Ird Institute Of Recherche Pour Le Developpement

Nouméa, New Caledonia

Ird Institute Of Recherche Pour Le Developpement

Nouméa, New Caledonia
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Guinoiseau D.,University Paris Diderot | Gelabert A.,University Paris Diderot | Allard T.,CNRS Institute of Mineralogy, Materials Physics and Cosmochemistry | Louvat P.,University Paris Diderot | And 2 more authors.
Geochimica et Cosmochimica Acta | Year: 2017

The complex behaviour of Zn and Cu at the soil-river interface was investigated in soil and riverine water samples from the Rio Negro basin, a secondary tributary of the Rio Amazonas, using their stable isotope compositions. This acidic and organic river drains two types of intensely weathered terrains: podzols in its upstream part, and lateritic soils downstream. Bulk soil particles, suspended particulate matter (SPM) as well as colloidal fractions were sampled across the whole basin during low and high water stages. In the basin, Zn and Cu are mostly exported from lateritic soils and transported by organic colloids where significant losses are observed in the downstream part of the river. The use of δ66Zn and δ65Cu measurements reveals distinct stories for these two metals in suspended sediments and colloids. In the colloids, the constant δ66Zncoll across the basin is induced by the same weak association mode between Zn and organic ligands, regardless of the origin of the water. By contrast, in SPM, the speciation of Zn and thus δ66ZnSPM differ according to the type of drained soils. Zn is associated with organic complexes in particles exported with water draining podzol whereas Zn2+ is incorporated in the structure of the remaining kaolinite clays in lateritic output. The stronger reactivity of Cu than Zn with organic ligands induces its complete complexation. Copper is controlled by refractory particulate organic matter (POM) and by reactive colloidal organic matter; the latter being enriched in 65Cu due to stronger binding interactions than in POM. While the Cu content remains constant in the upstream part of the Rio Negro, downstream, the decrease of SPM and colloidal Cu fluxes is associated with a constant δ65CuSPM and with an increase of δ65Cucoll at the Rio Negro outlet. Geochemical mass balance modelling, based on SPM, Cu and Zn fluxes in SPM and their associated isotopic signatures, confirms distinct host phases for Zn and Cu, and identifies the most probable places where losses of these two metals occur. In colloids, the observed Cu isotope fractionation (from 0.24 to 0.45‰) superimposed on the significant Cucoll loss is assumed to result from a new isotopic equilibrium in a low velocity and high productivity zone: Cu-rich colloids enriched in 63Cu aggregate and settle down, whereas the remaining heavy Cu is partially complexed on strong organic ligands secreted by phytoplankton, forming new Cu-colloids. © 2017 Elsevier Ltd

Benefice E.,Ird Institute Of Recherche Pour Le Developpement | Luna-Monrroy S.,Ird Institute Of Recherche Pour Le Developpement | Luna-Monrroy S.,Higher University of San Andrés | Lopez-Rodriguez R.,Inlasa Instituto Nacional Of Laboratorios En Salud
International Journal of Hygiene and Environmental Health | Year: 2010

Populations in Bolivian Amazonia are exposed to mercury contamination through fish ingestion. A group of 170 Amerindian women living along the banks of the Beni River were examined in order to detect any adverse effects on their health consistent with the toxic effects of mercury. The mercury content of the women's hair (H-Hg) was used as the bio-indicator of mercury exposure. The women answered a 24-h food recall questionnaire on the frequency of their fish consumption. They also underwent a clinical examination with their weight, stature, hemoglobin concentration in blood, and blood pressure being recorded. Significant relationships were found between fishing practices, the frequency of fish consumption and H-Hg levels with mercury contaminated women (H-Hg>5. μg/g) being more likely to present neurological abnormalities (paresthesia, static and dynamic imbalance, poor motor coordination) than non-contaminated women. No relationship was found between blood pressure and mercury levels. Women with higher H-Hg reported more infant deaths than did women with lower levels. A logistic regression analysis which included socio-cultural traits, fish consumption habits and health characteristics was performed in order to determine the risks of contamination. Contaminated women were more likely to belong to those communities pursuing traditional fishing activities; moreover these women tended to be younger and frailer than other. They also exhibited mild neurological abnormalities and reported more infant deaths. These findings should stimulate local communities to take preventive actions directed towards the more "traditional" and vulnerable groups of population. © 2010 Elsevier GmbH.

De Beaudrap P.,Ird Institute Of Recherche Pour Le Developpement | Diouf A.,Fann University Hospital Center | Bousso Niang K.,Fann University Hospital Center
Bulletin de la Societe de Pathologie Exotique | Year: 2014

In 1998, the cohort ANRS 1215 was launched in Senegal with one of the first African antiretroviral treatment programs. Four hundred forty four HIV-infected adults started on ART were included between 1998 and 2004, and followed up to 2010. Mortality before 6 months was 15.6/100 person-year (PY) and associated to the initial disease severity. It decreased to 3.36/100 PY thereafter. The cumulative risks of virologic failure at 60 months and of drug resistance at 48 months were 25% and 16%, respectively. © 2014, Springer-Verlag France.

Leopold M.,Private Bag | Leopold M.,Ird Institute Of Recherche Pour Le Developpement | Beckensteiner J.,Ird Institute Of Recherche Pour Le Developpement | Beckensteiner J.,French National Center for Scientific Research | And 3 more authors.
Marine Policy | Year: 2013

In the Pacific, coastal communities have compensated for chronically low capacity of governments to manage fisheries by implementing local regulations in their marine tenure areas. In order to investigate the performance of community-based fisheries management (CBFM) in Vanuatu, trajectories and factors of change in CBFM systems since the 1990s were analysed. Focal group interviews were conducted in seven villages on Efaté island in 2011 and supplemented by a review of supporting literature. Results reveal the increasing and excessive reliance of CBFM systems on external agencies that promoted overly complex management plans. Examination of trends in CBFM systems shows that community and national fishing rules that were highly acceptable by local societies were more likely to be enforced in the long run. In particular, the establishment of marine reserves was the most widespread and best enforced community rule for the purposes of conservation, ecotourism, and/or fisheries. Overall, the results challenge the current effectiveness of CBFM in achieving sustainability of reef fisheries in Vanuatu, and highlight the over-reliance on small marine reserves as a management tool. Community initiatives must be strengthened by new specific national regulations governing subsistence and commercial reef fisheries as part of a multi-scale co-management approach. © 2013 Elsevier Ltd.

Zulkafli Z.,Imperial College London | Buytaert W.,Imperial College London | Onof C.,Imperial College London | Lavado W.,Servicio Nacional de Meteorologia e Hidrologia SENAMHI | Guyot J.L.,Ird Institute Of Recherche Pour Le Developpement
Hydrology and Earth System Sciences | Year: 2013

Global land surface models (LSMs) such as the Joint UK Land Environment Simulator (JULES) are originally developed to provide surface boundary conditions for climate models. They are increasingly used for hydrological simulation, for instance to simulate the impacts of land use changes and other perturbations on the water cycle. This study investigates how well such models represent the major hydrological fluxes at the relevant spatial and temporal scales-an important question for reliable model applications in poorly understood, data-scarce environments. The JULES-LSM is implemented in a 360 000 km2 humid tropical mountain basin of the Peruvian Andes-Amazon at 12-km grid resolution, forced with daily satellite and climate reanalysis data. The simulations are evaluated using conventional discharge-based evaluation methods, and by further comparing the magnitude and internal variability of the basin surface fluxes such as evapotranspiration, throughfall, and surface and subsurface runoff of the model with those observed in similar environments elsewhere. We find reasonably positive model efficiencies and high correlations between the simulated and observed streamflows, but high root-mean-square errors affecting the performance in smaller, upper sub-basins. We attribute this to errors in the water balance and JULES-LSM's inability to model baseflow. We also found a tendency to under-represent the high evapotranspiration rates of the region. We conclude that strategies to improve the representation of tropical systems to be (1) addressing errors in the forcing and (2) incorporating local wetland and regional floodplain in the subsurface representation. © 2013 Author(s).

Kessler W.S.,National Oceanic and Atmospheric Administration | Cravatte S.,Ird Institute Of Recherche Pour Le Developpement | Cravatte S.,Toulouse University Midi-Pyrénées
Journal of Geophysical Research: Oceans | Year: 2013

The mean absolute geostrophic circulation of the Coral Sea is constructed from climatological hydrographic data referenced to a 1000 m velocity field derived from Argo float drift. Two branches of the South Equatorial Current (SEC) enter the Coral Sea between New Caledonia and the Solomon Islands: the broad, upper thermocline North Vanuatu Jet (NVJ), and the narrow North Caledonian Jet (NCJ) extending to at least 1500 m. Most of this incoming flow leaves to the Solomon Sea. Four distinct pathways through the Coral Sea are traced by their water properties: (1) The NCJ crosses the Sea to the coast of Australia and turns north at densities sigma 25-27.4 as the main source of the Gulf of Papua (GPC) western boundary current, eventually feeding the New Guinea Coastal Undercurrent; (2) part of the shallow NVJ turns into the Solomon Sea in midbasin, carrying high-salinity water above sigma 25.5; (3) another part of the NVJ continues to Australia, then turns north to join the GPC, extending it to the surface; (4) a shallow finger of NVJ water, traced by low oxygen above sigma 25, turns south along the coast, beginning the East Australian Current (EAC) at 15°S. Total transport from the Coral to the Tasman Sea is small and shallow; instead, most of the EAC is fed from south of New Caledonia, consistent with the Island Rule. However, large transport fractions occur in narrow jets close to coastlines and reefs and are not well sampled, precluding a quantitative estimate of meridional redistribution of the incoming SEC. Key Points Argo float drift references Coral Sea climatological geostrophic currents Interior and boundary current transports largely explained by the Island Rule Three distinct pathways carry the SEC through the Coral Sea to the equator © 2013 The Authors.

van Wynsberge S.,Ird Institute Of Recherche Pour Le Developpement | Andrefouet S.,Ird Institute Of Recherche Pour Le Developpement | Hamel M.A.,Ird Institute Of Recherche Pour Le Developpement | Hamel M.A.,James Cook University | Kulbicki M.,CIRAD - Agricultural Research for Development
PLoS ONE | Year: 2012

Species check-lists are helpful to establish Marine Protected Areas (MPAs) and protect local richness, endemicity, rarity, and biodiversity in general. However, such exhaustive taxonomic lists (i.e., true surrogate of biodiversity) require extensive and expensive censuses, and the use of estimator surrogates (e.g., habitats) is an appealing alternative. In truth, surrogate effectiveness appears from the literature highly variable both in marine and terrestrial ecosystems, making it difficult to provide practical recommendations for managers. Here, we evaluate how the biodiversity reference data set and its inherent bias can influence effectiveness. Specifically, we defined habitats by geomorphology, rugosity, and benthic cover and architecture criteria, and mapped them with satellite images for a New-Caledonian site. Fish taxonomic and functional lists were elaborated from Underwater Visual Censuses, stratified according to geomorphology and exposure. We then tested if MPA networks designed to maximize habitat richness, diversity and rarity could also effectively maximize fish richness, diversity, and rarity. Effectiveness appeared highly sensitive to the fish census design itself, in relation to the type of habitat map used and the scale of analysis. Spatial distribution of habitats (estimator surrogate's distribution), quantity and location of fish census stations (target surrogate's sampling), and random processes in the MPA design all affected effectiveness to the point that one small change in the data set could lead to opposite conclusions. We suggest that previous conclusions on surrogacy effectiveness, either positive or negative, marine or terrestrial, should be considered with caution, except in instances where very dense data sets were used without pseudo-replication. Although this does not rule out the validity of using surrogates of species lists for conservation planning, the critical joint examination of both target and estimator surrogates is needed for every case study. © 2012 Van Wynsberge et al.

Guillemot N.,Ird Institute Of Recherche Pour Le Developpement | Guillemot N.,Agrocampus Ouest | Chabanet P.,CIRAD - Agricultural Research for Development | Le Pape O.,Agrocampus Ouest
Coral Reefs | Year: 2010

The impacts of the unusually strong Cyclone Erica (March 2003) on coral reef habitats at a site located on the northwest coast of New Caledonia (South Pacific) were assessed using a 6-year data set (2002-2007). We examined the interannual variations of key variables describing reef habitats (live hard and soft corals, dead corals in place, coral debris, algae and relative proportion of mechanically vulnerable and resistant live hard corals). The cyclone-induced disturbances of habitats differed according to three reef types: patch reefs, barrier reefs far from passes (more than 3 km from the nearest pass) and barrier reefs near passes (less than 3 km from the nearest pass). Short-term mechanical damage was detected on the three-dimensional structure of reef habitats with a notable shift from a community dominated by mechanically vulnerable corals to one dominated by resistant corals on barrier reefs far from passes. The history of habitats and their pre-disturbance characteristics, in link with local hydrodynamics, was found to influence their short-term susceptibility to extreme events such as cyclones. However, the most significant effects appeared in the midterm (within 2 years after the cyclone) as the cover of live hard corals significantly decreased by approximately 45% between 2002 and 2004 on all reef types. The short- and midterm disturbances of coral reef habitats are discussed with regard to published temporal variations in reef fish assemblages, underlining the delayed effects of this cyclonic event on fish as well as benthic habitats. Coral reef habitats and live corals had shown significant patterns of recovery 4 years after the cyclone, followed by similar recovery in fish community, suggesting good resilience in a face of this major natural disturbance in an area under moderate anthropogenic pressure. © Springer-Verlag 2010.

Guillemot N.,Ird Institute Of Recherche Pour Le Developpement | Guillemot N.,Agrocampus Ouest | Kulbicki M.,CIRAD - Agricultural Research for Development | Chabanet P.,CIRAD - Agricultural Research for Development | Vigliola L.,Ird Institute Of Recherche Pour Le Developpement
PLoS ONE | Year: 2011

The relationship between species and the functional diversity of assemblages is fundamental in ecology because it contains key information on functional redundancy, and functionally redundant ecosystems are thought to be more resilient, resistant and stable. However, this relationship is poorly understood and undocumented for species-rich coastal marine ecosystems. Here, we used underwater visual censuses to examine the patterns of functional redundancy for one of the most diverse vertebrate assemblages, the coral reef fishes of New Caledonia, South Pacific. First, we found that the relationship between functional and species diversity displayed a non-asymptotic power-shaped curve, implying that rare functions and species mainly occur in highly diverse assemblages. Second, we showed that the distribution of species amongst possible functions was significantly different from a random distribution up to a threshold of ~90 species/transect. Redundancy patterns for each function further revealed that some functions displayed fast rates of increase in redundancy at low species diversity, whereas others were only becoming redundant past a certain threshold. This suggested non-random assembly rules and the existence of some primordial functions that would need to be fulfilled in priority so that coral reef fish assemblages can gain a basic ecological structure. Last, we found little effect of habitat on the shape of the functional-species diversity relationship and on the redundancy of functions, although habitat is known to largely determine assemblage characteristics such as species composition, biomass, and abundance. Our study shows that low functional redundancy is characteristic of this highly diverse fish assemblage, and, therefore, that even species-rich ecosystems such as coral reefs may be vulnerable to the removal of a few keystone species. © 2011 Guillemot et al.

Larmarange J.,University of Paris Descartes | Wade A.S.,Institute dHygiene Sociale | Diop A.K.,Institute dHygiene Sociale | Diop O.,Institute dHygiene Sociale | And 3 more authors.
PLoS ONE | Year: 2010

Background: Men who have sex with other men (MSM) are a vulnerable population in Africa that has been insufficiently explored. Given the high rate of bisexuality among MSM (73% in the past year), it is important to understand their risktaking behaviors regarding both men and women. Methodology/Principal Findings: A socio-behavioral survey was carried out in 2007 among 501 MSM recruited using the snowball sampling method. We explore in this article why a condom was not used during last sexual intercourse with a man and with a woman, taking into account the respondent's characteristics, type of relationship and the context of the sexual act. In the survey, 489 men reported that they had had sexual intercourse at least once with another man during the previous year, and 358 with a man and with a woman. The main risk factors for not using a condom at last sexual intercourse with another man were having sex in a public place (aOR = 6.26 [95%CI: 2.71-14.46]), non-participation in an MSM prevention program (aOR = 3.47 [95%CI: 2.12-5.69]), a 19 years old or younger partner (aOR = 2.6 [95%CI: 1.23-4.53]), being 24 years or younger (aOR = 2.07 [95%CI: 1.20-3.58]) or being 35 years or over (aOR = 3.08 [95%CI:1.11-8.53]) and being unemployed (aOR = 0.36 [95%CI: 0.10-1.25]). The last sexual intercourse with the respondent's wife was hardly ever protected (2%). With women, the other factors were a 15 years or younger partner (aOR = 6.45 [95%CI: 2.56-16.28]), being educated (primary: aOR = 0.45 [95%CI: 0.21-0.95], secondary or higher: aOR = 0.26 [95%CI: 0.11-0.62]), being a student (aOR = 2.20 [95%CI: 1.07-4.54]) or unemployed (aOR = 3.72 [95%CI: 1.31-10.61]) and having participated in a MSM prevention program (aOR = 0.57 [95%CI: 0.34-0.93]). Conclusion: Having participated in a prevention program specifically targeting MSM constitutes a major prevention factor. However, these programs targeting MSM must address their heterosexual practices and the specific risks involved. © 2010 Larmarange et al.

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