title: Trophic calculations reveal the mechanism of population-level variation in mercury concentrations between marine ecosystems: case studies of two polar seabirds.
abstract: The incorporation of quantitative trophic level analysis in ecotoxicological studies provides explanatory power to identify the factors, trophic or environmental, driving population-level variation in mercury exposure at large geographic scales. In the Antarctic marine ecosystem, mercury concentrations and stable isotope values in Adélie penguins (Pygoscelis adeliae) were compared between the Antarctic Peninsula and the Ross Sea. Correcting tissue δ(15)N values for baseline δ(15)N values revealed population-level differences in trophic position which contributes to differences in mercury. Data from Thick-billed murres (Uria lomvia) were synthesized from published values from Baffin Bay and Svalbard to demonstrate the utility of baseline δ(15)N values in identifying differences in environmental mercury exposure independent of diet. Here, we demonstrate the importance of calculating population-specific trophic level data to uncover the source of variation in mercury concentrations between geographically distinct populations of marine predators.
authors.affiliation: University of North Carolina Wilmington, Department of Biology and Marine Biology, 601 South College Rd., Wilmington, NC 28403, United States. Electronic address: rlb1196@uncw.edu.
authors.forename: Rebecka L
authors.initials: RL
authors.lastname: Brasso
authors.affiliation: Woods Hole Oceanographic Institution, 266 Woods Hole Rd., Woods Hole, MA 02543, United States.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Polito
mesh_terms: D000818:Animals; D000864:Antarctic Regions; D046091:Charadriiformes / Q000378:metabolism*; D017753:Ecosystem; D004784:Environmental Monitoring; D020387:Food Chain; D008628:Mercury / Q000032:analysis / Q000378:metabolism*; D046429:Spheniscidae / Q000378:metabolism*; D013538:Svalbard; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000378:metabolism*
chemical_list: D014874:Water Pollutants, Chemical; D008628:Mercury
keywords: Mercury; Population; Seabird; Spatial comparisons; Stable isotope analysis; Trophic level