BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Microbial activity beneath the Antarctic Ice Sheet: impacts beyond
  the ice margin? - Dr Jemma Wadham\, University of Bristol
DTSTART:20120530T153000Z
DTEND:20120530T163000Z
UID:TALK34006@talks.cam.ac.uk
CONTACT:Steven Palmer
DESCRIPTION:Once thought to be devoid of life\, the Antarctic Ice Sheet is
  now known to be a dynamic reservoir of organic carbon and metabolically a
 ctive microbial cells. At the ice-bed interface\, subglacial lake environm
 ents and till are believed to support low diversity microbial populations\
 , adapted to perennial cold\, anoxia and lack of light. The dynamic exchan
 ge of water between these shallow environments sustains nutrient and organ
 ic carbon supply to the subglacial zone\, and ultimately conveys meltwater
 s and sediments into the coastal ocean. The latter may be important for fe
 rtilizing the Southern Ocean with N\, P and Fe\, with potential implicatio
 ns for marine productivity and associated CO2 drawdown. Beyond the subglac
 ial lakes and the subglacial till complex are deep sedimentary basins up t
 o 14km thick located largely around the Antarctic periphery. Here\, sustai
 ned microbial activity over Myr timescales is likely to be important for t
 he cycling of organic carbon and elements in the deep sub-surface. These s
 edimentary basins may be hydrologically decoupled from shallower lake and 
 till environments by the presence of highly consolidated sediments which l
 imit the penetration of glacial meltwaters to depth. Organic carbon buried
  in these basins (e.g. marine sediments) during ice sheet formation is tho
 ught to be microbially cycled to methane gas\, which is stored as hydrate 
 within sediments\, stabilized by the high pressure/low temperature conditi
 ons. It has been demonstrated via numerical modeling that this methane sto
 re could be of a similar order of magnitude to that present as hydrate in 
 other globally significant reserves. In summary\, microbial activity benea
 th the Antarctic ice sheet is likely to have far reaching impacts beyond t
 he ice margin and may be important to consider in future global models of 
 biogeochemical cycling.
LOCATION:Scott Polar Research Institute\, main lecture theatre
END:VEVENT
END:VCALENDAR