Aquatic Sciences Meeting, Albuquerque 2001

PC16 Microbial Dynamics

Date: Thursday, February 15, 2001

Location: Southwest Hall

Kuznetsova, M, R, SUNY, Stony Brook, USA, marina.kuznetsova@sunysb.edu

Lee, C, , SUNY, Stony Brook, USA, cindy.lee@sunysb.edu

BIOLOGICAL CONTROL ON DFAA AND DCAA CONCENTRATIONS IN NEARSHORE SEA SURFACE MICROLAYERS

We analyzed dissolved free (DFAA) and combined (DCAA) amino acids in over 50 samples of microlayer (ML) and corresponding subsurface water (SS, 10 cm depth) in Long Island Sound, NY, and in the Caribbean Sea near the Venezuelan coast. ML enrichment varied significantly, from 1 to 50 for DFAA, and from 1.2 to 5.0 for DCAA. Much higher DFAA/DCAA ratios in the ML than in SS were common for nearshore microlayers. Rates of extracellular hydrolysis of peptides are higher in the ML than SS, so extracellular hydrolysis of naturally occurring DCAA to DFAA by microlayer biota is one of the most likely ways to explain higher DFAA/DCAA in ML samples. ML samples were incubated, and the fate of naturally occurring DCAA and DFAA followed. We did not observe any significant increase in the DFAA concentration as the DCAA was being consumed. Continuous input of proteinaceous matter from bulk water to ML was simulated by addition of BSA or Rubisco at different time points. DFAA concentrations still did not increase, suggesting that hydrolysis was tightly coupled with the product uptake.

This Session Listing

Aquatic Sciences Meeting, Albuquerque 2001

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