Water, Air, and Soil Pollution

, Volume 130, Issue 1, pp 75–86

Use of Stable Isotope Ratios for Evaluating Sulfur Sources and Losses at the Hubbard Brook Experimental Forest


  • M. J. Mitchell
    • SUNY-ESF
  • B. Mayer
    • University of Calgary
  • S. W. Bailey
    • USDA Forest Service, Northeastern Research Station
  • J. W. Hornbeck
    • USDA Forest Service, Northeastern Research Station
  • C. Alewell
    • BITÖKUniversität Bayreuth
  • C.T. Driscoll
    • Syracuse University
  • G.E. Likens
    • Institute of Ecosystem Studies

DOI: 10.1023/A:1012295301541

Cite this article as:
Mitchell, M.J., Mayer, B., Bailey, S.W. et al. Water, Air, & Soil Pollution (2001) 130: 75. doi:10.1023/A:1012295301541


Anthropogenic S emissions have been declining in eastern North America since the early 1970s. Declines in atmospheric S deposition have resulted in decreases in concentrations and fluxes of SO42− in precipitation and drainage waters. Recent S mass balance studies have shown that the outflow of SO42− in drainage waters greatly exceeds current S inputs from atmospheric deposition. Identifying the S source(s) which contribute(s) to the discrepancy in watershed S budgets is a major concern to scientists and policy makers because of the need to better understand the rate and spatial extent of recovery from acidic deposition. Results from S mass balances combined with model calculations and isotopic analyses of SO42− in precipitation and drainage waters at the Hubbard Brook Experimental Forest (HBEF) suggest that this discrepancy cannot be explained by either underestimates of dry deposited S or desorption of previously stored SO42−. Isotopic results suggest that the excess S may be at least partially derived from net mineralization of organic S as well as the weathering of S-bearing minerals.

atmospheric depositionorganic SS budgetsstable isotopeswatershedsweathering

Copyright information

© Kluwer Academic Publishers 2001