Monday, February 03, 2014, 12:00PM - 1:00PM
Visiting INSTAAR scientist and SUNY Oneonta
ARC room 620
Interactions between hydrology and limnology in a perennially ice-covered lake, Antarctica: An analog for lake processes on Mars
The McMurdo Dry Valleys (MDV) in Antarctica are widely considered to be the most Mars-like environment on Earth, such that perennially ice-covered lakes in the MDV provide insight into physical, chemical, and biological process that potentially occurred in Mars lakes. Lake Hoare, a 4-km-long closed basin, receives water from a glacial meltwater stream called Andersen Creek plus runoff from the Canada Glacier and overflow from an adjacent pond. This study investigated the fate of Andersen Creek water in Lake Hoare in order to indicate where stream sediments and nutrients may have been distributed in Mars lakes. On December 17, 2012, a LiCl tracer (Li+ 49 g/L, Cl- 251 g/L) was injected into the Andersen Creek weir for 2 hours during a peak discharge event. Simultaneously, water samples were collected at 30 minute intervals over four hours from 5 stream sites and 15 boreholes in the lake ice. Results showed that stream water dispersion was limited to a narrow region adjacent to the lake shoreline and did not penetrate into the lake interior. If Mars lakes behaved similarly, the morphology of shoreline deposits on Mars could be used to differentiate ice-covered lake deposits from ice-free lake deposits as a means of reconstructing paleoclimate. Moreover, the restriction of nutrient-rich water to shoreline regions indicates spatial heterogeneity in shallow biogeochemical processes within modern ice-covered lakes in Antarctica, and possibly within ancient ice-covered lakes on Mars.
Free and open to the public