Research Project Summary Information
Assessment of Chemistry & Benthic Communites:Assessment of chemistry and benthic communites (ST7613-1)
USGS National Center MS270
Effects of acidic deposition in New York include acidification of streams and soils, but neither the proportion of affected streams nor the spatial extent of soil acidification has been determined in acid-sensitive regions such as the Adirondack Mountains. Furthermore, insufficient data exist to determine if the acidity of streams has decreased in response to declines that have occurred in atmospheric deposition, and baseline data needed to evaluate future trends in the acidity of soils and streams is inadequate. Without this information, policies for restoring and protecting these natural resources cannot be developed without a large degree of uncertainty.
This survey will be done using a new approach for quantifying the length of stream reaches that are affected by chronic and episodic stream chemistry and would be implemented in the three following components: 1) sampling of streams at approximately 200 semi-randomly chosen locations, 2) additional sampling of specific sites that had been previously sampled multiple times in 1980-1982, and 3) collection of macroinvertebrates and periphytic diatoms at selected locations that provide a range of chemical and physical conditions. The USGS is responsible for overall project conduct and reporting. The Adirondack Lakes Survey Corporation and NYSDEC will participate in stream sampling and analysis, and the University of Texas will conduct the diatom component.
The project will be implemented for the purpose of both assessing acidic deposition impacts in this region, and as a pilot project that can be evaluated as a possible approach for assessing acidic deposition impacts in other regions of the Adirondack Mountains and New York State. The Oswegatchie-Black watersheds were chosen for this study because these watersheds comprise the region likely to be most impacted by acidic deposition within New York State, and possibly the country.
Of the 565 streams assessed, 66% (718 km of stream reaches) were identified as prone to acidification—likely to be acidified to levels harmful to biota. Of the 66% of streams found to be prone to acidification, approximately half were likely to be episodically acidified, and half were likely to be chronically acidified. The estimated base saturation of the B horizon for the watersheds studied was less than 20% for 90% of the watersheds, which is a likely result of base depletion by acidic deposition that has rendered this horizon ineffective at buffering inputs of acidity. The percentage of streams determined to be moderately to severely effected by acidic deposition on the basis of the diatom data ranged from 66% to 80%. Macroinvertebrate communities were moderately to severely effected in 52% of assessed streams. Finally, recovery from acidification in the Adirondack streams and outlets sampled in the early 1980s has been minimal, with the exception of Bald Mountain Brook and Fly Pond Outlet. The overall increase in ANCg for the 12 streams was 13 µeq L-1 over 23 years.
USGS National Center MS270
P.O. Box 71362 Department of Interior
Philadelphia, PA 28272
Environmental Monitoring & Research
NYSERDA Contact Information
R&D - Environment & Energy Res