penguins and fish, and ultimately, killer whales, seals and humans. Since penguins are significantly high up in the food web, the element is magnified and highly concentrated once it enters their bodies. Brasso explains that because mercury binds to proteins, researchers can use eggshells and feathers (with high protein content) to monitor mercury levels in the penguins.
birds. Their box design, which incorporates a square piece of sheet metal, a drinking straw, a piece of duct tape and a monofilament line was published in the Journal of Field Ornithology in 2008, and recognized for its nearly invisible trap door able to trick even the wariest birds. Once the birds were captured, blood and feather samples were taken and tested for mercury contamination.
Long periods of mercury exposure are damaging to a bird: it is a potent neurotoxin that leads to a decrease in egg laying, hatching and chick survival.
“In the boxes, we could handle them so they wouldn’t be phased,” Brasso says. “The mercury levels in those tree swallows were the highest reported in that species.”
When studying for her master’s thesis project, Brasso saw these effects firsthand in tree swallows. For the project, she and teammates built more than 200 birdhouse boxes in the Shenandoah Valley to attract cavity-nesting
Establishing a baseline understanding of mercury levels in remote parts of our planet by using birds as bio-monitors is a new line of research that excites Brasso.
“It’s hard going against companies to assess damage when you can’t put a clear label on how it’s impacting the environment and what it all means,” Brasso says. She will continue to build data on mercury levels in penguins by sampling penguin tissues across the Southern Hemisphere, in Antarctica, New Zealand, Africa and South America. Preliminary data suggests that current levels of mercury in brush-tailed penguins are too low to cause reproductive impairment or decreased survival. However, Brasso thinks the significant impacts of global climate change occurring in the Antarctic Peninsula may change that. Visit www.uncw.edu/penguins to learn more about this and other projects or to view recent blogs from Antarctica.
Rebecka Brasso
Arts & Sciences page 23