41 research outputs found
Estimation and Mapping of Wet and Dry Mercury Deposition Across Northeastern North America
Whereas many ecosystem characteristics and processes influence mercury accumulation in higher trophic-level organisms, the mercury flux from the atmosphere to a lake and its watershed is a likely factor in potential risk to biota. Atmospheric deposition clearly affects mercury accumulation in soils and lake sediments. Thus, knowledge of spatial patterns in atmospheric deposition may provide information for assessing the relative risk for ecosystems to exhibit excessive biotic mercury contamination. Atmospheric mercury concentrations in aerosol, vapor, and liquid phases from four observation networks were used to estimate regional surface concentration fields. Statistical models were developed to relate sparsely measured mercury vapor and aerosol concentrations to the more commonly measured mercury concentration in precipitation. High spatial resolution deposition velocities for different phases (precipitation, cloud droplets, aerosols, and reactive gaseous mercury (RGM)) were computed using inferential models. An empirical model was developed to estimate gaseous elemental mercury (GEM) deposition. Spatial patterns of estimated total mercury deposition were complex. Generally, deposition was higher in the southwest and lower in the northeast. Elevation, land cover, and proximity to urban areas modified the general pattern. The estimated net GEM and RGM fluxes were each greater than or equal to wet deposition in many areas. Mercury assimilation by plant foliage may provide a substantial input of methyl-mercury (MeHg) to ecosystems.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44443/1/10646_2004_Article_6259.pd
Nitrogen availability and forest productivity along a climosequence on Whiteface Mountain, New York
Frações oxidáveis do carbono orgânico total e macrofauna edáfica em sistema de integração lavoura-pecuária
Note on the Hydrometer Method of Particle-Size Analysis
Published as Scientific Journal Paper Series No. 8438 of the Minnesota Agricultural Experiment Station
Estimating plant biomass for undergrowth species of northeastern Minnesota forest communities
Topographic variation in soil water and nitrogen for two forested landforms in Minnesota, USA
Biomass Estimation Equations for Wetland Tall Shrubs
Published as Miscellaneous Journal Paper Series No. 1866 of the Minnesota Agricultural Experiment Station.Research supported by the Department of Energy, and the Agricultural Experiment Station and Departments
of Soil Science and Forest Resources, University of Minnesota, St. Paul, MN