Sulfate exports from multiple catchments in a glaciated forested watershed in western New York, USA

Landscape variations in stream water SO42− and δ34SSO4 in a boreal stream network

“…Low SO 4 2À concentrations in wetland dominated streams are in accordance with results from a recent study in North America (Inamdar and Mitchell, 2008). It has also been shown that wetlands which are saturated throughout the year retain most of the SO 4 2À (Devito and Hill, 1997), which most probably is the case in the Krycklan region.…”

“…Previous studies also report on net export of SO 4 2À from forested catchments (Mitchell et al, 1996(Mitchell et al, , 2001Eimers and Dillon, 2002;Inamdar and Mitchell, 2008;Mö rth et al, 2008) and also that a large export occurs during snow melt Shanley et al, 2005Shanley et al, , 2008.…”

An empirical approach to modeling methylmercury concentrations in an Adirondack stream watershed

“…These patterns are consistent with the roles of SO 4 2− ‐reducing bacteria as a key driver of methylation [ Gilmour et al ., ] and DOC as a key agent for Hg binding and transport (with thiol groups, the key binding sites). Similar patterns among MeHg, DOC, and SO 4 2− have been observed in the Adirondacks and in other settings [ Branfireun and Roulet , ; Selvendiran et al ., ] and are believed to reflect temperature‐driven seasonal patterns in SO 4 2− reduction [ DeVito and Hill , ; Inamdar and Mitchell , ], in the rates of DOC release from soil organic matter degradation [ Christ and David , ; Clark et al ., ], and consequently Hg methylation and mobilization. The seasonal increase in FMeHg concentrations is also correlated with an increase in stream Fe concentrations ( r = 0.74, p < 0.001; data not shown), and because Fe‐reducing bacteria are also capable of methylating Hg [ Fleming et al ., ], a role for Fe‐reducers cannot be ruled out.…”

Groundwater flushing of solutes at wetland and hillslope positions during storm events in a small glaciated catchment in western New York, USA

“…Our previous observations from PPBW Mitchell, 2006, 2007b;2008a) indicated that DOC and DON were derived from surficial sources (throughfall, forest floor, and surficial soils) and thus indicative of surficial flow paths while Mg, SO 4 , and Si were derived from till and mineral weathering (Inamdar and Mitchell, 2008b) and thus representative of deeper hydrologic flow paths. Other studies in glaciated catchments in the northeast United States (Shanley and Peters, 1993;Hornbeck et al, 1997;Hill et al, 1999) have also reported that Mg and Si are derived primarily from till and deeper mineral soils, and GWs that are in contact with this strata typically have higher concentrations of these solutes.…”