Biology & Medicine

Dr. Polly Penhale Program Manager

B-310-M	NSF/OPP Award 02-30276
Station: McMurdo Station
RPSC POC: Jessie Crain
Research Site(s): Lake Bonney, Lake Vanda
Dates in Antarctica: Early November to mid December

What limits denitrification and bacterial growth in Lake Bonney, Taylor Valley?

Dr. Bess B. Ward Princeton University Department of Geosciences bbw@princeton.edu [No website]

Photo not available.

Deploying Team Members:

Jenny Baeseman . Gregory D. O'Mullan . Charles G. Trick . Caroline L. Tuit . Bess B. Ward . Mark L. Wells

Research Objectives: Denitrification is the main loss term for fixed nitrogen from ecosystems, and thus its rate and regulation may directly affect primary production and carbon cycling over short and long time scales. This group’s previous investigation of the role of bioactive metals in regulating denitrification in cultured bacteria and permanently ice-covered Lake Bonney in the Taylor Valley of East Antarctica suggested that specific metals might be important in limiting bacterial growth in the lake and specifically in inhibiting denitrification. This year they will undertake new experiments to assess the viability and metabolic capabilities of the bacteria in Lake Bonney. Ag toxicity, general metal toxicity and oxygen concentration will be investigated for their effect on denitrification in Lake Bonney by using a suite of "sentinel" strains of denitrifying bacteria (isolated from the lake) incubated in Lake Bonney water and subjected to various treatments. The physiological responses of these strains to changes in metal and oxygen concentration will be quantified by flow cytometric detection of single cell probes whose sensitivity and interpretation has been optimized for the sentinel strains.