Chemical communication and
forces structuring marine communities

Dick Zimmer-Faust, Ph.D.
University of California, Los Angeles

Wednesday, January 21, 1998
3:30 p.m.—MBARI Pacific Forum

Chemical communication mediates a variety of critical ecological interactions. The sense of smell is important in locating mates, shelter, and food, although animals employ similar means to avoid being eaten by detecting and fleeing from predators. The study of chemical communication presents a formidable challenge. It demands simultaneous measurements of chemical release, fluid dynamics, and biological response to a chemical signal. For this reason, my laboratory is combining investigations on the chemistry and microscale transport of signal molecules that control animal navigation in turbulent odor plumes. Through field and laboratory studies, we are developing theory on chemical signals and their roles in mediating search behavior and ecological interactions. Because predator-prey interactions and habitat selection and colonization by larvae are among the most important forces structuring marine communities, we have chosen to concentrate our efforts in these areas.

Our research on predation has defined the hydraulic environment and constraints imposed by turbulence on chemical signal transmission and detection. The hydrodynamic properties whereby blue crab predators successfully track prey scents have been established for estuarine field habitats. We are currently working to isolate and purify the attractant(s) released from prey at shallow water and deep-sea sites, as well as to develop algorithms used by animals in tracking odor plumes in 2- and 3-dimensions. Our work with larvae is emphasizing patterns of colonization on the seafloor. We are particularly interested in the roles played by low-molecular-weight basic peptides in controlling larval settlement from the water column onto benthic substrata. By applying mathematical models to describe the physical chemistry of inductive compounds, we have established quantitative structure–activity relationships between environmental signal molecules and larval behavioral and developmental responses. Methods for selectively improving benthic substrates through controlled diffusional releases of synthetic peptide analogs recently have been developed and successfully employed in field habitats. This seminar will thus explore our research on the dynamics of environmental chemical signals and the importance of such cues in regulating behavioral and ecological processes.

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