Do songbirds in wetlands show higher mercury bioaccumulation relative to conspecifics in non-wetland habitats?
| Autor: | Rebecka L. Brasso, Virginia L. Winder, Katie Ann Rittenhouse |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
0106 biological sciences
Food Chain Health Toxicology and Mutagenesis chemistry.chemical_element Wetland 010501 environmental sciences Management Monitoring Policy and Law Toxicology 01 natural sciences Songbirds chemistry.chemical_compound Animals Ecosystem Methylmercury 0105 earth and related environmental sciences Trophic level geography geography.geographical_feature_category Ecology food and beverages Biota General Medicine Mercury Mercury (element) 010602 entomology nervous system chemistry Bioaccumulation Salt marsh Wetlands Environmental science Water Pollutants Chemical Environmental Monitoring |
| Zdroj: | Ecotoxicology (London, England). 29(8) |
| ISSN: | 1573-3017 |
| Popis: | Environmental conditions in wetlands facilitate favorable biogeochemical conditions for the conversion of inorganic mercury into methylmercury. For this reason, wetlands are increasingly classified as mercury hotspots, places where biota exhibit elevated mercury concentrations. While it is clear that wetlands play an important role in methylmercury production, factors such as geographic variation in mercury deposition, wetland type, and trophic dynamics can cause variation in mercury dynamics and bioaccumulation in biota occupying wetlands or connected to wetland trophic systems. Here, we use songbirds as bioindicators in a two-pronged approach aimed at evaluating the state of our understanding of mercury bioaccumulation by songbirds in wetland ecosystems. First, we use a case study in southeast Missouri to compare blood mercury concentrations in tree swallows (Tachycineta bicolor) and eastern bluebirds (Sialia sialis) occupying wetland and non-wetland habitats to test the hypothesis that songbirds in wetlands will have higher mercury bioaccumulation than those in non-wetlands. Adult tree swallows in wetlands had significantly higher blood mercury concentrations than those in non-wetlands; however, no difference between ecosystems was detected in eastern bluebirds. Second, we present a review of the current literature on mercury in songbirds in wetland ecosystems across North America. Mercury concentrations in songbirds varied among wetland types and with geographic location, often in an unpredictable manner. Mercury concentrations in songbird blood varied 3–10 fold at locations separated only by ~10 to several hundred kilometers. This magnitude of difference in blood mercury concentrations among wetlands exceeds documented differences between wetland and non-wetland ecosystems. Therefore, we caution against the automatic assumption that songbirds occupying wetlands will have higher mercury bioaccumulation than conspecifics living in other habitats. |
| Databáze: | OpenAIRE |
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