bluuebunny/crossref_metadata_2025_split huggingface dataset:
Using historical biological data to evaluate status and trends in the Big Darby Creek watershed (Ohio, USA)
Authors: Schubauer-Berigan Mary K , Smith Marc , Hopkins Jeff , Cormier Susan M 
Published: March 2010

Abstract
Assessment of watershed ecological status and trends is challenging for managers who lack randomly or consistently sampled data, or monitoring programs developed from a watershed perspective. This study investigated analytical approaches for assessment of status and trends using data collected by the Ohio Environmental Protection Agency as part of state requirements for reporting stream quality and managing discharge permits. Fish and benthic macroinvertebrate metrics collected during three time periods (1979–1981, 1986–1989, 1990–1993) were analyzed for the mainstem of Big Darby Creek, a high-quality warm-water stream in central Ohio, USA. Analysis of variance of transformed metrics showed significant differences among time periods for six fish metrics. In addition, significant positive linear trends were observed for four metrics plus the index of biotic integrity score, and negative linear trends for two fish metrics. An analysis of a subset of sites paired by location and sampled over the three periods reflected findings using all available data for the mainstem. In particular, mean estimates were very similar between the reduced and full data sets, whereas standard error estimates were much greater in the reduced subset. Analysis of serial autocorrelation patterns among the fish metrics over the three time periods suggests changes in the nature of stressors over time. A comparison within the most recent time period showed significantly better condition for Big Darby Creek mainstem than for Hellbranch Run (the easternmost subwatershed), after adjusting for watershed size. The consistency of paired and nonrandomized results suggested that either type of data might be judiciously used for this watershed assessment. Results indicated that overall biological condition of the mainstem of the Big Darby Creek watershed has significantly improved since the early 1980s.
Empirical stressor–response relationships for prospective risk analysis
Authors: Gordon Steven I , Majumder Sarada 
Published: March 2010

Abstract
Environmental modeling has long been a recognized part of environmental risk assessment. Traditionally, environmental models have been deterministic models for specific processes over small areas using spatially aggregated subunits for data collection and processing. For an analysis of environmental risk factors on a regional scale, such models are not always appropriate because of uncertainties in the processes, heterogeneity of the environment, and extensive data requirements. Under such circumstances, statistical modeling of the environment can offer useful insights because it deals with a combination of processes and provides a broad view of the degree and significance of the factors impacting ecological resources on a regional scale. Using data from the Eastern Cornbelt Plains ecoregion of Ohio, USA, we have developed several statistical models relating anthropogenic activities on the watershed and a set of stream condition variables to the biological quality of stream segments. The effects of land use and in-stream physical and chemical factors on the biological indicator, the index of biotic integrity, have been studied using nested watersheds as geographic units. The effects of scale and spatial aggregation have been integrated into the model. A geographic information system database was built using Arc/Info® software (Environmental Systems Research Institute, Redlands, CA, USA) for integrating and summarizing data. The results can be used as a screening model to help planners review the potential cumulative impacts of human activities on indicators of fish community structure. Future work will try to account more explicitly for distance decay of pollutants and the effects of underlying geology and soils on variations in biological diversity.
Can biological assessments discriminate among types of stress? A case study from the Eastern Corn Belt Plains ecoregion
Authors: Norton Susan B , Cormier Susan M , Smith Marc , Jones R Christian 
Published: March 2010

Abstract
We investigated the feasibility of using the structure of fish and benthic macroinvertebrate communities to distinguish among major types of stressors (e.g., siltation, nutrient enrichment, and stream structural degradation) using spatially and temporally matched data on stressors and responses. The 19 stressor variables addressed stream chemistry and in-stream habitat and included biological oxygen demand (BOD), total suspended solids, nitrogen, phosphorus, and components of the Qualitative Habitat Evaluation Index. The 42 response variables addressed fish and invertebrate community structure and included many of the component metrics of the Index of Biological Integrity and the Invertebrate Community Index as well as variables specifically calculated for this project. All data were collected between 1988 and 1994 by the Ohio Environmental Protection Agency in the Eastern Corn Belt Plains ecoregion. Prior to analysis, variables were transformed to near normality, and variables significantly correlated with drainage area were fit to regression models and the resulting residuals used in the analyses. Multivariate analyses included factor and discriminant analysis. The first six stressor factors explained 69% of the variation. Discriminant functions formed using the response variables significantly separated site clusters classified into high, medium, and low categories along stressor gradients. Both fish and macroinvertebrate variables were important in distinguishing site categories. For example, percentage Tanytarsini midges and percentage Glyptotendipes were important in distinguishing sites having high and low BOD. Percentage darters was associated with sites having high scores for stream corridor structure and low concentrations of inorganic nutrients, and percentage round-bodied suckers was associated with sites having low BOD and low concentrations of zinc and lead. These results indicate that diagnostic models may be developed that will be useful for site-specific and regional assessments.
Using regional exposure criteria and upstream reference data to characterize spatial and temporal exposures to chemical contaminants
Authors: Cormier Susan M , Lin Edith LC , Millward Michael R , Schubauer-Berigan Mary K , Williams Daniel E , Subramanian Bhagya , Sanders Randall , Counts Bernie , Altfater David 
Published: March 2010

AbstractAnalyses of biomarkers in fish were used to evaluate exposures among locations and across time. Two types of references were used for comparison, an upstream reference sample remote from known point sources and regional exposure criteria derived from a baseline of fish from reference sites throughout Ohio, USA. Liver, bile, and blood were sampled from white suckers (Catostomus commersoni) and common carp (Cyprinus carpio) collected during 1993 and 1996 in the Ottawa River near Lima, Ohio. Levels of exposure were measured for petroleum by naphthalene-type metabolites, combustion by-products by benzo[a]pyrene-type metabolites, coplanar organic compounds by ethoxyresorufin-O-deethylase (EROD) activity, and urea by blood urea nitrogen (BUN) levels. The four biomarkers analyzed proved effective in determining differences between reference and polluted sampling sites, between geographically close (&lt;0.5 km) sites, and between sampling years at sites common in both years. Calculated exposure criteria levels of the polycyclic aromatic hydrocarbon bile metabolites were found to be a conservative approximation of levels from a designated reference site and could thereby permit comparison of biomarker levels of fish from the Ottawa River to a regional reference level. Polycyclic aromatic hydrocarbon bile metabolite and EROD activity levels were more reflective of spatial patterns of contamination than BUN, although all biomarkers indicated differences overtime. Biomarkers from white suckers seemed to be more responsive in detecting changes in contaminant levels than the same biomarkers from common carp. Lower levels in 1996 of all biomarkers at many sites suggested lower exposures than in 1993 and could be indicative of some improvement over the period.
From plan to practice: Implementing watershed-based strategies into local, state, and federal policy
Authors: Jones Alice L , Gordon Steven I 
Published: March 2010

Abstract
Planners are becoming increasingly interested in watershed-based plans as a way to more accurately reflect the natural landscape processes that cross the borders of political jurisdictions. Although developing plans that cross political boundaries is a relatively simple matter, establishing the transboundary authority necessary to implement such plans is often a much different matter. We investigated the regulatory mechanisms under which a watershed-based storm-water management plan could be implemented in the Big Darby Creek, Ohio, USA, a national scenic river currently facing critical threats from nonpoint sediment- and pollutant-loaded storm-water runoff in the rapidly urbanizing portions of the watershed. The watershed encompasses portions of 7 counties, 11 incorporated areas, and 26 townships, each of which has some authority over land use and storm water. The transboundary options explored include creation of a storm-water utility, creating a conservancy district, or an independent approach requiring all jurisdictions in the watershed to simultaneously adopt a series of storm-water ordinances. We evaluated these options on a number of characteristics, including their relative ability to control runoff quality and quantity, the locus of political control and enforcement authority under each, funding considerations, and the likelihood of acceptance given the region's existing political realities. Although a central authority such as a conservancy district or storm-water management district would likely be most effective in protecting water quality, the long tradition of local controls on land use makes this politically infeasible. Thus, we argue that a watershed-based protection plan for the Darby region will require the simultaneous independent approach. The case study of the Big Darby suggests that the successful implementation of watershed-based plans may be more dependent on the plan's political savvy than its technical superiority.
Proximity-based measure of land use impacts to aquatic ecosystem integrity
Authors: Wente Stephen P 
Published: March 2010

Abstract
A proximity-based measure of land-use impacts to aquatic ecosystem integrity based on both the relative abundance and spatial distribution of land uses within a watershed is developed and evaluated. This hydrologic proximity measure assumes that the impact of the land use at a specific position in the watershed upstream from a sample site is related to the relative volume of water that would be expected to flow through that position during a storm event. In order to evaluate the utility of this measure, the fit of several models based on land use and habitat assessment measures to biological integrity data is compared to the fit of a similar model based on hydrologic proximity measures. This hydrologic proximity model explained more of the variability in observed Hilsenhoff biotic index scores (R2 = 0.92) than land use impacts estimated as the watershed surface area occupied by each land use (R2 = 0.83), U.S. Environmental Protection Agency habitat assessment methods (R2 = 0.68), or Ohio Environmental Protection Agency habitat assessment methods (R2 = 0.68). Additionally, an algorithm based on the hydrologic proximity measure is presented for optimizing land use conversion projects to enhance biological integrity.
Vulnerability of ecosystems of the mid-Atlantic region, USA, to climate change
Authors: Lassiter Ray R , Box Elgene O , Wiegert Richard G , Johnston John M , Bergengren Jon , Suárez Luis A 
Published: March 2010

Abstract
Changes in the distribution of vegetation in the mid-Atlantic region of the United States were explored for two climate-change scenarios. The equilibrium vegetation ecology (EVE) model was used to project the distribution of life forms and to combine these into biomes for a doubled-CO2 scenario generated by the GENESIS earth system model. The species model, a climate-envelope model, was used to project the distribution of 200 woody plant species for a climate-change scenario with mean 2°C warming, enhanced winter warming, and no net evapotranspiration. Results from EVE suggest a considerable northward shift of both northern and southern boundaries of the biomes that occur in the mid-Atlantic region. The species model, using the climate scenario with no net evapotranspiration, more closely examines the isolated effect of temperature. This model predicts that most species will persist in their present location, with considerable expansion northward and with a small fraction of the species throughout the region experiencing dieback. Present-day ranges of several vertebrate species, considered with anticipated climatic changes, suggest that animal range changes will also occur.
Modeling, mapping, and managing critical loads for forest ecosystems using a geographic information system: Approach of Wallonia, Belgium, to the study of long-range transboundary air pollution effects on ecosystems in Europe
Authors: Eloy Sara 
Published: March 2010

Abstract
This critical load approach has been developed to guide policies aimed at reducing atmospheric pollutant emissions as part of the Geneva Convention on Long-Range Transboundary Air Pollution (CLRTAP). Belgium, and more precisely the Walloon region, fit into this policy. To the best of our knowledge, the critical load for an ecosystem is defined as the maximal amount of one or more pollutant deposits below which no harmful impact appears in the ecosystem. The assessment method chosen for the Walloon region and tested during its forest ecosystem surveys is based on a simple mass balance model. This model involves management of much spatial data and, therefore, requires implementation of a geographic information system. This work has allowed the Walloon region to participate in ongoing CLRTAP negotiations and has provided an important tool with which to construct regional strategies to reduce the levels of acid pollutants.
Integrating mesocosm experiments with field and laboratory studies to generate weight-of-evidence risk assessments for large rivers
Authors: Culp Joseph M , Lowell Richard B , Cash Kevin J 
Published: March 2010

AbstractRegional assessments on large rivers often are complicated because these ecosystems receive multiple, interacting effluent discharges. Confounding factors, such as complicated mixing hydraulics and historical loading effects, can result in equivocal field data that lend weak inference to ecological risk assessments. Our approach to this problem develops a strategy that defines important mechanisms of pollutant effects through the combined use of laboratory and field measurements, riverside mesocosm experiments, and the incorporation of indicators at several trophic levels. We integrate these different types of information through weight-of-evidence postulates that provide logical guidelines for establishing causation in ecological risk assessment. Using this approach, retrospective risk assessments on the Fraser River, British Columbia, Canada, indicated that the major effect of present effluent discharges has been one of nutrient enrichment and stimulation of food web productivity. In fact, the Fraser River study suggests that small increases in effluent concentration in the river may produce negative ecological effects because of contaminant stresses. The combination of field experiments with this weight-of-evidence approach yielded the scientific justification for a conceptual model that describes community shifts across a nutrient–contaminant gradient. We conclude that the use of stream mesocosms with the weight-of-evidence approach is highly useful for establishing a mechanistic understanding of community responses to stressors at a regional scale. In addition, this approach will be useful when greater understanding of a particular class of anthropogenic stressors (e.g., specific types of effluent) is required to improve regulatory guidelines.
Diel temperature effects on the exchange of elemental mercury between the atmosphere and underlying waters
Authors: Loux Nicholas T 
Published: March 2010

Abstract
Ample scientific literature demonstrates that elemental mercury evasion from natural waters displays a diel cycle; evasion rates measured during the day are typically two to three times the values observed at night. The traditional explanation for this phenomenon is that water column elemental mercury concentrations display a diel cycle, with elemental mercury concentrations occurring at their highest values during the day. The present study tests the hypothesis that diel atmospheric temperature cycles also may play a significant role in diel mercury evasion rates. A chemical potential model is used to provide a thermodynamic framework for the development of nonisothermal Henry's law constants to describe atmospheric–aqueous partitioning of elemental mercury under temperature disequilibrium conditions. The effects of temperature disequilibrium on aqueous diffusive layer transport properties also are examined. Findings suggest that under one set of real-world temperature disequilibrium conditions, diel evasion rate variations of up to 44% can be anticipated. Given the inability to consider the effects of temperature disequilibrium on aqueous diffusive layer thicknesses, the actual effects of temperature disequilibrium on rates of mercury evasion may exceed this value. Finally, the temperature disequilibrium phenomenon may be most significant for atmospheric–aqueous exchange of trace toxicants that do not experience dynamic environmental speciation behavior.
Structure-toxicity assessment of metabolites of the aerobic bacterial transformation of substituted naphthalenes
Authors: LeBlond Jeffrey D , Applegate B ruce M. , Menn Fu-Minn , Schultz T Wayne , Sayler Gary S. 
Published: March 2010

Abstract
Pseudomonas fluorescens 5R, a naphthalene-degrading bacterium isolated from manufactured gas plant soil contaminated with polycyclic aromatic hydrocarbons, was examined for its degradative capacity of a number of substituted naphthalenes. In general, those compounds substituted on only one ring with an electrically neutral substituent were found to be transformed primarily to substituted salicylic acids according to the classical (NAH7) naphthalene dioxygenase-initiated upper pathway reactions of the naphthalene degradative pathway (i.e., the NAH system). Dimethylnaphthalenes with a substituent on each ring, and certain halogenated naphthalenes, were transformed via a monohydroxylation reaction to form hydroxylated dead-end products. Of the substituted salicylic acids examined, only 3- and 4-methylsalicylic acid, the respective products of the degradation of 1- and 2-methylnaphthalene, were further degraded by salicylate hydroxylase and catechol 2,3-dioxygenase, the first two enzymes of the NAH lower pathway. Using the Tetrahymena pyriformis acute toxicity assay, many of the monohydroxylated products of incomplete biodegradation were found to be polar narcotics. Substituted salicylic acids that are not further degraded by the NAH lower pathway were found to be toxic via carboxylic acid narcosis.
Interactions between soil, toxicant, and alux-marked bacterium during solid phase–contact toxicity testing
Authors: Shaw Liz J , Beaton Yvonne , Glover L Anne , Killham Kenneth , Meharg Andrew A 
Published: March 2010

AbstractBioluminescence-based, solid-contact toxicityassaysallow test bacterium and toxicant tointeract atthesolid-solution interface. A lux-marked bacterium, Burkholderia sp. RASC, and 2,4-dichlorophenol (2,4-DCP) were used to characterize these interactions. In the basic bioassay, cells were added to soil slurries containing 2,4-DCP (0–120 μg ml−1). After 15 min, soil was removed by centrifugation, and bioluminescence in the supernatant was determined. Investigation of 2,4-DCP adsorption to soil revealed that sorption was linear and not significantly (p &gt; 0.1) affected by the presence of Burkholderia cells. The numbers of culturable Burkholderia cells in the assay supernatant were 48.2 to 64.8% of the inoculum and independent of the soil weight. The effect of soil on 2,4-DCP toxicity was investigated by comparing soil aqueous extract and contact assays. The percentage bioluminescence for the contact assay was consistently higher than the extract assay at all test concentrations, and counts of viable Burkholderia cells were enhanced by the presence of 2,4-DCP in the contact assay. Expressing results as specific bioluminescence decreased the variability in response and the discrepancy in results between the two protocols. We suggest that solid-contact assays need improvement to ensure defined contact between cells and solid phase, and that the reporting of specific activity should be emphasized.
Responses of Folsomia fimetaria (Collembola: Isotomidae) to copper under different soil copper contamination histories in relation to risk assessment
Authors: Scott-Fordsmand Janeck J , Krogh Paul Henning , Weeks Jason M 
Published: March 2010

Abstract
The collembolan Folsomia fimetaria L. was exposed in the laboratory to a range of elevated soil copper concentrations under two different contamination histories. These results were compared with the in situ abundance of F. fimetaria in a copper-contaminated field site. In the laboratory studies, an EC10 of 337 mg Cu/kg was observed for soil spiked with copper 1 d before the experiment. Using soil from a field site contaminated with copper more than 70 years previously, no effect was observed at concentrations as great as 2911 mg Cu/kg. Reproduction was threefold more sensitive than mortality or growth. Differences in copper sensitivity between sexes and between juvenile clutches were also indicated. The abundance of F. fimetaria showed no change with soil copper concentrations during the first year (spring sampling) of in situ observations. During the second year (autumn sampling), a reduced number per area was observed with increasing soil copper concentrations. Both the presence and abundance of other euedaphic collembolans generally exhibited distribution patterns similar to those of F. fimetaria. Thus, the contamination history and the toxicological endpoint were very important for interpreting the outcome of the standard laboratory toxicity test. Laboratory studies to some extent reflected the in situ abundance, but this depended on the contamination history and the field sampling time. Laboratory experiments using new copper-spiked soil provided the lowest effect levels.