The Soil Environment Of The Mcmurdo Dry Valleys Antarctica

Active layer soils host an extensive shallow groundwater system in the polar desert environment of the McMurdo Dry Valleys (MDV), Antarctica. The properties of these soils influence how groundwater-and thus energy, solutes, and carbon-are distributed through the near-subsurface of the MDV, and therefore provide an important control on many landscape-scale processes such as hillslope drainage and thermokarst formation. In order to characterize variability in active layer soil properties, we measured the saturated hydraulic conductivity (k), grain-size distribution, and thermal properties (e.g., diffusivity, D) of >50 soil samples in the MDV. We find that the physical properties of soils are organized longitudinally along MDV valley axes: soils down-valley near the coast have a higher percentage of fine-sized sediments (fine sand, silt, clay) and lower hydraulic conductivities than soils collected up-valley. These results suggest that the organization of modern soil properties is a relict signature from past glaciations that have deposited tills of decreasing age towards the valley mouths, modified lightly by fluvial activity acting over geological and microclimate gradients. Further, we show that all water-holding soils exhibit a positive feedback between water content and thermal diffusivity, and that, importantly, this feedback is much stronger for some soils than for others. Together, our results predict where low-k, high-D soil properties overlap in bare terrestrial Antarctic settings, rapid thawing of ground ice can occur as meltwater allows heat to penetrate deeply into permafrost-affected soils to accelerate conductive thaw and active layer thickening.

This book divides Antarctica into eight ice-free regions and provides information on the soils of each region. Soils have been studied in Antarctica for nearly 100 years. Although only 0.35% (45,000 km2) of Antarctica is ice-free, its weathered, unconsolidated material qualify as “soils”. Soils of Antarctica is richly illustrated with nearly 150 images and provisional maps are provided for several key ice-free areas.

Explores soil as a nexus for water, chemicals, and biologically coupled nutrient cycling Soil is a narrow but critically important zone on Earth's surface. It is the interface for water and carbon recycling from above and part of the cycling of sediment and rock from below. Hydrogeology, Chemical Weathering, and Soil Formation places chemical weathering and soil formation in its geological, climatological, biological and hydrological perspective. Volume highlights include: The evolution of soils over 3.25 billion years Basic processes contributing to soil formation How chemical weathering and soil formation relate to water and energy fluxes The role of pedogenesis in geomorphology Relationships between climate soils and biota Soils, aeolian deposits, and crusts as geologic dating tools Impacts of land-use change on soils The American Geophysical Union promotes discovery in Earth and space science for the benefit of humanity. Its publications disseminate scientific knowledge and provide resources for researchers, students, and professionals. Find out more about this book from this Q&A with the Editors

Presents information from the primary abiotic forces defining the system, and from the present hydrology, biogeochemistry and physics of major sites of organic carbon production of the McMurdo Dry Valleys. Additionally, research on the physical, chemical, and biological properties of the dry valley soils is included. The role of environmental management in long-term ecological studies is also addressed. The accompanying CDROM provides details and scale to visualize the McMurdo Dry Valleys from an ecosystem perspective.

The McMurdo Dry Valleys form the largest relatively ice-free area on the Antarctic continent. The perennially ice-covered lakes, ephemeral streams and extensive areas of exposed soil are subject to low temperatures, limited precipitation and salt accumulation. The dry valleys thus represent a region where life approaches its environmental limits. This unique ecosystem has been studied for several decades as an analog to environments on other planets, particularly Mars. For the first time, the detailed terrestrial research of the dry valleys is brought together here, presented from an astrobiological perspective. Chapters include a discussion on the history of research in the valleys, a geological background of the valleys, setting them up as analogs for Mars, followed by chapters on the various sub-environments in the valleys such as lakes, glaciers and soils. Includes concluding chapters on biodiversity and other analog environments on Earth.

"The McMurdo Dry Valleys form the largest relatively ice-free area on the Antarctic continent. The perennially ice-covered lakes, ephemeral streams and extensive areas of exposed soil are subject to low temperatures, limited precipitation and salt accumulation. The dry valleys thus represent a region where life approaches its environmental limits. This unique ecosystem has been studied for several decades as an analog to environments on other planets, particularly Mars. For the first time, the detailed terrestrial research of the dry valleys is brought together here, presented from an astrobiological perspective. Chapters include a discussion on the history of research in the valleys, a geological background of the valleys, setting them up as analogs for Mars, followed by chapters on the various sub-environments in the valleys such as lakes, glaciers and soils. Includes concluding chapters on biodiversity and other analog environments on Earth"--Provided by publisher.