Hydrologic Cycling of Mercury and Organic Carbon in a Forested Upland–Bog Watershed

The hydrologic cyvling of total Hg (HgT) and organic C (OC) was studies for a 1-yr period in a northern Minnesota forested watershed, consisting of an upland surrounding a bog peatland with a narrow lagg at their interface. Throughfall and sternflow contributed twice as much HgT as seven times as much OC to the forested watershed than atmospheric deposition in a nearby opening. Fluxes in upland runoff accounted for 16% of the HgT and 8% of the OC inputs to the lagg and were dominated by interflow transport. Bog runoff accounted for 57% of the HgT and 83% of the OC inputs to the lagg. For an annual cycle, upland soils were sinks for both HgT and OC, while bog soils were sinks for HgT but sources of OC. Fluxes to the lagg accounted for 184% of the HgT and 87% of the OC transported from the watershed outlet. We speculate that HgT was lost in the lagg by both volatilization and soil accumulation. Total Hg and dissolved organic C (DOC) are positively related in both throughfall and stemflow, with stemflow showing the strongest relationships. In the soil system, HgT-DOC relationships deteriorate and HgT-particulate organic C (POC) relationships dominate. Water residence time in contact with OC appears to be important in determining the relationships between HgT and OC. At the stream outlet, our data suggest that ~70% of the HgT transported from the watershed is associated with POC, while 30% is associated with DOC.

[1]  B. Allard,et al.  Subcatchment Output of Mercury and Methylmercury at Svartberget in Northern Sweden , 1995 .

[2]  E. Steinnes,et al.  Atmosperic deposition of mercury in Norway: temporal and spatial trends , 1991 .

[3]  D. F. Grigal,et al.  Atmospheric Inputs of Mercury and Organic Carbon into a Forested Upland/Bog Watershed , 1999 .

[4]  Anthropogenic influences on the global mercury cycle: A model-based analysis , 1995 .

[5]  D. F. Grigal,et al.  Mercury and Organic Carbon Relationships in Streams Draining Forested Upland/Peatland Watersheds , 1999 .

[6]  D. DeMarini,et al.  Mutagenicity and chemical analysis of emissions from the open burning of scrap rubber tires. , 1994, Environmental science & technology.

[7]  Paul K. Barten,et al.  The peatland hydrologic impact model: development and testing. , 1987 .

[8]  Martin M. Shafer,et al.  Influences of watershed characteristics on mercury levels in wisconsin rivers. , 1995, Environmental science & technology.

[9]  Steven J. Eisenreich,et al.  Export of dissolved organic carbon and acidity from peatlands , 1989 .

[10]  Y. Lee,et al.  Measurement of methylmercury and mercury in run-off, lake and rain waters , 1991 .

[11]  D. F. Grigal.  Elemental dynamics in forested bogs in northern Minnesota , 1991 .

[12]  T. Meyers,et al.  Atmospheric concentrations and deposition of Hg to A deciduous forest atwalker branch watershed, Tennessee, USA , 1991 .

[13]  D. F. Grigal,et al.  Regional trends in mercury distribution across the Great Lakes states, north central USA , 1992, Nature.

[14]  K. Brooks,et al.  Streamflow response from an ombrotrophic mire , 1988 .

[15]  J. Rudd,et al.  Importance of Wetlands as Sources of Methyl Mercury to Boreal Forest Ecosystems , 1994 .

[16]  D. R. Timmons,et al.  WATERBORNE NUTRIENT FLOW THROUGH AN UPLAND-PEATLAND WATERSHED IN MINNESOTA' , 1982 .

[17]  M. E. Brigham,et al.  Increasing Rates of Atmospheric Mercury Deposition in Midcontinental North America , 1992, Science.

[18]  T. Meyers,et al.  Micrometeorological measurements of mercury vapor fluxes over background forest soils in eastern Tennessee , 1995 .

[19]  Atmospheric mercury in northern Wisconsin: Sources and species , 1995 .

[20]  W. Fitzgerald.  Cycling of Mercury between the Atmosphere and Oceans , 1986 .

[21]  J. Rudd,et al.  Production and Loss of Methylmercury and Loss of Total Mercury from Boreal Forest Catchments Containing Different Types of Wetlands , 1996 .

[22]  S. Lindberg,et al.  Application of throughfall methods to estimate dry deposition of mercury , 1992 .

[23]  John A. Sorensen,et al.  Airborne mercury deposition and watershed characteristics in relation to mercury concentrations in water, sediments, plankton, and fish of eighty Northern Minnesota lakes , 1990 .

[24]  Charles T. Driscoll,et al.  The role of dissolved organic carbon in the chemistry and bioavailability of mercury in remote Adirondack lakes , 1995 .

[25]  E. Schuster,et al.  The behavior of mercury in the soil with special emphasis on complexation and adsorption processes - A review of the literature , 1991 .

[26]  Å. Iverfeldt.  Mercury in forest canopy throughfall water and its relation to atmospheric deposition , 1991 .

[27]  E. Crecelius,et al.  Determination of mercury in seawater at sub-nanogram per liter levels , 1983 .

[28]  Lars Håkanson,et al.  Mercury in the surface water of Swedish forest lakes —concentrations, speciation and controlling factors , 1991 .

[29]  D. Krabbenhoft,et al.  Mercury cycling in the Allequash Creek watershed, northern Wisconsin , 1995 .

[30]  Ki‐Hyun Kim,et al.  Foliar exchange of mercury vapor: Evidence for a compensation point , 1995 .

[31]  A. Heyes,et al.  The hydrology and methylmercury dynamics of a Precambrian shield headwater peatland , 1996 .

[32]  Kjell Johansson,et al.  Mercury in swedish forest soils and waters — Assessment of critical load , 1991 .

[33]  E. Bringmark,et al.  Occurence and transport of mercury within a small catchment area , 1991 .

[34]  J. Munthe,et al.  Mechanisms of deposition of methylmercury and mercury to coniferous forests , 1995 .

[35]  G. Mierle.  Aqueous inputs of mercury to precambrian shield lakes in ontario , 1990 .