Aquatic Sciences Meeting, Albuquerque 2001

SS15 Biomechanics: Making the Connection Between Physics and Biology at the Organismal Level (Disciplinary Connections)

Date: Wednesday, February 14, 2001, Time: 10:00:00 AM

Location: Mesilla

Graham, M, H, Center for Population Biology, University of California, Davis, CA, 95616, USA, mhgraham@ucdavis.edu

FLOW MODIFIES COUPLING BETWEEN ZOOSPORE PRODUCTION AND SUPPLY IN GIANT KELP

Propagule supply is fundamental in regulating the strength of demographic and genetic interactions in natural populations. I studied coupling between giant kelp (Macrocystis pyrifera) zoospore production and supply in a southern California kelp forest in 1999. Zoospores were quantified from sea water collected in the forest interior at intervals spanning minutes to months. Temporal variability in zoospore concentration was random and relatively constant at intervals < 24 hr, but highly structured at longer time scales with large fluctuations reflecting changes in adult reproductive condition. This tight coupling between the production and supply of zoospores was due to a lack of strong currents in the forest interior; drag of adult plants dampened flow keeping zoospores close to their release sites. Coupling was validated at two additional interior sites. Lower plant densities along the forest edges, however, resulted in rapid uni-directional flows likely transporting zoospores far from adults. Here, sampling indicated that zoospore supply was de-coupled from local zoospore production. These results indicate that the importance of local reproductive output to zoospore supply is scale-dependent, driven largely by flow modification of adults.

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Aquatic Sciences Meeting, Albuquerque 2001

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