Spotlight on a Researcher – Abigail Renegar, Ph.D.

 Abigail Renegar, Ph.D. is a Research Scientist in the Department of Marine and Environmental Sciences in the Halmos College of Arts and Sciences at Nova Southeastern University (NSU). Dr. Renegar received her Bachelor of Science (B.S.) in Marine Biology and Aquaculture from Florida Institute of Technology in Melbourne, Florida. Following her B.S., she obtained her Master of Science and Ph.D. in Marine Biology from NSU. Subsequently she joined NSU in 2015 as a Research Scientist in the Department of Marine and Environmental Sciences. Currently, she serves as the Director of the Coral Histology Laboratory, the Marine Toxicology Laboratory, and the Onshore Coral Nursery/SEACOR Coral System located at the NSU Guy Harvey Oceanographic Research Center. Her research is primarily focused on the acute and chronic impacts of land-based sources of pollution and climate change on coral reefs.

Of all ocean environments, coral reefs are often regarded as the most vital; reef ecosystems support total ocean productivity by providing habitat and resources for many marine species. They also serve as a natural barrier that protects coastal communities from violent storms and waves and have significant economic value as they support fisheries and generate business associated with tourism and recreation. Unfortunately, reefs are also one of the most vulnerable ecosystems as they are threatened by climate change, ocean acidification, pollution, and habitat destruction. Evaluating the effects of current and emerging chemicals of environmental concern on scleractinian corals and other reef organisms is a key area of Dr. Renegar’s research.

One of the major classes of marine pollutants threatening coral reefs are petroleum hydrocarbons. Coral reefs are located in shallow coastal waters, and their proximity to shipping channels and coastal human activities make them highly vulnerable to oil spills. Currently, the impact of oil spills on coral reefs is not well understood because of variability in methods previously used to measure impact. This has resulted in knowledge gaps regarding preparedness and the ideal response to protect coral reefs in the case of an oil spill. To address this issue, Dr. Renegar’s lab is working to design a better mechanistic approach that can be implemented to evaluate the toxicity of crude oils and other complex substances to corals.

In two recent articles,  researchers from Dr. Renegar’s lab reported the toxic effects of petroleum hydrocarbons on multiple Atlantic coral species (https://www.sciencedirect.com/science/article/abs/pii/S0025326X21005944?via%3Dihub and https://www.nature.com/articles/s41598-020-80055-0 ). The findings published in these papers establish the lethal and sublethal thresholds of chemicals known to be present in oil spills (toluene, 1-methylnaphthalene and phenanthrene) for five coral species: Acropora cervicornis, Porites astreoides, Siderastrea siderea, Stephanocoenia intersepta, and Solenastrea bournoni. The assays designed and reported by Dr. Renegar’s lab to determine the time-dependent exposure toxicity of these representative hydrocarbons employs a quantitative modeling framework based on vulnerability assessment of single hydrocarbons and additivity concepts to predict the effect of oil spills on corals and coastal tropical environments. The method developed and implemented by Dr. Renegar will enable other researchers to assess the threat posed by these chemicals to coral reefs around the world and close the knowledge gap regarding impacts of oil spills on coral species. The data published in these two research articles facilitate a better understanding of the risks to coral from petroleum hydrocarbon exposure and enables more informed decision-making for protecting coral reefs and coastal ecosystems from oil spills.

In addition to conducting research to understand the effects of pollutants on coral reef ecosystems, Dr. Renegar also serves as one of the researchers leading the NSU Coral Nursery initiative. This initiative is aimed at taking measures to prevent coral die-offs and restore Florida’s coral reefs. NSU coral researchers have developed both on-shore and off-shore nurseries to grow corals, which are then out-planted to various reefs to help them rebound from the negative effects of coral diseases, marine pollutants, ocean acidification, and increasing ocean temperatures that have negatively impacted the reefs. Dr. Renegar along with her colleague and associate professor, Joana Figueiredo, Ph.D., oversee the propagation of key reef-building coral species through micro-fragmentation of coral. This method of asexually reproducing coral allows them to grow faster so they can be outplanted to the reef quicker, thus helping restoration of coral biomass.

Dr. Renegar’s research over more than a decade has produced multiple publications in peer-reviewed journals and presentations at national scientific conferences. The development of a comprehensive toxicity assay for scleractinian corals supports a better understanding of the effects of many chemical contaminants, including metals, insecticides, herbicides, industrial organic chemicals, antifouling chemicals, and others on coral reef ecosystems. This research, when combined with a targeted environmental testing program, will aid in the identification of regional contaminants of greatest concern based on the sub-lethal effects of chronic exposures and the potential interactive effects of various chemicals for coral. Dr. Renegar’s work at NSU supports informed management strategies targeted at reducing the impacts of chemical pollutants on coral reef ecosystems in the context of global climate change and provides new key information on the present and future status of reefs in the Anthropocene.