Borehole temperature, submarine permafrost methane concentrations and pore water chemistry measured on borehole BK-2, central Laptev Sea shelf ...

• Main Authors: Overduin, Pier Paul, Liebner, Susanne, Knoblauch, Christian, Günther, Frank, Wetterich, Sebastian, Schirrmeister, Lutz, Hubberten, Hans-Wolfgang, Grigoriev, Mikhail N
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA 2015
• Subjects: Permafrost Research Periglacial Dynamics @ AWI AWI_PerDyn; Ice; laptev; Laptev Sea; permafrost; Sea ice
• Online Access: https://dx.doi.org/10.1594/pangaea.846279; https://doi.pangaea.de/10.1594/PANGAEA.846279

Submarine permafrost degradation has been invoked as a cause for recent observations of methane emissions from the seabed to the water column and atmosphere of the East Siberian shelf. Sediment drilled 52 m down from the sea ice in Buor Khaya Bay, central Laptev Sea revealed unfrozen sediment overlying ice-bonded permafrost. Methane concentrations in the overlying unfrozen sediment were low (mean 20 µM) but higher in the underlying ice-bonded submarine permafrost (mean 380 µM). In contrast, sulfate concentrations were substantially higher in the unfrozen sediment (mean 2.5 mM) than in the underlying submarine permafrost (mean 0.1 mM). Using deduced permafrost degradation rates, we calculate potential mean methane efflux from degrading permafrost of 120 mg/m**2 per year at this site. However, a drop of methane concentrations from 190 µM to 19 µM and a concomitant increase of methane d13C from -63 per mil to -35 per mil directly above the ice-bonded permafrost suggest that methane is effectively oxidized ... : Supplement to: Overduin, Pier Paul; Liebner, Susanne; Knoblauch, Christian; Günther, Frank; Wetterich, Sebastian; Schirrmeister, Lutz; Hubberten, Hans-Wolfgang; Grigoriev, Mikhail N (2015): Methane oxidation following submarine permafrost degradation: Measurements from a central Laptev Sea shelf borehole. Journal of Geophysical Research: Biogeosciences, 120(5), 965-978 ...