Ecology of coastal benthic communities in a changing ocean

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Human impacts including climate change are negatively affecting marine ecosystems in Canada and around the world. The long-term objective of my research program is to increase our understanding of the patterns of distribution and abundance of bottom-dwelling invertebrates in coastal marine ecosystems and the processes underlying them, including human impacts. This research program builds on my previous research on the ecology and biodiversity of coastal ecosystems. The short-term objectives over the next 5 years focus on increasing our understanding of the influence of ocean acidification and warming in these ecosystems. Anthropogenic emissions of CO2 have resulted in increased ocean temperature and ocean acidification (increased CO2 and decreased pH and carbonate saturation), and these impacts are projected to increase in the future. Understanding the effects of climate change in coastal waters is complicated by the large amount of natural variability in seawater pH and temperature in coastal systems. In addition, organisms living within sediment are exposed to more acidic conditions due to microbial decomposition, resulting in present-day carbonate saturation states in sediment low enough to dissolve bivalve shells. The proposed research will use a combination of lab and field experiments to test the effects of increased CO2 and decreased pH in seawater and in the sediment on communities of sediment-dwelling invertebrates, including commercially harvested clams. We will also examine whether marine species in the Maritimes are shifting the latitude at which they live and moving northwards in response to increasing seawater temperature. Finally, we will use pH and temperature data to develop models of habitat suitability for two commercially and ecologically important species, the soft shell clam and the American lobster, which will aid in assessing their vulnerability to the effects of climate change. The Canadian Maritimes are an important region to address these questions since the Gulf of Maine/Bay of Fundy is a hotspot for ocean warming. This research will be carried out by graduate and undergraduate students, providing training for PhD, MSc, and honours students at UNB. The proposed research will enhance our understanding of the effects of climate change on shallow coastal marine ecosystems, which are extremely productive and important to the coastal economy in Canada. This research will provide information valuable for management of coastal ecosystems in Canada in terms of conservation of ecosystems and assessment of vulnerability of commercially harvested species to climate change.