Regional variations and drivers of mercury and selenium concentrations in Steller sea lions
| Autor: | Vladimir N. Burkanov, Judith M. Castellini, Lorrie D. Rea, Todd M. O’Hara, Brian S. Fadely, J.P. Avery, Michael J. Rehberg |
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| Rok vydání: | 2020 |
| Předmět: |
Environmental Engineering
010504 meteorology & atmospheric sciences animal diseases Zoology chemistry.chemical_element 010501 environmental sciences 01 natural sciences Russia Selenium Dry weight Pregnancy medicine Environmental Chemistry Animals Sea lion Waste Management and Disposal 0105 earth and related environmental sciences Trophic level Lanugo biology δ15N Mercury biology.organism_classification Pollution Mercury (element) Sea Lions chemistry Female medicine.symptom Eumetopias jubatus Alaska Water Pollutants Chemical |
| Zdroj: | The Science of the total environment. 744 |
| ISSN: | 1879-1026 |
| Popis: | Mercury (Hg) can be neurotoxic to mammals and impact reproduction, whereas selenium (Se) is an important antioxidant known to ameliorate some adverse effects of Hg. Total Hg concentrations ([THg]) were measured in lanugo (pelage grown in utero) of 812 Steller sea lion (Eumetopias jubatus) pups across Alaska and Russia to assess fetal exposure during late gestation. The molar ratio of total Se to THg (TSe:THg) was determined in whole blood collected from 291 pups. Stable isotope ratios of carbon and nitrogen were measured in sections of vibrissae (whiskers, n = 498) and in lanugo (n = 480) of pups grown during late gestation to track diet variations between adult females that can drive Hg and Se exposure during this critical fetal development period. Lanugo [THg] ranged from 1.4 to 73.7 μg/g dry weight with the lowest median [THg] in Southeast Alaska. Pups from the Western Aleutian Islands had higher median lanugo [THg] than pups from other metapopulations in Alaska. Over 25% of pups in the Western Aleutian Islands had [THg] above published risk thresholds (20 μg/g) for other mammals. Whole blood molar TSe:THg was significantly lower in the Western Aleutian Islands and in some parts of the Central Aleutian Islands with higher molar ratios found in the Eastern Aleutian Islands and Central Gulf of Alaska. This suggests a limitation on potential protective functions of Se in the western regions with the highest relative [THg]. The Central Aleutian Island pups with [THg] over 20 μg/g had higher δ15N ratios than pups with lower [THg] suggesting dams consuming higher trophic level prey is a key driver for Hg exposure. However, regional differences likely reflect variability in diet of the dam during gestation and in Hg food web dynamics between oceanic regimes east and west of key passes in the Aleutian Islands. |
| Databáze: | OpenAIRE |
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