Hi, I’m Corinne Renshaw, a 2023 Hollings scholar. I spent my summer internship with the Ocean Acidification Program taking a close look at 13 years of data from a coral reef in Florida.
January 2023 marked the beginning of the world’s fourth known global coral bleaching event. NOAA expects the event to be the greatest worldwide mass coral reef bleaching event since reports of coral bleaching began at the end of the 20th century. In summer 2023, the Florida Keys Reef Tract suffered a marine heatwave and severe coral bleaching, followed by mass mortality rates about three times greater than any previous bleaching event. During my Hollings internship, I found evidence that even a generally resilient reef of the Florida Reef Tract may be experiencing stress due to high temperatures and ocean acidification.
Hollings scholar Corinne Renshaw presenting her internship work at the 2024 Education and Science Symposium in Silver Spring, Maryland. (Image credit: Kara Murphy)
Ongoing research about the 2023 event
Though the exact factors that brought about this 2023 mass bleaching event are still inconclusive, the 2023 marine heatwave is a large factor. Coral ecologists at the Atlantic Oceanographic and Meteorological Laboratory (AOML) in Key Biscayne, Florida, are studying the response of various coral species to high water temperature and low pH. Coral species that are more sensitive to high sea surface temperatures, such as staghorn coral (Acropora cervicornis), have not recovered following the 2023 event.
Recent research by Chris Langdon, Ph.D., suggests that species resilient to temperature changes may be more susceptible to ocean acidification and vice versa. This is why the goal of my Hollings internship was to measure long term temperature and ocean acidification at Cheeca Rocks in the Florida Keys Reef Tract and examine how coral bleaching stress during 2023 may have impacted the reef since.
My internship project
With mentorship by Ana Palacio, Ph.D., and Ian Enochs, Ph.D., and the efforts of talented scientists within the Ocean Acidification Program (OAP), I consolidated and interpreted 13 years of data trends from a Moored Autonomous Buoy at Cheeca Rocks. I analyzed the data in Python using a model offsite link developed by Adrienne Sutton, Ph.D.
I discovered that although Cheeca Rocks is a resilient reef, its temperature and carbon dioxide concentrations had significantly increased over time. This means that both temperature and ocean acidification were creating worse conditions for coral. Looking at the 2023 data, high summer sea surface temperatures correlated with higher CO2 concentrations through the fall. This may be an indication of coral stress following intense summer heat waves. I presented these conclusions at the Office of Education’s Science and Education Symposium and highlighted the AOML’s ongoing laboratory and field experiments that target this issue.
Other experiences during my internship
In between coding, I had the opportunity to be involved with ocean acidification research in the Coral Reef Ecosystems Lab. Featured below is a new system that instantaneously monitors the pH and dissolved oxygen levels within a tank, which are used to configure other water chemistry parameters. A similar measuring system was also deployed at Cheeca Rocks throughout the summer, which I had the chance to observe. Overall, my experience with AOML has taught me a wealth of information about coastal ecosystems in the light of climate change. The knowledge and passion of AOML scientists has given me hope for a future with resilient coral reefs.
Corinne Renshaw, 2023 Hollings scholar
Corinne is a class of 2023 Hollings scholar and Marine Environmental Science major at Nova Southeastern University.
