Fingerprinting the Impacts of Environmental Change within Coral Reef Ecosystems

Coral reef ecosystems are known to be in a global state of decline, largely attributed to sea-surface warming, ocean acidification, pollution, disease, and other direct human contributions. The impending transition away from calcium carbonate (CaCO3) substrates to macroalgae dominance within these environments could translate to major losses in marine biodiversity, erosion of protective coastal barriers, stress on major fisheries, and numerous other sociocultural and economic impacts. 

My research combines discrete and autonomous measurements of carbonate chemistry, trace metal, and carbon isotope variability within coral reef environments, quantitative decomposition models of biogeochemical fluxes within reefs, and high-resolution mass spectrometry to investigate various geochemical proxies as fingerprints of stress-induced changes in reef metabolism and community composition. 

Specifically, I will report on (1) the limitations of assuming canonical metabolic closing of carbon and oxygen budgets on reefs, (2) temporal variability in the seawater Sr/Ca ratio on reefs as an indicator of calcifier community composition, and (3) variability in the δ13C value of seawater dissolved inorganic carbon (DIC) on reefs as a proxy for benthic primary producer community composition. 

The ultimate goal of this work is to construct a sophisticated and quantitative toolkit for detecting and monitoring trophic transitions within reefs around the world.