Work T.M.,U.S. Geological Survey |
Aeby G.S.,Hawaii Institute of Marine Biology |
Lasne G.,Center Ird Of Noumea |
Tribollet A.,French National Center for Scientific Research
Journal of Invertebrate Pathology | Year: 2014
We surveyed the reefs of Grande Terre, New Caledonia, for coral diseases in 2010 and 2013. Lesions encountered in hard and soft corals were systematically described at the gross and microscopic level. We sampled paired and normal tissues from 101 and 65 colonies in 2010 and 2013, respectively, comprising 51 species of corals from 27 genera. Tissue loss was the most common gross lesion sampled (40%) followed by discoloration (28%), growth anomalies (13%), bleaching (10%), and flatworm infestation (1%). When grouped by gross lesions, the diversity of microscopic lesions as measured by Shannon-Wiener index was highest for tissue loss, followed by discoloration, bleaching, and growth anomaly. Our findings document an extension of the range of certain diseases such as Porites trematodiasis and endolithic hypermycosis (dark spots) to the Western Pacific as well as the presence of a putative cnidarian endosymbiont. We also expand the range of species infected by cell-associated microbial aggregates, and confirm the trend that these aggregates predominate in dominant genera of corals in the Indo-Pacific. This study highlights the importance of including histopathology as an integral component of baseline coral disease surveys, because a given gross lesion might be associated with multiple potential causative agents. © 2014.
Cuypers Y.,University Pierre and Marie Curie |
Bouruet-Aubertot P.,University Pierre and Marie Curie |
Marec C.,Laval University |
Marec C.,Center Ird Of Noumea
Biogeosciences | Year: 2012
One of the main purposes of the BOUM experiment was to find evidence of the possible impact of submesoscale dynamics on biogeochemical cycles. To this aim physical as well as biogeochemical data were collected along a zonal transect through the western and eastern basins of the Mediterranean Sea. Along this transect 3-day fixed point stations were performed within anticyclonic eddies during which microstructure measurements of the temperature gradient were collected over the top 100 m of the water column. We focus here on the characterization of turbulent mixing. The analysis of microstructure measurements revealed a high level of turbulent kinetic energy (TKE) dissipation rate in the seasonal pycnocline and a moderate level below with mean values of the order of 10 -6 W kg -1 and 10 -8 W kg -1, respectively. The Gregg Henyey (Gregg, 1989) fine-scale parameterization of TKE dissipation rate produced by internal wave breaking, and adapted here following Polzin et al. (1995) to take into account the strain to shear ratio, was first compared to these direct measurements with favorable results. The parameterization was then applied to the whole data set. Within the eddies, a significant increase of dissipation at the top and base of eddies associated with strong near-inertial waves is observed. Vertical turbulent diffusivity is increased both in these regions and in the weakly stratified eddy core. The stations collected along the East-West transect provide an overview of parameterized TKE dissipation rates and vertical turbulent diffusivity over a latitudinal section of the Mediterranean Sea. Strong TKE dissipation rates are found within the first 500 m and up to 1500 m above the bottom. Close to the bottom where the stratification is weak, the inferred vertical turbulent diffusivity can reach K z≃10 -3 m 2 s -1 and may therefore have a strong impact on the upward diffusive transport of deep waters masses. ©2012 Author(s).
Zarzoso-Lacoste D.,French National Center for Scientific Research |
Ruffino L.,French National Center for Scientific Research |
Vidal E.,French National Center for Scientific Research |
Vidal E.,Center Ird Of Noumea
Journal of Zoology | Year: 2011
Invasive rats (Rattus spp.) are renowned bird predators and have been identified as a leading cause of island bird population declines and extinctions. Recently, new questions have been raised regarding the mechanisms and the severity of impact of invasive rat predation on bird populations. We investigated the predatory capacity of the invasive black rat Rattus rattus on bird eggs using captive trials on wild-trapped individuals. Five factors were specifically tested for their influence on egg predation success: egg size, egg state, rat body mass, gender and habitat. Our results showed that rats only managed to prey on intact eggs when these were small (canary) and that they had great difficulty preying on medium-sized (hen) and even small (quail)-sized intact eggs, regardless of the rat' body mass, gender and habitat. Conversely, rats preyed extensively on previously damaged eggs of all sizes. Our findings suggest that preying on intact bird eggs without specific learning skills, such as rolling an egg to break it, may be challenging for the black rats. Moreover, our findings strongly indicate that bird susceptibility to egg predation by rats varies with island contexts and may depend on a combination of multiple additive and synergic factors. Experiments that allow for testing the multiple evolutionary and ecological factors explaining between-island or between-population variation in rodent impacts are needed to promote a better overview of the processes involved in bird population declines. © 2011 The Authors. Journal of Zoology © 2011 The Zoological Society of London.
Pringault O.,Center Ird Of Noumea |
Viret H.,Center Ird Of Noumea |
Duran R.,University of Pau and Pays de l'Adour
Marine Pollution Bulletin | Year: 2010
The removal of nickel in marine tropical sediments (New Caledonia) was studied in microcosms. Removal of Ni2+ was strongly enhanced by the presence of bacteria, with rates up to twofold higher than those observed under sterilized conditions. After 8days of incubation, Ni2+ concentration in the water column ranged from 30% to 50% of the initial concentration according to sediment origin. Addition of glucose stimulated bacterial processes and resulted in a complete disappearance of Ni2+ in the water phase. Incubation under anoxic conditions slightly affects the microbial structure inferred from T-RFLP analysis irrespective of Ni2+ spiking, whereas incubation under oxic conditions resulted to moderate modification of the microbial structure, changes that might be more marked in the presence of Ni2+. Five different T-RFs were observed in almost all microcosms with relative abundance between 5% and 30%. Incubation with glucose resulted in the dominance of a common T-RF, with relative abundance up to 39%. © 2010 Elsevier Ltd.
Hedouin L.,International Atomic Energy Agency |
Hedouin L.,CNRS Coastal and Marine Environment Laboratory |
Hedouin L.,Center Ird Of Noumea |
Pringault O.,Center Ird Of Noumea |
And 5 more authors.
Water Research | Year: 2011
The bioaccumulation and retention capacities of some key local contaminants of the New Caledonia lagoon (Ag, As, Cd, Co, Cr, Cu, Mn, Ni and Zn) have been determined in the oyster Isognomon isognomon and the edible clam Gafrarium tumidum during transplantation experiments. In a first set of experiments, oysters and clams from a clean site were transplanted into contaminated sites. Uptake kinetics determined in the field indicated that for Cr and Cu in oysters and Co, Ni, and Zn in clams, concentrations in transplanted bivalves reached those of resident organisms after 100d, whereas for the other elements, it would require a longer time for transplanted bivalves to reach the same levels as in the resident populations (e.g., up to 3 years for Cd). However, the slow uptake rate for metals observed in the latter transplantation is rather related to low bioavailability of metals at the contaminated sites than to low bioaccumulation efficiency of the organisms. Indeed, results of a second transplantation experiment into two highly contaminated stations indicated a faster bioaccumulation of metals in both bivalves. Results of both transplantations point out that the clam G. tumidum is a more effective bioindicator of mining contamination than I. isognomon, since it is able to bioaccumulate the contaminants to a greater extent. However the very efficient metal retention capacity noted for most elements indicates that organisms originating from contaminated sites would not be suitable for monitoring areas of lower contamination. Hence, geographical origin of animals to be transplanted in a monitoring perspective should be carefully selected. © 2010 Elsevier Ltd.
Zarzoso-Lacoste D.,Aix - Marseille University |
Corse E.,Batiment Villemin |
Vidal E.,Center Saint Charles |
Vidal E.,Center Ird Of Noumea
Molecular Ecology Resources | Year: 2013
While the morphological identification of prey remains in predators' faeces is the most commonly used method to study trophic interactions, many studies indicate that this method does not detect all consumed prey. Polymerase chain reaction-based methods are increasingly used to detect prey DNA in the predator food bolus and have proven efficient, delivering highly accurate results. When studying complex diet samples, the extraction of total DNA is a critical step, as polymerase chain reaction (PCR) inhibitors may be co-extracted. Another critical step involves a careful selection of suitable group-specific primer sets that should only amplify DNA from the targeted prey taxon. In this study, the food boluses of five Rattus rattus and seven Rattus exulans were analysed using both morphological and molecular methods. We tested a panel of 31 PCR primer pairs targeting bird, invertebrate and plant sequences; four of them were selected to be used as group-specific primer pairs in PCR protocols. The performances of four DNA extraction protocols (QIAamp® DNA stool mini kit, DNeasy® mericon food kit and two of cetyltrimethylammonium bromide-based methods) were compared using four variables: DNA concentration, A260/A280 absorbance ratio, food compartment analysed (stomach or faecal contents) and total number of prey-specific PCR amplification per sample. Our results clearly indicate that the A260/A280 absorbance ratio, which varies between extraction protocols, is positively correlated to the number of PCR amplifications of each prey taxon. We recommend using the DNeasy® mericon food kit (QIAGEN), which yielded results very similar to those achieved with the morphological approach. © 2013 Blackwell Publishing Ltd.
Entoloma pseudomurrayi sp. nov., a new yellow Entoloma from a mountain Nothofagus forest in New Caledonia [Entoloma pseudomurrayi sp. nov., un nouvel entolome jaune des forêts néo-calédoniennes de montagne à Nothofagus]
Eyssartier G.,etangs de Beon |
Ducousso M.,Center Ird Of Noumea |
Buyck B.,CNRS Systematics, Biodiversity and Evolution Institute
Cryptogamie, Mycologie | Year: 2010
The authors describe and illustrate Entoloma pseudomurryai sp. nov., a new Entoloma with lemon yellow cap, from a mountain Nothofagus forest in New Caledonia. The species is suggested to belong to section Psittacina (Romagn.) Singer of subgenus Inocephalus Noordel., thereby emending the definition to include also species that are not blue. The discussion comments on close species and presents the typical features of this species group. © 2010 Adac.
Le Borgne R.,Center Ird Of Noumea |
Douillet P.,Metropolitan Autonomous University |
Fichez R.,Metropolitan Autonomous University |
Torreton J.-P.,Montpellier University
Marine Pollution Bulletin | Year: 2010
The New Caledonia SW lagoon is wide (5-20 nautical miles) and semi-closed. It is influenced by both the open ocean and the high island within a meteorological context subject to seasonal, inter-annual and longer term variations. The short-term variability (>1. day) of meteorological, hydrographical and planktonic parameters is illustrated by a 5-month long time series and is linked to local or remote wind, and precipitation. Seasonal and inter-annual variabilities, inferred from a 10-year long station by spectral analysis, appear clearly for all parameters. Seasonality is the main scale of variability as the island lies near the tropic of Capricorn. Inter-annual variability of a 3-4. year periodicity is poorly related to the Southern oscillation index (an equatorial climatic index), stressing the need for a separate tropical index. Long term trends appear on several parameters but their reliability depends on the length of the records. Considering only the longest records (1958-2005), surface temperature appears to have increased since the end of the 1960s in Noumea area. Finally, as a result of greater terrestrial influence, shallower depths, and longer water turnover times close to shore, the temporal variability amplitude decreases from the shore to the barrier reef. © 2010 Elsevier Ltd.
Mercier L.,Montpellier University |
Mouillot D.,Montpellier University |
Bruguier O.,Montpellier University |
Vigliola L.,Center Ird Of Noumea |
Darnaude A.M.,Montpellier University
Marine Ecology Progress Series | Year: 2012
Precise knowledge of lifetime migrations is vital in exploited fish species, since all essential habitats must be protected to maintain sustainable stock levels. The present study used multi-element otolith fingerprints of the gilthead sea bream Sparus aurata (L.) to discriminate its main juvenile and adult habitats in the Languedoc-Roussillon region (Gulf of Lions, northwest Mediterranean) and infer the lifetime migrations of 12 individuals from the area (11 from the present day and 1 from the Roman era). This allowed for the first time the identification of key habitats for the successful completion of the species' life cycle in the Gulf of Lions, and the connectivity between them. Our results revealed that lagoon use by S. aurata is probably ancient (>2500 yr) and confirmed its current commonness. Yet, although most observed migration patterns were in accordance with the migratory behavior previously described for the species, strong inter-individual variations and new patterns in habitat use were detected. At the juvenile stage, a preference for shallow lagoons with low salinities was evidenced. Nevertheless, the first year of life can also be successfully completed in marine conditions. At the adult stage, lagoon use was shown to occur until at least age 4 yr, with periods of lagoon residency of up to 11 mo in a year, often including winter months. Because overwintering in the lagoons was previously thought to be impossible for S. aurata due to low temperatures, this finding has important implications for future stock management, especially since the species breeds in winter. © Inter-Research 2012.
Bourgeois S.,Center Ird Of Noumea |
Hochard S.,Center Ird Of Noumea |
Pringault O.,Center Ird Of Noumea
Aquatic Microbial Ecology | Year: 2010
Microphytobenthos (MPB) is an important primary producer in coastal ecosystems. In oligotrophic environments, its activity may be controlled by the availability of organic or inorganic compounds but also by its migration behavior. The objective of this study was to determine, in MPBcolonized subtidal sediments, the consequences of short-term enrichments (<24 h) of organic (alanine, glutamate, and glucose) and inorganic (ammonium, phosphate) compounds on MPB vertical migration and metabolisms, net production (NP), areal gross production (AGP), and community respiration (R). Two contrasting stations located in the southwest lagoon of New Caledonia were investigated: 1 under strong anthropogenic influence and 1 under more oceanic influence. Both stations were dominated by epipelic diatoms. Differences in net primary production were explained by diurnal variation of MPB biomass at the sediment surface, showing the importance of MPB migration in the functioning of these subtidal environments. However, a stimulation or inhibition of MPB migration did not necessarily impact the net primary production of the system; this strongly depends upon the interactions between the autotrophic and heterotrophic compartments, the latter being controlled by the environmental conditions. For the station under low anthropogenic influence, AGP and R were both significantly stimulated by alanine, glucose, and ammonium, and significantly inhibited by phosphate. The similar responses of AGP and R to enrichments suggest that autotrophs and heterotrophs were tightly coupled. Conversely, in the station under strong anthropogenic influence, AGP and R responded differently. Addition of ammonium inhibited AGP without having an impact on R, whereas addition of phosphate inhibited R whilst having no measurable effect on AGP. In this station, the coupling between autotrophs and heterotrophs was weakened, suggesting that the carbon demand of the heterotrophic compartment is probably sustained by the supplies of allochthonous organic matter rather than by exudates from the autotrophic compartment. © Inter-Research 2010.