You are here:
RECOVERY OF SURFACE WATERS IN THE NORTHEASTERN U.S. FROM DECREASES IN ATMOSPHERIC DEPOSITION OF SULFUR
Citation:
Driscoll, C. T., G. E. Likens, AND M. Church. RECOVERY OF SURFACE WATERS IN THE NORTHEASTERN U.S. FROM DECREASES IN ATMOSPHERIC DEPOSITION OF SULFUR. Water, Air, and Soil Pollution 105(1-2):319-329, (1998).
Description:
A simple mass flux model was developed to simulate the response of SO concentrations in surface waters to past and anticipated future changes in atmospheric deposition of SO . Values of bulk (or wet) SO deposition and dry deposition of S determined from measured air concentrations and a desposition velocity were insufficient to balance watershed SO export at the Hubbard Brook Experimental Forest, NH and for a regional survey of watersheds in the northeastern U.S. We propose two explanations for the unmeasured S source: 1) a significant underestimation of dry S deposition, and/or 2) internal watershed S sources, such as weathering and/or mineralization of soil organic S. Model simulations based on these two mechanisms agreed closely with measured stream SO concentrations at Hubbard Brook. Close agreement between measured and model predicted results precluded identification of which of the two mechanisms controlled long-term trends in stream SO . Model simulations indicated that soil adsorption reactions significantly delayed the response of stream waters to declines in SO inputs since 1970, but could not explain the discrepancy in watershed S budgets. Extrapolation of model predictions into the future demonstrates that uncertainty in the source of the S imbalance in watersheds has important implications for assessments of the recovery of surface water acid neutralizing capacity in response to anticipated future reductions in SO2 emissions.