|Teaching & Research
Benthic marine ecology, marine biology, invertebrate fisheries, aquaculture, subtidal ecosystems.
esearch in my laboratory is directed towards understanding the biological interactions and physical processes that determine the structure and dynamics of benthic marine populations and communities. The work addresses fundamental issues in theoretical ecology as well as applied aspects of invertebrate fisheries and aquaculture. A major area of research has been the study of the rocky subtidal ecosystem off Nova Scotia, which alternates between two community states, kelp beds and coralline barrens, depending upon the abundance of grazing sea urchins. Using observational and experimental approaches, my students and I examine processes that regulate the dynamics of urchin populations, such as reproduction and spawning, larval dispersal and settlement, predation and disease. Many of these studies have direct application for the sea urchin fisheries and aquaculture. In recent years, we have witnessed a massive disruption of this ecosystem by two "alien" species. The first, an encrusting bryozoan (Membranipora membranacea), has defoliated kelp beds and thus facilitated the spread of the second alien, an invasive green alga (Codium fragile).
Our research is currently focussed on interactions between these aliens and the native community, and on the impact of these invasions on the structure and function of the coastal ecosystem.
We have also worked extensively on the wave-swept rocky shores, investigating physical and biological processes that determine the distribution and abundance of intertidal organisms. In particular, we are interested in the effects of recruitment variability, predation and wave disturbance on patch dynamics and intertidal community organization. Most recently, we have concentrated on the ecology of Codium, which is invading intertidal and shallow subtidal habitats with equal rapacity. I periodically water my roots in tropical marine ecology through various studies in the Caribbean, Australia, East Africa, and the Galapagos. For example, I have recently revisited the subject of my PhD research (a Caribbean seastar named Oreaster) in a project aimed at understanding the impact of declining population size on the reproductive potential of free-spawning marine invertebrates.