Isotopic evidence for the provenance and turnover of organic carbon by soil microorganisms in the Antarctic dry valleys
Article first published online: 30 DEC 2008
© 2008 The Authors. Journal compilation © 2008 Society for Applied Microbiology and Blackwell Publishing Ltd
Special Issue: Polar Microbiology. With guest editors Craig Cary, Alison Murray, and Ian McDonald
Volume 11, Issue 3, pages 597–608, March 2009
How to Cite
Hopkins, D. W., Sparrow, A. D., Gregorich, E. G., Elberling, B., Novis, P., Fraser, F., Scrimgeour, C., Dennis, P. G., Meier-Augenstein, W. and Greenfield, L. G. (2009), Isotopic evidence for the provenance and turnover of organic carbon by soil microorganisms in the Antarctic dry valleys. Environmental Microbiology, 11: 597–608. doi: 10.1111/j.1462-2920.2008.01830.x
- Issue published online: 2 MAR 2009
- Article first published online: 30 DEC 2008
- Received 21 July, 2008; accepted 30 October, 2008.
The extremely cold and arid Antarctic dry valleys are one of the most environmentally harsh terrestrial ecosystems supporting organisms in which the biogeochemical transformations of carbon are exclusively driven by microorganisms. The natural abundance of 13C and 15N in source organic materials and soils have been examined to obtain evidence for the provenance of the soil organic matter and the C loss as CO2 during extended incubation (approximately 1200 days at 10°C under moist conditions) has been used to determine the potential decay of soil organic C. The organic matter in soils remote from sources of liquid water or where lacustrine productivity was low had isotope signatures characteristic of endolithic (lichen) sources, whereas at more sheltered and productive sites, the organic matter in the soils that was a mixture mainly lacustrine detritus and moss-derived organic matter. Soil organic C declined by up to 42% during extended incubation under laboratory conditions (equivalent to 50–73 years in the field on a thermal time basis), indicating relatively fast turnover, consistent with previous studies indicating mean residence times for soil organic C in dry valley soils in the range 52–123 years and also with recent inputs of relatively labile source materials.