Permafrost thawing and CO2 efflux of frozen peatlands: relationship, spatial variability, trend of climate change (Western Siberia, Russia)

Lead Author Anna, Bobrik
Institution Contact Department of Soil Science Lomonosov Moscow State University 1-12, Leninskie Gory 119992, Moscow, Russia
Co-Authors Georgy Matyshak, Lomonosov Moscow State University, Russia Olga Goncharova, Lomonosov Moscow State University, Russia
Theme Theme 1: Vulnerability of Arctic Environments
Session Name 1.1 Climate Change and Environmental Management in the Arctic
Presentation Type Poster
Abstract text Climate change, recorded in recent decades in the North West Siberia, leads to a change in soils temperature regime, changing plant associations, gradual degradation of permafrost and changing landscape as a whole. Soil CO2 emission is one of the major pathways by which CO2 fixed be terrestrial plants is released back into the atmosphere. Understanding of the contribution of northern terrestrial ecosystems in global carbon cycle is very important for the assessment of interaction between oceans, atmosphere and land. We investigated the spatial and temporal variability of active layer thickness and CO2 efflux of CALM R1 grid. The research CALM site R1 (Nadym Grid) (N65°20', E72°55’) is located on north of West Siberia (Russia) within the zone of sporadic permafrost of north taiga. Soil carbon dioxide emission is low and does not differ from year to year (156 ± 21 – 2013; 132±17 – 2014; 170±30 – 2015) mgCO2m-2h-1. Average content of TOC in the upper 15 cm of soil is high (34,24±1,92%). The climatic record (weather station “Nadym”) indicates a progressive warming of annual air temperatures of ~2°C over the past 17 years (an average of -6°C to -4°C). For last 17-years period of CALM R1 measurements was determined that active layer thickness is characterized by high spatial and temporal variability. Area with small active layer thickness (<50 cm) decreased from 14% to 0% in this period. Areas with deepest thaw (more than 200 cm) increased from 16 to 56%. Average active layer thickness increases from 119±6 to 166±8 cm from 1997 to 2014. The values of microbial biomass are high, but permafrost and hydrothermal conditions inhibit soil biological processes. So the main factor, which determines the soil carbon efflux, is the depth of permafrost table; it determines the organic matter transformation processes.