Skip to Main Content
Decreased atmospheric sulfur deposition across the southeastern U.S.: When will watersheds release stored sulfate?Author(s): Karen C. Rice; Todd M. Scanlon; Jason A. Lynch; Bernard J. Cosby
Source: Environmental Science & Technology. 48(17): 10071-10078.
Publication Series: Scientific Journal (JRNL)
Station: Northern Research Station
Download Publication (3.78 MB)
DescriptionEmissions of sulfur dioxide (SO2) to the atmosphere lead to atmospheric deposition of sulfate (SO42-), which is the dominant strong acid anion causing acidification of surface waters and soils in the eastern United States. Since passage of the Clean Air Act and its Amendments, atmospheric deposition of SO2 in this region has declined by over 80%, but few corresponding decreases in streamwater SO42- concentrations have been observed in unglaciated watersheds. We calculated SO42- mass balances for 27 forested, unglaciated watersheds from Pennsylvania to Georgia, by using total atmospheric deposition (wet plus dry) as input. Many of these watersheds still retain SO42-, unlike their counterparts in the northeastern U.S. and southern Canada. Our analysis showed that many of these watersheds should convert from retaining to releasing SO42- over the next two decades. The specific years when the watersheds crossover from retaining to releasing SO42- correspond to a general geographical pattern of later net watershed release from north to south. The single most important variable that explained the crossover year was the runoff ratio, defined as the ratio of annual mean stream discharge to precipitation. Percent clay content and mean soil depth were secondary factors in predicting crossover year. The conversion of watersheds from net SO42- retention to release anticipates more widespread reductions in streamwater SO42- concentrations in this region.
- Check the Northern Research Station web site to request a printed copy of this publication.
- Our on-line publications are scanned and captured using Adobe Acrobat.
- During the capture process some typographical errors may occur.
- Please contact Sharon Hobrla, firstname.lastname@example.org if you notice any errors which make this publication unusable.
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
CitationRice, Karen C.; Scanlon, Todd M.; Lynch, Jason A.; Cosby, Bernard J. 2014. Decreased atmospheric sulfur deposition across the southeastern U.S.: When will watersheds release stored sulfate?. Environmental Science & Technology. 48(17): 10071-10078.
- Nitrogen and sulfur desposition and forest nutrient status in the valley of Mexico
- Biogeochemistry of beetle-killed forests: Explaining a weak nitrate response
- Biogeochemical cycling of carbon, nitrogen, and sulfur at the Howland Integrated Forest Study site, Howland, Maine
XML: View XML