Coral reefs are the most intensely grazed ecosystems in the world. For example, in some coral reefs, over 90% of the daily algal primary production is consumed by herbivorous fishes, urchins, and other invertebrates. To cope with grazing pressure and the wide variety of coral reef herbivores, marine algae and cyanobacteria have evolved diverse strategies and adaptations that enable them to tolerate or avoid herbivory. Among these adaptations, the production of chemicals that are noxious or distasteful to herbivores has been well documented in tropical seaweeds. These chemically-defended algae, in turn, provide refuge (“enemy-free space”) to small invertebrates that suffer high losses from predation.
While the complexity of these multitrophic interactions has been well studied in marine algae, less is known about such phenomena for marine benthic cyanobacteria. In many coral reefs, large filamentous benthic cyanobacteria are normal components of the community, occurring in densities similar to those of algae or sessile invertebrates.
In this talk, I will address the complexity of cyanobacterial-grazer interactions and draw parallels between the ecologies of benthic cyanobacteria and eukaryotic algae. In particular, I will focus on the production of cyanobacterial secondary metabolites and their role as feeding deterrents. The ecology of marine plant-herbivore interactions has direct and indirect consequences for a number of human health issues. As one example, I will discuss how algal/cyanobacterial antiherbivore strategies influence the flux and bioaccumulation of ciguatoxins. These compounds, produced by a benthic epiphytic dinoflagellate, are responsible for the onset of ciguatera seafood poisoning in humans.
The chemical diversity of marine algae and cyanobacteria has prompted great interest from the standpoint of drug discovery and a number of cyanobacterial or algal compounds are at different stages of development as potential anticancer drugs. Improved knowledge of marine plant-herbivore interactions can be used to focus human exploration of potentially useful marine natural products.
Presenter:
Dr. Edwin Cruz-Rivera
Assistant Professor/Director, Marine Sciences Program
Department of Biology, Jackson State University
Friday
July 20, 2007
11:00 a.m.
Pacific Ocean Science and Technology Building (POST) 723
Refreshments will be served after the seminar in POST 121
The Pacific Research Center for Marine Biomedicine (PRCMB) is a newly established center at the University of Hawaii dedicated to trans-disciplinary research designed to gain new knowledge about the profound impacts of the ocean on human health. The Center is funded by the National Science Foundation and the National Institute of Environmental Health Sciences.
BACK