Assessing downstream aquatic habitat availability relative to headwater reservoir management in the Henrys Fork Snake River

Reservoirs are sometimes managed to meet agricultural and other water demands, while also maintaining streamflow for aquatic species and ecosystems. In the Henrys Fork Snake River, Idaho (USA), irrigation-season management of a headwater reservoir is informed by a flow target in a management reach ~95 km downstream. The target is in place to meet irrigation demand and maintain aquatic habitat within the 11.4 km management reach and has undergone four flow target assignments from 1978 to 2021. Recent changes to irrigation-season management to maximize reservoir carryover warranted investigation into the flow target assignment. Thus, we created a streamflow-habitat model using hydraulic measurements, habitat unit mapping, and published habitat suitability criteria for Brown Trout (Salmo trutta), Rainbow Trout (Oncorhynchus mykiss), and Mountain Whitefish (Prosopium williamsoni). We used model output to compare habitat availability across two management regimes (1978–2017 and 2018–2021). We found that efforts to minimize reservoir releases in 2018–2021 did not reduce mean irrigation-season fish habitat relative to natural flow, but did reduce overall fish habitat variability during the irrigation season compared to streamflow management in 1978–2017. Field observations for this research led to an adjusted flow target in 2020 that moved the target location downstream of intervening irrigation diversions. Using our model output, we demonstrated that moving the location of the target to account for local irrigation diversions will contribute to more consistently suitable fish habitat in the reach. Our study demonstrates the importance of site selection for establishing environmental flow targets.     

SIZE EFFECTS ON THE THERMAL CONDUCTIVITY OF THIN METALLIC WIRES: MICROSCALE IMPLICATIONS

This study examines the influence of radial thickness on the thermal conductivity of thin metallic wires. While size effects on the electrical conductivity of thin wires have been discussed in the literature, research into size effects on thermal conductivity still requires investigation. At such small length scales, the assumption that the reduced electrical conductivity can be simply related to the reduced thermal conductivity through a Wiedemann-Franz relation is subject to question. This study uses the Boltzmann transport equation for electrons to determine the thermal conductivity of a thin wire directly. Electrons are treated as the primary heat carriers in a thin wire with a thermal gradient along the axis. A single-crystal, defect-free, metallic thin wire is considered in the derivation. An expression is presented which accounts for the radial size effects on axial thermal conductivity. The derived thermal conductivity is compared to expressions for the reduced electrical conductivity, and the applicability of the Wiedemann-Franz relation is discussed.     

Susceptibility of Listeria monocytogenes isolated from food in Italy to antibiotics

The susceptibility of 148 strains of Listeria monocytogenes isolated from food to antibiotics currently used in veterinary and human therapy was determined by standard agar dilution and disk diffusion methods. The antibiotics included amikacin, amoxicillin, cefazolin, chloramphenicol, erythromycin, flumequine, fosfomycin, gentamicin, kanamycin, lincomycin, oxytetracycline, rifampicin, spiramycin, streptomycin, tetracycline, tobramycin and vancomycin. Soussy's breakpoints and MIC(50)-MIC(90) values were used to classify the strains into sensitive, moderately sensitive and resistant groups.This work is part of a wider surveillance program on listeriosis started in Italy in 1995.     

Water Governance in Canada: Innovation and Fragmentation

This paper explores Canada's approach to water governance. It argues that fragmented governance has had negative impacts on Canada's ability to manage water resources adequately (particularly in the context of urbanization, agriculture and resource extraction), and to deal with new issues (such as climate change). Further, it argues that Canada's highly decentralized approach to water governance creates challenges of integration, coordination and data availability. The paper explores possible future strategies for innovations in water governance that may have the potential to improve water management outcomes.     

Alkylresorcinols as antioxidants: hydrogen donation and peroxyl radical‐scavenging effects

Alkylresorcinols, resorcinol derivatives with a long hydrocarbon chain at position 5 of the phenolic ring, have been reported to act as antioxidants and protect polyunsaturated fatty acids against peroxidation. Their structures with meta‐dihydroxy substitutions do not, however, support active hydrogen donation and scavenging of peroxyl radicals responsible for propagation of lipid oxidation. This study compares the antioxidant properties of 5‐n‐pentadecylresorcinol and α‐tocopherol using two model systems: (i) the DPPH· model to test their ability for hydrogen atom donation; and (ii) a triacylglycerol oxidation model to test their ability for scavenging peroxyl radicals. In agreement with theoretical expectations, results from both models showed 5‐n‐pentadecylresorcinol to have very low hydrogen donation and peroxyl radical‐scavenging potency. © 2000 Society of Chemical Industry     

Predicting suspended sediment concentration from nephelometric turbidity in organic‐rich waters

Nephelometric turbidity is an optical index for the side scattering of light caused by fine particles suspended in water. When a mixed composition of suspended inorganic and organic materials, including dissolved organic material, is present, turbidity measurements can be affected by the different optical properties of the organic and inorganic materials present, and different turbidimeters are more or less sensitive to these influences. Two different methods of nephelometric turbidity measurement were assessed (using instruments confirming to two different turbidity standard methods: EPA 180.1 and ISO 7027). We investigated the influence of particulate organic matter and coloured dissolved organic matter on relationships between turbidity and suspended sediment concentration for rivers in diverse Otago catchments, in the South Island of New Zealand. The presence of organic matter and dissolved colour affected turbidity measurement owing to light absorption; however, turbidity measurement following the ISO 7027 standard, which specifies near infrared radiation at wavelengths where organic absorption is very weak, was less affected by organics. As a result, rating equations between suspended sediment and turbidity may be significantly different with ISO 7027 compared with EPA 180.1 methods.     

Sources of mercury wet deposition in Eastern Ohio, USA

In the fall of 2002, an enhanced air monitoring site was established in Steubenville, Ohio as part of a multi-year comprehensive mercury monitoring and source apportionment study to investigate the impact of local and regional coal combustion sources on atmospheric mercury deposition in the Ohio River Valley. This study deployed advanced monitoring instrumentation, utilized innovative analytical techniques, and applied state-of-the-art statistical receptor models. This paper presents wet deposition data and source apportionment modeling results from daily event precipitation samples collected during the calendar years 2003-2004. The volume-weighted mean mercury concentrations for 2003 and 2004 were 14.0 and 13.5 ng L(-1), respectively, and total annual mercury wet deposition was 13.5 and 19.7 microg m(-2), respectively. Two new EPA-implemented multivariate statistical models, positive matrix factorization (PMF) and Unmix, were applied to the data set and six sources were identified. The dominant contributor to the mercury wet deposition was found by both models to be coal combustion (approximately 70%). Meteorological analysis also indicated that a majority of the mercury deposition found at the Steubenville site was due to local and regional sources.     

Environmental and genetic variation of soybean seed protein content under Central European growing conditions

Seed protein content is important for both feed and food utilisation of soybean. In soybeans grown in Central Europe, considerable variation in protein content was due to seasonal influences, as demonstrated in different experiments from a breeding programme. In soybean genotypes of early maturity groups, average to high protein content (range 399—476 g kg⁻¹) was found in years with high air temperature and moderate rates of rainfall during the seed‐filling period, whereas seed protein content was drastically reduced (range 265–347 g kg⁻¹) in seasons of insufficient nitrogen fixation or higher amounts of precipitation during seed filling. In a set of 60 genotypes, protein content was increased both by late nitrogen fertilisation before the onset of seed filling and by inoculation of seed with nitrogen‐fixing rhizobia. Despite the high degree of environmental modification, genetic variation of seed protein content was considerable, and genotype × environment interaction was of low magnitude. Therefore selection of early maturing soybean genotypes with improved seed protein content appears to be feasible and is only limited by the moderately negative correlation between protein content and seed yield. © 2000 Society of Chemical Industry     

Limnological features of Funil Reservoir (R.J., Brazil) and indicator properties of rotifers and cladocerans of the zooplankton community

Funil Reservoir receives inflow from a highly industrialized region and acts as a natural sink to pollutants. Among the consequences of the uncontrolled nutrient loading is the constant presence and periodic heavy blooms of Microcystis aeruginosa . This study verified limnological features and zooplankton assemblage of the Funil Reservoir focusing on the environmental-indicator properties of rotifers and cladocerans. The summer bloom of M. aeruginosa caused reductions in water transparency, nitrate and orthophosphate concentrations and raises in chlorophyll a , pH, dissolved oxygen and chemical oxygen demand values. All zooplankton species presented spatial and temporal variations with the exception of the copepods, which were present in all samples. According to canonical correspondence analysis, ammonium was the variable most related to zooplankton variability and different Rotifera and Cladocera assemblages indicated distinct environment conditions. Rotifer taxa associated with increases of water temperature and chlorophyll a concentration were found with high densities during M. aeruginosa blooms. Species of rotifer and cladocerans are suggested as indicators that can be used to identify different physical and chemical gradients or eutrophic increases in Funil Reservoir.