Aquatic Sciences Meeting, Albuquerque 2001

CS20 Microbial Dynamics

Date: Friday, February 16, 2001, Time: 10:30:00 AM

Location: Ruidoso/Pecos

Wilhelm, S, W, The University of Tennessee, Knoxville, USA, wilhelm@utk.edu

Poorvin, L, , The University of Tennessee, Knoxville, USA, lpoorvin@utk.edu

Hutchins, D, A, The University of Delaware, Lewes, USA, dahutch@udel.edu

VIRAL REGENERATION OF BIOAVAILABLE IRON IN THE COASTAL CALIFORNIAN UPWELLING

Recent studies demonstrate that iron availability limits primary production in upwelling zones along the California coast where total iron concentrations dip below 0.5 nM during periods of relaxation. As part of studies examining the impact of iron on the planktonic communities in this region, we examined the role of viruses as recycling agents of bioavailable iron. Natural communities of plankton were isotopically labeled with 55Fe, then rinsed with a titanium-citrate-EDTA wash to remove surface-associated iron. These cells, now containing only intracellular 55Fe, were resuspended into whole seawater. Virus-host contact rates in samples were subsequently increased 10-13 fold, and lytic activity allowed to proceed for 48h. Incubations were terminated by size fractionation and iron retained in the different size classes determined. The results demonstrate that an enhancement of the abundance of infectious viral particles increased iron retention by ca. 150 - 200% in the larger size classes, seemingly through a recycling of organically complexed iron to the phytoplankton community. This information has been used to generate a model for the recycling of iron through marine biota that includes both viruses and grazers.

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Aquatic Sciences Meeting, Albuquerque 2001

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