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This research group focuses on the ecology and physiology of benthic algae and seagrasses under environmental change through the following research themes:
Coupling between land and sea
Eutrophication is an increasingly widespread ecological problem, taking place at global, national, and local spatial scales. The impacts of eutrophication are seen in worsening water quality, impaired water uses, algal blooms, loss of seagrasses, and threats to important fish stocks and resources. Stable isotopic methods are useful to detect sources of anthropogenic nutrients entering coastal waters. Our group is interested in assessing which types of primary producers are better indicators of eutrophication for different ecosystems, what are the differences in isotopic signatures between nutrient sources and sinks, and how are isotopic signatures linked to shifts in food web structure.
Top-down and bottom-up controls of benthic communities
Seagrass, algal, and coral communities are naturally controlled by top-down and bottom-up forces, such as grazing and nutrients or light. Because macroalgae often occupy the same space as both seagrasses and corals, changes in top-down and bottom-up controls may directly or indirectly affect their relative abundance and increase competitive interactions among these different groups of organisms. We examine the relative importance of top-down and bottom-up controls on benthic primary producer communities by monitoring changes in community composition along environmental gradients and by using in situ nutrient enrichment and grazer exclusion experiments.
Physiological responses of algae and seagrasses to environmental change
Coastal waters are experiencing both global and local changes that influence their chemical, biological, and physical environments. Increasing CO2 emissions to the atmosphere are expected to result in acidification and temperature increases of coastal waters. Local increases in anthropogenic nutrient inputs and sedimentation are also changing the water quality. Through both laboratory and field studies, we examine physiological responses of seagrasses and macroalgae to abiotic stressors to determine their tolerance limits and to predict their competitive success in changing environments.
Nutrient uptake mechanisms
Seagrasses and algae have quite different nutrient uptake strategies, storage capacity, and metabolism due to differences in their morphology (vascular/nonvascular). Through laboratory and field nutrient enrichment experiments we assess nutrient uptake, storage, and assimilation and measure responses including nutrient uptake rates, growth, tissue nutrient content, stable isotopes, and enzyme activity associated with nutrient assimilation. Comparative studies on nutrient uptake among groups of marine plants and algae and their capacity to remove excess nutrient loads from coastal waters and in aquaculture facilities are investigated.