Aquatic Sciences Meeting, Albuquerque 2001

PC16 Microbial Dynamics

Date: Thursday, February 15, 2001

Location: Southwest Hall

Fritsen, C, H, Desert Research Institute, Reno, USA, cfritsen@dri.edu

Priscu, J, C, Montana State University, Bozeman , USA, ubijp@gemini.oscs.montana.edu

NUTRIENT BUDGETS FOR MICROBIAL COMMUNITIES IN PERENNIAL ANTARCTIC LAKE ICE

Perennial ice covers in the McMurdo Dry Valleys of Antarctica harbor slow-growing cyanobacterial assemblages. These assemblages grow primarily during the austral summer and autumn periods when solar heating leads to the production of liquid water in the ice matrices and induces the movement of cyanobacteria/bacteria/sediment aggregates downward through the ice covers on an annual basis. We recently have constructed nutrient budgets for the ice cover habitats which includes ice dynamics, ice chemistry, microbial growth dynamics and results from production and growth bioassays. Our synthesis indicates that these semi-isolated systems are highly regenerative microcosms relative to the time-scales of the supply of nutrients from ice dynamics whereas the nutrients originating from the combined sedimentary and ice sources supply the materials necessary for the long-term viability of biota in these frozen media. Our results also indicate a beneficial role of freezing during the dark winter months when energy and nutrient supplies are minimized. Such findings contribute to our understanding of the basic coupling between physical and biological processes effecting the long-term viability, activity and function of microbial life in extreme polar environments.

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Aquatic Sciences Meeting, Albuquerque 2001

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