The United States' use of coal results in many environmental alterations. In the Appalachian coal belt region, one widespread alteration is conversion of forest to reclaimed mineland. The goal of this study was to quantify the changes to ecosystem structure and function associated with a conversion from forest to reclaimed mine grassland by comparing a small watershed containing a 15-year-old reclaimed mine with a forested, reference watershed in western Maryland. Major differences were apparent between the two watersheds in terms of biogeochemistry. Total C, N, and P pools were all substantially lower at the mined site, mainly due to the removal of woody biomass but also, in the case of P, to reductions in soil pools. Mineral soil C, N, and P pools were 96%, 79%, and 69% of native soils, respectively. Although annual runoff from the watersheds was similar, the mined watershed exhibited taller, narrower storm peaks as a result of a higher soil bulk density and decreased infiltration rates. Stream export of N was much lower in the mined watershed due to lower net nitrification rates and nitrate concentrations in soil. However, stream export of sediment and P and summer stream temperature were much higher. Stream leaf decomposition was reduced and macroinvertebrate community structure was altered as a result of these changes to the stream environment. This land use change leads to substantial, long-term changes in ecosystem capital and function.

There is evidence that oxidation of CH4 to CO2 by methanotrophic bacteria in forest soil is a major sink for atmospheric CH4, even though growth of the bacteria on such low CH4 concentrations (<1.7 µL L−1) is perplexing. Measurements of CH4 and CO2 in a northern hardwood ecosystem in the Adirondack Park in the state of New York indicated that: (i) soil CH4 concentrations were mostly higher than the concentration of CH4 in forest air, with concentrations as high as 500 µL L−1 at the 0.1‐m depth in the early and late parts of the growing season; (ii) soil CO2 concentrations ranged from the atmospheric level to as high as 19 000 µL L−1 at the 0.2‐m depth in midsummer; (iii) net consumption of atmospheric CH4 emission by soil in midsummer averaged only 0.25 mg m−2 d−1, which is low compared with findings for most forest ecosystems; and (iv) methanogenesis occurred in soil samples throughout the profile when incubated anaerobically as well as aerobically with CH3F to inhibit methanotrophs. The prominent activity of methanogenic bacteria producing CH4 in the spring and autumn could support the growth of methanotrophic bacteria that otherwise consume atmospheric CH4 when methanogens are not active. Therefore, CH4 dynamics in this Spodosol represent the balance between CH4 production and CH4 oxidation, which is similar to the CH4 dynamics in many wetland ecosystems.

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Acid mine drainage (AMD) affects thousands of stream miles in the Appalachian region of the USA and results in elevated concentrations of iron and aluminum in the stream water and sediments and wide ranging pH values. It was hypothesized that these conditions would lead to increased P buffering capacity of the sediments which in turn would cause a decrease in dissolved reactive phosphorus (DRP) in the water column. In the lab fresh Fe, Al, and Mn oxide precipitates all adsorbed DRP strongly but over different pH ranges. Sulfate and calcium ions inhibited adsorption of DRP with Fe oxides but the effect was less apparent with Al oxides. In the field DRP concentration was reduced 54-90% just downstream of an AMD input compared to upstream of the input. In addition the sediment buffering capacity increased and equilibrium phosphate concentration decreased dramatically downstream of the AMD inputs. The strength of the effect and the widespread occurrence of AMD suggest that AMD could be altering the P dynamics of streams and rivers throughout the Appalachian region.

The objective of this study was to evaluate the nitrogen (N) biogeochemistry of an 18-22 year old forested watershed in western Maryland. We hypothesized that this watershed should not exhibit symptoms of N saturation. This watershed was a strong source of nitrate (NO 3 À ) to the stream in all years, with a mean annual export of 9.5 kg N ha À1 year À1 and a range of 4.4-18.4 kg N ha À1 year À1 . During the 2001 and 2002 water years, wet deposition of inorganic N was 9.0 kg N ha À1 year À1 and 6.3 kg N ha À1 year À1 , respectively. Watershed N export rates in 2001 and 2002 water years were 4.2 kg N ha À1 year À1 and 5.3 kg N ha À1 year À1 , respectively. During the wetter water years of 2003 and 2004, the watershed exported 15.0 kg N ha À1 year À1 and 18.4 kg N ha À1 year À1 , rates that exceeded annual wet deposition of N by a factor of two (7.5 kg N ha À1 year À1 in 2003) and three (5.5 kg N ha À1 year À1 in 2004). Consistent with the high rates of N export, were high concentrations (2.1-3.3%) of N in foliage, wood (0.3%) and fine roots, low C:N ratios in the forest floor (17-24) and mineral soil (14), high percentages (83-96%) of the amount of mineralized N that was nitrified and elevated N concentrations (up to 3 mg N l À1 ) in soil solution. Although this watershed contained a young aggrading forest, it exhibited several symptoms of N saturation commonly observed in more mature forests.