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Taylor Valley Lakes

Oxygen stable isotopes and chloride concentration in the surface waters of Taylor Valley Lakes, Antarctica, during the past 40 years. Julie M. Brown*, W. B. Lyons*, K. A. Welch*, P . Doran, C. B. Dowling, D. M. McKnight, and J. C. Priscu *The Ohio State University School of Earth Sciences

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Taylor Valley Lakes

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  1. Oxygen stable isotopes and chloride concentration in the surface waters of Taylor Valley Lakes, Antarctica, during the past 40 years Julie M. Brown*, W. B. Lyons*, K. A. Welch*, P. Doran, C. B. Dowling, D. M. McKnight, and J. C. Priscu *The Ohio State University School of Earth Sciences 4 November 2012

  2. Taylor Valley Lakes 163° • Geography • Hydrology & meteorology Lake Fryxell 77°35’ 162° Andersen Creek Lake Hoare Lake Bonney 77°45’

  3. Taylor Valley Lake Levels Change in lake depth since January 1972 (meters) ’92 – ’01* ‘02 – ‘11 ’72 – ‘91 * Flood year Year Figure courtesy of Peter Doran, Univ. Illinois, Chicago

  4.  lake level  lake level  lake level  lake level Data courtesy of Peter Doran, Univ. Illinois, Chicago

  5. Taylor Valley lakes water isotope vs. depth work • Matsubaya et al. (1979) • Lyons et al. (1999) • Gooseff et al. (2006) • 2005-2006 season courtesy of Carolyn Dowling, Ball State University • 2011-2012 season with the aid of the MCM-LTER group “Limno Team” Photo courtesy of A. Chiuchiolo

  6. Annual/decadal variations in salinityand δ18O of lake surface waters ‘03 – ‘11:  lake levels ’92 – ’02:  lake levels ’72 – ’91:   lake levels

  7. Historical δ18O Canada Glacier ice and melt regimes to Lake Hoare Map -29.5‰ -31.2‰ Andersen Creek -33.7‰ Canada Glacier Lake Hoare (δ18O -35.9‰ to -32.4‰) N Oxygen isotope data compiled by D. Leslie, Ohio State

  8. Lake Hoare basin δ18O December and January Canada Glacier Andersen Creek -31.2‰ to -28.4‰* glacier snow and ice -33.7‰ to -29.5‰ lake ice +3‰ enrichment** freezing (February - November) Lake Hoare surface waters -35.9‰ to -32.4‰ * Anderson Creek data from 2010 and from personal communication with D. Leslie, Ohio State ** O’Neil (1968)

  9. Conclusions • The Taylor Valley lake surface waters vary with time isotopically • Heterogeneous glacier ice • Degree of variability depends on hydrology • Isotopic fractionation processes vary with climate • Lake Hoare surface waters are getting isotopically lighter during last 5-6 years • Significant melting of the foot of Canada Glacier relative to Andersen Creek water

  10. Future work • Continued annual (and seasonal) collection of lake water column isotope data • More spatial Taylor Valley glacier ice isotope samples • Model isotope data of streams, glaciers, and lakes (and lake ice)

  11. Acknowledgements • This work was supported by NSF Grant OPPP-ANT-1115245 • MCM-LTER project • Dr. W. Berry Lyons, Kathleen Welch, Deborah Leslie, Christopher Gardner, ‘11-‘12 MCM-LTER “Limno Team”

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