Mercury budget of an upland-peatland watershed
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Biogeochemistry. Vol. 50 p. 95-109. (2000)
Inputs, outputs, and pool sizes of total mercury (Hg) were measured in a forested 10 ha,watershed consisting of a 7 ha hardwood-dominated upland surrounding a 3 ha coniferdominated peatland. Hydrologic inputs via throughfall and stemflow, 13 +/- 0.4/ug m-2 yr-1 over the entire watershed, were about double precipitation inputs in the open and were significantly higher in the peatland than in the upland (19.6 vs. 9.8/ug m-2 yr-1). Inputs of Hg via litterfall were 12.3 +/- 0.7/ug m-2 yr-1,/sup> , not different in the peatland and upland (11.7 vs. 12.5 ug m-2 yr-1). Hydrologic outputs via streamflowwere 2.8 +/- 0.3/ug m-2 yr-1 and the contribution from the peatland was higher despite its smaller area. The sum of Hg inputs were less than that in the overstory trees, 33+/-3 ug m-2 above-ground, and much less than either that in the upland soil, 5250+/-520ug m-2, or in the peat, 3900+/-100ug m-2 in the upper 50cm. The annual flux of Hg measured in streamflow and the calculated annual accumulation in the peatland are consistent with values reported by others. A sink for Hg of about 20ug m-2 yr-1 apparently exists in the upland, and could be due to either or both storage in the soil or volatilization.
Keywordsatmospheric deposition; litterfall; mercury cycling; wetland; throughfall
Grigal, D. F.; Kolka, Randy K.; Fleck, J. A.; Nater, E. A. 2000. Mercury budget of an upland-peatland watershed. Biogeochemistry. Vol. 50 p. 95-109. (2000)