Project abstract
Climate change poses a serious threat to the persistence of coral reefs and the predators like sharks that call them home. However, the relationship between reef health and shark abundances remain uncertain, and we know little about how it might change under future projected climate change. This is particularly true in marginal reef environments like the Tropical Eastern Pacific, which experience large climate variability due to seasonal upwelling and ENSO (El Niño–Southern Oscillation).
Our project leverages a past climatic episode in the Gulf of Panama—an ENSO-driven shutdown of reef accretion and loss of coral habitat—to investigate how reef-associated sharks respond to reef degradation following climate stress. The reef shutdown, which lasted over 2,500 years (4.2–1.5ka), has been well-documented through estimates of reef accretion rates and analyses of coral community composition in reef matrix cores collected throughout the region. It represents an analogue for future conditions.
To explore the consequences for sharks, this project will employ a novel paleoecological approach using fossil shark scales (dermal denticles) as a proxy for shark abundance and community structure. The intern will measure the accumulation of dermal denticles in reef matrix cores from several sites across the Gulf of Panama, which experience different intensities of upwelling, to reconstruct shark abundances before, during, and after the reef collapse. They will also classify denticles into different morphotypes using an in-house reference collection to track changes in the functional composition of shark communities through time across this event. Outputs from this project aim to predict how different ecological groups of sharks will respond to similar episodes of climate-driven reef degradation in the future, extending the timescales over which we can study climate impacts on shark communities.
Skills required
Interns will assist with sampling and processing coral reef matrix cores to isolate tiny fossilized shark dermal denticles. This work involves sieving and weighing sediment samples, treating samples with acetic acid, and sorting through sediment grains under a microscope to recover dermal denticles and other microfossils, which requires patience and organization. Interns will also photograph and measure dermal denticles under a microscope. The internship could result in deliverables such as a scientific poster, conference talk, and/or contribution to a peer-reviewed article, in addition to the completed thesis. Interns will take part in sharing their research with the public through lab tours and other outreach activities.
Minimum qualifications: previous experience in processing paleontological samples and analysing microfossils; previous experience with microscopy; knowledge of statistical methods and experience in programming languages such at R; ability to work independently and with groups of people from diverse backgrounds; attention to detail; and commitment to science communication and public outreach.
Mentor name: Aaron O’Dea
Link to lab page: https://odealab.com/
Co-mentor(s): Erin Dillon
Location of internship: Naos Marine Laboratory
