Hydrological and Biogeochemical Modeling of Taylor Valley Lakes, East Antarctica
Taylor Valley, McMurdo Dry Valleys, East Antarctica contains three perennially ice-covered lakes located in closed basins. The lakes respond to climatic changes on seasonal and decadal scales due to their existence on a very narrow climatic spectrum. The climate has to be sufficiently warm during th...
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ftunivillchic:oai:dspace-prod.lib.uic.edu:10027/18909 2023-05-15T13:31:50+02:00 Hydrological and Biogeochemical Modeling of Taylor Valley Lakes, East Antarctica Obryk, Maciej K. Doran, Peter Dombard, Andrew Kenig, Fabien Plotnick, Roy McKay, Chris 2014-05 http://hdl.handle.net/10027/18909 en eng Copyright 2014 Maciej K. Obryk Antarctica Limnology Polar desert thesis text 2014 ftunivillchic 2018-09-19T06:20:15Z Taylor Valley, McMurdo Dry Valleys, East Antarctica contains three perennially ice-covered lakes located in closed basins. The lakes respond to climatic changes on seasonal and decadal scales due to their existence on a very narrow climatic spectrum. The climate has to be sufficiently warm during the austral summer to induce glacial melt yet cold enough to maintain the ice covers year round. This thesis is focused on better understanding and constraining the sensitivity of past and present lakes to changes in climatic forcings. Melt water generation for large proglacial lakes, that existed during the Last Glacial Maximum, is attributed to strong westerly winds that increase surface air temperature above freezing, prolonging the melt season. The high frequency of westerly winds during the Last Glacial Maximum, based on the ice core record from Taylor Dome, is responsible for generation of enough glacial melt to sustain large proglacial lakes during this time period, suggesting that summer surface air temperatures were as warm as present day. Contemporary lakes are much smaller, however, the effect of strong westerly winds on modern lakes is equally profound. Strong winds are responsible for aeolian sediment deposition on the surface of the ice covers. The deposited sediment, on the other hand, absorbs more solar radiation and preferentially decreases the ice thickness around it. The localized ice thinning allows a greater amount of light penetration into the water column, which is negatively correlated with chlorophyll-a concentration. This negative correlation does not indicate changes in biomass; rather, it is a result of the short-term photo-adaptation of phytoplankton to the light intensity by increasing/decreasing light harvesting antenna size. The ice thicknesses in Taylor Valley lakes have been fluctuating since the first measurements were obtained. A one-dimensional physics-based ice thickness model was developed capable of reproducing 16 years of ice thickness trends for two different lakes. The model is based on surface radiative fluxes while considering heat fluxes from the water column. Deep lakes with well-developed temperature maximum can facilitate or hinder ice thickness growth/decay due to the heat flux from the underlying water column. This finding suggests that not all perennially ice-covered lakes can be used as a proxy for climatic changes. Thesis Antarc* Antarctica East Antarctica ice core McMurdo Dry Valleys polar desert University of Illinois at Chicago: UIC INDIGO (INtellectual property in DIGital form available online in an Open environment) Austral East Antarctica McMurdo Dry Valleys Taylor Dome ENVELOPE(157.667,157.667,-77.667,-77.667) Taylor Valley ENVELOPE(163.000,163.000,-77.617,-77.617) |
institution |
Open Polar |
collection |
University of Illinois at Chicago: UIC INDIGO (INtellectual property in DIGital form available online in an Open environment) |
op_collection_id |
ftunivillchic |
language |
English |
topic |
Antarctica Limnology Polar desert |
spellingShingle |
Antarctica Limnology Polar desert Obryk, Maciej K. Hydrological and Biogeochemical Modeling of Taylor Valley Lakes, East Antarctica |
topic_facet |
Antarctica Limnology Polar desert |
description |
Taylor Valley, McMurdo Dry Valleys, East Antarctica contains three perennially ice-covered lakes located in closed basins. The lakes respond to climatic changes on seasonal and decadal scales due to their existence on a very narrow climatic spectrum. The climate has to be sufficiently warm during the austral summer to induce glacial melt yet cold enough to maintain the ice covers year round. This thesis is focused on better understanding and constraining the sensitivity of past and present lakes to changes in climatic forcings. Melt water generation for large proglacial lakes, that existed during the Last Glacial Maximum, is attributed to strong westerly winds that increase surface air temperature above freezing, prolonging the melt season. The high frequency of westerly winds during the Last Glacial Maximum, based on the ice core record from Taylor Dome, is responsible for generation of enough glacial melt to sustain large proglacial lakes during this time period, suggesting that summer surface air temperatures were as warm as present day. Contemporary lakes are much smaller, however, the effect of strong westerly winds on modern lakes is equally profound. Strong winds are responsible for aeolian sediment deposition on the surface of the ice covers. The deposited sediment, on the other hand, absorbs more solar radiation and preferentially decreases the ice thickness around it. The localized ice thinning allows a greater amount of light penetration into the water column, which is negatively correlated with chlorophyll-a concentration. This negative correlation does not indicate changes in biomass; rather, it is a result of the short-term photo-adaptation of phytoplankton to the light intensity by increasing/decreasing light harvesting antenna size. The ice thicknesses in Taylor Valley lakes have been fluctuating since the first measurements were obtained. A one-dimensional physics-based ice thickness model was developed capable of reproducing 16 years of ice thickness trends for two different lakes. The model is based on surface radiative fluxes while considering heat fluxes from the water column. Deep lakes with well-developed temperature maximum can facilitate or hinder ice thickness growth/decay due to the heat flux from the underlying water column. This finding suggests that not all perennially ice-covered lakes can be used as a proxy for climatic changes. |
author2 |
Doran, Peter Dombard, Andrew Kenig, Fabien Plotnick, Roy McKay, Chris |
format |
Thesis |
author |
Obryk, Maciej K. |
author_facet |
Obryk, Maciej K. |
author_sort |
Obryk, Maciej K. |
title |
Hydrological and Biogeochemical Modeling of Taylor Valley Lakes, East Antarctica |
title_short |
Hydrological and Biogeochemical Modeling of Taylor Valley Lakes, East Antarctica |
title_full |
Hydrological and Biogeochemical Modeling of Taylor Valley Lakes, East Antarctica |
title_fullStr |
Hydrological and Biogeochemical Modeling of Taylor Valley Lakes, East Antarctica |
title_full_unstemmed |
Hydrological and Biogeochemical Modeling of Taylor Valley Lakes, East Antarctica |
title_sort |
hydrological and biogeochemical modeling of taylor valley lakes, east antarctica |
publishDate |
2014 |
url |
http://hdl.handle.net/10027/18909 |
long_lat |
ENVELOPE(157.667,157.667,-77.667,-77.667) ENVELOPE(163.000,163.000,-77.617,-77.617) |
geographic |
Austral East Antarctica McMurdo Dry Valleys Taylor Dome Taylor Valley |
geographic_facet |
Austral East Antarctica McMurdo Dry Valleys Taylor Dome Taylor Valley |
genre |
Antarc* Antarctica East Antarctica ice core McMurdo Dry Valleys polar desert |
genre_facet |
Antarc* Antarctica East Antarctica ice core McMurdo Dry Valleys polar desert |
op_rights |
Copyright 2014 Maciej K. Obryk |
_version_ |
1766021175360618496 |