Kuznetsova, M. State University of New York, mkuznetsova@ccmail.sunysb.edu
Lee, C. State University of New York, cindylee@notes.cc.mail.sunysb.edu

For marine biota the thin microlayer of water at the air-sea interface represents a unique physico-chemical habitat. We used a recently developed approach for studying extracellular peptide hydrolysis to measure hydrolysis in the surface microlayer over a year. Peptide decomposition was always faster in surface microlayers than in waters a few cm below the surface. Distribution of hydrolytic activity between the surface and underlying water varied greatly seasonally. While rates of peptide hydrolysis were generally higher in both microlayer and bulk water samples in spring/summer than in fall/ winter, the gradient in activity with depth was greatest in winter. We found no direct correlation between numbers of bacteria in the microlayer and enhancement in peptide decomposition rates. The increase in specific (per cell) hydrolytic activity in the surface microlayer relative to subsurface water is more likely related to the accumulation of dissolved matter at the air-sea interface, which is controlled by dynamic physical processes at the boundary between these two differing and interacting environments. Subsurface water samples rapidly formed a new surface microlayer, which again exhibited faster peptide hydrolysis than underlying water. This is probably due to stripping of DOC from the bulk water during formation of the new microlayer.
Day: Thursday, Feb. 4
Time: Poster
Location: Sweeney Center
Code: SS04TH1400S