Subglacial Lake Whillans, West Antarctica; Solute Dynamics and Fluxes to the Ross Sea
Mark L Skidmore1, Alexander B Michaud2, Amanda Achberger3, Carlo Barbante4, Brent Craig Christner3, Jill Mikucki5, Andrew Mitchell6, John C Priscu7, Alicia M. Purcell8, Will van Gelder9, Trista Vick-Majors10 and WISSARD Science Team, (1)Stockholm University, Department of Physical Geography, Stockholm, Sweden, (2)Montana State University, Bozeman, United States, (3)Louisiana State University, Baton Rouge, LA, United States, (4)Ca' Foscari University, Department of Environmental Sciences, Informatics and Statistics, Venice, Italy, (5)University of Tennessee, Department of Microbiology, Knoxville, United States, (6)Aberystwyth University, Geography & Earth Sciences, Aberystwyth, United Kingdom, (7)Desert Research Institute, Division of Earth and Ecosystem Sciences, Reno, United States, (8)University of Tennessee, Knoxville, TN, United States, (9)Montana State University, Bozeman, MT, United States, (10)Michigan Technological University, Biological Sciences, Houghton, MI, United States
Abstract:
Subglacial Lake Whillans is located beneath the Whillans Ice Stream in West Antarctica. The lake is situated beneath 800 m of ice and ~ 70 km upstream of the grounding line where Whillans Ice Stream terminates into the Ross Sea. Subglacial Lake Whillans is a shallow lake and a component of a complex subglacial hydrological system that may resemble a large wetland along the Siple Coast of West Antarctica. Subglacial Lake Whillans drains and refills on a sub-decadal time scale discharging water towards the Ross Sea.
Water and sediment samples were recovered from the lake, using clean access drilling technologies, in January, 2013. Isotopic analysis of the lake waters indicates basal meltwater from the ice sheet as the dominant water source. Geochemical analysis of the lake water reveals it is freshwater with mineral weathering as a significant solute source, with a minor contribution from sea water likely from relict marine sediments. Subglacial hydrothermal activity upstream may also contribute solutes. Nutrients N and P are present at micromolar concentrations. Sediment porewaters from shallow cores (~ 40 cm depth) of the subglacial lake sediments indicate increasing solute concentration with depth, with up to ~ five times greater solute concentrations than in the lake water. The waters and sediment contain metabolically active organisms which are likely involved in elemental cycling within the lake system.
Here we will discuss solute sources to the lake, solute dynamics within the lake waters and sediment, and the fluxes of solute and nutrients to the Ross Sea and their implications for these marine ecosystems.
