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On the Thermal Anomaly of Lake UnterseeReported here is the outcome from a student internship undertaken with Dr. Chris McKay at the NASA Ames Research Center. The project for this internship focuses on Lake Untersee, an Earth analog for icy moons. The anoxic hole of Lake Untersee has a thermal bump that was first observed by Wand et al., 1997 and has been confirmed several times (Wand et al., 2006; Andersen 2011). The expected thermal profile of the hole is linear from 0 C at the thermocline to approximately 4 C, the ground temperature in Antarctica, at the bottom. Instead, there is an increase from 0 C near the thermocline to 5 C which is maintained for 7 m, then a linear profile to approximately 4 C near the bottom. Thermal modeling was conducted to quantify the energy input required to maintain the bump. The results revealed 2 sources. Chemical reactions and radiative energy were analyzed as possible explanation. The chemical analysis revealed a peak in Chlorophyll a at the same depth as the shallower source and several interesting reactions with maximum rates at the same location as the lower depth source. However, the energy released from these reactions was orders of magnitude smaller than required source. The radiation analysis revealed a profile with two peaks in similar locations to the sources and a total energy input within a factor of 1.5 of the required sources. The conclusion from this work is that photosynthesis and the chemical reactions support microbial life in the water column which in turn acts as an opacity to convert radiative energy into thermal energy. Recommendations for future work are aimed at quantifying the quantity and types of microbes present in the water column. Beyond the work of the project, two field trips are described and a discussion on benefits to the student of the internship is given.
Document ID
20150018251
Acquisition Source
Ames Research Center
Document Type
Other
Authors
Bevington, James (International Space Univ., Inc. Moffett Field, CA, United States)
Date Acquired
September 24, 2015
Publication Date
August 21, 2015
Subject Category
Exobiology
Inorganic, Organic And Physical Chemistry
Report/Patent Number
ARC-E-DAA-TN25912
Funding Number(s)
CONTRACT_GRANT: ISU-08022012-ARC
Distribution Limits
Public
Copyright
Public Use Permitted.
Keywords
Earth analog for icy moons
Lake Untersee

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