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Delphine Nicolas Aurélie Chaalali Hilaire Drouineau Jérémy Lobry Ainhize Uriarte Angel Borja Philippe Boët 《Regional Environmental Change》2011,11(3):639-649
The aim of this study was to determine whether the latitudinal distribution of fish species that use estuaries to complete
their entire life cycle has shifted northward as an expected consequence of global warming. The mean latitude of past fish
species distributions found in 1970s’ literature was compared with the mean latitude of distributions today based on fish
density indices collected in 55 tidal estuaries along the Atlantic European seaboard, from Portugal to Scotland. Among the
15 most common species, 11 displayed a positive difference between current and past mean latitudes suggesting a northward
shift of the populations. Using the occurrence of subtropical species in temperate areas as an indicator of water warming,
the northernmost range limit of 10 subtropical species was subsequently focused on. Six of them were recorded up to their
past northern latitudinal limit. These results reinforced the idea that a number of fish species associated to estuaries have
migrated northwards over the last 30 years, possibly due to water warming. These ecological changes can get important managerial
implications, i.e. in the assessment of the ecological status in European directives. 相似文献
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Brient L Lengronne M Bertrand E Rolland D Sipel A Steinmann D Baudin I Legeas M Le Rouzic B Bormans M 《Journal of environmental monitoring : JEM》2008,10(2):248-255
In many countries, the presence of cyanobacteria in freshwater bodies used for both drinking water and recreational purposes is under increasing public health attention. Water managers are considering how to implement monitoring that leads to a minimization of the risks incurred by the users of potentially contaminated sites. To address this question, this study involved assessing the performance of a submersible probe for measuring phycocyanin-specific fluorescence as a function of cyanobacterial biomass, with the aim of applying it as a tool for surveillance management. Its advantages and limits compared to more traditional analyses are discussed. The monitoring of cyanobacteria in the water bodies of western France was carried out using a minifluorimeter specific to the fluorescence of phycocyanin, a pigment specific to cyanobacteria. The results are compared with the analyses recommended by the World Health Organisation (chlorophyll a and cell counting). This study based on nearly 800 samples shows a significant correlation between the phycocyanin content and the cyanobacterial biomass, expressed as the number of cells per mL (R2 = 0.73). This submersible probe is simple and rapid to use, making it possible to take into account horizontal and vertical heterogeneities in the proliferation growth. In this way, we are able to detect at an early stage the conditions that could potentially lead to a risk, in order to start sampling. Due to its sensitivity, this tool proves suitable for monitoring aimed at reducing the risks incurred by the users of contaminated sites and launching preventative actions. The use of the phycocyanin probe provides an effective tool to complement traditional analyses of cyanobacterial presence. It is suggested that a surveillance protocol based on phycocyanin concentration can significantly improved the accuracy of the extent of cyanobacterial bloom development in the light of spatial and temporal variabilities associated with these occurrences. 相似文献
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Brigitte Simon-Bouy Agnès Taillandier Delphine Fauvert Isabelle Brun-Heath Jean-Louis Serre Carmen G. Armengod Martin G. Bialer Michèle Mathieu Jacques Cousin David Chitayat Jan Liebelt Barbara Feldman Marion Gérard-Blanluet Stefani Körtge-Jung Cath King Hannele Laivuori Martine Le Merrer Sarju Mehta Christina Jern Saba Sharif Fabienne Prieur Gabriele Gillessen-Kaesbach Andreas Zankl Etienne Mornet 《黑龙江环境通报》2008,28(11):993-998
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Megrim, Lepidorhombus whiffiagonis, and four spot megrim, Lepidorhombus boscii, are two marine fish species of high commercial interest. Despite their quite heavy exploitation little is known on the genetic
structure of their populations. The present work aimed at characterizing the first seven microsatellites markers available
for the two megrim species. These new markers were in a second step employed to describe the population structure of the two
species among their almost entire habitat range (Atlantic and Mediterranean samples). Our study confirmed the existence of
a strong genetic difference between Atlantic and Mediterranean megrim species already described in the literature for L. whiffiagonis on the basis of variations at ribosomal genes. Additionally our analysis gave the first evidences of a strong genetic differentiation
among Atlantic populations in both megrim species (within Atlantic global FST in L. whiffiagonis and L. boscii were respectively 0.158 and 0.145). When describing megrim population structure, the comparison between allele-frequency-based
tests (FST comparisons) and genotype-based inferences (Bayesian approach) gave evidences of a hierarchical structure of the populations.
In conclusion, our work enlighten the existence of two different stocks within the Atlantic Ocean and one in the Mediterranean
Sea that will clearly need to be managed separately. As the present results do not fully support the current megrim stock
boundaries they will surely help to rethink megrim management policies in the future. 相似文献
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Emmanuel Mignot Ivana Vinkovic Delphine Doppler Nicolas Riviere 《Environmental Fluid Mechanics》2014,14(5):1027-1041
When two open-channel flows merge in a three-branch subcritical junction, a mixing layer appears at the interface between the two inflows. If the width of the downstream channel is equal to the width of each inlet channel, this mixing layer is accelerated and is curved due to the junction geometry. The present work is dedicated to simplified geometries, considering a flat bed and a \(90^{\circ }\) angle where two configurations with different momentum ratios are tested. Due to the complex flow pattern in the junction, the so-called Serret–Frenet frame-axis based on the local direction of the velocity must be employed to characterize the flow pattern and the mixing layer as Cartesian and cylindrical frame-axes are not adapted. The analysis reveals that the centerline of the mixing layer, defined as the location of maximum Reynolds stress and velocity gradient, fairly fits the streamline separating at the upstream corner, even though a slight shift of the mixing layer towards the center of curvature is observed. The shape of the mixing layer appears to be strongly affected by the streamwise acceleration and the complex lateral confinement due to the side walls and the corners of the junction, leading to a streamwise increase of the mean velocity along the centerline and a decrease of the velocity difference. This results in a specific streamwise evolution of the mixing layer width, which reaches a plateau in the downstream region of the junction. Finally, the evaluation of the terms in the Reynolds-Averaged-Navier–Stokes equations reveals that the streamwise and normal acceleration and the pressure gradient remain dominant, which is typical of accelerated and rotational flows. 相似文献
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Mathieu Pernice Delphine Pichon Isabelle Domart-Coulon Jocelyne Favet Renata Boucher-Rodoni 《Marine Biology》2007,150(5):749-757
The recent application of molecular tools to address associations between bacteria and marine invertebrates has provided access
to an immense diversity of unidentified microbes resistant to cultivation. However, the role of bacteria as partners in animal
physiology remains unclear and in most cases difficult to investigate in the absence of adequate condition of cell growth
and proliferation. In this work, we studied the reservoir of microbes associated with the excretory organs of Nautilus macromphalus as a model. Using the bacterial 16S RNA gene as a marker, we compared three complementary approaches for bacterial detection:
bacterial DNA extraction from N. macromphalus tissues (“molecular approach”), strain isolation to provide a bacterial culture collection (“microbiological approach”) and
finally, maintenance of N. macromphalus excretory organ cells with associated bacteria (“cellular approach”). Our results stress the potential of the “cellular approach”
as a promising new tool as it promotes the detection of as yet uncultured β-proteobacteria and spirochaetes associated with
N. macromphalus, and serves as a foundation for future studies describing potential roles that these bacteria may play in Nautilus. 相似文献