Coral reefs are iconic ecosystems throughout the planet’s tropical belt, including Florida, the Gulf of Mexico, and the Caribbean Sea. They are valuable for their intrinsic beauty, economic and tourist value, as incubators for fisheries, and for the physical protection they provide the land against the oceans. Coral reefs are also one of the world’s most threatened resources due to a variety of environmental stressors. From the perspective of Oil Spill Preparedness and Response (OSPR), coral reefs, with particular focus on the impacts on the coral animal itself, represent one of the highest valued natural resources for protection in Net Environmental Benefit Analysis (NEBA) of response methods and environmental damage. Previous research evaluating hydrocarbon toxicity to corals and coral reefs has generally focused on community-level effects (relatively little is known at the individual and cellular level) and results are often not comparable between studies due to variability in hydrocarbon exposure characterization and evaluation of coral health/mortality during exposure. Overall, this represents an important knowledge gap in oil spill preparedness and response as it relates to the potential impact of oil spills on coral reefs.
Ongoing research by this laboratory has sought to fill the data gap in hydrocarbon toxicity to corals through development and application of a standardized toxicity testing protocol using single hydrocarbons, which considers coral response at multiple levels of resolution and is applicable to many coral species and test scenarios. This research was developed with input from research partners in government and the response community in order to design study outputs that would integrate with existing toxicity models and emerging 3D plume models to better inform response decision-makers on the potential impact of transported spilled oil or dispersed oil on coral reefs. Thus far, this study has demonstrated significant lethal and sublethal impacts of single hydrocarbons to one species of shallow-water scleractinian coral.
The central objective of the proposed project is to expand on this existing work by including four additional important species of Atlantic scleractinian corals. Single hydrocarbon testing promotes determination of a critical body burden (CBB) using the target lipid model. The CBB can be used to compare species sensitivity, as well as to predict the toxicity of other hydrocarbons. The results of this work will guide subsequent experimentation utilizing oil water accommodated fraction (WAF), and chemically enhanced water accommodated fractions (CEWAF). A central goal of these experiments is to address the lack of knowledge which exists regarding environmental effects of the petroleum/dispersant system on scleractinian corals, which are key coastal organisms (Theme 3). This new information will allow determination of thresholds of acceptable/unacceptable impact, and prediction of impact severity and choice of treatment based on expected impact. The sum of experimental results, when integrated into existing/emerging response support tools, will provide input to managers for the visualization, prediction, and understanding of oil impacts on key organisms and specific habitats, significantly improving response. This applied science approach to a practical issue allows improvement in decision-frameworks for reaction, response and mitigation should an oil spill potentially impact coral reefs (Theme 4).