A5028896628- Environmental Toxicology and Ecotoxicology
- Soil and Water Nutrient Dynamics
- Fish Ecology and Management Studies
- Aquatic Invertebrate Ecology and Behavior
- Pesticide and Herbicide Environmental Studies
- Hydrology and Watershed Management Studies
- Aquatic Ecosystems and Phytoplankton Dynamics
- Heavy metals in environment
- Marine and coastal ecosystems
- Water Quality and Pollution Assessment
- Pharmaceutical and Antibiotic Environmental Impacts
- Sustainability and Ecological Systems Analysis
- Wastewater Treatment and Nitrogen Removal
- Ecosystem dynamics and resilience
- Toxic Organic Pollutants Impact
- Freshwater macroinvertebrate diversity and ecology
- Microbial Community Ecology and Physiology
- Marine Bivalve and Aquaculture Studies
- Mercury impact and mitigation studies
- Urban Stormwater Management Solutions
- Forest Insect Ecology and Management
- Land Use and Ecosystem Services
- Groundwater and Isotope Geochemistry
- Animal testing and alternatives
- Insect and Pesticide Research
Virginia Tech
1998-2023
Center for Environmental Health
1990
Summary 1. Rates of whole‐system metabolism (production and respiration) are fundamental indicators ecosystem structure function. Although first‐order, proximal controls well understood, assessments the interactions between distal controls, such as land use geographic region, lacking. Thus, influence on stream across regions is unknown. Further, there limited understanding how may alter variability in regions. 2. Stream was measured nine streams each eight ( n = 72) United States Puerto...
We measured uptake length of 15 NO 3 − in 72 streams eight regions across the United States and Puerto Rico to develop quantitative predictive models on controls length. As part Lotic Intersite Nitrogen eXperiment II project, we chose nine each region corresponding natural (reference), suburban‐urban, agricultural land uses. Study spanned a range human use maximize variation concentration, geomorphology, metabolism. tested causal model predicting using structural equation modeling. The...
We measured denitrification rates using a field 15 NO 3 − tracer‐addition approach in large, cross‐site study of nitrate uptake reference, agricultural, and suburban‐urban streams. 49 72 streams studied. Uptake length due to ( S Wden n) ranged from 89 m 184 km (median 9050 m) there were no significant differences among regions or land‐use categories, likely because the wide range conditions within each region land use. N 2 production far exceeded O all The fraction total removal water 0.5%...
Oxygen availability is decreasing in many lakes and reservoirs worldwide, raising the urgency for understanding how anoxia (low oxygen) affects coupled biogeochemical cycling, which has major implications water quality, food webs, ecosystem functioning. Although increasing magnitude prevalence of been documented freshwaters globally, challenges disentangling oxygen temperature responses have hindered assessment effects on carbon, nitrogen, phosphorus concentrations, stoichiometry (chemical...
Since toxicants are spread over ecological landscapes, it seems likely that they have effects at level of organization. Landscape ecotoxicology examines the toxic chemicals on larger scales than traditional environmental toxicology. This approach is characterized by use endpoints appropriate to spatial scale across which a toxicant dispersed, attention interactions between physical and temporal patterns process impairment, integration multiple lines evidence for toxicity various scales. In...
The death of eastern hemlock (Tsuga canadensis) trees in response to infestation by the introduced woolly adelgid (Adelges tsugae) may affect ecosystem processes and structure streams. Prior mortality, we documented conditions eight small streams their associated riparian forests within Appalachian Mountains North Carolina, U.S.A. Hemlock was dominant tree species on all sites always with rhododendron (Rhododendron maximum). Significant trends increasing canopy openness, light annual...
Abstract Short-term, single-species toxicity tests are used to identify, regulate and monitor the discharge of problem effluents into receiving ecosystems. The ability protect entire ecosystems has been questioned, microcosm have proposed as additional tools for reducing uncertainty in environmental risk assessment. We compared responses a complex effluent microcosms indigenous macroinvertebrates protozoans with observed acute Daphnia magna, Ceriodaphnia dubia Pimephales promelas chronic...
Abstract Naturally derived protozoan communities developed on polyurethane foam (PF) substrates were used to evaluate the toxic effects of cadmium. The ability resist displacement from a structural equilibrium in acute cadmium exposures was evaluated. number species remaining after 2 d inversely related concentration. concentration required for 50% reduction relative control (EC50) 4,000 μg Cd/L. Chronic evaluated by observing colonization barren PF islands source (PF epicenter) 28 d....
Abstract Microcosm toxicity tests using naturally derived protozoan communities were used to estimate permissible concentrations of copper. In with copper sulfate, taxonomic richness was adversely affected at ≧12.7 μg/L after 21 days. Colonization also μg Cu/L. Concentrations affecting composition, chlorophyll and biomass concentrations, nutrient retention ranged from ≦6.6 ≧59.5 A Cu concentration expected affect only 5% taxa (EC 05 ) predicted test data as 3.2 (1.6–4.8) similar a effect...
Aufwuchs communities were developed on artificial substrates in a local pond. Second-generation identical laboratory systems receiving three levels of zinc (Zn): background, 73, and 172 μg∙L −1 . After 21 d, second-generation exposed to five concentrations Zn ranging from background 10 078 for 48 h. Protozoan under stress initially less rich taxonomically but subsequently lost fewer species response acute exposures. Richness remaining after exposure high [Formula: see text] was similar all...