Atmospheric carbon emission from North Asian Lakes: A factor of global significance

Partial pressures of CO2 and CH4 were measured directly or calculated from pH and DIC measurements for 20 lakes on the Yakutian Lowland, North Slope of Verkhoyansky Mountain Ridge, the Kolyma Lowland and in the estuary of the Lena River. Most of the northern landscapes were presented in the sample, which are between the High Arctic (Tiksi area) and the Low Arctic/Subarctic (Chersky area). All limnic waters were supersaturated significantly with respect to the atmospheric pressure of CO2 and CH4. The content of CH4 in High Arctic lakes ranged usually between 10−1 and 10−2 μM in the surface layer and between 100 and 10−2 μM in the bottom layer. These values are about 102 times lower than in Low Arctic/Subarctic lakes. The partial pressure of CO2 (PCO2) ranged usually between 400 and 6000 ppm in the Tiksi site and between 4000 and 20,000 ppm in the Chersky site, although extreme values of PCO2 reached up to 27,000 ppm in the bottom layer of subarctic thaw lakes. The fall-winter shipboard measurements show that the value of PCO2 varied significantly from the Bering Sea to the Laptevs Sea. The surface waters of the Laptevs Sea were undersaturated by CO2, whereas other arctic seas east of the Laptevs seas were slightly supersaturated. The shallow coastal waters from the Laptevs Sea to the Bering Sea were usually 1.5-3-fold supersaturated by CO2. The shipboard measurement of CH4 in the arctic seas shows that the concentration of CH4 was usually less than 0.015 μM. It confirms the previous air-flight data that show a 10–15% increase of CH4 over land. The analysis of up-to-date experimental results and glaciological data concerning air palaeovariations of CH4 and CO2 shows that evolution of the northern lakes might be a significant factor in the present and the past.