Editor: Riks Laanbroek
When a habitat freezes solid: microorganisms over-winter within the ice column of a coastal Antarctic lake
Article first published online: 2 MAR 2011
© 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved
FEMS Microbiology Ecology
Volume 76, Issue 3, pages 401–412, June 2011
How to Cite
Foreman, C. M., Dieser, M., Greenwood, M., Cory, R. M., Laybourn-Parry, J., Lisle, J. T., Jaros, C., Miller, P. L., Chin, Y.-P. and McKnight, D. M. (2011), When a habitat freezes solid: microorganisms over-winter within the ice column of a coastal Antarctic lake. FEMS Microbiology Ecology, 76: 401–412. doi: 10.1111/j.1574-6941.2011.01061.x
Present address: Rose M. Cory, University of North Carolina Chapel Hill, Chapel Hill, NC 27599, USA.
- Issue published online: 6 MAY 2011
- Article first published online: 2 MAR 2011
- Accepted manuscript online: 29 JAN 2011 09:48AM EST
- Received 11 May 2010; revised 21 January 2011; accepted 25 January 2011., Final version published online 2 March 2011.
- lake ice;
A major impediment to understanding the biology of microorganisms inhabiting Antarctic environments is the logistical constraint of conducting field work primarily during the summer season. However, organisms that persist throughout the year encounter severe environmental changes between seasons. In an attempt to bridge this gap, we collected ice core samples from Pony Lake in early November 2004 when the lake was frozen solid to its base, providing an archive for the biological and chemical processes that occurred during winter freezeup. The ice contained bacteria and virus-like particles, while flagellated algae and ciliates over-wintered in the form of inactive cysts and spores. Both bacteria and algae were metabolically active in the ice core melt water. Bacterial production ranged from 1.8 to 37.9 μg C L−1 day−1. Upon encountering favorable growth conditions in the melt water, primary production ranged from 51 to 931 μg C L−1 day−1. Because of the strong H2S odor and the presence of closely related anaerobic organisms assigned to Pony Lake bacterial 16S rRNA gene clones, we hypothesize that the microbial assemblage was strongly affected by oxygen gradients, which ultimately restricted the majority of phylotypes to distinct strata within the ice column. This study provides evidence that the microbial community over-winters in the ice column of Pony Lake and returns to a highly active metabolic state when spring melt is initiated.