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dc.contributor.advisorDoran, Peteren_US
dc.contributor.authorObryk, Maciej K.en_US
dc.date.accessioned2014-06-20T19:24:14Z
dc.date.available2016-06-21T09:30:12Z
dc.date.created2014-05en_US
dc.date.issued2014-06-20
dc.date.submitted2014-05en_US
dc.identifier.urihttp://hdl.handle.net/10027/18909
dc.description.abstractTaylor 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.en_US
dc.language.isoenen_US
dc.rightsen_US
dc.rightsCopyright 2014 Maciej K. Obryken_US
dc.subjectAntarcticaen_US
dc.subjectLimnologyen_US
dc.subjectPolar deserten_US
dc.titleHydrological and Biogeochemical Modeling of Taylor Valley Lakes, East Antarcticaen_US
thesis.degree.departmentEarth and Environmental Sciencesen_US
thesis.degree.disciplineEarth and Environmental Sciencesen_US
thesis.degree.grantorUniversity of Illinois at Chicagoen_US
thesis.degree.levelDoctoralen_US
thesis.degree.namePhD, Doctor of Philosophyen_US
dc.type.genrethesisen_US
dc.contributor.committeeMemberDombard, Andrewen_US
dc.contributor.committeeMemberKenig, Fabienen_US
dc.contributor.committeeMemberPlotnick, Royen_US
dc.contributor.committeeMemberMcKay, Chrisen_US
dc.type.materialtexten_US


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