University of New Caledonia
  • Nouméa, New Caledonia
Recent publications
L1 French participants learned novel L2 English words over two days of learning sessions, with half of the words presented with their orthographic forms (Audio-Ortho) and half without (Audio only). One group heard the words pronounced by a single talker, while another group heard them pronounced by multiple talkers. On the third day, they completed a variety of tasks to evaluate their learning. Our results show a robust influence of orthography, with faster response times in both production (Picture naming) and recognition (Picture mapping) tasks for words learned in the Audio-Ortho condition. Moreover, formant analyses of the Picture naming responses show that orthographic input pulls pronunciations of English novel words towards a non-native (French) phonological target. Words learned with their orthographic forms were pronounced more precisely (with smaller Dispersion Scores), but were misplaced in the vowel space (as reflected by smaller Euclidian distances with respect to French vowels). Finally, we found only limited evidence of an effect of talker-based acoustic variability: novel words learned with multiple talkers showed faster responses times in the Picture naming task, but only in the Audio-only condition, which suggests that orthographic information may have overwhelmed any advantage of talker-based acoustic variability.
Thus far, no long-term in situ observation of planktonic biomass have been undertaken to optimize the black-lip pearl oyster aquaculture in the remote Tuamotu atolls. The feasibility of using data from the OLI sensor onboard Landsat-8 satellite to determine chlorophyll a concentrations (Chla) in a deep atoll, Ahe, was then assessed over the 2013–2021 period using 153 images. Validations with in situ observations were satisfactory, while seasonal and spatial patterns in Chla were evidenced within the lagoon. Then, a bioenergetic modelling exercise was undertaken to estimate oyster life-history traits when exposed to the retrieved Chla. The outputs provide spatio-temporal variations in pelagic larval duration (11.1 to 30.6 days), time to reach commercial size (18.8 to 45.3 months) and reproductive outputs (0.5 to 1.7 event year⁻¹). This first study shows the potential of using remote sensing to monitor the trophic status of deep pearl farming lagoons and help aquaculture management.
Modern nautilids ( Nautilus and Allonautilus ) have often been studied by paleontologists to better understand the anatomy and ecology of fossil relatives. Because direct observations of these animals are difficult, the analysis of light stable isotopes (C, O) preserved in their shells has been employed to reveal their habitat and life history. We aim to (1) reconstruct the habitat depth of Nautilus macromphalus and (2) decipher the fraction of metabolic carbon in its shell by analyzing oxygen and carbon isotopes (δ ¹⁸ O, δ ¹³ C) in the septa of two specimens in combination with analyses of water samples from the area. Additionally, we investigate whether morphological changes during ontogeny are reflected in the isotopic values of the shells. Results reveal that the patterns of change of δ ¹⁸ O and δ ¹³ C in the septa of N . macromphalus pre- and post-hatching are consistent with previous studies. Values of δ ¹⁸ O water range from 0.7 to 1.4‰ (VSMOW), with a maximum value coincident with a salinity maximum at ~150 m. We use the temperature and δ ¹⁸ O water profiles to calculate equilibrium values of δ ¹⁸ O aragonite with depth. Comparing these values with the measured δ ¹⁸ O of the septa shows that the habitat depth of N . macromphalus is ~140 m pre-hatching and ~370 m post-hatching. Using δ ¹³ C of shell carbonate and published data on metabolic carbon, the fraction of metabolic carbon is reconstructed as ~21% and 14% pre- and post-hatching, respectively. The reconstructed depth pre-hatching is slightly shallower than in N . pompilius from the Philippines and Fiji, but the post-hatching depth is similar. However, it is important to emphasize that these estimates represent average over time and space because nautilus is a mobile animal. Lastly, the changes in morphological parameters and the changes in δ ¹³ C and δ ¹⁸ O during ontogeny do not coincide except at hatching and at the onset of maturity.
PM2.5 characterizations are essential in understanding its impact on the health of the exposed population. Sampled PM2.5 by Mani et al. (2020) was characterized to determine atmospheric metal concentration and inhalation health risk in Suva and Lautoka Cities, the only two cities in Fiji and one of the largest in the South Pacific Islands. Twenty-two elements (Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, P, Pb, S, Si, Sr, V, Zn) were analyzed using ICP-OES. Black Carbon (BC) sampling was also done at three different sites in Suva City, namely, Fiji National University Samabula Intersection site, Suva City Bus Station site and the Reservoir Road Community Settlement Site as well as at Lautoka City Bus Station. Mean BC concentrations over the sampling period were found to be 3.9 ± 2.9 (median = 3.3 μg/m³), 2.6 ± 2.7 μg/m³ (median = 1.7 μg/m³), 2.4 ± 2.3 μg/m³ (median = 1.7 μg/m³) and 4.0 ± 4.7 μg/m³ (median = 2.4 μg/m³) respectively. Health risk assessments (Carcinogenic Risk (CR) and Non-Carcinogenic Risk (HQ)) were also done to assess the risk of inhalation exposure in adults and children. The Hazard Index for children in Lautoka (HI = 1.03) was found to slightly exceed the safe level of 1. This study provides the first inventory of atmospheric particulate bound metal concentrations and diurnal BC profiles in Fiji and informs policy makers and scientists for further studies.
Amidst global environmental changes, predicting species' responses to future environments is a critical challenge for preserving biodiversity and associated human benefits. We explored the original idea that coral competitive performances, the ability of corals to preempt ecological space on the reef through territorial warfare, serve as indicators of species’ ecological niches and environmental windows, and therefore, responses to future environments. Our surveys indicated that coral performances varied with taxonomic identity, size and position along environmental gradients, highlighting complex interplays between life-history, warfare-strategy and niche segregation. Our results forewarn that growing alterations of coastal environments may trigger shifts in coral dominance, with the decline of major reef-building taxa like acroporids, and emphasize the importance of limiting human impacts for coastal resilience. Our empirical approach untangles the complexity of species' battle-like interactions and can help identify winners and losers in various communities caught in the interplay between ecological niches, environmental windows and global changes.
Indonesia hosts the largest number of active volcanoes, several of which are renowned for climate-changing historical eruptions. This pedigree might suggest a substantial fraction of global volcanic sulfur emissions from Indonesia and are intrinsically driven by sulfur-rich magmas. However, a paucity of observations has hampered evaluation of these points—many volcanoes have hitherto not been subject to emissions measurements. Here we report new gas measurements from Indonesian volcanoes. The combined SO2 output amounts to 1.15 ± 0.48 Tg/yr. We estimate an additional time-averaged SO2 yield of 0.12-0.54 Tg/yr for explosive eruptions, indicating a total SO2 inventory of 1.27-1.69 Tg/yr for Indonesian. This is comparatively modest—individual volcanoes such as Etna have sustained higher fluxes. To understand this paradox, we compare the geodynamic, petrologic, magma dynamical and shallow magmatic-hydrothermal processes that influence the sulfur transfer to the atmosphere. Results reinforce the idea that sulfur-rich eruptions reflect long-term accumulation of volatiles in the reservoirs.
New Caledonia is home to one of the largest remaining populations of dugongs (Dugong dugon) and is located at the southeastern limit of the species’ range. Local knowledge suggests that current levels of removal due to anthropogenic pressures are unsustainable, while trends suggest an ongoing decline in the population. Considering this unfavorable conservation context, this study aimed to assess the New Caledonian dugong population’s resilience by determining its level of genetic diversity and degree of isolation relative to other populations. Mitochondrial DNA (mtDNA) control region sequences (n = 55) collected from live and dead dugongs in New Caledonia were compared to a global dataset of previously published sequences (n = 631) representing dugong populations throughout the species range. The New Caledonian dugong population displayed the lowest level of mtDNA diversity documented worldwide (3 haplotypes with 1 base pair difference), suggesting a recent origin of the current population through limited colonization events. Population structure analyses indicate a strong genetic differentiation with all the putative populations represented in the global dataset, including large neighbouring Australian populations. These results show that the dugong population in New Caledonia is particularly isolated, fragile, and vulnerable to anthropogenic threats and diseases with low potential for resilience through incoming gene flow. Our findings call for an instant conservation response and consideration for IUCN population assessment to support the long-term survival of the New Caledonian dugong population.
Purpose The Cunoniaceae are a major component of the New Caledonian flora with 91 endemic species that are highly unusual in that multiple metals are hyperaccumulated in different species. This makes it an ideal model system for studying the nature of the hyperaccumulation phenomenon. Methods X-ray fluorescence spectroscopy (XRF) scanning of all herbarium collections of the Cunoniaceae was undertaken at the Herbarium of New Caledonia to reveal incidences of nickel (Ni) and manganese (Mn) accumulation. Following on, the Mn hyperaccumulating P. reticulata and the Ni hyperaccumulating P. xaragurensis were selected for detailed follow-up investigations using synchrotron-based X-ray fluorescence microscopy (XFM). Results The systematic XRF screening of herbarium specimens showed that numerous species have high foliar Mn and Ni with species either accumulating Ni or Mn, but not both elements simultaneously. Soil ‘extractable’ Mn and Ni concentrations associated with Pancheria reticulata and P. xaragurensis greatly varies between the species. The XFM data shows that P. reticulata has a distinctive distribution pattern with Mn concentrated in large hypodermal cells. This contrasts with P. xaragurensis where Ni was mainly localized in and around the epidermis, and hypodermal cells were not observed. Conclusions Manganese and Ni accumulation are differently localized in Pancheria species growing on ultramafic soils, which is not explained by contrasting soils conditions, but represents different ecophysiological adaptations.
Human impact increasingly alters global ecosystems, often reducing biodiversity and disrupting the provision of essential ecosystem services to humanity. Therefore, preserving ecosystem functioning is a critical challenge of the twenty-first century. Coral reefs are declining worldwide due to the pervasive effects of climate change and intensive fishing, and although research on coral reef ecosystem functioning has gained momentum, most studies rely on simplified proxies, such as fish biomass. This lack of quantitative assessments of multiple process-based ecosystem functions hinders local and regional conservation efforts. Here we combine global coral reef fish community surveys and bioenergetic models to quantify five key ecosystem functions mediated by coral reef fishes. We show that functions exhibit critical trade-offs driven by varying community structures, such that no community can maximize all functions. Furthermore, functions are locally dominated by few species, but the identity of dominant species substantially varies at the global scale. In fact, half of the 1,110 species in our dataset are functionally dominant in at least one location. Our results reinforce the need for a nuanced, locally tailored approach to coral reef conservation that considers multiple ecological functions beyond the effect of standing stock biomass.
Knowledge of marine fish diversity remains largely incomplete in the Con Dao Archipelago, the oldest marine protected area in Vietnam. Previous investigations of diversity established a species checklist for Con Dao but did not specifically target pre-settlement stages of reef fishes and short-life pelagic species even though they provide information on local biodiversity and on the ecological functions of their habitat. Species identification of small fishes is usually challenging, but in the present study, DNA barcode-based identification was used to update the species checklist for Con Dao marine coastal habitats. Fishes were sampled monthly over a 1-year period using light traps in coral reef, seagrass, and harbour habitats. Among a total of 11,509 individuals captured, 1248 specimens were selected for DNA barcoding analyses based on morphological differences, 1012 were successfully sequenced, and their COI sequences uploaded to the BOLD database. Among the 163 corresponding BINs, 120 were recorded for the first time in Vietnam while 40 (25%) were new to BOLD. It was impossible to assign a complete species name to 59 BINs (36%), because of gaps in the taxonomical coverage or mislabelled DNA barcodes (probably due to species misidentification). Among species observed in this study and belonging to 18 orders and 35 families, 85 and 59 were new records for Con Dao and Vietnam, respectively. The high proportion of new species records are probably related to the sampling gear used that is particularly appropriate for sampling cryptobenthic species of the families Gobiidae, Tripterygiidae, and Blenniidae. From a methodological standpoint, this study demonstrates that accuracy of the DNA barcode-based species identification can be greatly improved by careful revision of BINs, phylogenetic relationships with sibling BINs, and by using the taxonomical literature which can provide sequences of reference species.
Extreme reef environments have become useful natural laboratories to investigate physiological specificities of species chronically exposed to future-like climatic conditions. The lagoon of Bouraké in New Caledonia (21°56′56.16′′ S; 125°59′36.82′′ E) is one of the only reef environments studied where the three main climatic stressors predicted to most severely impact corals occur. In this lagoon, temperatures, seawater pHT and dissolved oxygen chronically fluctuate between extreme and close-to-normal values (17.5–33.85 °C, 7.23–7.92 pHT units and 1.87–7.24 mg O2 L⁻¹, respectively). In March 2020, the endosymbiont functions (chl a, cell density and photosynthesis) and respiration rates were investigated in seven coral species from this lagoon and compared with those of corals from an adjacent reference site using hour-long incubations mimicking present-day and future conditions. Corals originating from Bouraké displayed significant differences in these variables compared to reference corals, but these differences were species-specific. Photosynthetic rates of Bouraké corals were all significantly lower than those of reference corals but were partially compensated by higher chlorophyll contents. Respiration rates of the Bouraké corals were either lower or comparable to those of reference corals. Conversely, photosynthesis and respiration rates of most studied species were similar regardless of the incubation conditions, which mimicked either present-day or future conditions. This study supports previous work indicating that no unique response can explain corals’ tolerance to sub-optimal conditions and that a variety of mechanisms will be at play for corals in a changing world.
New Caledonia is particularly affected by nickel open pit mining activities because of the presence of ultramafic soils rich in metals. The particles dispersed by atmospheric transport and soil erosion during the excavation of nickel end up by deposition or leaching in rivers where they may be bioaccumulated by organisms living downstream the mines. Despite alarming freshwater metals concentrations, no study investigated the level of their bioaccumulation in eels, and if high bioaccumulation levels occur, the potential consequences on their health. The aim of this study was to determine how eels Anguilla marmorata are impacted in situ by metals issued from mining activity by measuring: morphometric parameters; metal concentrations in tissues and organs and transcription levels of target genes encoding proteins involved in several metabolic key functions. Among organs, liver was found to be the most affected by mining with average nickel concentrations of 5.14 mg/kg versus 1.63 mg/kg for eels away from mines leading to dysregulation of numerous genes involved in oxidative stress, DNA repair, apoptosis, reproduction and both lipid and mitochondrial metabolisms. This study should allow us to define in an integrated way if metals released by mining activities influence metals bioaccumulation in eels and induce biological effects.
Herein we report an unprovoked shark attack on a scuba diver in New Caledonia. The species responsible for the attack was identified as a tiger shark (Galeocerdo cuvier), based on both the victim’s testimony and forensic examination. The victim suffered significant loss of soft tissues from one thigh, which resulted in hemorrhagic shock. Even though the event occurred at a remote location, miles away from the nearest hospital, appropriate first aid, immediate deployment of an alert system, and prompt helicopter transfer by an emergency rescue team allowed the victim to be transferred to an intensive care unit in stable condition and to undergo surgery within 4 h of being bitten. Early coverage of exposed bone was performed, followed up with negative pressure dressing, antibiotic treatment, hyperbaric oxygen therapy, and a split skin graft. In spite of the massive muscular loss incurred, the victim was able to regain her ability to walk within 6 wk of the incident. Shark attacks on scuba divers are rare and seldom reported, especially in New Caledonia.
Among animal species, the songs of male humpback whales (Megaptera novaeangliae) are a rare example of social learning between entire populations. Understanding fine-scale similarity in song patterns and structural features will better clarify how accurately songs are learned during inter-population transmission. Here, six distinct song types (2009–2015) transmitted from the east Australian to New Caledonian populations were quantitatively analysed using fine-scale song features. Results found that New Caledonian whales learned each song type with high accuracy regardless of the pattern’s complexity. However, there were rare instances of themes (stereotyped patterns of sound units) only sung by a single population. These occurred more often in progressively changing ‘evolutionary’ songs compared to rapidly changing ‘revolutionary’ songs. Our results suggest that populations do not need to reduce complexity to accurately learn song patterns. Populations may also incorporate changes and embellishments into songs in the form of themes which are suggested to be learnt as distinct segments. Maintaining complex song patterns with such accuracy suggests significant acoustic contact, supporting the hypothesis that song learning may occur on shared feeding grounds or migration routes. This study improves the understanding of inter-population mechanisms for large-scale cultural transmission in animals.
Mangrove forests play an important role in the balance of biodiversity. However, they are threatened by agriculture, aquaculture, urbanization and global warming. That’s why it is imperative to monitor this ecosystem and understand how it evolves in the face of these threats in order to better preserve it. The traditional methods are invasive and time consuming. Besides, it is often difficult to get into mangroves because of the particular structure of some species, so measurements cannot be taken in those areas. That’s why it is very interesting to use aerial data provided by unmanned aerial vehicles (UAVs) photos or airborne laser scanning systems (ALS). Moreover, some representative elements of mangroves are only a few tens of centimeters high. This is the case of pneumatophores. Traditional measurements would be much too long. In this case, it is interesting to use terrestrial laser scanning systems (TLS) to make measurements and to follow them. A research project began in 2021 to try to understand how urban mangroves develop in semi-arid regions, using remote sensing techniques (photogrammetry, airborne and terrestrial laser scanning). The purpose of this paper is first to present the project and the issues of monitoring mangrove forests. Then, it proposes a state of the art of the methodologies used to record mangrove. Finally, it presents the different acquisitions made as well as the first results of species classification based on photogrammetric point cloud processing. The assessment based on ground truth shows already promising results.
Background: The prevalence of sexually transmitted infections (STIs) is high in New Caledonia (NC), but there are no data on Mycoplasma genitalium (MG). However, the syndromic treatment of urethritis used in the territory includes a single dose of azithromycin, which could generate resistance in MG. Methods: We recruited 217 men referred to the Noumea public medical centre (CMP) with signs of urethritis and meeting the inclusion criteria from May 2016 to March 2018. Each was tested for Neisseria gonorrhoeae (NG), Chlamydia trachomatis (CT), Trichomonas vaginalis (TV) and for the first time in NC for MG by polymerase chain reaction (PCR). Results: The prevalence of MG was 10.1% (22/217). Azithromycin resistance of MG (mutation in the 23S rRNA gene) could only be assessed for 10 of the 22 strains. Only one (1/10; 10%) was resistant. The prevalence of other STIs tested was high, as CT, NG and/or TV were associated in 77.3% (17/22) of MG-positive cases. Conclusions: Although co-infections further justify syndromic management, the presence of MG in NC urethritis cases could call treatment guidelines into question.
ABSTRACT New Caledonia is known for the diversity of its geological substrates, which have shaped its highly original and diverse flora. Here, the effect of the soil on the vegetation is described for several contact zones between ultramafic and other substrates. The main vegetation formations on soils derived from ultramafic rocks are described: low and medium altitude rainforests, high altitude rainforests, and maquis. The main types of maquis and the biological characteristics of maquis species are also presented
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193 members
Olivier Galy
  • Interdisciplinary Laboratory for Research in Education, EA 7483, University of New Caledonia, Noumea
Claude Maillaud
  • ISEA (EA 7484) & Laboratory for Chemistry of Natural Substances
Nazha Selmaoui
  • ISEA (Institut des Sciences Exactes et Appliquées)
Avenue James Cook (Nouville), 98850, Nouméa, New Caledonia
Head of institution
Jean Peeters, Président