TY - JOUR
T1 - Lacustrine responses to decreasing wet mercury deposition rates-results from a case study in northern Minnesota
AU - Brigham, Mark E.
AU - Sandheinrich, Mark B.
AU - Gay, David A.
AU - Maki, Ryan P.
AU - Krabbenhoft, David P.
AU - Wiener, James G.
PY - 2014/6/3
Y1 - 2014/6/3
N2 - 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, SO 4-2, 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 (MeHg aq) 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, MeHg aq 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 Hg fish. The diverging responses among the study lakes exemplify the complexity of ecosystem responses to decreased loads of atmospheric pollutants.
AB - 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, SO 4-2, 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 (MeHg aq) 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, MeHg aq 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 Hg fish. The diverging responses among the study lakes exemplify the complexity of ecosystem responses to decreased loads of atmospheric pollutants.
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U2 - 10.1021/es500301a
DO - 10.1021/es500301a
M3 - Article
C2 - 24837007
AN - SCOPUS:84901950584
SN - 0013-936X
VL - 48
SP - 6115
EP - 6123
JO - Environmental Science and Technology
JF - Environmental Science and Technology
IS - 11
ER -