CO2-exchange in tundra ecosystems of Vaygach island in an unusually warm and dry vegetation season

Abstract

In the summer of 2013, field studies on the CO₂ exchange in the tundra ecosystems of Vaygach Island were conducted by the chamber method. Models establishing the relationship between the values of CO₂ fluxes and key ecological factors, such as temperature, photosynthetic active radiation, the leaf mass of vascular plants, and the depth of soil thawing, have been proposed. According to the model estimates, during the vegetation season of 2013, the tundra ecosystems of Vaygach Island were a source of CO₂ emission into the atmosphere (31.9 ± 17.1 g C m^–2 season^–1) with a gross primary production of 136.6 ± 18.9 g C m^–2 season^–1 and an ecosystem respiration of 168.5 ± 18.4 g C m^–2 season^–1. The CO₂ emission from the soil surface (soil respiration) was, on average, 67.3% of the ecosystem respiration. Unusually warm and dry weather conditions in the summer of 2013 were the cause of carbon losses by tundra ecosystems. The air temperature during summer months was twice as high as the values of the climatic norm for 1961^–1990. A trend revealed in the works of recent decades of an increased carbon sink to the tundra ecosystems in the circumpolar Arctic may be interrupted by an increased frequency and scale of unusually warm weather events.