Steady-state sulfur critical loads and exceedances for protection of aquatic ecosystems in the U.S. southern Appalachian Mountains

Todd C. McDonnell; Timothy J. Sullivan; Paul F. Hessburg; Keith M. Reynolds; Nicholas Povak; Bernard J. Cosby; William Jackson; R. Brion Salter

doi:10.1016/j.jenvman.2014.07.019

Treesearch

Steady-state sulfur critical loads and exceedances for protection of aquatic ecosystems in the U.S. southern Appalachian Mountains

Formally Refereed

Authors:

Todd C. McDonnell, Timothy J. Sullivan, Paul F. Hessburg, Keith M. Reynolds, Nicholas Povak, Bernard J. Cosby, William Jackson, R. Brion Salter

Year:

2014

Type:

Scientific Journal

Station:

Pacific Northwest Research Station

DOI:

https://doi.org/10.1016/j.jenvman.2014.07.019

Source:

Journal of Environmental Management

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Download (PDF 6.14 MB): https://research.fs.usda.gov/download/treesearch/48812.pdf

Abstract

Atmospherically deposited sulfur (S) causes stream water acidification throughout the eastern U.S. Southern Appalachian Mountain (SAM) region. Acidification has been linked with reduced fitness and richness of aquatic species and changes to benthic communities. Maintaining acid-base chemistry that supports native biota depends largely on balancing acidic deposition with the natural resupply of base cations. Stream water acid neutralizing capacity (ANC) is maintained by base cations that mostly originate from weathering of surrounding lithologies. When ambient atmospheric S deposition exceeds the critical load (CL) an ecosystem can tolerate, stream water chemistry may become lethal to biota. This work links statistical predictions of ANC and base cation weathering for streams and watersheds of the SAM region with a steady-state model to estimate CLs and exceedances. Results showed that 20.1% of the total length of study region streams displayed ANC

Keywords

acidification, sulfur, Southern Appalachian Mountains, critical load, stream

Citation

McDonnell, Todd C.; Sullivan, Timothy J.; Hessburg, Paul F.; Reynolds, Keith M.; Povak, Nicholas A.; Cosby, Bernard J.; Jackson, William; Salter, R. Brion. 2014. Steady-state sulfur critical loads and exceedances for protection of aquatic ecosystems in the U.S. southern Appalachian Mountains. Journal of Environmental Management. 146: 407-419.