IPSO FACTO

Marseille, France

IPSO FACTO

Marseille, France

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Coudray S.,French Research Institute for Exploitation of the Sea | Dufresne C.,French Research Institute for Exploitation of the Sea | Emery E.,French Research Institute for Exploitation of the Sea | Duffa C.,Institute for Radiological Protection and Nuclear Safety | And 5 more authors.
Techniques - Sciences - Methodes | Year: 2013

Since 2008, a local-scale hydrodynamic model of the Bay of Toulon has been developed by Ifremer to be used in junction with the Veolia Girac wastewater Simulator in order to represent bacterial contamination in sea water related to plume outftow. This model was built with the MARS3D numerical code to generate, every 30 minutes, the current components, salinity and temperatures values. The grid has a 25 meters horizontal resolution and 30 unequally-spaced vertical sigma levels. The calibration and validation process of such model requires many measuring devices: CTD profiler for vertical stratification, TSG (thermosalinograph) for surface salinity maps, ADCP (acoustic Doppler current profiler) to get the vertical distribution of currents along a trajectory, ADCP fixed at the bottom to get on one point the long term variations in the water column, ARGO drifters to have the sub-surface path of the current along the boundary conditions of the model. The particular interest of each System will be discussed in this study, focusing on the method used to refine the model parameters in order to best match the measured reality. At the end of this validation process, the model should be able to reproduce accurately the flow of water at the release points of unregulated rain discharge along the coast. By coupling this hydrodynamic model with the optional module MARS3D/MET&0R, we can then perform Escherichia coli dispersion simulations, which take into account the light intensity variations Inight/day cycles), and predict the contamination levels at beaches and swimming areas, 24 hours after the storm event.


Durrieu de Madron X.,University of Perpignan | Guieu C.,University Pierre and Marie Curie | Sempere R.,French National Center for Scientific Research | Conan P.,University Pierre and Marie Curie | And 91 more authors.
Progress in Oceanography | Year: 2011

The semi-enclosed nature of the Mediterranean Sea, together with its smaller inertia due to the relative short residence time of its water masses, make it highly reactive to external forcings, in particular variations of water, energy and matter fluxes at the interfaces. This region, which has been identified as a " hotspot" for climate change, is therefore expected to experience environmental impacts that are considerably greater than those in many other places around the world. These natural pressures interact with the increasing demographic and economic developments occurring heterogeneously in the coastal zone, making the Mediterranean even more sensitive. This review paper aims to provide a review of the state of current functioning and responses of Mediterranean marine biogeochemical cycles and ecosystems with respect to key natural and anthropogenic drivers and to consider the ecosystems' responses to likely changes in physical, chemical and socio-economical forcings induced by global change and by growing anthropogenic pressure at the regional scale. The current knowledge on and expected changes due to single forcing (hydrodynamics, solar radiation, temperature and acidification, chemical contaminants) and combined forcing (nutrient sources and stoichiometry, extreme events) affecting the biogeochemical fluxes and ecosystem functioning are explored. Expected changes in biodiversity resulting from the combined action of the different forcings are proposed. Finally, modeling capabilities and necessity for modeling are presented. A synthesis of our current knowledge of expected changes is proposed, highlighting relevant questions for the future of the Mediterranean ecosystems that are current research priorities for the scientific community. Finally, we discuss how these priorities can be approached by national and international multi-disciplinary research, which should be implemented on several levels, including observational studies and modeling at different temporal and spatial scales. © 2011 Elsevier Ltd.


PubMed | Aix - Marseille University, IPSO FACTO and CNRS Mediterranean Institute for Biodiversity and Ecology Marine and Continental
Type: Journal Article | Journal: Ecology and evolution | Year: 2015

Studying population-by-environment interactions (PEIs) at species range margins offers the opportunity to characterize the responses of populations facing an extreme regime of selection, as expected due to global change. Nevertheless, the importance of these marginal populations as putative reservoirs of adaptive genetic variation has scarcely been considered in conservation biology. This is particularly true in marine ecosystems for which the deep refugia hypothesis proposes that disturbed shallow and marginal populations of a given species can be replenished by mesophotic ones. This hypothesis therefore assumes that identical PEIs exist between populations, neglecting the potential for adaptation at species range margins. Here, we combine reciprocal transplant and common garden experiments with population genetics analyses to decipher the PEIs in the red coral, Corallium rubrum. Our analyses reveal partially contrasting PEIs between shallow and mesophotic populations separated by approximately one hundred meters, suggesting that red coral populations may potentially be locally adapted to their environment. Based on the effective population size and connectivity analyses, we posit that genetic drift may be more important than gene flow in the adaptation of the red coral. We further investigate how adaptive divergence could impact population viability in the context of warming and demonstrate differential phenotypic buffering capacities against thermal stress. Our study questions the relevance of the deep refugia hypothesis and highlights the conservation value of marginal populations as a putative reservoir of adaptive genetic polymorphism.


Pairaud I.L.,French Research Institute for Exploitation of the Sea | Bensoussan N.,IPSO FACTO | Garreau P.,French Research Institute for Exploitation of the Sea | Faure V.,IPSO FACTO | And 2 more authors.
Ocean Dynamics | Year: 2014

In the framework of climate change, the increase in ocean heat wave frequency is expected to impact marine life. Large-scale positive temperature anomalies already occurred in the northwestern Mediterranean Sea in 1999, 2003 and 2006. These anomalies were associated with mass mortality events of macrobenthic species in coastal areas (0-40 m in depth). The anomalies were particularly severe in 1999 and 2003 when thousands of kilometres of coasts and about 30 species were affected. The aim of this study was to develop a methodology to assess the current risk of mass mortality associated with temperature increase along NW Mediterranean continental coasts. A 3D regional ocean model was used to obtain the temperature conditions for the period 2001-2010, for which the model outputs were validated by comparing them with in situ observations in affected areas. The model was globally satisfactory, although extremes were underestimated and required correction. Combined with information on the thermo-tolerance of a key species (the red gorgonian P. clavata) as well as its spatial distribution, the modelled temperature conditions were then used to assess the risk of mass mortality associated with thermal stress for the first time. Most of the known areas of observed mass mortality were found using the model, although the degree of risk in certain areas was underestimated. Using climatic IPCC scenarios, the methodology could be applied to explore the impacts of expected climate change in the NW Mediterranean. This is a key issue for the development of sound management and conservation plans to protect Mediterranean marine biodiversity in the face of climate change. © 2013 Springer-Verlag Berlin Heidelberg.


Escoffier N.,University Paris Diderot | Escoffier N.,Ecole Polytechnique Federale de Lausanne | Bensoussan N.,IPSO FACTO | Vilmin L.,MINES ParisTech | And 6 more authors.
Environmental Science and Pollution Research | Year: 2016

Large rivers are important components of the global C cycle. While they are facing an overall degradation of their water quality, little remains known about the dynamics of their metabolism. In the present study, we used continuous multi-sensors measurements to assess the temporal variability of gross primary production (GPP) and ecosystem respiration (ER) rates of the anthropized Seine River over an annual cycle. Downstream from the Paris urban area, the Seine River is net heterotrophic at the annual scale (−226 gO2 m−2 year−1 or −264 gC m−2 year−1). Yet, it displays a net autotrophy at the daily and seasonal scales during phytoplankton blooms occurring from late winter to early summer. Multivariate analyses were performed to identify the drivers of river metabolism. Daily GPP is best predicted by chlorophyll a (Chla), water temperature (T), light, and rainfalls, and the coupling of daily GPP and Chla allows for the estimation of the productivity rates of the different phytoplankton communities. ER rates are mainly controlled by T and, to a lesser extent, by Chla. The increase of combined sewer overflows related to storm events during the second half of the year stimulates ER and the net heterotrophy of the river. River metabolism is, thus, controlled at different timescales by factors that are affected by human pressures. Continuous monitoring of river metabolism must, therefore, be pursued to deepen our understanding about the responses of ecosystem processes to changing human pressures and climate. © 2016 Springer-Verlag Berlin Heidelberg


Teixido N.,Stazione Zoologica Anton Dohrn | Bensoussan N.,IPSO FACTO | Gori A.,CSIC - Institute of Marine Sciences | Fiorillo I.,CSIC - Institute of Marine Sciences | Viladrich N.,Institute of Environmental Science and Technology ICTA Edifici Z s n Cerdanyola del Valles Spain
Marine Ecology | Year: 2015

Understanding processes that contribute to a better comprehension of the population dynamics of long-lived species is critical for the maintenance and potential recovery of such species. Despite the abundance of soft corals in Mediterranean rocky reefs, little information exists on their life histories and reproductive patterns. In this study, we assessed the main reproductive characteristics and early life-history traits of the long-lived soft coral Alcyonium acaule. The sex ratio was 1:1; the smallest fertile colonies were one finger in size (2.1 ± 0.6 cm in height), and both colony and polyp fertility increased with colony size. Likewise, the number of eggs and spermary sacs per polyp increased significantly with colony size, whereas the diameter of the female and male sexual products did not. Over 6 years of observations (2007-2012), spawning occurred primarily in July, after the seawater reached 20 °C, in a single spawning episode per year. Approximately 80% of female colonies released eggs, which were retained on the surface of the mother colony by mucous strings for up to a few days. High fertilization rates were observed during spawning in 2008 and 2009 (94.9% and 87.0%, respectively). The timing of development was ~24 h for the blastulae, ~48-72 h for the planulae and 8-22 days for metamorphosis into primary polyps. Survivorship of planulae was relatively high (~50% at 45 days after release), but only 24% of larvae metamorphosed into primary polyps, and their survivorship was moderate after 2 months (65% in 2008 and 74% in 2009). Asexual reproduction was negligible, indicating that sexual reproduction is the main mechanism supporting the maintenance and recovery of populations. © 2015 Blackwell Verlag GmbH.


Teixido N.,CSIC - Institute of Marine Sciences | Teixido N.,Stazione Zoologica Anton Dohrn | Bensoussan N.,IPSO FACTO | Gori A.,CSIC - Institute of Marine Sciences | And 2 more authors.
Marine Ecology | Year: 2016

Understanding processes that contribute to a better comprehension of the population dynamics of long-lived species is critical for the maintenance and potential recovery of such species. Despite the abundance of soft corals in Mediterranean rocky reefs, little information exists on their life histories and reproductive patterns. In this study, we assessed the main reproductive characteristics and early life-history traits of the long-lived soft coral Alcyonium acaule. The sex ratio was 1:1; the smallest fertile colonies were one finger in size (2.1 ± 0.6 cm in height), and both colony and polyp fertility increased with colony size. Likewise, the number of eggs and spermary sacs per polyp increased significantly with colony size, whereas the diameter of the female and male sexual products did not. Over 6 years of observations (2007-2012), spawning occurred primarily in July, after the seawater reached 20 °C, in a single spawning episode per year. Approximately 80% of female colonies released eggs, which were retained on the surface of the mother colony by mucous strings for up to a few days. High fertilization rates were observed during spawning in 2008 and 2009 (94.9% and 87.0%, respectively). The timing of development was ~24 h for the blastulae, ~48-72 h for the planulae and 8-22 days for metamorphosis into primary polyps. Survivorship of planulae was relatively high (~50% at 45 days after release), but only 24% of larvae metamorphosed into primary polyps, and their survivorship was moderate after 2 months (65% in 2008 and 74% in 2009). Asexual reproduction was negligible, indicating that sexual reproduction is the main mechanism supporting the maintenance and recovery of populations. © 2016 Blackwell Verlag GmbH.


Kersting D.K.,University of Barcelona | Bensoussan N.,IPSO FACTO | Linares C.,University of Barcelona
PLoS ONE | Year: 2013

Recurrent climate-induced mass-mortalities have been recorded in the Mediterranean Sea over the past 15 years. Cladocora caespitosa, the sole zooxanthellate scleractinian reef-builder in the Mediterranean, is among the organisms affected by these episodes. Extensive bioconstructions of this endemic coral are very rare at the present time and are threatened by several stressors. In this study, we assessed the long-term response of this temperate coral to warming sea-water in the Columbretes Islands (NW Mediterranean) and described, for the first time, the relationship between recurrent mortality events and local sea surface temperature (SST) regimes in the Mediterranean Sea. A water temperature series spanning more than 20 years showed a summer warming trend of 0.06°C per year and an increased frequency of positive thermal anomalies. Mortality resulted from tissue necrosis without massive zooxanthellae loss and during the 11-year study, necrosis was recorded during nine summers separated into two mortality periods (2003-2006 and 2008-2012). The highest necrosis rates were registered during the first mortality period, after the exceptionally hot summer of 2003. Although necrosis and temperature were significantly associated, the variability in necrosis rates during summers with similar thermal anomalies pointed to other acting factors. In this sense, our results showed that these differences were more closely related to the interannual temperature context and delayed thermal stress after extreme summers, rather than to acclimatisation and adaption processes. © 2013 Kersting et al.

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