Browsing by Author "Timpano, Anthony J."

Now showing 1 - 13 of 13
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    Assessing Flow-driven Effects on Local and Downstream Water Quality in Central Appalachian Headwater Streams Influenced by Surface Coal Mining
    Schoenholtz, Stephen H.; McLaughlin, Daniel L.; Entrekin, Sally A.; Hotchkiss, Erin R.; Timpano, Anthony J.; Cianciolo, Thomas R.; Word, Clayton S. (Virginia Tech. Powell River Project, 2020-10)
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    Benthic Macroinvertebrate Community Temporal Dynamics and Their Response to Elevated Specific Conductance in Appalachian Coalfield Headwater Streams
    Boehme, 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.
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    Chronic Toxicity of Trace-Metal Mixtures to Juvenile Freshwater Mussels
    Timpano, Anthony J.; Jones, Jess W. (Virginia Tech. Powell River Project, 2019)
    Funding from Powell River Project in FY2019 provided partial support for completion of data analysis and communication of findings from a prior ecotoxicological study funded by The Nature Conservancy (TNC). Our communications included oral presentations at two scientific meetings, three webinar presentations to federal agency staff, preparation of a final technical report, and preparation of a manuscript for publication in a peer-reviewed journal. Completed analyses of study results and sharing of findings should aid efforts to conserve and restore mussel populations in the Clinch and Powell rivers, thus advancing the environmental science mission of the Powell River Project to enhance management and restoration of environmental resources affected by mining in the Appalachian coalfield. This Annual Report contains a summary of research findings from the study supported by TNC, followed by a summary of activities described above that were supported directly by Powell River Project.
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    Combined effects of copper, nickel, and zinc on growth of a freshwater mussel (Villosa iris) in an environmentally relevant context
    Timpano, Anthony J.; Jones, Jess W.; Beaty, Braven; Hull, Matthew; Soucek, David J.; Zipper, Carl E. (Elsevier, 2022-01)
    Trace metals rarely contaminate freshwaters independently, hence regulatory limits based on single-metal toxicity may be underprotective of aquatic life. This could be especially the case for rare and sensitive fauna like freshwater mussels, such as those suppressed in the Clinch and Powell Rivers in eastern USA where trace metals are long-term contaminants but at concentrations below regulatory limits. We hypothesized metal mixtures may be exerting combined effects on mussels, resulting in greater toxicity than would be predicted based on single-metal exposures. To test that hypothesis, we conducted two experiments exposing juvenile rainbow mussels (Villosa iris) for 42 days to dissolved copper, nickel, and zinc, individually and in three-metal mixtures, in an environmentally-relevant context of water with chemistry (hardness 155 mg/L as CaCO3, dissolved organic carbon 1.7-2.3 mg/L, pH 8.4) similar to that of the Clinch River, which receives alkaline mine drainage. We used a toxic unit approach, selecting test concentrations based on literature values for the lower of 28-day survival or growth (length) effect concentrations for Villosa iris or Lampsilis siliquoidea (fatmucket). Our first experiment confirmed survival and growth effects when acute and chronic water quality criteria, respectively, are approached and/or exceeded. Our second experiment, at lower concentrations, showed no effects on survival but combined effects on growth were evident: a mixture of Cu, Ni, and Zn (7.2 +/- 1.2, 65.3 +/- 6.1, 183 +/- 32 mu g/L, respectively) inhibited growth (dry weight) by 95% versus 73%, 74%, and 83% inhibition for single-metal exposures to Cu, Ni, and Zn of similar concentration (8.0 +/- 1.1, 63.5 +/- 4.8, 193 +/- 31 mu g/L, respectively). Furthermore, a mixture of Cu, Ni, and Zn with individual concentrations 21%, 29%, and 37% of their water quality criteria (3.4 +/- 1.2, 21.8 +/- 1.8, and 62.1 +/- 8.4 mu g/L, respectively) inhibited growth (dry weight) by 61% relative to controls. Our observation of combined effects suggests that regulatory limits based on single-metal toxicity may be underprotective of freshwater mussels when multiple metals are present.
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    Comparison of benthic macroinvertebrate assessment methods along a salinity gradient in headwater streams
    Pence, Rachel A.; Cianciolo, Thomas R.; Drover, Damion R.; McLaughlin, Daniel L.; Soucek, David J.; Timpano, Anthony J.; Zipper, Carl E.; Schoenholtz, Stephen H. (Springer, 2021-12-01)
    Benthic macroinvertebrate community assessments are used commonly to characterize aquatic systems and increasingly for identifying their impairment caused by myriad stressors. Yet sampling and enumeration methods vary, and research is needed to compare their abilities to detect macroinvertebrate community responses to specific water quality variables. A common assessment method, rapid bioassessment, uses subsampling procedures to identify a fixed number of individual organisms regardless of total sample abundance. In contrast, full-enumeration assessments typically allow for expanded community characterization resulting from higher numbers of identified organisms within a collected sample. Here, we compared these two sampling and enumeration methods and their abilities to detect benthic macroinvertebrate response to freshwater salinization, a common stressor of streams worldwide. We applied both methods in headwater streams along a salinity gradient within the coal-mining region of central Appalachia USA. Metrics of taxonomic richness, community composition, and trophic function differed between the methods, yet most metrics exhibiting significant response to SC for full-enumeration samples also did for rapid bioassessment samples. However, full-enumeration yielded taxonomic-based metrics consistently more responsive to the salinization gradient. Full-enumeration assessments may potentially provide more complete characterization of macroinvertebrate communities and their response to increased salinization, whereas the more cost-effective and widely employed rapid bioassessment method can detect community alterations along the full salinity gradient. These findings can inform decisions regarding such tradeoffs for assessments of freshwater salinization in headwater streams and highlight the need for similar research of sampling and enumeration methodology in other aquatic systems and for other stressors.
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    Levels of Dissolved Solids Associated with Aquatic Life Effects in Headwater Streams of Virginia Central Appalachian Coalfield Region
    Timpano, Anthony J.; Schoenholtz, Stephen H.; Zipper, Carl E.; Soucek, David J. (Virginia Tech. Powell River Project, 2011)
    Benthic macroinvertebrate communities in headwater streams influenced by Appalachian coal mining often differ from communities in minimally disturbed streams. Elevated levels of total dissolved solids (TDS) associated with mining have been suggested as stressors to these communities. In studies of such streams conducted to date, both non-TDS stressors and elevated TDS have been present as potential influences on biota. In the study reported here the association between dissolved salts and benthic macroinvertebrate community structure was examined using a familylevel multimetric index and genus-level taxa sensitivity distributions. Test sites were selected along a gradient of elevated TDS, with non-TDS factors of reference quality. Virginia Stream Condition Index (VASCI) scores were regressed against log-transformed measures of TDS, specific conductance, and sulfate (SO4 2-) using ordinary least squares and quantile regression techniques. Biological effects, as defined by VASCI scores <60 indicating stressed or severely stressed conditions, were observed with increasing probability from 0% at ≤ 190 mg/L TDS to 100% at ≥ 1,108 mg/L TDS, with 50% probability of effects observed at 422 mg/L TDS. Associations between water quality measures and biological condition were variable, with approximately 48% of the variance explained by TDS. Genus-level analysis using a field sensitivity distribution approach indicated 95% of reference genera were observed at sites with TDS ≤ 281 mg/L, and 80% of genera were observed at sites with TDS ≤ 411 mg/L. This is evidence that TDS, specific conductance, or SO4 2-can be used to establish dissolved solids levels for streams influenced by Appalachian coal mining above which aquatic life effects are increasingly probable.
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    Levels of Dissolved Solids Associated with Aquatic Life Effects in Headwater Streams of Virginia's Central Appalachian Coalfield Region
    Timpano, Anthony J. (Virginia Tech, 2011-03-16)
    Benthic macroinvertebrate communities in headwater streams influenced by Appalachian coal mining often differ from communities in minimally distrubed streams. Total dissolved solids (TDS) associated with mining have been suggested as stressors to these communities. In studies of such streams conducted to date, both non-TDS stressors and elevated TDS have been present as potential influences on biota. Here the association between dissolved salts and benthic macroinvertebrate community structure was examined using a family-level multimetric index and genus-level taxa sensitivity distributions. Test sites were selected along a gradient of elevated TDS, with non-TDS factors of reference quality. Virginia Stream Condition Index (VASCI) scores were regressed against log-transformed measures of TDS, specific conductance, and sulfate (SO42-) using ordinary least squares and quantile regression techniques. Biological effects, as defined by VASCI scores indicating stressed or severely stressed conditions, were observed with increasing probability from 0% at ≤ 190 mg/L TDS to 100% at ≥ 1,108 mg/L TDS, with 50% probability of effects observed at 422 mg/L TDS. Associations between water quality measures and biological condition were variable, with approximately 48% of the variance explained by TDS. Genus-level analysis using a field sensitivity distribution approach indicated 95% of reference genera were observed at sites with TDS ≤ 281 mg/L, and 80% of genera were observed at sites with TDS ≤ 411 mg/L. This is evidence that TDS, specific conductance, or SO42- can be used to establish dissolved solids levels for streams influenced by Appalachian coal mining above which aquatic life effects are increasingly probable.
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    Spatiotemporal Patterns of Major Ions and Trace Elements in the Powell River
    Timpano, Anthony J.; Jones, Jess W. (Virginia Tech. Powell River Project, 2020)
    Freshwater mussel populations in the Powell River have been in decline over several decades, with no indication of recovery. Identification of the cause(s) of mussel decline and continued suppression is a critical step toward improving water quality and restoring mussel populations in the Powell River. Toxicity from major ions and/or trace elements released from coal-mine discharges is hypothesized as a candidate but experimentation is needed to test that hypothesis. This study generated critical data on concentrations of major ions and trace elements, along with their spatial and temporal variation, which will enable accurate characterization and thus replication of environmentally-relevant exposure conditions for such experiments. We sampled water-column (surface) and substrate interstitial (pore) water seven times over the course of one year at nine locations in Powell River spanning 157 river kilometers. We found major ions and trace elements exhibited considerable longitudinal and intra-annual seasonal variation, with highest concentrations observed for most measured constituents in late summer/fall concurrent with low river discharge, and in river segments nearest coal-mining and other land uses that can increase erosion potential (urbanization, agriculture, forestry). Concentrations of trace elements were generally low relative to water-quality criteria in filtered surface and pore water with the exception of selenium, which regularly exceeded 40% of its chronic criterion but rarely exceeded it. In contrast, substantial amounts of trace elements were associated with interstitial fine sediment particles, with all toxic elements except arsenic having potential to exceed their chronic criteria if they were to become bioavailable, especially copper and lead. Although most major ions were well-correlated between surface and pore water, trace elements were less so, rendering prediction of pore-water concentrations from surface-water concentrations less likely. These results demonstrate the potential unreliability of estimating potential toxic exposures to benthic organisms from surface-water concentrations alone, and underscore the need for further research of all environmental compartments that may serve as sources and routes by which aquatic life, especially freshwater mussels, may be exposed to trace elements. The data generated by this study will facilitate such research by enabling characterization of realistic exposures to trace elements, to include how their spatial and temporal variation influence such exposures.
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    Spawning and gravidity of the endangered freshwater mussel Epioblasma capsaeformis (Bivalvia: Unionidae) in captivity for production of glochidia
    Jones, Jess W.; Henley, William F.; Timpano, Anthony J.; Frimpong, Emmanuel A.; Hallerman, Eric M. (2020-11-02)
    Understanding the reproductive biology of the endangered Epioblasma capsaeformis of the eastern United States is critical to conservation efforts at mussel hatcheries. We studied how males influenced gravidity among females held in captivity. Percent males (0%, 33%, 50%, and 67%) within a holding system was used as the predictor variable. Our response variables were percent females observed gravid, number of eggs and glochidia per gravid female, total eggs (sum of eggs and glochidia) per gravid female, and proportion of total eggs successfully fertilized and developed into glochidia. Mean percent of females gravid in the male treatments were 73%, 85%, 69%, and 60%, respectively, with no evidence that treatments differed significantly from one another. However, the treatment without males had significantly lower mean number of total eggs observed (4,533 vs. 5,868 to 7,330), with fewer viable glochidia (1,354 vs. 5,645 to 6,920). Most of the eggs in the treatment without males were unfertilized at experiment completion (3,179 vs. 206 to 410), with a much lower percentage of transformed glochidia (27% vs. 94 to 97%). Our study documents the important role that males play in fertilizing females for production of glochidia and that key reproductive processes occurred in captivity.
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    Taxon and trait-based sampling curves can be used as a tool for assessing impairment in salinized headwater streams
    James, Aryanna; Pence, Rachel A.; Pond, Gregory; Schoenholtz, Stephen H.; Timpano, Anthony J.; Zipper, Carl E.; Entrekin, Sally A. (Elsevier, 2022-06-01)
    Many ecosystems are losing biodiversity, raising concern for the services they provide. However, the extent of loss is uncertain, especially for diverse insects, because of incomplete sampling. Modeling techniques for estimating upper bounds on diversity are needed to assess benthic freshwater insect abundances, taxa richness, and diversity because some species are declining at alarming rates while others are increasing. In central Appalachian streams of the U.S.A., aquatic insect communities have lost diversity following salinization caused by mining activities. However, the number of taxa observed are dependent upon sampling effort. Incomplete sampling could misrepresent biodiversity and functional losses. Our goal was to use taxon sampling curves to estimate sampling effort required to maximize the probability of accurate benthic macroinvertebrate characterization in dominant riffle habitats of headwater streams. We collected 5 to 10 quantitative benthic macroinvertebrate samples in each of six, first-order streams in the central Appalachian region. For our single-habitat, mesoscale approach, we predicted: (1) macroinvertebrate taxa richness would be the most robust indicator of salinization response compared to diversity, evenness, and density, (2) less sampling effort would be needed to capture taxonomic richness in salinized streams compared to reference streams, and (3) response diversity would also be lower in salinized streams because select trait states would be represented by fewer taxa. Results suggested nominally lower taxa richness, evenness, and diversity in some salinized streams but not in all despite greater or more variable within-stream densities. Nonetheless, sampling effort required to characterize macroinvertebrate communities did not differ between reference and salinized streams, though uneven within-stream taxa distributions corresponded with greater sampling effort requirements for complete characterization. Benthic macroinvertebrate community characteristics were different where higher densities and richness of small-bodied and fast-developing taxa were more common in salinized streams. Response diversity depended on trait states. For example, only about five shredder taxa were represented in salinized streams compared to eight taxa in reference streams. Despite some indication of lower response diversity across some functional feeding groups, more than five samples were needed for robust comparisons. Taxon and trait-based sampling curves suggest that greater overall sampling effort is needed and equal samples per stream was critical for complete diversity assessments regardless of the level of mining-induced salinization. Model-based sampling curves can serve as a tool to assess upper bounds on diversity metrics and sample-effort rigor.
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    Temporal Dynamics of Benthic Macroinvertebrate Communities and Their Response to Elevated TDS in Appalachian Coalfield Streams
    Boehme, 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.
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    Total Dissolved Solids in Appalachian Coalfield Streams: Current Research Approaches
    Zipper, 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.
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    Toward improved assessment of freshwater salinization as a benthic macroinvertebrate stressor
    Timpano, Anthony J. (Virginia Tech, 2017-09-27)
    Salinization of freshwaters by human activities is of growing concern globally. Salt pollution can cause adverse effects to aquatic biodiversity, ecosystem function, ecosystem services, and human health. In many regions of the world, and in coal-mining-influenced streams of the temperate forests of Appalachia USA, specific conductance (SC), a surrogate measure for the dissolved major ions composing salinity, has been linked to decreased diversity of benthic macroinvertebrates. However, assessments used to reach this conclusion have generally not accounted for temporal variability of salinity, as most studies use "snapshot" SC data collected concurrently with biological data at a single point in time. Effective management of salinization requires tools to accurately monitor and predict salinity while accounting for temporal variability. To improve those tools, I conducted analyses of 4.5 years of salinity and benthic macroinvertebrate data from 25 forested headwater streams spanning a gradient of salinity where non-salinity stressors were minimized. My objectives were to: 1) model the annual pattern of salinity, 2) determine if salinity measures derived from continuous data are more precise than snapshot SC as predictors of aquatic biology, and 3) quantify response to salinity of the benthic macroinvertebrate community. A sinusoidal model of the annual cycle of SC using daily measurements for 4.5 years revealed that salinity naturally deviated ± 20% from annual mean levels, with minimum SC occurring in late winter and maximum SC occurring in late summer. The pattern was responsive to seasonal dilution as driven by catchment evapotranspiration dynamics. Alternative discrete sampling intervals can approximate the pattern revealed by continuous SC data if sampling intervals are ≤ 30 days. Continuous SC variables did not significantly improve precision for prediction of benthic macroinvertebrate metrics (p > 0.1) as compared to snapshot SC using generalized additive mixed models. Results suggest that snapshot SC is a capable predictor of benthic macroinvertebrate community structure if sampling is carefully timed. However, continuous SC data can quantify chronic salt exposure, which supports a hypothesis to explain how temporal variability of field-based observations of salt sensitivity of benthic macroinvertebrate taxa may be influenced by life stage. Benthic macroinvertebrate community structure diverged from reference condition as salinity increased, with stronger relationships in Spring than in Fall. Intra-seasonal variation in community structure was also revealed across sampling dates. Non-Baetidae Ephemeroptera were most sensitive to salinity, with richness and abundance lower than reference at SC > 200 =µS/cm in Spring based on snapshot SC. Equivalent effects were predicted by mean monthly SC of 250-300 µS/cm from the prior Fall. Continuous conductivity monitoring may improve assessment of salinity effects because they can describe life-cycle exposure, which may aid investigations of mechanisms driving field-based observations of benthic-macroinvertebrate community alteration.