For the past 30 years, several soil scientists from New Zealand have been studying soils in Antarctica to determine their properties and their significance in respect to weathering processes, glacial history and landscape evolution.
The soils are Cold Desert soils, formed in the coldest and driest environment on Earth. Notwithstanding the severe climate, where mean annual temperatures for much of the continent range from -15°C to -50°C, significant variation in soil properties has existed, largely as a function of available moisture. A distinctive feature of the soils is their very great age. Some land surfaces are now considered to date from the middle Miocene or earlier. The extreme aridity and great age of these soils provide a unique background for the study of cryopedology and geocryology.
Recent research by our New Zealand group in the McMurdo Dry Valley region has focused largely on the properties of permafrost and the impacts of humans on the Antarctic environment. Extensive disturbances in the vicinity of major bases have significantly influenced the soils, the biology and the permafrost. Such disturbances are now forbidden under the Environment Protocol to the Antarctic Treaty.
To predict human impact on permafrost in Antarctica, our research has concentrated on determining the properties of permafrost in the McMurdo coastal environment over a wide range of sites, comparing the permafrost at undisturbed sites with that at sites disturbed 35 years ago, investigating the propert:es of permafrost in differing soil climatic zones, and measuring the summer water content and other physical and chemical properties of the active layer. The movement of contaminants from point sources and the rates and extent of tracer movements in the soil and permafrost at experimental sites are also being studied, providing useful information on soil moisture movement.
An experiment to determine the rate of de-watering of ice-cemented permafrost, using a neutron probe in aluminum access tubes, is currently in progress. Various site climate and soil climate parameters are also being measured. Other experiments have measured the rate at which ground disturbance from typical field work activity occurs. Assessment of sites disturbed up to 30 years ago in field investigations is providing a measure of natural regenerative processes.
Our investigations to date have shown that permafrost and active layer properties vary greatly from place to place. They also confirm the very fragile nature of the Antarctic landscape and the very long time scales over which processes in Antarctica operate. This understanding will help to minimize the impacts of humans within the Antarctic environment and to predict the impacts of global climate change on exposed land surfaces of Antarctica.
Submitted by Iain B. Campbell