Aquatic Sciences Meeting, Albuquerque 2001

CS25 Organic Carbon Dynamics

Date: Wednesday, February 14, 2001, Time: 2:45:00 PM

Location: Acoma/Zuni/Tesuque

Perez, M, T, NIOZ, Texel, Netherlands, maite@nioz.nl

Pausz, , C, NIOZ, Texel, Netherlands, clemens@nioz.nl

Herndl, G, J, NIOZ, Texel, Netherlands, herndl@nioz.nl

INFLUENCE OF FLAGELLATE GRAZING ON THE PRODUCTION AND UTILIZATION OF BACTERIOPLANKTON-DERIVED AMINO ACIDS

The only significant source of D-amino acids in the sea is the cell wall of bacterioplankton. To determine the release rates of enantiomeric amino acids from bacterioplankton, laboratory experiments were performed to assess the role of flagellate grazing on bacteria in producing cell wall derived dissolved amino acids and their subsequent utilization by bacteria. The concentrations of D-amino acids derived from the bacterial cell wall increased over time in seawater cultures with natural communities of flagellates and bacteria. In contrast, in the control cultures containing only bacterioplankton, the concentrations of D-amino acids remained close to the initial levels throughout the experiments. D- and L-amino acid uptake measurements indicated that the bacterial community is able to adapt to use D-enantiomers as efficiently as L-amino acids. Molecular size fractionation of DOM collected from the North Sea showed that most of the bacterial-derived amino acids are found in the HMW fraction (> 1 kDa). These experiments indicate that flagellate grazing is an important mechanism to produce cell wall derived DOM and that a specific bacterioplankton community is adapted to utilize this bacterioplankton-derived DOM.

Return to This Session's Schedule · Complete Session Listing ·

Aquatic Sciences Meeting, Albuquerque 2001

Quicklinks