Natural spatial subsidies in continental Antarctic soil

The importance of these spatial subsidies on productivity and biological diversity of dry valley soils was investigated over several seasons in the Garwood Valley. Sampling of the soil, microbial mats and foam from each identified landform and from Lake Colleen was undertaken for analysis of a variety of soil biological and chemical properties in order to gain an idea of the general spatial variation of these properties (before experimental work) and to determine the size of the soil microbial communities, the rates of microbial respiration and the abundance of selected invertebrate groups.

Soil samples were collected and analysed to quantify carbon and nitrogen pools, potential decomposition and nitrogen release under optimal conditions and potential microbial use of a variety of test C and N substrates. The importance of spatial subsidy materials on the four different landforms was tested with the addition of lakeshore foam and algal mats at two levels of application, plus appropriate treatment controls.