Methane dynamics in three different Siberian water bodies under winter and summer conditions

• Published in: Biogeosciences
• Main Authors: I. Bussmann, I. Fedorova, B. Juhls, P. P. Overduin, M. Winkel
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2021
• Subjects: Ecology; QH540-549.5; Life; QH501-531; Geology; QE1-996.5; Arctic; Tiksi; Ice; lena river; permafrost; Tiksi Bay; Siberia
• Online Access: https://doi.org/10.5194/bg-18-2047-2021; https://doaj.org/article/0071ddfe2c614fbb89b51f0a6f1b8714

Arctic regions and their water bodies are affected by a rapidly warming climate. Arctic lakes and small ponds are known to act as an important source of atmospheric methane. However, not much is known about other types of water bodies in permafrost regions, which include major rivers and coastal bays as a transition type between freshwater and marine environments. We monitored dissolved methane concentrations in three different water bodies (Lena River, Tiksi Bay, and Lake Golzovoye, Siberia, Russia) over a period of 2 years. Sampling was carried out under ice cover (April) and in open water (July–August). The methane oxidation (MOX) rate and the fractional turnover rate ( k ′ ) in water and melted ice samples from the late winter of 2017 was determined with the radiotracer method. In the Lena River winter methane concentrations were a quarter of the summer concentrations (8 nmol L −1 vs. 31 nmol L −1 ), and mean winter MOX rate was low (0.023 nmol L −1 d −1 ). In contrast, Tiksi Bay winter methane concentrations were 10 times higher than in summer (103 nmol L −1 vs. 13 nmol L −1 ). Winter MOX rates showed a median of 0.305 nmol L −1 d −1 . In Lake Golzovoye, median methane concentrations in winter were 40 times higher than in summer (1957 nmol L −1 vs. 49 nmol L −1 ). However, MOX was much higher in the lake (2.95 nmol L −1 d −1 ) than in either the river or bay. The temperature had a strong influence on the MOX ( <math xmlns="http://www.w3.org/1998/Math/MathML" id="M14" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi>Q</mi><mn mathvariant="normal">10</mn></msub><mo>=</mo><mn mathvariant="normal">2.72</mn><mo>±</mo><mn mathvariant="normal">0.69</mn></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="86pt" height="12pt" class="svg-formula" dspmath="mathimg" md5hash="6feb1c9dd7151ba58ac02a347754260d"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" ...