title: Influence of in ovo mercury exposure, lake acidity, and other factors on common loon egg and chick quality in Wisconsin.
abstract: A field study was conducted in Wisconsin (USA) to characterize in ovo mercury (Hg) exposure in common loons (Gavia immer). Total Hg mass fractions ranged from 0.17 µg/g to 1.23 µg/g wet weight in eggs collected from nests on lakes representing a wide range of pH (5.0-8.1) and were modeled as a function of maternal loon Hg exposure and egg laying order. Blood total Hg mass fractions in a sample of loon chicks ranged from 0.84 µg/g to 3.86 µg/g wet weight at hatch. Factors other than mercury exposure that may have persistent consequences on development of chicks from eggs collected on low-pH lakes (i.e., egg selenium, calcium, and fatty acid mass fractions) do not seem to be contributing to reported differences in loon chick quality as a function of lake pH. However, it was observed that adult male loons holding territories on neutral-pH lakes were larger on average than those occupying territories on low-pH lakes. Differences in adult body size of common loons holding territories on neutral-versus low-pH lakes may have genetic implications for differences in lake-source-related quality (i.e., size) in chicks. The tendency for high in ovo Hg exposure and smaller adult male size to co-occur in low-pH lakes complicates the interpretation of the relative contributions of each to resulting chick quality.
authors.affiliation: Upper Midwest Environmental Sciences Center, US Geological Survey, La Crosse, Wisconsin, USA.
authors.forename: Kevin P
authors.initials: KP
authors.lastname: Kenow
authors.affiliation: Wisconsin Department of Natural Resources, Rhinelander, Wisconsin, USA.
authors.forename: Michael W
authors.initials: MW
authors.lastname: Meyer
authors.affiliation: Large Lakes Research Station, US Environmental Protection Agency, Grosse Ile, Michigan, USA.
authors.forename: Ronald
authors.initials: R
authors.lastname: Rossmann
authors.affiliation: Upper Midwest Environmental Sciences Center, US Geological Survey, La Crosse, Wisconsin, USA.
authors.forename: Brian R
authors.initials: BR
authors.lastname: Gray
authors.affiliation: Department of Chemistry and Biology, Ryerson University, Toronto, Ontario, Canada.
authors.forename: Michael T
authors.initials: MT
authors.lastname: Arts
mesh_terms: D000818:Animals; D001717:Birds / Q000378:metabolism*; D049628:Body Size / Q000187:drug effects; D002118:Calcium / Q000032:analysis / Q000097:blood; D002645:Chickens / Q000378:metabolism*; D002849:Chromatography, Gas; D005260:Female; D006863:Hydrogen-Ion Concentration; D060106:Lakes / Q000737:chemistry*; D008297:Male; D008628:Mercury / Q000032:analysis* / Q000097:blood / Q000633:toxicity; D008767:Methylmercury Compounds / Q000032:analysis / Q000097:blood; D010063:Ovum / Q000737:chemistry* / Q000378:metabolism; D012643:Selenium / Q000032:analysis / Q000097:blood; D013054:Spectrophotometry, Atomic; D014922:Wisconsin
chemical_list: D008767:Methylmercury Compounds; D008628:Mercury; D012643:Selenium; D002118:Calcium
keywords: Common loon; Gavia immer; In ovo exposure; Mercury; Methylmercury