Aquatic Sciences Meeting, Albuquerque 2001

CS39 Trace Metal Limitation of Biogeochemistry

Date: Tuesday, February 13, 2001, Time: 10:30:00 AM

Location: Dona Ana

Ward, B, B, Princeton University, Princeton, NJ, USA, bbw@princeton.edu

Granger, J, , Princeton University, Princeton, NJ, USA, jgranger@princeton.edu

Wells, M, L, University of Maine, Orono, ME, USA, mlwells@maine.edu

Maldonado, M, T, University of Maine, Orono, ME, USA, maria.maldonado@maine.edu

DENITRIFICATION IN AN ANTARCTIC LAKE: A ROLE FOR TRACE METAL REGULATION?

Lake Bonney, a permanently ice-covered lake in Taylor Valley, East Antarctica, is a natural experiment designed to investigate regulation of denitrification in natural environments. The absence of nitrate in the west lobe of the lake, and its anomalous accumulation (over 150 µM) in the east lobe in strongly suboxic conditions, imply that denitrification occurs in the west lobe, but not in the east. Previous work in Lake Bonney has all but ruled out control by the usual variables, such as oxygen, organic carbon and nitrate. In order to investigate whether trace metal concentrations could play a role, we measured denitrification under trace metal clean conditions in complete depth profiles in both lobes of the lake. A normal depth distribution of denitrification was detected in the west lobe, but none in the east. Total dissolved metal concentrations, measured by ICP-MS, were very high, and imply that toxicity, rather than metal limitation, may be a factor in controlling biological activity in the lake. Manipulation experiments indicate that chelator additions may stimulate activity.

This Session Listing

Aquatic Sciences Meeting, Albuquerque 2001

Quicklinks