evidence of widespread active methane seepage in the Southern Ocean,
off the sub-Antarctic island of South Georgia
extensive active seepage area was discovered north of South Georgia.
input of organic matter leads to high rates of formation and
emission of methane.
emissions were restricted to glacially-formed fjords and cross-shelf
might be more common in polar and sub-polar regions than previously
extensive submarine cold-seep area was discovered on the northern
shelf of South Georgia during R/V Polarstern cruise ANT-XXIX/4 in
surveys documented the presence of 133 gas bubble emissions, which
were restricted to glacially-formed fjords and troughs. Video-based
sea floor observations confirmed the sea floor origin of the gas
emissions and spatially related microbial mats.
methane transport from these emissions into the hydrosphere was
proven by relative enrichments of dissolved methane in near-bottom
waters. Stable carbon isotopic signatures pointed to a predominant
microbial methane formation, presumably based on high organic matter
sedimentation in this region.
known from many continental margins in the world's oceans, this is
the first report of an active area of methane seepage in the
finding of substantial methane emission related to a trough and
fjord system, a topographical setting that exists commonly in
glacially-affected areas, opens up the possibility that methane
seepage is a more widespread phenomenon in polar and sub-polar
regions than previously thought.