Aquatic Sciences Meeting, Albuquerque 2001

SS06 Carbon Fluxes at Ocean and Large Lake Margins (Environmental Connections)

Date: Friday, February 16, 2001, Time: 10:15:00 AM

Location: Cochiti/Taos

Verdugo, P, , University of Washington, Seattle, USA, verdugo@u.washington.edu

Orellana, M, V, University of Washington, Seattle, USA, morellan@u.washington.edu

Chin, W, C, John Hopkins University, Baltimore, USA, wcchin@worldnet.att.net

CONCENTRATION OF DOM-ASSEMBLED MARINE MICROGELS (DOM-AG) IN THE PUGET SOUND SEAWATER USING FLOW CYTOMETRY.

Notwithstanding their critical significance in global carbon cycling (1), DOM assembly has only been studied in the laboratory, under diffusional regimes (2). The existence of DOM-AG in native seawater, where DOM polymer assembly results from both diffusional and conventional regimes, has not been investigated. Here we show that DOM-AG similar to those spontaneously assembled in the laboratory are present in 10 um-filtered native seawater. DOM-AG bind Ca and are stabilized by Ca bonds (2). We designed experiments to label particles in native filtered seawater with tetracycline-HCl, a fluorescent probe for bound Ca. Labeled particles were counted and sorted using flow cytometry. They were then resuspended in seawater containing 10 mM EDTA or tested for polymer gel phase transition at pH 4.5. Only fluorescent particles that dispersed following Ca chelation or those that underwent phase transition at low pH were counted as DOM-AG. These preliminary results indicate that DOM-AG can indeed be found in native seawater. Preliminary budgets of DOM-AG in Puget Sound vary from 6.6 ex4 /ml in 6 um-filtered samples to 2 ex5 / ml in 10 um-filtered samples. Supported by NSF grants from the Polar and Biocomplexity Programs to PV. Wells, M. L. Nature 391, 530-531 (1998). Chin, W-C., M. V. Orellana, & P. Verdugo. Nature 391, 568-572 (1998).

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Aquatic Sciences Meeting, Albuquerque 2001

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