Injury and mortality of fish during downstream passage through hydropower turbines is among the leading direct impacts of hydropower. Understanding the relationships among various strike variables ...and injury and mortality rates are necessary for improvements in turbine design. We subjected three species of fish to simulated blade strike in laboratory studies with different blade thicknesses, impact velocities, and body orientations to develop relationships between these variables and probability of injury and mortality. Midbody strikes resulted in higher mortality than head strikes, and tail strikes produced the least mortality. Lateral strikes caused more mortality than dorsal and ventral strikes, and higher strike velocities and thinner blades contributed to increased mortality. Several injury types were significantly associated with increased mortality, including injuries to the operculum, gills, viscera, heart, liver, swim bladder, muscle, and bone fractures. Results from this study will be used to define biologically based design criteria that can be used by turbine designers to improve designs (e.g., increased leading-edge thickness and slower turbine speeds) to minimize the probability and impact of blade strike.
The fish and plant communities in a pond contaminated with polychlorinated biphenyls (PCBs) in East Tennessee, USA, were manipulated to reduce ecological and human-health risk associated with ...exposure to the chemical contaminants. We evaluated the success of the remedial action using a habitat valuation approach, as well as measuring PCB concentrations in fish. Risk reduction objectives included: alter the fish community to favor fish that do not resuspend, bioaccumulate, or biomagnify PCBs; stabilize contaminated sediments to improve water quality; and stabilize shoreline soils and enhance riparian habitat. Fish targeted for removal included gizzard shad, largemouth bass, and nonnative carp. Reduced PCB concentrations in fish have characterized the new bluegill-dominated community, although a weir-overtopping event led to the need for additional removals of gizzard shad and largemouth bass. Sunfish abundance is high, as was intended. Moreover, amphibian and waterbird diversities have increased in the years following biomanipulation, possibly owing to improvements in the riparian zone and increased structural (vegetation) complexity in both the aquatic and terrestrial environment. Thus, the remedial action has improved aspects of habitat value, and PCB concentrations in sunfish have dropped below the remediation level (risk-based target value) for this pond (1 µg/g in fish fillets or 2.3 µg/g in whole body fish).
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This paper addresses an uncommon but effective option for remediation of environmental contaminants in aquatic environments, biomanipulation. PCBs have important implications for human health and ecosystems. The paper combines analyses of PCB concentrations, habitat valuation, and water quality metrics, following biomanipulation of a pond. The 10-year study is longer than most published studies of environmental contaminants. The relevance is confirmed through funding from the US Department of Energy’s Environmental Management program, and federal and state regulatory agencies have shown interest in the findings. Biomanipulation is a less expensive and effective remediation alternative, compared to excavation of chemical contaminants.
This paper addresses an uncommon but effective option for remediation of environmental contaminants in aquatic environments, biomanipulation. PCBs have important implications for human health and ecosystems. The paper combines analyses of PCB concentrations, habitat valuation, and water quality metrics, following biomanipulation of a pond. The 10-year study is longer than most published studies of environmental contaminants. The relevance is confirmed through funding from the US Department of Energy’s Environmental Management program, and federal and state regulatory agencies have shown interest in the findings. Biomanipulation is a less expensive and effective remediation alternative, compared to excavation of chemical contaminants.
•An ecological manipulation in a contaminated pond reduced PCB concentrations in fish.•Habitat value metrics were measured over a 15-y period.•The pond transitioned from gizzard shad and largemouth bass dominance to sunfish.•PCB concentrations in bluegill decreased below risk-based targets.•Habitat metrics for most taxa are at least equal to those before biomanipulation.
Otoliths are frequently used to infer environmental conditions or fish life history events based on trace-element concentrations. However, otoliths can be comprised of any one or combination of the ...three most common polymorphs of calcium carbonate-aragonite, calcite, and vaterite-which can affect the ecological interpretation of otolith trace-element results. Previous studies have reported heterogeneous calcium carbonate compositions between left and right otoliths but did not provide quantitative assessments of polymorph abundances. In this study, neutron diffraction and Raman spectroscopy were used to identify and quantify mineralogical compositions of Chinook salmon Oncorhynchus tshawytscha otolith pairs. We found mineralogical compositions frequently differed between otoliths in a pair and accurate calcium carbonate polymorph identification was rarely possible by visual inspection alone. The prevalence of multiple polymorphs in otoliths is not well-understood, and future research should focus on identifying otolith compositions and investigate how variations in mineralogy affect trace-element incorporation and potentially bias environmental interpretations.
Human activities can be powerful drivers of ecosystem change within catchments. While most long‐term catchment studies have been conducted at pristine sites, such studies are less common from sites ...more impacted by human activity. The Oak Ridge National Laboratory's Biological Monitoring and Abatement Program (BMAP) was developed in the mid‐1980s to (1) assess compliance with environmental regulations, (2) identify causes of adverse ecological impacts, (3) provide data for human and ecological risk assessments, and (4) evaluate the effectiveness of remedial actions taken to mitigate the impacts of contaminants in soils, groundwater, and surface water by documenting ecological recovery on the Oak Ridge Reservation (ORR), a federally owned 33 476‐acre site in eastern Tennessee, managed by the US Department of Energy. The ORR is composed of multiple watersheds containing many small to mid‐size streams. BMAP uses an integrated approach for determining stream health; its databases include long‐term seasonal records of contaminant concentrations in water and biota, data from aquatic toxicity testing, and surveys of macroinvertebrate and fish assemblages from impacted and reference streams. These long‐term data provide valuable records of degradation and recovery in catchment ecosystems. Our objective here is to describe our study system and data series in order to increase awareness of the availability of these long‐term data to the catchment science community.
The Oak Ridge Reservation (ORR) is a federally owned site in eastern Tennessee, USA, managed by the U.S. Department of Energy with a long history of impacts from human activities. We present long‐term data for determining stream health in multiple watersheds on the ORR, including long‐term seasonal records of contaminant concentrations in water and biota, data from aquatic toxicity testing, and surveys of macroinvertebrate and fish assemblages from impacted and reference streams.
Prolonged and severe sleep deprivation is associated with alterations of natural and cellular immune function. To determine whether alterations of immune function also occur after even a modest loss ...of sleep, the effects of early-night partial sleep deprivation on circulating numbers of white blood cells, natural killer (NK) cell number and cytotoxicity, lymphokine-activated killer (LAK) cell number and activity, and stimulated interleukin-2 (IL-2) production were studied in 42 medically and psychiatrically healthy male volunteers. After a night of sleep deprivation between 10 P.M. and 3 A.M., a reduction of natural immune responses as measured by NK cell activity, NK activity per number of NK cells, LAK activity, and LAK activity per number of LAK precursors (CD16,56, CD25) was found. In addition, concanavalin A-stimulated IL-2 production was suppressed after sleep deprivation due to changes in both adherent and nonadherent cell populations. After a night of recovery sleep, NK activity returned to baseline levels and IL-2 production remained suppressed. These data implicate sleep in the modulation of immunity and demonstrate that even a modest disturbance of sleep produces a reduction of natural immune responses and T cell cytokine production.
Challenges exist in the wastewater treatment of dyes produced by the world's growing textiles industry. Common problems facing traditional wastewater treatments include low retention values and ...breaking the chemical bonds of some dye molecules, which in some cases can release byproducts that can be more harmful than the original dye. This research illustrates that track-etched polycarbonate filtration membranes with 100-nanometer diameter holes can be functionalized with azo dye direct red 80 at 1000 µM, creating a filter that can then be used to remove the entire negatively charged azo dye molecule for a 50 µM solution of the same dye, with a rejection value of 96.4 ± 1.4%, at a stable flow rate of 114 ± 5 µL/min post-functionalization. Post-functionalization, Na
and NO3
ions had on average 17.9%, 26.0%, and 31.1% rejection for 750, 500, and 250 µM sodium nitrate solutions, respectively, at an average flow rate of 177 ± 5 µL/min. Post-functionalization, similar 50 µM azo dyes had increases in rejection from 26.3% to 53.2%. Rejection measurements were made using ultraviolet visible-light spectroscopy for dyes, and concentration meters using ion selective electrodes for Na
and NO3
ions.
The effect of coal ash exposure on fish health in freshwater communities is largely unknown. Given the large number of possible pathways of effects (e.g., toxicological effect of exposure to multiple ...metals, physical effects from ash exposure, and food web effects), measurement of only a few health metrics is not likely to give a complete picture. The authors measured a suite of 20 health metrics from 1100+ fish collected from 5 sites (3 affected and 2 reference) near a coal ash spill in east Tennessee over a 4.5‐yr period. The metrics represented a wide range of physiological and energetic responses and were evaluated simultaneously using 2 multivariate techniques. Results from both hierarchical clustering and canonical discriminant analyses suggested that for most species × season combinations, the suite of fish health indicators varied more among years than between spill and reference sites within a year. In a few cases, spill sites from early years in the investigation stood alone or clustered together separate from reference sites and later year spill sites. Outlier groups of fish with relatively unique health profiles were most often from spill sites, suggesting that some response to the ash exposure may have occurred. Results from the 2 multivariate methods suggest that any change in the health status of fish at the spill sites was small and appears to have diminished since the first 2 to 3 yr after the spill. Environ Toxicol Chem 2014;33:1903–1913. Published 2014 Wiley Periodicals, Inc. This article is a US Government work and, as such, is in the public domain in the United States of America.
Reservoirs are a significant source of carbon (C) to the atmosphere, but their emission rates vary in space and time. We compared C emissions via diffusive and ebullitive pathways at several stations ...in six large hydropower reservoirs in the southeastern US that were previously sampled in summer 2012. We found that carbon dioxide (CO2) diffusion was the dominant flux pathway during 2012 and 2022, with only three exceptions where methane (CH4) diffusion or CH4 ebullition dominated. CH4 diffusion rates were positively associated with water temperature. However, we found no clear predictors of CH4 ebullition, which had extremely high variability, with rates ranging from 0 to 739 mg C m−2 day−1. For CO2 diffusion, the direction of the flux shifted between 2012 and 2022, where all but three stations across all reservoirs emitted CO2 in summer 2012, but every station sequestered CO2 in summer 2022. Here, indicators of greater algal production were associated with CO2 sequestration, including surface chlorophyll‐a concentration, surface dissolved oxygen saturation, and pH. Additional sampling campaigns outside the summer season highlighted the importance of seasonal phenology in primary production on the direction of CO2 diffusive fluxes, which shifted to positive CO2 fluxes by the end of August as productivity decreased. Our results demonstrate the importance of capturing CO2 sequestration in field and modeling measurements and understanding the seasonal drivers of these estimates. Measuring C emissions from multiple pathways in reservoirs and understanding their spatiotemporal responses and variability are vital to reducing uncertainties in global upscaling efforts.
Plain Language Summary
Inland waters, including reservoirs used for many different purposes, contribute greenhouse gases like carbon dioxide and methane to the atmosphere. With 34 times more global warming potential than carbon dioxide, methane is of particular concern since reservoirs emit disproportionally large amounts of it. However, our ability to quantify reservoir emissions is limited by high variability in these emissions over space and time. In this study, we measured emissions from several stations across six reservoirs and compared these emissions to a previous study from 2012 to understand potential longer‐term variation in emissions and assess driver variables. Overall, we found that algal productivity was an important driver of fluxes among the reservoirs and could in fact lead to carbon dioxide sequestration. However, the seasonal phenology in algal productivity and related variables were also important to understand when considering emissions variability within a reservoir and over time. As we continue to collect emissions measurements from reservoirs, studies focused on multiple spatial and temporal scales (i.e., day and night) can improve upscaled estimates of greenhouse gas emissions to better quantify the role of reservoirs in the global carbon cycle.
Key Points
Reservoirs are a major source of carbon emissions, but spatial and temporal variability leads to uncertain modeled or upscaled estimates
Across six reservoirs, summer CO2 diffusion was the dominant flux pathway and showed sequestration, linked to increased algal productivity
Changes in algal productivity influence the direction of CO2 diffusion with key implications for assessing net reservoir emissions
On December 22, 2008 a dike containing coal fly ash from the Tennessee Valley Authority Kingston Fossil Plant near Kingston Tennessee USA failed and resulted in the largest coal ash spill in U.S. ...history. Coal ash, a by-product of coal combustion, is known to contain multiple contaminants of concern, including arsenic and selenium. The purpose of this study was to investigate species differences in the bioaccumulation of arsenic and selenium and potential factors contributing to these differences (i.e., trophic dynamics and gut pH) in the vicinity of the Kingston coal ash spill. Elevated levels of arsenic and selenium were observed in various tissues of largemouth bass, white crappie, bluegill and redear sunfish from sites associated with the Kingston coal ash spill. Highest concentrations of selenium were found in redear sunfish with liver concentrations as high as 24.83mg/kg dry weight and ovary concentrations up to 10.40mg/kg dry weight at coal ash-associated sites. Investigations into the gut pH and trophic dynamics of redear sunfish and bluegill demonstrated a large difference in the gut physiology between these two species. Redear sunfish stomach and intestinal pH was found to be 1.1 and 0.16 pH units higher than in bluegill, respectively. In addition, fish from coal ash-associated sites showed enrichment differences (15N and 13C) compared to no ash sites, indicating differences in food web dynamics between sites. These results imply the incorporation of coal ash-associated compounds into local food webs and/or a shift in diet at ash sites compared to the no ash reference sites. Based on these results, further investigation into a broader food web at ash-associated sites is warranted.
► Environmental investigation of the largest coal ash spill in US history. ► Selenium and arsenic bioaccumulation is elevated in fish at coal ash-associated sites. ► Trophic dynamics (stable isotopes C and N) are shifted at coal ash-associated sites. ► Physiological differences in the gut of redear sunfish and bluegill exist. ► Potential evidence of coal ash constituents being incorporated into the food chain.
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