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.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.