Abstract
We examined sediment melt-migration dynamics in the ice cover of Lake Fryxell, Taylor Valley, McMurdo Dry Valleys, Antarctica, using a combination of laboratory experiments, field observations, and modeling. The specific objectives were to determine the thermal conditions required for sediment melt and how sediment migration rates vary with meteorological forcings and ice microstructure. These characteristics are relevant to the influence of climate change on lake ice structure and ecosystem processes in polar regions. Sediment began melting through laboratory ice at −2 °C in simulated summer conditions, with warmer ice producing faster melt rates. An energy balance model, supported by our laboratory experiments, demonstrated that subsurface sediment can melt down to an equilibrium depth of ∼2 m in two years. Field experiments and modeling revealed that surficial sediment melts at about half the rate of subsurface sediment because of heat losses to shallow, cold ice and the cold, dry atmosphere. Gravity flow of sediment along grain boundaries was pronounced in laboratory ice warmer than −1 °C. This mechanism produced a flux of 0.1 g m−2 hr−1, a significant value relative to published benthic sedimentation rates for these lakes indicating an important sediment sorting mechanism.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.