Temporal Variations in Physical and Chemical Features of Cryoconite Holes on Canada Glacier, McMurdo Dry Valleys, Antarctica
Cryoconite holes in the McMurdo Dry Valleys are ice-lidded, thus isolating the pools of water from the atmosphere and from potential surface melt. Hourly measurements of ice and water temperature and water electrical conductivity (EC) were recorded to broadly characterize the physical and chemical c...
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ftportlandstate:oai:pdxscholar.library.pdx.edu:geog_fac-1013 2023-05-15T13:58:46+02:00 Temporal Variations in Physical and Chemical Features of Cryoconite Holes on Canada Glacier, McMurdo Dry Valleys, Antarctica Fountain, Andrew G. Nylen, Thomas H. Tranter, Martyn Bagshaw, Elizabeth A. 2008-01-19T08:00:00Z application/pdf https://pdxscholar.library.pdx.edu/geog_fac/14 https://pdxscholar.library.pdx.edu/cgi/viewcontent.cgi?article=1013&context=geog_fac unknown PDXScholar https://pdxscholar.library.pdx.edu/geog_fac/14 https://pdxscholar.library.pdx.edu/cgi/viewcontent.cgi?article=1013&context=geog_fac Geography Faculty Publications and Presentations McMurdo Dry Valleys (Antarctica) Glaciers -- Antarctica -- McMurdo Dry Valleys Meltwater -- Antarctica -- McMurdo Dry Valleys Ablation (Aerothermodynamics) Environmental Sciences Glaciology text 2008 ftportlandstate 2022-01-09T19:25:32Z Cryoconite holes in the McMurdo Dry Valleys are ice-lidded, thus isolating the pools of water from the atmosphere and from potential surface melt. Hourly measurements of ice and water temperature and water electrical conductivity (EC) were recorded to broadly characterize the physical and chemical changes on daily to seasonal timescales. Overall, subsurface ice/water temperatures were typically several degrees warmer than air temperatures, underscoring the importance of subsurface solar heating. At no time was surface melt observed and the holes melted from within. Detailed differences in the timing and magnitude of both temperature and EC variations during melt-out and freezeup existed between holes despite short separation distances (m). We attribute these differences to small-scale changes in the optical characteristics of the ice and perhaps different efficiencies in hydrologic connections between holes. The holes melt-deepened quickly in the first half of the summer before slowing to a rate equal to the rate of surface ablation that kept hole depth constant for the remainder of the season. The relatively constant EC of the hole waters during midsummer indicates that these holes were connected to a subsurface water system that flushed the holes with fresher meltwater. The early and late season ECs are dominated by freeze-thaw effects that concentrate/dilute the solutes. We speculate that high solute concentrations imply high nutrient concentrations in early summer that may help alleviate potential stresses caused by the production of new biomass after the winter freeze. Text Antarc* Antarctica Canada Glacier glacier* McMurdo Dry Valleys Portland State University: PDXScholar Canada Canada Glacier ENVELOPE(162.983,162.983,-77.617,-77.617) McMurdo Dry Valleys |
institution |
Open Polar |
collection |
Portland State University: PDXScholar |
op_collection_id |
ftportlandstate |
language |
unknown |
topic |
McMurdo Dry Valleys (Antarctica) Glaciers -- Antarctica -- McMurdo Dry Valleys Meltwater -- Antarctica -- McMurdo Dry Valleys Ablation (Aerothermodynamics) Environmental Sciences Glaciology |
spellingShingle |
McMurdo Dry Valleys (Antarctica) Glaciers -- Antarctica -- McMurdo Dry Valleys Meltwater -- Antarctica -- McMurdo Dry Valleys Ablation (Aerothermodynamics) Environmental Sciences Glaciology Fountain, Andrew G. Nylen, Thomas H. Tranter, Martyn Bagshaw, Elizabeth A. Temporal Variations in Physical and Chemical Features of Cryoconite Holes on Canada Glacier, McMurdo Dry Valleys, Antarctica |
topic_facet |
McMurdo Dry Valleys (Antarctica) Glaciers -- Antarctica -- McMurdo Dry Valleys Meltwater -- Antarctica -- McMurdo Dry Valleys Ablation (Aerothermodynamics) Environmental Sciences Glaciology |
description |
Cryoconite holes in the McMurdo Dry Valleys are ice-lidded, thus isolating the pools of water from the atmosphere and from potential surface melt. Hourly measurements of ice and water temperature and water electrical conductivity (EC) were recorded to broadly characterize the physical and chemical changes on daily to seasonal timescales. Overall, subsurface ice/water temperatures were typically several degrees warmer than air temperatures, underscoring the importance of subsurface solar heating. At no time was surface melt observed and the holes melted from within. Detailed differences in the timing and magnitude of both temperature and EC variations during melt-out and freezeup existed between holes despite short separation distances (m). We attribute these differences to small-scale changes in the optical characteristics of the ice and perhaps different efficiencies in hydrologic connections between holes. The holes melt-deepened quickly in the first half of the summer before slowing to a rate equal to the rate of surface ablation that kept hole depth constant for the remainder of the season. The relatively constant EC of the hole waters during midsummer indicates that these holes were connected to a subsurface water system that flushed the holes with fresher meltwater. The early and late season ECs are dominated by freeze-thaw effects that concentrate/dilute the solutes. We speculate that high solute concentrations imply high nutrient concentrations in early summer that may help alleviate potential stresses caused by the production of new biomass after the winter freeze. |
format |
Text |
author |
Fountain, Andrew G. Nylen, Thomas H. Tranter, Martyn Bagshaw, Elizabeth A. |
author_facet |
Fountain, Andrew G. Nylen, Thomas H. Tranter, Martyn Bagshaw, Elizabeth A. |
author_sort |
Fountain, Andrew G. |
title |
Temporal Variations in Physical and Chemical Features of Cryoconite Holes on Canada Glacier, McMurdo Dry Valleys, Antarctica |
title_short |
Temporal Variations in Physical and Chemical Features of Cryoconite Holes on Canada Glacier, McMurdo Dry Valleys, Antarctica |
title_full |
Temporal Variations in Physical and Chemical Features of Cryoconite Holes on Canada Glacier, McMurdo Dry Valleys, Antarctica |
title_fullStr |
Temporal Variations in Physical and Chemical Features of Cryoconite Holes on Canada Glacier, McMurdo Dry Valleys, Antarctica |
title_full_unstemmed |
Temporal Variations in Physical and Chemical Features of Cryoconite Holes on Canada Glacier, McMurdo Dry Valleys, Antarctica |
title_sort |
temporal variations in physical and chemical features of cryoconite holes on canada glacier, mcmurdo dry valleys, antarctica |
publisher |
PDXScholar |
publishDate |
2008 |
url |
https://pdxscholar.library.pdx.edu/geog_fac/14 https://pdxscholar.library.pdx.edu/cgi/viewcontent.cgi?article=1013&context=geog_fac |
long_lat |
ENVELOPE(162.983,162.983,-77.617,-77.617) |
geographic |
Canada Canada Glacier McMurdo Dry Valleys |
geographic_facet |
Canada Canada Glacier McMurdo Dry Valleys |
genre |
Antarc* Antarctica Canada Glacier glacier* McMurdo Dry Valleys |
genre_facet |
Antarc* Antarctica Canada Glacier glacier* McMurdo Dry Valleys |
op_source |
Geography Faculty Publications and Presentations |
op_relation |
https://pdxscholar.library.pdx.edu/geog_fac/14 https://pdxscholar.library.pdx.edu/cgi/viewcontent.cgi?article=1013&context=geog_fac |
_version_ |
1766267103679086592 |