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Hydropower is the largest renewable electrical energy source in the world and has a total global capacity of approximately 1,010 GW from 150 countries. Although hydropower has many environmental advantages, hydropower dams have potential adverse ecological impacts such as fish passage, water quality, and habitat alterations.
Marine spatial planning (MSP) should assist managers in guiding human activities toward sustainable practices and in minimizing user conflicts in our oceans. A necessary first step is to quantify spatial patterns of marine assemblages in order to understand the ecosystem's structure, function, and services. However, the large spatial scale, high economic value, and density of human activities in nearshore habitats often makes quantifying this component of marine ecosystems especially daunting. To address this challenge, we developed an assessment method that employs abiotic proxies to rapidly characterize marine assemblages in nearshore benthic environments with relatively high resolution. We evaluated this assessment method along 300 km of the State of Maine's coastal shelf (<100 m depth), a zone where high densities of buoyed lobster traps typically preclude extensive surveys by towed sampling gear (i.e., otter trawls). During the summer months of 2010–2013, we implemented a stratified-random survey using a small remotely operated vehicle that allowed us to work around lobster buoys and to quantify all benthic megafauna to species. Stratifying by substrate, depth, and coastal water masses, we found that abiotic variables explained a significant portion of variance (37–59%) in benthic species composition, diversity, biomass, and economic value. Generally, the density, diversity, and biomass of assemblages significantly increased with the substrate complexity (i.e., from sand-mud to ledge). The diversity, biomass, and economic value of assemblages also decreased significantly with increasing depth. Last, demersal fish densities, sessile invertebrate densities, species diversity, and assemblage biomass increased from east to west, while the abundance of mobile invertebrates and economic value decreased, corresponding mainly to the contrasting water mass characteristics of the Maine Coastal Current system (i.e., summertime current direction, speed, and temperature). Integrating modeled predictions with existing GIS layers for abiotic conditions allowed us to scale up important assemblage attributes to define key foundational ecological principles of MSP and to find priority regions where some bottom-disturbing activities would have minimal impact to benthic assemblages. We conclude that abiotic proxies can be strong forcing functions for the assembly of marine communities and therefore useful tools for spatial extrapolations of marine assemblages in congested (heavily used) nearshore habitats.
ω-3 polyunsaturated fatty acids (PUFAs), which are abundant in fish oils, are known to scavenge lipid peroxyl radicals and potentiate host immune defence. As UVB-induced oxidative stress and inflammation have been implicated in apoptotic cell death, this study was aimed to investigate the anti-inflammatory, anti-oxidative, and anti-apoptotic capacity of fat-1 transgenic mice capable of converting ω-6 to ω-3 PUFAs. Wild-type (WT) C57BL/6 mice and fat-1 mice were maintained on the AIN-93 diet supplemented with 10% safflower oil rich in ω-6 PUFAs for 5 weeks. The ω-3/ω-6 PUFA ratio was significantly higher in the dorsal skin of fat-1 mice than that in the WT mice. Upon single exposure to UVB (5.0 kJ/m{sup 2}) radiation, fat-1 mice showed inflammatory as well as oxidative tissue damage and the expression of pro-inflammatory enzymes, cyclooxygenases-2 and inducible nitric oxide synthase in the skin to a much lesser extent than the WT mice. The protection of fat-1 mice from UVB-induced skin inflammation was associated with decreased phosphorylation of STAT3. Moreover, UVB-induced apoptosis was attenuated in fat-1 mouse skin. In comparison to WT animals, higher levels of Nrf2 and its target proteins, such as heme oxygenase-1, NAD(P)H:quinone oxidoreductase-1 and thioredoxin-1, were found in the skin of fat-1 mice.
Highlights: • Morpholino-based knockdown of ctps during early development produces zebrafish embryos with curved spines and tissue oedema. • Knockdown of ctps1a, and not ctps1b, induces more severe, longer-lasting defects. • Phenotypes are exacerbated when morpholinos against both gene variants are supplied together at uneven ratios. • The same phenotypes were recovered from embryos treated with DON, a CTPS activity-inhibiting drug. CTP Synthase (CTPS) is a metabolic enzyme that is recognized as a catalyst for nucleotide, phospholipid and sialoglycoprotein production. Though the structural characteristics and regulatory mechanisms of CTPS are well-understood, little is known regarding the extent of its involvement during the early developmental stages of vertebrates. Zebrafish carries two CTPS genes, annotated as ctps1a and ctps1b. Phylogenetic analyses show that both genes had diverged from homologues in the ancestral Actinopterygii, Oreochromis niloticus. Conservation of common CTPS-catalytic regions further establishes that both proteins are likely to be functionally similar to hsaCTPS. Here, we show that ctps1a is more critical throughout the initial period of embryonic development than ctps1b. The effects of concurrent partial knockdown are dependent on ctps1a vs ctps1b dosage ratios. When these are equally attenuated, abnormal phenotypes acquired prior to the pharyngula period disappear in hatchlings (48hpf); however, if either gene is more attenuated than the other, these only become more pronounced in advanced stages. Generally, disruption to normal ctps1a or ctps1b expression levels by morpholinos culminates in the distortion of the early spinal column as well as multiple-tissue oedema. Other effects include slower growth rates, increased mortality rates and impaired structural formation of the young fish's extremities. Embryos grown in DON, a glutamine-analogue drug and CTPS antagonist, also exhibit similar characteristics, thus strengthening the validity of the morpholino-induced phenotypes observed. Together, our results demonstrate the importance of CTPS for the development of zebrafish embryos, as well as a disparity in activity and overall importance amongst isozymes.
The response of counterflow diffusion flames to sub-breakdown DC and AC electric fields, as well as their superposition with ns pulse discharge waveforms, is studied in the plane-to-plane electrode geometry. Sub-breakdown DC and low-frequency AC electric fields cause the flame displacement toward the grounded electrode, in the direction of the applied field, indicating that the body force on the positive ions exceeds that on the electrons and negative ions. As the AC frequency increases, the flame response becomes less pronounced, due to the reduction of the electrohydrodynamic (EHD) body force impulse over the AC half-period. The electric field in the electrode gap is determined by ps Electric Field Induced Second Harmonic (E-FISH) generation, with absolute calibration using sub-breakdown ns pulses overlapped with the measured electric field waveform. The results show that the electric field distribution across the flame in the current saturation regime follows the Laplacian field. This indicates that the space charge density in the gap is too low to distort the applied DC or AC field, consistent with the kinetic modeling predictions. Combining a nanosecond pulse discharge with a sub-breakdown DC field generates a diffuse plasma across the entire gap. Time-resolved and spatially resolved measurements of the electric field in the discharge indicate the ionization wave propagation between the electrodes. The present results do not exhibit a detectable flame displacement enhancement by ns discharge pulses combined with a sub-breakdown field, observed previously. Kinetic modeling calculations show that the absence of this effect in the plane-to-plane geometry is due to the rapid plasma self-shielding. This indicates that alternative electrode geometries limiting the self-shielding would be more effective for the plasma / electric field enhanced flameholding and flame stabilization applications.
Environmental impacts of small scale projects are often assessed poorly, or not assessed at all. This paper examines the usability of the Rapid Impact Assessment Matrix (RIAM) as a tool to prioritize project proposals for small scale water restoration projects in relation to proposals' potential to improve the environment. The RIAM scoring system was used to assess and rank the proposals based on their environmental impacts, the costs of the projects to repair the harmful impacts, and the size of human population living around the sites. A four-member assessment group (The expert panel) gave the RIAM-scores to the proposals. The assumed impacts of the studied projects at the Eastern Finland water systems were divided into the ecological and social impacts. The more detailed assessment categories of the ecological impacts in this study were impacts on landscape, natural state, and limnology. The social impact categories were impacts to recreational use of the area, fishing, industry, population, and economy. These impacts were scored according to their geographical and social significance, their magnitude of change, their character, permanence, reversibility, and cumulativeness. The RIAM method proved to be an appropriate and recommendable method for the small-scale assessment and prioritizing of project proposals. If the assessments are well documented, the RIAM can be a method for easy assessing and comparison of the various kinds of projects. In the studied project proposals there were no big surprises in the results: the best ranks were received by the projects, which were assumed to return watersheds toward their original state.
Wood-degrading fungi efficiently decompose wood using a series of steps that are regulated across time and space. RNA sequencing with “bulk” sampling method has indicated processes controlled at the transcription level at different decay stages and locations along hyphal networks. To further understand these regulatory mechanisms, a high-resolution technique for gene expression determination is required. In this work, Fluorescence In Situ Hybridization (FISH) of mRNA was tested and optimized in the ‘brown rot’-type (carbohydrate-selective; lignin-rich residues) model fungus Postia (Rhodonia) placenta to image gene expression at the hyphal scale, <10 micrometers. The mRNA of one housekeeping gene Tef1a and three wood-decaying genes Cel28a, Cel5b and Qrd1 were tested in hyphae grown in liquid nutrients and wood substrate. The 20 bp-long DNA probes were successfully delivered intracellularly to give sufficient hybridization signal for imaging. Ahead of hybridization, permeabilization by lyticase and proteinase K treatments proved to be the critical step to increase probe and mRNA accessibility. Tyramide signal amplification was used after hybridization to enhance signal. This gave qualitative measures of mRNA of the four target genes, which were generally in line with previous expression patterns generated from coarser-scale RNA-seq and qRT-PCR studies. These techniques were not without challenges, and future optimization using multiple probe fragments for each mRNA molecule is proposed.
Purpose: To present a novel marker-flange, addressing source-reconstruction uncertainties due to the artifacts of a titanium intracavitary applicator used for magnetic resonance imaging (MRI)-guided high-dose-rate (HDR) brachytherapy (BT); and to evaluate 7 different MRI marker agents used for interstitial prostate BT and intracavitary gynecologic HDR BT when treatment plans are guided by MRI. Methods and Materials: Seven MRI marker agents were analyzed: saline solution, Conray-60, copper sulfate (CuSO{sub 4}) (1.5 g/L), liquid vitamin E, fish oil, 1% agarose gel (1 g agarose powder per 100 mL distilled water), and a cobalt–chloride complex contrast (C4) (CoCl{sub 2}/glycine = 4:1). A plastic, ring-shaped marker-flange was designed and tested on both titanium and plastic applicators. Three separate phantoms were designed to test the marker-flange, interstitial catheters for prostate BT, and intracavitary catheters for gynecologic HDR BT. T1- and T2-weighted MRI were analyzed for all markers in each phantom and quantified as percentages compared with a 3% agarose gel background. The geometric accuracy of the MR signal for the marker-flange was measured using an MRI-CT fusion. Results: The CuSO{sub 4} and C4 markers on T1-weighted MRI and saline on T2-weighted MRI showed the highest signals. The marker-flange showed hyper-signals of >500% with CuSO{sub 4} and C4 on T1-weighted MRI and of >400% with saline on T2-weighted MRI on titanium applicators. On T1-weighted MRI, the MRI signal inaccuracies of marker-flanges were measured <2 mm, regardless of marker agents, and that of CuSO{sub 4} was 0.42 ± 0.14 mm. Conclusion: The use of interstitial/intracavitary markers for MRI-guided prostate/gynecologic BT was observed to be feasible, providing accurate source pathway reconstruction. The novel marker-flange can produce extremely intense, accurate signals, demonstrating its feasibility for gynecologic HDR BT.
The reference condition paradigm has served as the standard for assessing the outcomes of restoration projects, particularly their success in meeting project objectives. One limitation of relying solely on the reference condition in designing and monitoring restoration projects is that reference conditions do not necessarily elucidate impairments to effective restoration, especially diagnosing the causal mechanisms behind unsuccessful outcomes. We provide a spatial framework to select both reference and non-reference streams to guide restoration planning and long-term monitoring through reliance on altered ecosystems to understand processes that govern ecosystem biophysical properties and ecosystem responses to restoration practices. We then applied the spatial framework to East Fork Poplar Creek (EFPC), Tennessee (USA), a system receiving 30 years of remediation and pollution abatement actions from intense industrialization, pollution, and urbanization. Out of >13,000 stream reaches, we identified anywhere from 4 to 48 reaches, depending on the scenario, that could be used in restoration planning and monitoring for specific sites. Furthermore, comparison of fish species composition at these sites compared to EFPC sites were used to generate hypotheses of mechanisms limiting the ecological recovery following remediation. We suggest that understanding the relative role of anthropogenic pressures in governing ecosystem responses is required to successful, process-driven restoration.
The use of zebrafish (Danio rerio) is increasing as an intermediate preclinical model, to prioritize drug candidates for mammalian testing. As the immune system of the zebrafish is quite similar to that of mammals, models of inflammation are being developed for the screening of new drugs. The characterization of these models is crucial for studies that seek for mechanisms of action and specific pharmacological targets. It is well known that copper is a metal that induces damage and cell migration to hair cells of lateral line of zebrafish. Extracellular nucleotides/nucleosides, as ATP and adenosine (ADO), act as endogenous signaling molecules during tissue damage by exerting effects on inflammatory and immune responses. The present study aimed to characterize the inflammatory status, and to investigate the involvement of the purinergic system in copper-induced inflammation in zebrafish larvae. Fishes of 7 days post-fertilization were exposed to 10 μM of copper for a period of 24 h. The grade of oxidative stress, inflammatory status, copper uptake, the activity and the gene expression of the enzymes responsible for controlling the levels of nucleotides and adenosine were evaluated. Due to the copper accumulation in zebrafish larvae tissues, the damage and oxidative stress were exacerbated over time, resulting in an inflammatory process involving IL-1β, TNF-α, COX-2 and PGE{sub 2}. Within the purinergic system, the mechanisms that control the ADO levels were the most involved, mainly the reactions performed by the isoenzyme ADA 2. In conclusion, our data shed new lights on the mechanisms related to copper-induced inflammation in zebrafish larvae. - Graphical abstract: This scheme provides a chronological proposition for the biochemical events induced by copper in zebrafish larvae. The dashed line shows the absorption of copper over the exposure time. After 1 h of exposure to copper, the release of PGE{sub 2} occurs, followed by an increase of MPO (as a consequence of neutrophil migration), increased expression of genes involved in inflammatory events (IL-1β and TNF-α) and, reduction of the anti-inflammatory cytokine IL-10 at 4 h. At 24 h, the copper concentration is found highly increased, what is coincident with oxidative stress. Regarding the purinergic system, it is possible to observe an inhibition of ecto-5′-NT and ADA, with the consequent increase of AMP and ADA, respectively, at 24 h. The expression of enzyme-related genes shows a decrease in the expression of ecto-5′-NT and variable expressions of ADA subfamily enzymes. - Highlights: • Copper led to increased oxidative stress, and decreased the antioxidants' defenses. • Copper induced time-related changes of IL-1β, TNF-α, IL-10 and PGE{sub 2} levels. • ADA activity controls the levels of adenosine in copper-induced inflammation. • ADA 2 is the main ADA subfamily involved. • The purinergic system seems to be involved in the resolution of inflammation.
This study examines the movement of food item and the estimation of gastric emptying time using the X-radiography techniques, in the clownfish (Amphiprion ocellaris) fed in captivity. Fishes were voluntarily fed to satiation after being deprived of food for 72 hours, using pellets that were tampered with barium sulphate (BaSO{sub 4}). The movement of food item was monitored over different time of feeding. As a result, a total of 36 hours were needed for the food items to be evacuated completely from the stomach. Results on the modeling of meal satiation were also discussed. The size of satiation meal to body weight relationship was allometric, with the power value equal to 1.28.
While the advective flux from cool melt runoff can be a significant source of thermal energy to mountainous rivers, it has been a much less addressed process in river temperature modeling and thus our understanding is limited with respect to the spatiotemporal effect of melt on river temperatures at the watershed scale. In particular, the extent and magnitude of the melt cooling effect in the context of a warming climate are not yet well understood. To address this knowledge gap, we improved a coupled hydrology and stream temperature modeling system, Distributed Hydrology Soil Vegetation Model and River Basin Model (DHSVM-RBM), to account for the thermal effect of cool snowmelt runoff on river temperatures. The model was applied to a snow-fed river basin in the Pacific Northwest to evaluate the responses of snow, hydrology, stream temperatures, and potential fish growth to future climates. Historical simulations suggest that snowmelt can notably reduce the basin-wide peak summer temperatures particularly at high-elevation tributaries, while the thermal impacts of melt water can persist through the summer along the mainstem. Ensemble climate projections suggested that a warming climate will decrease basin mean peak snow and summer streamflow by 92% and 60% by the end of the century. Due to the compounded influences of warmer temperatures, lower flows and diminished cooling from melt, rivers reaches in high elevation snow-dominated areas were projected to be most vulnerable to future climate change, showing the largest increases in summer peak temperatures. As a result, thermal habitat used by anadromous Pacific salmon was projected to exhibit substantially lower growth potential during summer in future. These results have demonstrated the necessity of accounting for snowmelt influence on stream temperature modeling in mountainous watersheds.
Hydrologic alteration continues to affect aquatic biodiversity asknowledge of the spawning requirements of fishes, especially keystone or foundation species, becomes more critical for conservation and management. Our objectives are to quantify the spawning micro- and mesohabitat use of river chub Nocomis micropogon, a gravel mound nesting minnow, in a hydrologically regulated river in North Carolina, USA. At the microhabitat scale, substrate sizes on nests were compared with pebble counts in 1-m2 adjacent quadrats. Average depths and current velocities at nests were compared with measurements from paired transects. At the mesohabitat scale, generalised linear mixed models (GLMMs) were used to identify the importance of average bed slope, average depth and percentages of rock outcrops (a measure of flow heterogeneity and velocity shelters) for predicting nest presence and abundance. To relate nesting activities to hydrologic alteration from dam operation, nest dimensions were measured before and after a scheduled discharge event approximately six times that of base flow. In addition, linear regression was used to predict changes in the use of flow refugia and overhead cover with increased fluvial distance from the dam. Microhabitats in which nests were placed had, on average, slower current velocities and shallower depths. Gravel diameters of nests were significantly smaller than substrate particles adjacent to nests. GLMMs revealed that mesohabitats with nests were shallower, had more moderate slopes and greater proportions of rock outcrops than mesohabitats without nests. Finally, the scheduled discharge event significantly flattened nests. Near the dam, nests were built in close proximity ( 2 m) to velocity shelters; this relationship diminished with distance from the dam. River chubs are spawning habitat specialists. Because multiple species rely on river chub nests for reproduction and food, the needs of this species should be considered when managing instream flows.
From 2010 to 2015, box core grabs were collected at permanent stations around the Pacific Marine Energy Center - North Energy Test Site (PMEC-NETS) off Newport, Oregon. At each box core station a conductivity, temperature, depth (CTD) cast was conducted. These data include the CTD from the bottom of the cast, sediment grain size analysis, total organic carbon and nitrogen analysis (for the first 3 years only) and macrofaunal organism abundances as retained on a 1 mm mesh sieve. From 2012 to 2015, additional box core grabs were collected around two of the anchors deployed at PMEC-NETS to assess potential changes to sediment conditions and/or organism abundances. From 2013 to 2015, box core samples also were collected in and around the South Energy Test Site (PMEC-SETS). The CTD, grain size, and organism abundances are included. Additionally from 2010 to 2015 beam trawls were conducted at 9 stations (a subset of the box core stations) around PMEC-NETS and CTD casts were conducted before the start of each trawl. Again the CTD data from the bottom of the cast are included. Organism data are fish densities based on the estimated number of meters covered by the trawl. No trawls were conducted at PMEC-SETS.
This dataset contains the underwater 360-degree video files recorded with a Boxfish 360 camera in La Jolla, CA, near a gravity base anchor of the CalWave xWave wave energy converter in December 2021 over three days, at dawn, noon, and dusk. It was generated to test the ability of using this type of camera mounted on an aluminum frame as a video lander to monitor the artificial reef effect of marine energy devices and associated seafloor structures. The Boxfish 360 is made of 3 cameras each recording its own set of videos. The videos are MOV files that can be viewed individually with any video reader but need to be stitched together to create the 360-degree footage. This dataset contains all the raw video files collected at dawn, noon and dusk on 11/30/2021, 12/01/2021 and 12/02/2021, for about 1h each time. This dataset is associated with the journal manuscript below (linked in resources): Hemery, L.G.; Mackereth, K.F.; Gunn, C.M.; Pablo, E.B. Use of a 360-Degree Underwater Camera to Characterize Artificial Reef and Fish Aggregating Effects around Marine Energy Devices. J. Mar. Sci. Eng. 2022, 10, 555. https://doi.org/10.3390/jmse10050555
Four days (June 14-17, 2021) of ARIS acoustic camera data from the main research barge of the Tanana River Test Site operated by UAF. Data are collected sidelooking with the turbine in part of the field of view. This data was collected as part of a fish collision risk study. An acoustic camera was used rather than a traditional underwater camera due to the high levels of suspended sediments at the Tanana River Test Site.
This report presents the environmental dose assessment methods and the estimated potential doses to the offsite public from 2015 Savannah River Site (SRS) atmospheric and liquid radioactive releases. Also documented are potential doses from special-case exposure scenarios - such as the consumption of deer meat, fish, and goat milk.
Non-powered dams represent 97% of dams in the United States and their energy generation potential has not been fully realized. The use of an Archimedes screw turbine to generate power at non-powered dams offers a dual benefit; producing electricity, and acting as downstream fish passage, helping to reconnect previously separated ecosystems. In this study, we assess the technical, environmental, social, and economic feasibility of generating power at non-powered U.S. dam sites using Archimedes screw turbines by integrating mechanical constraints, social impact metrics, proximity to infrastructure, and environmental sensitivity data. Results account for future precipitation predictions and show, between 2024 and 2050, the number of sites where Archimedes screw turbines are viable decreases by one site, but overall generation capacity increases due to increased flow rates across persisting locations. Our analysis identified 82 non-powered dam sites with a mean generation capacity of 49 kW that meet the mechanical requirements for Archimedes screw turbine technology in 2024. Our analysis presents a framework for considering social, environmental, and economic impacts of specific turbine technologies to convert non-powered dams to generate power.