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, Nor th Slope of Verkhoyansky Mountain Ridge, the Kolyma Lowland and in the estuary of the Lena River. Most of the northern landscapes were prese nted in the sample, which are between the High Arctic (Tiksi area) and the Low Arctic/Subarctic (Chersky area). All limnic waters were super saturated significantly with respect to the atmospheric pressure of CO 2 and CH4. The content of CH4 in High Arctic lakes ranged usually betw een 10(-1) and 10(-2) mu M in the surface layer and between 100 and 10 (-2) mu M in the bottom layer. These values are about 10(2) times lowe r than in Low Arctic/Subarctic lakes. The partial pressure of CO2 (PCO 2) ranged usually between 400 and 6000 ppm in the Tiksi site and betwe en 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 l akes. The fall-winter shipboard measurements show that the value of PC O2 varied significantly from the Bering Sea to the Laptevs Sea. The su rface waters of the Laptevs Sea were undersaturated by CO2, whereas ot her arctic seas east of the Laptevs seas were slightly supersaturated. The shallow coastal waters from the Laptevs Sea to the Bering Sea wer e usually 1.5-3-fold supersaturated by CO2. The shipboard measurement of CH4 in the arctic seas shows that the concentration of CH4 was usua lly less than 0.015 mu M. It confirms the previous air-flight data tha t show a 10-15% increase of CH4 over land. The analysis of up-to-date experimental results and glaciological data concerning air palaeovaria tions of CH4 and CO2 shows that evolution of the northern lakes might be a significant factor in the present and the past.