Control of reproduction in benthic marine invertebrates

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Reproductive success in marine invertebrates depends on the synchronization of gamete synthesis and spawning. Mechanisms through which this is achieved involve a number of steps, including perception of environmental cues and interactions via chemical signals. My research has been aimed at determining the roles played by exogenous and endogenous factors in the reproductive success of boreal and tropical species. Initial work with sea cucumbers has revealed that inter-individual chemical communication acts together with environmental factors to ensure synchronous gametogenesis and mass-spawning and that perivisceral coelomic fluid becomes bioactive during spawning events. We also found that many echinoderms and molluscs display lunar and circadian rhythms of aggregation and reproduction. Due to a recent breakthrough in the holding of deep-sea invertebrates, a new segment of my work focuses on the factors underlying reproduction in bathyal species, which are presumably exposed to limited environmental fluctuations, yet may still exhibit seasonal breeding cycles. The short term goals of the present research program are to: 1) find evidence of chemical communication in other marine invertebrates using the techniques developed for sea cucumbers; 2) compare the importance of environmental and chemical cues in the reproductive processes of species from various depths with different breeding periodicities; 3) investigate the level of reproductive synchrony in deep-sea species and elucidate the factors involved in ensuring it; 4) refine knowledge of the bioactive properties of body components over the reproductive cycle using multilevel analyses and bioassays; and 5) investigate the concept of "sentinel" individuals (believed to be more receptive to environmental cues, and to use chemical signals to relay those to conspecifics). The long term goals are to clarify the respective roles played by external factors and interspecific exchanges and investigate how the former can perhaps be translocated via the latter. Better knowledge of biological rhythms and chemical communication in benthic animals could help devise new aquaculture techniques and improved ways to protect marine habitats from environmental disturbances.