Browsing by Author "Boehme, Elizabeth A."
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- Benthic Macroinvertebrate Community Temporal Dynamics and Their Response to Elevated Specific Conductance in Appalachian Coalfield Headwater StreamsBoehme, Elizabeth A.; Schoenholtz, Stephen H.; Zipper, Carl E.; Soucek, David J.; Timpano, Anthony J. (Virginia Tech. Powell River Project, 2013)Protecting integrity of benthic macroinvertebrate communities, which are used to assess stream condition in Appalachian coalfield headwater streams, is essential. Previous studies have suggested elevated total dissolved solids (TDS) and closely related specific conductance (SC) in streamwater have negative effects on sensitive benthic macroinvertebrates (Timpano 2011, Bernhardt et al. 2012, Cormier et al. 2013a, Cormier et al. 2013b), although effects varied based on selected metric, chosen effect level, and in some cases, potential influence of confounding water-quality- or physical-habitat conditions. Most importantly, previous studies have relied on point-in-time measurements of SC, which may not be representative of exposure levels in the days, weeks, or months prior to sampling of benthic macroinvertebrates.
- Temporal Dynamics of Benthic Macroinvertebrate Communities and Their Response to Elevated Specific Conductance in Headwater Streams of the Appalachian CoalfieldsBoehme, Elizabeth A. (Virginia Tech, 2013-08-27)Prior studies have demonstrated Appalachian coal mining often causes elevated specific conductance (SC) in streams, and others have examined SC effects on benthic macroinvertebrate communities using point-in-time SC measurements. However, both SC and benthic macroinvertebrate communities exhibit temporal variation. Twelve Appalachian headwater streams with minimally impacted physical habitat and reference-quality physicochemical conditions (except elevated SC) were sampled ten to fourteen times each for benthic macroinvertebrates between June 2011 and November 2012. In situ loggers recorded SC at 15-minute intervals. Streams were classified by mean SC Level (Reference 17-142 S/cm, Medium 262-648 S/cm, and High 756-1,535 S/cm). Benthic macroinvertebrate community structure was quantified by the Virginia Stream Condition Index and other metrics. Structural metric differences among SC Levels and month of sampling were explored. Reference-SC streams exhibited significantly higher scores on most metrics, supporting previous findings that SC may act as a biotic stressor, even in streams lacking limitations from degradation of physical habitat or other physicochemical conditions. Temporal variation was greatest in Medium-SC streams, which had the most metrics exhibiting significant differences among months and the greatest range of monthly means for six metrics. Metrics involving % Plecoptera and/or % Trichoptera were not sensitive to elevated SC, as Leuctridae and Hydropsychidae exhibited increased abundance in streams with elevated SC. Best scores for benthic macroinvertebrate community metrics differed based on selected metric, SC Level, and month. Consequently, timing of sampling is important, particularly in streams with elevated SC because community metric scores may be impacted by dominant taxa life history patterns.
- Temporal Dynamics of Benthic Macroinvertebrate Communities and Their Response to Elevated TDS in Appalachian Coalfield StreamsBoehme, Elizabeth A.; Schoenholtz, Stephen H.; Soucek, David J.; Timpano, Anthony J. (Virginia Tech. Powell River Project, 2012)Maintaining integrity of benthic macroinvertebrate communities in Appalachian coalfield headwater streams is a key concern. Total dissolved solids (TDS) are ubiquitous as dissolved constituents in surface waters and often occur at elevated levels in streams draining Appalachian coal mines. Most TDS in surface waters originate from the dissolution of rock and mineral materials that are exposed to the natural elements; this process is accelerated in mining regions, as surface mines cause large volumes of fresh, unweathered rock material to be fractured, brought to the surface, and exposed to accelerated weathering processes. The concentration of TDS is closely related to specific conductance (SC), which is the ability for water to conduct a current at 25º C. We have been conducting research to identify benthic macroinvertebrate community composition relationships with TDS in southwestern Virginia’s mining area, where geology and environmental conditions are similar to adjacent coal‐mining areas of eastern Kentucky and southern West Virginia. This report summarizes the first year of a two‐year study, aimed to expand understanding of temporal variability within the benthic macroinvertebrate community in elevated‐TDS streams. Eleven sets of benthic macroinvertebrate and water quality grab samples have been collected to date and are being analyzed; and continuous conductivity loggers have been installed in all streams. Sampling will conclude in November 2012.
- Total Dissolved Solids in Appalachian Coalfield Streams: Current Research ApproachesZipper, Carl E.; Schoenholtz, Stephen H.; Soucek, David J.; Timpano, Anthony J.; Boehme, Elizabeth A. (Virginia Tech. Powell River Project, 2011)Issues concerning total dissolved solids (TDS) in streams affected by mining operations are important to the coal industry. In this article, we present background concerning TDS as a water quality concern, and we describe ongoing Virginia Tech research approaches to address this issue.