219 research outputs found

    Evaluation of streamwater composition changes in the Vosges Mountains (NE France): 1955–2005

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    n 1995, in the southwestern Vosges Mountains (NE France), 158 of 395 streams (40%) had a pH lower than 5.5 at baseflow. As elsewhere in Europe, acid deposition has decreased since the seventies, as has base cation deposition. In order to assess the response of streamwater to decreasing deposition, we compared their present chemical composition to their former composition. All comparisons showed a decrease in sulphate concentration, which was greater on granite than on sandstone. In addition calcium, magnesium and aluminium concentrations generally decreased. Acidity in streams draining granite decreased in spring, especially during the eighties, decreases were not observed on sandstone. Continuous monitoring of 5 streams since 1998 confirmed that Al concentrations decreased while changes in pH were small. Chemical trends in streams from the Vosges massif fell between those measured in Northern Europe and Central Europe. This study provides the first broad-scale overview of surface water acidification and recovery in France and emphasizes the need for continuous monitoring to assess long-term changes in aquatic ecosystems

    AmbiĂȘncias de Risco : pesquida de campo sobre a experiĂȘncia difusa dos riscos de contaminaçao em BarĂŁo de MauĂ 

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    Ce projet repose sur une collaboration scientifique pluridisciplinaire entre l'Ă©quipe CRESSON (UMR 1563 AAU), l'Ă©quipe Territoire (UMR 5194 PACTE) et la CETESB (Agence Environnementale de l'Etat de SĂŁo Paulo). Financement : PEPS Interdisciplinaire CNRS 2015 : FaiDoRA Faibles Doses, Risques, Alertes.L'objectif de cette recherche est de mieux comprendre la maniĂšre dont des territoires Ă  risque sont habitĂ©s et vĂ©cus par les habitants. Elle s'appuie sur diverses disciplines telles que la sociologie, les sciences politiques, la psychologie environnementale, l'anthropologie, l'urbanisme et l'architecture. Cette recherche s'intĂ©resse aux ambiances de risque, du point de vue de l'expĂ©rience sensible habitante et de la vulnĂ©rabilitĂ© quotidienne des milieux de vie. Cette recherche Ă©tudie les situations de risque Ă  partir des "faibles doses" d’exposition. BarĂŁo de MauĂĄ correspond Ă  une telle situation puisqu'on a affaire depuis plus de 20 ans Ă  des risques diffus de contamination des sols et des eaux souterraines par un ensemble de substances toxiques. Ce document tente de restituer, pour les habitants, le travail d'enquĂȘte rĂ©alisĂ© par un groupe de chercheurs franco-brĂ©siliens Ă  BarĂŁo de MauĂĄ, du 1er au 5 juin 2015

    Commercial fishing patterns influence odontocete whale-longline interactions in the Southern Ocean

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    The emergence of longline fishing around the world has been concomitant with an increase in depredation-interactions by odontocete whales (removal of fish caught on hooks), resulting in substantial socio-economic and ecological impacts. The extent, trends and underlying mechanisms driving these interactions remain poorly known. Using long-term (2003–2017) datasets from seven major Patagonian toothfish (Dissostichus eleginoides) longline fisheries, this study assessed the levels and inter-annual trends of sperm whale (Physeter macrocephalus) and/or killer whale (Orcinus orca) interactions as proportions of fishing time (days) and fishing area (spatial cells). The role of fishing patterns in explaining between-fisheries variations of probabilities of odontocete interactions was investigated. While interaction levels remained globally stable since the early 2000s, they varied greatly between fisheries from 0 to >50% of the fishing days and area. Interaction probabilities were influenced by the seasonal concentration of fishing effort, size of fishing areas, density of vessels, their mobility and the depth at which they operated. The results suggest that between-fisheries variations of interaction probabilities are largely explained by the extent to which vessels provide whales with opportunities for interactions. Determining the natural distribution of whales will, therefore, allow fishers to implement better strategies of spatio-temporal avoidance of depredation

    Time-resolved kinetic assessment of the role of singlet and triplet excited states in the photocatalytic treatment of pollutants at different concentrations

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    [EN] A kinetic-based rationale to assess the role of each excited species in thermodynamically favoured photocatalytic processes at different pollutant concentrations, has been developed and illustrated with new experimental data. Specifically, 2,4,6-triphenylthiapyrylium (TPTP+) salt has been chosen as a representative organic compound capable to act as photocatalyst, and the possible involvement of its excited states in the photodegradation of pollutants commonly found in aqueous ecosystems has been investigated using five chemicals, namely acetaminophen, acetamiprid, caffeine, clofibric acid and carbamazepine. First, steady-state photolysis has been carried out under simulated solar irradiation in the presence of TPTP+, and second, photophysical measurements (fluorescence and laser flash photolysis) have been performed in order to obtain reliable fast kinetic data. Thermodynamic considerations allow ruling out energy transfer processes, while the kinetic results are in good agreement with an electron transfer to the triplet excited state of TPTP+. Hence, the higher the intersystem crossing quantum yield the better. Although quenching of the singlet excited state is also observed, the contribution of this reactive species is only minor, due to its shorter lifetime. In general, the efficiency of a photocatalyst should be enhanced at higher pollutant concentrations, at which the intrinsic decay of the triplet excited state is minimized. (C) 2016 Elsevier B.V. All rights reserved.Financial support from Spanish Government (Grants SEV-2012-0267, CTQ2012-38754-C03-03 and CTQ2015-69832-C4-4-R) and Generalitat Valenciana (Prometeo Program) is gratefully acknowledged. R. Martinez-Haya thanks financial support from Spanish Government (Grant SEV-2012-0267). We also thank support from VLC/Campus.Martínez-Haya, R.; Gomis, J.; Arques Sanz, A.; Marín García, ML.; Amat Payå, AM.; Miranda Alonso, MÁ. (2017). Time-resolved kinetic assessment of the role of singlet and triplet excited states in the photocatalytic treatment of pollutants at different concentrations. Applied Catalysis B Environmental. 203:381-388. https://doi.org/10.1016/j.apcatb.2016.10.042S38138820

    Biodiversity of 52 chicken populations assessed by microsatellite typing of DNA pools

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    In a project on the biodiversity of chickens funded by the European Commission (EC), eight laboratories collaborated to assess the genetic variation within and between 52 populations from a wide range of chicken types. Twenty-two di-nucleotide microsatellite markers were used to genotype DNA pools of 50 birds from each population. The polymorphism measures for the average, the least polymorphic population (inbred C line) and the most polymorphic population (Gallus gallus spadiceus) were, respectively, as follows: number of alleles per locus, per population: 3.5, 1.3 and 5.2; average gene diversity across markers: 0.47, 0.05 and 0.64; and proportion of polymorphic markers: 0.91, 0.25 and 1.0. These were in good agreement with the breeding history of the populations. For instance, unselected populations were found to be more polymorphic than selected breeds such as layers. Thus DNA pools are effective in the preliminary assessment of genetic variation of populations and markers. Mean genetic distance indicates the extent to which a given population shares its genetic diversity with that of the whole tested gene pool and is a useful criterion for conservation of diversity. The distribution of population-specific (private) alleles and the amount of genetic variation shared among populations supports the hypothesis that the red jungle fowl is the main progenitor of the domesticated chicken

    Stormwater quality performance of a macro-pervious pavement car park installation equipped with channel drain based oil and silt retention devices

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    AbstractThis paper reports the results of a two year field monitoring exercise intended to investigate the pollution abatement capabilities of a novel system which offers an alternative to the, now well established, pervious pavement system as a source control device for stormwater management. The aim of this study was to determine the effectiveness of a live installation of a macro-pervious pavement system (MPPS) (operated as a visitors' car park at a prison in Central Scotland) in retaining and treating a range of pollutants which originate from automobile use or become concentrated on the parking surface from the wider environment. The MPPS is a sub-class of pervious pavement system where the vast majority of the surface is impermeable. It directs stormwater into a pervious sub surface storage/attenuation zone through a series of distinct infiltration points fast enough to prevent flooding during the design storm. In the particular system studied here the infiltration points consist of a network of oil/silt separation devices with extensive further pollutant retention/degradation provided during the passage of stormwater through the sub surface zone. Approximately 12 months after the car park was completed a sampling regime was instigated in which grab samples were collected at intervals from each of the three sub catchments whilst, simultaneously, samples were collected directly from the, pollutant retaining, infiltration devices. Through investigation of samples collected at the upstream end of the system, the retention of significant amounts of hydrocarbons and heavy metals in the initial collection devices has been illustrated and the analysis of effluent samples collected at the outlet points indicate that the system is capable of producing effluent which is of a standard comparable to that expected from a traditional pervious pavement system and is acceptable for direct release into a surface water receptor. The system offers the opportunity to accrue the benefits of a pervious pavement when the use of traditional paving surfaces is the preferred option

    Marine ecosystem assessment for the Southern Ocean: birds and marine mammals in a changing climate

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    The massive number of seabirds (penguins and procellariiformes) and marine mammals (cetaceans and pinnipeds) – referred to here as top predators – is one of the most iconic components of the Antarctic and Southern Ocean. They play an important role as highly mobile consumers, structuring and connecting pelagic marine food webs and are widely studied relative to other taxa. Many birds and mammals establish dense breeding colonies or use haul-out sites, making them relatively easy to study. Cetaceans, however, spend their lives at sea and thus aspects of their life cycle are more complicated to monitor and study. Nevertheless, they all feed at sea and their reproductive success depends on the food availability in the marine environment, hence they are considered useful indicators of the state of the marine resources. In general, top predators have large body sizes that allow for instrumentation with miniature data-recording or transmitting devices to monitor their activities at sea. Development of scientific techniques to study reproduction and foraging of top predators has led to substantial scientific literature on their population trends, key biological parameters, migratory patterns, foraging and feeding ecology, and linkages with atmospheric or oceanographic dynamics, for a number of species and regions. We briefly summarize the vast literature on Southern Ocean top predators, focusing on the most recent syntheses. We also provide an overview on the key current and emerging pressures faced by these animals as a result of both natural and human causes. We recognize the overarching impact that environmental changes driven by climate change have on the ecology of these species. We also evaluate direct and indirect interactions between marine predators and other factors such as disease, pollution, land disturbance and the increasing pressure from global fisheries in the Southern Ocean. Where possible we consider the data availability for assessing the status and trends for each of these components, their capacity for resilience or recovery, effectiveness of management responses, risk likelihood of key impacts and future outlook

    Runs of homozygosity in killer whale genomes provide a global record of demographic histories

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    Runs of homozygosity (ROH) occur when offspring inherit haplotypes that are identical by descent from each parent. Length distributions of ROH are informative about population history; specifically, the probability of inbreeding mediated by mating system and/or population demography. Here, we investigated whether variation in killer whale (Orcinus orca) demographic history is reflected in genome-wide heterozygosity and ROH length distributions, using a global data set of 26 genomes representative of geographic and ecotypic variation in this species, and two F1 admixed individuals with Pacific-Atlantic parentage. We first reconstructed demographic history for each population as changes in effective population size through time using the pairwise sequential Markovian coalescent (PSMC) method. We found a subset of populations declined in effective population size during the Late Pleistocene, while others had more stable demography. Genomes inferred to have undergone ancestral declines in effective population size, were autozygous at hundreds of short ROH (1.5 Mb) were found in low latitude populations, and populations of known conservation concern. These include a Scottish killer whale, for which 37.8% of the autosomes were comprised of ROH >1.5 Mb in length. The fate of this population, in which only two adult males have been sighted in the past five years, and zero fecundity over the last two decades, may be inextricably linked to its demographic history and consequential inbreeding depression
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