The results confirm the contribution of river systems, particularly of Siberian rivers, to the regional carbon budget and can be used to consider this contribution in climate models.
|
