Aquatic Sciences Meeting, Albuquerque 2001

SS19 Revisiting Redfield: C:N:P Stoichiometry in Aquatic Ecosystems (Disciplinary Connections)

Date: Tuesday, February 13, 2001, Time: 11:15:00 AM

Location: Acoma/Zuni/Tesuque

Passow, U, , Alfred Wegener Institut, Bremerhaven, Germany, upassow@awi-bremerhaven.de

Engel, A, , Institut für Meereskunde, Kiel, Germany, aengel@ifm.uni-kiel.de

THE ROLE OF TRANSPARENT EXOPOLYMER PARTICLES (TEP) IN DETERMINING C:N RATIOS OF PARTICULATE MATTER

Particulate organic matter which displays a fairly constant C:N ratio (Redfield ratio) consists of different particle types, including organisms, detritus and transparent exopolymer particles (TEP). Whereas the C:N-ratio of cells frequently lies below Redfield, the C:N ratio of TEP, which are formed abiotically from exuded polysaccharides is higher. The mean molar C:N ratios of TEP derived from cultures and natural diatom populations grown under different conditions exhibited a mean value of 26. This is considered a low estimate, as the nitrogen fraction can be explained through adsorption of amino acids onto TEP. The TEP-derived carbon concentration was calculated in 6 marine environments, based on the derived relationship between carbon and TEP. The contribution of TEP-carbon to the total carbon pool was large, in some cases as high as the POC contribution. TEP are also an essential component of marine snow and contribute appreciably to carbon flux. Because TEP are enriched in carbon over nitrogen, an increase in the formation rate of TEP due to global warming would provide a pathway for the sequestration of excess carbon to the deeper water column.

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Aquatic Sciences Meeting, Albuquerque 2001

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