Oxygen Supersaturation in Ice-Covered Antarctic Lakes: Biological Versus Physical Contributions
Freezing in ice-covered lakes causes dissolved gases to become supersaturated while at the same time removing gases trapped in the ablating ice cover. Analysis of N 2 , O 2 , and Ar in bubbles from Lake Hoare ice shows that, while O 2 is ∼2.4 times supersaturated in the water below the ice, only 11%...
| Published in: | Science |
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| Main Authors: | , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
American Association for the Advancement of Science (AAAS)
1992
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1126/science.11539819 https://www.science.org/doi/pdf/10.1126/science.11539819 |
| Summary: | Freezing in ice-covered lakes causes dissolved gases to become supersaturated while at the same time removing gases trapped in the ablating ice cover. Analysis of N 2 , O 2 , and Ar in bubbles from Lake Hoare ice shows that, while O 2 is ∼2.4 times supersaturated in the water below the ice, only 11% of the O 2 input to this lake is due to biological activity: 89% of the O 2 is derived from meltwater inflow. Trapped bubbles in a subliming ice cover provide a natural "fluxmeter" for gas exchange: in Lake Hoare as much as 70% of the total gas loss may occur by advection through the ice cover, including ∼75% of the N 2 , ∼59% of the O 2 , and ∼57% of the Ar losses. The remaining gas fractions are removed by respiration at the lower boundary (O 2 ) and by molecular exchange with the atmosphere in the peripheral summer moat around the ice. |
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