Stable sulfur isotopes of sulfate in precipitation and stream solutions in a northern hardwood watershed

Abstract

Stable S isotopes of SO42‐ in precipitation, throughfall, and stream water solutions in a northern hardwood watershed (Bear Brook Watershed, Maine) were examined to determine sources of stream SO42‐ and to identify watershed processes that may affect atmospherically deposited SO42‐ prior to reaching the streams. Similarity among temporal patterns in δ34S of precipitation, throughfall, stream SO42‐ (range: +3.4 to +9.4‰), and of stream SO42‐ (5–10%) indicate that the δ34S values of stream SO42‐ are controlled principally by atmospheric deposition. Lack of correlation between δ34S of stream SO42‐ and stream , elevational position, and stream discharge supports the interpretation that fractionation of stable S isotopes within the watershed appears to have, at most, a minor influence on δ34S of stream SO42‐.