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Formation and character of an ancient 19-m ice cover and underlying trapped brine in an "ice-sealed" east Antarctic lake.
- Source :
-
Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 2003 Jan 07; Vol. 100 (1), pp. 26-31. Date of Electronic Publication: 2002 Dec 23. - Publication Year :
- 2003
-
Abstract
- Lake Vida, one of the largest lakes in the McMurdo Dry Valleys of Antarctica, was previously believed to be shallow (<10 m) and frozen to its bed year-round. New ice-core analysis and temperature data show that beneath 19 m of ice is a water column composed of a NaCl brine with a salinity seven times that of seawater that remains liquid below -10 degrees C. The ice cover thickens at both its base and surface, sealing concentrated brine beneath. The ice cover is stabilized by a negative feedback between ice growth and the freezing-point depression of the brine. The ice cover contains frozen microbial mats throughout that are viable after thawing and has a history that extends to at least 2,800 (14)C years B.P., suggesting that the brine has been isolated from the atmosphere for as long. To our knowledge, Lake Vida has the thickest subaerial lake ice cover recorded and may represent a previously undiscovered end-member lacustrine ecosystem on Earth.
- Subjects :
- Antarctic Regions
Seawater
Temperature
Thermodynamics
Ice
Sodium Chloride
Subjects
Details
- Language :
- English
- ISSN :
- 0027-8424
- Volume :
- 100
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Proceedings of the National Academy of Sciences of the United States of America
- Publication Type :
- Academic Journal
- Accession number :
- 12518052
- Full Text :
- https://doi.org/10.1073/pnas.222680999