Isotopic assessment of NO₃⁻ and SO₄²⁻ mobility during winter in two adjacent watersheds in the Adirondack Mountains, New York

Abstract

[1] Biogeochemical cycling of N and S was examined at two watersheds in the Adirondack Mountains, New York, to better understand the retention and loss of these elements during winter and spring snowmelt. were observed in forest floor and mineral soil leachates, groundwater, and streams. Over the winter observation period, most of the NO 3 À and SO 4 2À in stream water was from a watershed-derived source, whereas atmospheric contributions were relatively minor. Despite differences in soil water NO 3 À concentrations between watersheds, the isotopic composition of NO 3) was similar, and indicated that in both watersheds most of the NO 3 À was produced by nitrification in the forest soils. Although there was likely some contribution of SO 4 2À from microbial oxidation of carbon-bonded sulfur, most of the stream water SO 4 2À appeared to be derived from weathering of Scontaining bedrock or parent material. The decreased d 18 O values of NO 3 À and SO 4 2À in upper soil horizons indicate that atmospheric deposition of N and S was not directly linked with stream water losses, even during winter and spring snowmelt.

Mercury transport in response to storm events from a northern forest landscape

“…Principal component analysis (PCA, McHale et al, 2002) focusing on NO 3 sources and isotopic assessments of NO 3 and SO 4 2 (Piatek et al, 2005;Campbell et al, 2006;Mitchell et al, 2006) has been conducted previously at Archer Creek. In addition to multiple stream sampling locations, McHale et al (2002) evaluated the contribution of shallow/deep soil water, shallow/deep wetland pore water, groundwater, and throughfall as potential runoff sources using end-member mixing analysis (EMMA).…”

Comparisons of watershed sulfur budgets in southeast Canada and northeast US: new approaches and implications

“…Previous analysis at Arbutus watershed, including estimates of dry deposition, suggested that an internal S source was required to balance the S budget (Park et al 2003). Results using SO 4 2-isotopic evidence (d 18 O and d 34 S) (Campbell et al 2006) and spatial patterns of SO 4 2-concentrations (Piatek et al 2009) have suggested that some subcatchments of the Arbutus Watershed have a strong internal S source. Previous work at Cone Pond has suggested the potential importance of a fire in 1820 that heavily burned 85% of the watershed.…”

Unusual seasonal patterns and inferred processes of nitrogen retention in forested headwaters of the Upper Susquehanna River

“…Previous studies have observed increases in stream d 18 O-NO 3 -values during snowmelt indicating modest contributions (up to *35%) to stream NO 3 -directly from melting snow or other precipitation source (e.g., Spoelstra et al 2001;Burns and Kendall 2002;Pardo et al 2004;Piatek et al 2005;Campbell et al 2006;Hales et al 2007 . 6a).…”