Charlotte Steeves

McGill University
M.Sc. candidate

Supervisor: Brian Leung
Hector Guzman, Smithsonian Tropical Research Institute
Start: 2019-09-03
End: 2021-12-17


Examining exposure to persistent organic pollutants in developing Brown and Blue-Footed Booby chicks: A minimally-invasive field approach
Marine plastic pollution and plastic-associated organic pollutants are considered ubiquitous throughout the world’s oceans. Exposure to hydrophobic organic pollutants via dietary sources is cited as one of the leading global threats to migratory seabirds. Isla Bona, located within the nutrient-rich Gulf of Panama, hosts over 50,000 migratory nesting seabirds annually, making it a particularly vulnerable region to plastic-associated pollution. Prior studies have suggested that exposure to such toxins can have adverse effects on seabird development and health over time. However, the majority of field methods involve invasive procedures that cause stress and harm to individuals, generating a pressing need to implement minimally-invasive field tests to document exposure to organic pollutants in seabirds. In recent literature, preen oil and feathers have been used to examine exposure to organic pollutants in seabirds. However, this field method is relatively novel and few studies have focused on the exposure to hydrophobic organic pollutants during the early developmental (pre-fledging) stage of seabird chicks, with even fewer studies focused within the neotropics. Exposure to organic pollutants will be examined in pre-fledged chicks of brown and blue footed boobies (Sula leucogaster and Sula nebouxii) on Isla Bona. We will extract preen-oil samples and feathers from chicks on nesting sites to test for exposure to organic pollutants using minimally-invasive swabbing and feather collection methods. Samples will be processed using GC-MS analysis (Gas Chromatography Mass Spectrometry) or FT-IR (Fourier-Transform Infrared Spectroscopy) to quantify concentrations and identify individual congeners of polychlorinated bisphenols and other organic compounds present within the samples. We will model two possible pathways of exposure to organic pollutants via dietary sources and embryotic exposure in pre-fledged chicks by testing regurgitation and egg samples respectively. Our three main objectives are listed below: 1. Explore the effectiveness of minimally-invasive field methods to determine exposure to organic pollutants in pre-fledged Brown and Blue-Footed Booby chicks through preen oil and feather samples. 2. Quantify levels of organic pollutants and distinguish between congener profiles from preen oil secretions, feathers, eggs, and regurgitation samples in pre-fledged chicks. 3. Model two potential pathways of exposure to organic pollutants during the developmental stages from hatching to fledging through estimations of bioenergetics and toxicokinetics unique to developing pelagic seabirds.


seabirds, microplastics, ecotoxicology, seabird energetics, marine conservation, organic pollutants, PCB, panama, neotropics, Gulf of Panama