Sulfur and nitrogen budgets for five forested appalachian plateau basins

Abstract

Sulfur and nitrogen input±output budgets were estimated for ®ve forested Appalachian Plateau basins in Pennsylvania for the period October 1988 to March 1990. Wet and dry deposition inputs were determined on a weekly basis from data collected at atmospheric deposition monitoring stations located near the study sites. Stream export was estimated from intensively sampled stream chemistry and continuous discharge data collected on all ®ve basins. On four of the ®ve basins, deposited sulfur was essentially in balance with stream¯ow export of sulfur (92±120% exported) for the 1989 water year. The ®fth basin had net retention of deposited sulfur, with only 42% exported. All ®ve basins retained the vast majority of deposited nitrogen (only 3±18% exported). The fraction of atmospherically deposited sulfur exported in stream¯ow was greater by a mean factor of 14 versus nitrogen, implying that sulfur dominates base cation leaching processes on these non-carbonate-based catchments. Although basins in the study were relatively homogeneous in terms of topography, climate, geology and land use, local basin conditions caused signi®cant dierences in input±output budgets, pointing to the need for replicated basin studies in a region.

Long-Term Effects of Acidic Deposition on Water Quality in a High-Elevation Great Smoky Mountains National Park Watershed: Use of an Ion Input–Output Budget

“…In general, dominance of net SO 4 2− and NO 3 − fluxes in NDW deposition was consistent with other data across eastern USA where streams have been impacted by acidic deposition Sullivan et al 2004;NADP 2006). In NDW, throughfall deposition of net SO 4 2− flux was about twice that found in lower elevation MidAtlantic watersheds and around 300 eq ha −1 year −1 lower than the empirical model predicted data of net sulfate deposition for this area (Dow and DeWalle 1997;Castro and Morgan 2000;Weathers et al 2006). Dry and cloud deposition of SO 4 2− throughfall fluxes can be roughly estimated by the difference of throughfall and wet deposition fluxes because canopy uptake rate of SO 4 2− is quite small in comparison (Cape et al 1992;Johnson and Lindberg 1992;Draaijers et al 1997).…”

“…Key biogeochemical processes operating in watersheds can be inferred from ion inputoutput budgets. For example, Dow and DeWalle (1997) found one watershed retained 58% of its net SO 4 2− atmospheric inputs compared to four other mid-Atlantic watersheds in which stream SO 4 2− was in balance or was exported in greater mass than atmospheric inputs. Sulfate retention has mostly been attributed to soil adsorption (Evans et al 1997;King et al 2006).…”

“…An analysis of the NDW data from 1993 through 1997 found that about 50% of net NO 3 − input was exported annually, suggesting soils were N-saturated (Van Miegroet et al 2001; Barker et al 2002). In contrast, NO 3 − was mostly retained in study watersheds in the northeastern USA and Canada (Mitchell et al 1996;Dow and DeWalle 1997;Yanni et al 2000).…”

Nitrogen Excess in North American Ecosystems: Predisposing Factors, Ecosystem Responses, and Management Strategies

“…Fire history can have major effects on ecosystem N balance (Hornbeck et al 1997). Low-to moderate-intensity fires generally enhance N retention in the long term by reducing site N capital and increasing postfire vegetative demand (Dow and DeWalle 1997). Highintensity fires adversely affect soil structure, organic matter content, nutrient status, and plant productivity.…”

Seasonal Variations of Dissolved Nitrogen and DOC:DON Ratios in an Intermittent Mediterranean Stream

“…Source: (A) À vila et al (2002), (B), (C)Durand et al (1992), (D)Britton (1991), (E) Meixner and Fenn (in press), (F)Bernal et al (2002), (G)Riggan et al (1985), (H)Adams et al (1997), (I)Dow and DeWalle (1997), (J)Kortelainen et al (1997), (K)Williams and Melack (1997), (L)Campbell et al (2000), (M)Lovett et al (2000), (N)Coats and Goldman (2001), (O)Sickman et al (2001), (P)Lewis (2002) and (Q)Vanderbilt et al (2003).…”