Project abstract
Reef sharks are essential to ecosystem health. However, they are facing a drastic global decline driven by industrial fishing. Current conservation goals are largely based on studies of shark populations already threatened by human presence, hindering our understanding of shark population decline and the urgency of shark community recovery. The fossil record can provide missing historical context to reconstruct more accurate baselines, understand population changes across time, and aid future management decisions. In Panama, fossil shark scales (dermal denticles) from sediment cores have been used to quantify the relative abundance of sharks before major human impact, particularly in the Caribbean basin. Our project will apply this new paleoecological proxy in the Panamanian Pacific to reconstruct shifts in shark abundance and community structure over the last ~6000 years. We will focus on sediment cores collected from two sites (Isla Iguana and Isla Contadora) in the Gulf of Panama, a dynamic region marked by seasonal upwelling. Using a purpose-built in-house reference collection, the intern will classify fossil denticles into established functional groups, which correspond with different ecological groups of sharks. Additionally, they will measure the fossil denticles to track variation in denticle morphology—and associated ecological traits—through time across key transitions in human impact and environmental change. A downcore analysis of the relative abundance of each functional group will reflect how shark communities have changed over time and highlight whether human pressures have fundamentally affected community composition in the Pacific.
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. 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
