Ocean Acidification (OA): Increasing concentrations of carbon dioxide from human activities are having large effects on the chemistry of the oceans. Increasing CO2 and decreasing pH are making it more costly for marine organisms to build shells. We are investigating the impacts of OA on the growt...
Ocean Acidification (OA): Increasing concentrations of carbon dioxide from human activities are having large effects on the chemistry of the oceans. Increasing CO2 and decreasing pH are making it more costly for marine organisms to build shells. We are investigating the impacts of OA on the growth of several species, including sea urchins, sea stars, abalone (larvae and adults), barnacles, and mussels. Our goals are to understand how changes in growth will result in changes in population dynamics and community structure.
Thermal Stress and Global Warming: Intertidal organisms already live very close to their thermal tolerance limits, which means that even small changes in temperature can have important impacts on intertidal communities. We are using observational and manipulative techniques in the field to determine how different species respond to stress, and how rising temperatures will change interspecific interactions such as competition, predation, facilitation, and disease.
Climate change and salinity stress: The Strait of Georgia is strongly influenced by outflow from the Fraser River. Fraser River flow, and thus local salinity, change from year to year and over longer scales with warming and shifts in precipitation. We are studying the impacts of these changes on predation by the keystone predator Pisaster, and predicting how future increases in salinity will influence mussel bed communities.
Long-term ecological change: Documenting historical ecological change in response to climate forcing is challenging due to the scarcity of data. We are now using available historical datasets to examine the effects of warming, salinity change, and sea level change on zonation patterns on rocky shores. We also take advantage of organisms like turban snails that record their own growth history in the form of annual growth bands.
The return of the sea otter in British Columbia: After being hunted to local extinction, sea otters have been reintroduced to Vancouver Island, where their populations are expanding. We are examining the impacts of sea otters on the ecosystem in terms of the trophic cascade that facilitates kelp beds, and the importance of both otter predation and kelp production on ecologically and economically important invertebrates.