Methane fluxes from the sea to the atmosphere across the Siberian shelf seas

• Published in: Geophysical Research Letters
• Main Authors: Thornton, Brett F., Geibel, Marc C., Crill, Patrick M., Humborg, Christoph, Mörth, Carl-Magnus
• Format: Article in Journal/Newspaper
• Language: English
• Published: Stockholms universitet, Institutionen för geologiska vetenskaper 2016
• Subjects: Arctic; methane; Laptev Sea; East Siberian Sea; methane flux; Earth and Related Environmental Sciences; Geovetenskap och miljövetenskap; arctic methane; laptev
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-133242; https://doi.org/10.1002/2016GL068977

The Laptev and East Siberian Seas have been proposed as a substantial source of methane (CH4) to the atmosphere. During summer 2014, we made unique high-resolution simultaneous measurements of CH4 in the atmosphere above, and surface waters of, the Laptev and East Siberian Seas. Turbulence-driven sea-air fluxes along the ship's track were derived from these observations; an average diffusive flux of 2.99mgm(-2) d(-1) was calculated for the Laptev Sea and for the ice-free portions of the western East Siberian Sea, 3.80mgm(-2)d(-1). Although seafloor bubble plumes were observed at two locations in the study area, our calculations suggest that regionally, turbulence-driven diffusive flux alone accounts for the observed atmospheric CH4 enhancements, with only a local, limited role for bubble fluxes, in contrast to earlier reports. CH4 in subice seawater in certain areas suggests that a short-lived flux also occurs annually at ice-out.