| Autor: |
Brigham ME; U.S. Geological Survey, 2280 Woodale Drive, Mounds View, Minnesota 55112, United States., Sandheinrich MB, Gay DA, Maki RP, Krabbenhoft DP, Wiener JG |
| Jazyk: |
angličtina |
| Zdroj: |
Environmental science & technology [Environ Sci Technol] 2014 Jun 03; Vol. 48 (11), pp. 6115-23. Date of Electronic Publication: 2014 May 16. |
| DOI: |
10.1021/es500301a |
| Abstrakt: |
We present a case study comparing metrics of methylmercury (MeHg) contamination for four undeveloped lakes in Voyageurs National Park to wet atmospheric deposition of mercury (Hg), sulfate (SO4(-2)), and hydrogen ion (H+) in northern Minnesota. Annual wet Hg, SO4(-2), and H+ deposition rates at two nearby precipitation monitoring sites indicate considerable decreases from 1998 to 2012 (mean decreases of 32, 48, and 66%, respectively). Consistent with decreases in the atmospheric pollutants, epilimnetic aqueous methylmercury (MeHgaq) and mercury in small yellow perch (Hgfish) decreased in two of four lakes (mean decreases of 46.5% and 34.5%, respectively, between 2001 and 2012). Counter to decreases in the atmospheric pollutants, MeHgaq increased by 85% in a third lake, whereas Hgfish increased by 80%. The fourth lake had two disturbances in its watershed during the study period (forest fire; changes in shoreline inundation due to beaver activity); this lake lacked overall trends in MeHgaq and Hgfish. The diverging responses among the study lakes exemplify the complexity of ecosystem responses to decreased loads of atmospheric pollutants. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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