Soil climate monitoring in Antarctica

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Antarctica, the coldest place on earth, has an area of about 14 million sq. km. About 98% of the continent is covered by ice, which averages about 2100 m thick. This vast ice sheet contains the earth’s largest fresh water reserve. Of the ice-free ground, only 0.3% is available for soils to form.

Currently there are seven soil climate stations in Antarctica, which monitor a range of ambient atmospheric parameters, and soil moisture and temperature.

A group of researchers with USDA-NRCS and other organizations describe in the latest issue of Soil Survey Horizons how the Natural Resources Conservation Service (NRCS) became involved in this monitoring effort in Antarctica, along with a brief summary of the sites, soils, instrumentation, data, and the significance of the data. They describe a cooperative soil climate monitoring project in the McMurdo Dry Valleys and other ice-free areas of the Ross Island Region of Antarctica.

Relatively little is known about soil climate in Antarctica and the effect that it has on other processes, such as weathering, and on the pedogenic behavior of cold and dry soils. Also, soil moisture and temperature are key influences on the viability of microorganisms and plants in Antarctic soil ecosystems. Information obtained from this project could have implications for soil management and interpretations in other cold areas, such as Alaska.

Most importantly for the NRCS, this project provided an opportunity to gather data in an area sensitive to global climate change. A long-term record of soil climate provides base-line information for global climate change and active layer thickness monitoring. Also, long-term data will be useful for defining normal conditions, departures from normal, trends, and cyclic events. It will also provide information on the magnitude of year-to-year variability.

Relatively little is known about soil climate in Antarctica. This research describes a cooperative soil climate monitoring project in the McMurdo Dry Valleys and other ice-free areas of the Ross Island Region of Antarctica. There are seven soil climate stations that monitor air temperature, relative humidity, wind speed and direction, solar radiation, and soil moisture and temperature in which hourly measurements are recorded. The initial project objective, in 1999, was to determine the impact of fuel spills on the biological, chemical, and physical properties of Antarctic soils, which was lead by Landcare Research of New Zealand. When the initial project ended in 2002, the control sites were continued as long-term monitoring stations. At each site, soils were described and sampled for characterization analyses.

The soils are coarse textured with significant amounts and sizes of coarse fragments throughout the profile with little soil development (or horizonation). Mean annual air temperatures (MAAT) range from −17 to −24°C. The mean annual soil temperatures (MAST) range from −14.6 to −23.5°C. The average maximum thaw depth ranged from 5.5 cm to more than 85 cm. Average active layer water contents are low and tend to increase with depth. The data, soil descriptions, soil characterization data, and station records from this project are available through the National Soil Survey Center’s web page (http://soils.usda.gov/survey/scan/). As long as the project continues, annual maintenance and data retrieval are necessary. The importance of this project is that it provides NRCS an opportunity to gather data in an area sensitive to global climate change.

Data from this monitoring project are shared with the Circumpolar Active Layer Monitoring (CALM) program as part of their network. The primary goal of the CALM program is to observe the response of the active layer and near-surface permafrost to climate change over long (multi-decadal) time scales. The CALM network was established in the 1990s and has more than 125 sites in both hemispheres (For more see: http://www.udel.edu/Geography/calm/).

Also available through the National Soil Survey Center’s web page is information on global climate change, put together by the NRCS National Leader for Global Climate Change. The web address is http://soils.usda.gov/survey/global_climate_change.html.

Soil Climate Monitoring Project in the Ross Island Region of Antarctica by C. A. Seybold, D. S. Harms, M. Balks, J. Aislabie, R. F. Paetzold, J. Kimble, and R. Sletten.
Feature published in Soil Survey Horizons, Summer 2009.

Photo is of a soil climate station at Minna Bluff. The winds were 35 to 40 mph—see blowing snow in the background. One person downloads the data while another holds the door open and blocks the wind. Photo provided by the authors.
 
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