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La ciguatéra est une intoxication alimentaire par organismes marins dont la clinique est polymorphe et doit faire éliminer des diagnostics différentiels. Un patient était hospitalisé pour un syndrome fébrile quelques jours après l'apparition de signes cliniques évocateurs d'une ciguatéra après avoir consommé un poisson du lagon. Il présentait également des signes neurologiques centraux et l'IRM cérébrale mettait en évidence une lésion du corps calleux. Une infection cutanée liée aux lésions de grattage était la cause de cet état fébrile et un diagnostic de CLOCCS était porté devant les lésions à l'IRM. Une atteinte neurologique centrale dans la ciguatéra est possible mais rare, un CLOCCS pouvant faire partie de ces atteintes. Un syndrome fébrile doit en revanche faire envisager un diagnostic alternatif ou une complication. Ciguatera is a food poisoning caused by marine organisms and has a polymoprhic clinic. Differential diagnoses need to be eliminated. A patient was hospitalized for a febrile syndrome a few days after the appearance of clinical signs suggestive of ciguatera after consuming lagoon fish. He also presented with central neurological signs and brain MRI revealed a lesion of the corpus callosum. A skin infection linked to the scratching lesions was the cause of this febrile state and a diagnosis of CLOCCS was made based on the lesions on MRI. A central neurological involvement in ciguatera is possible but rare, CLOCCS may be one of them. On the other hand, a febrile syndrome should lead to consider an differential diagnosis or a complication. [ABSTRACT FROM AUTHOR]

This article presents a comprehensive description of the safety system of a real installation that comprises PV panels, lithium-ion batteries, an electrolyzer, H 2 storage, a fuel cell, and a barium chloride/ammonia thermochemical prototype for heat recovery and cooling production. Such a system allows for the increase of the overall efficiency of the H 2 chain by exploiting the waste heat and transforming it into a cooling effect, particularly useful in tropical regions like French Polynesia. The study provides a great deal of detail regarding practical aspects of the system implementation and a consistent reference to the relevant standards and regulations applicable to the subject matter. More specifically, the study covers the ATEX classification of the site, the safety features of each component, the electrical power distribution, the main safety instrumented system, fire safety and the force ventilation system. The study also includes safety assessment and a section on lessons learned that could serve as guidance for future installations. In addition, an extensive amount of technical data is readily available to the reader in repository (P&ID, electrical diagrams, etc.). • Comprehensive description of the safety system of a real installation. • Great deal of detail regarding practical aspects of the system implementation. • Consistent referencing to the relevant standards applicable to the subject matter. • Layout of lessons learned and guidance for future installations. • Extensive technical data available in repository (P&ID, electrical diagrams, etc.). [ABSTRACT FROM AUTHOR]

• We retrieved all Zika virus (ZIKV) complete coding sequences shown in the databases between 1947 and 2022. • We analyzed 717 sequences for their phylogeography. • Thailand ZIKV 2006 filled the 40 years-gap after discovering the Asian sublineage. • The 2007 Micronesia and 2013 French Polynesia ZIKV belonged to distinct sublineages. • The Micronesia and French Polynesia ZIKV spread from South East Asia separately. We conducted molecular characterization, demonstrated the geographical distribution of Zika virus (ZIKV) circulating worldwide from 1947 to 2022 and explored the potential genetic recombination site in the Thailand ZIKV genomes. We constructed phylogenetic trees based on ZIKV coding sequences (CDS) and determined the geographical distribution of the representative viruses by genetic relationship and timeline. We determined genetic recombination among ZIKV and between ZIKV and other flaviviruses using similarity plot and bootscan analyzes, together with the phylogeny encompassing the CDS and eight subgenomic regions. The phylogenetic trees comprising 717 CDS showed two distinct African and Asian lineages. ZIKV in the African lineage formed two sublineages, and ZIKV in the Asian lineage diversified into the Asian and American sublineages. The 1966 Malaysian isolate was designated the prototype of the Asian sublineage and formed a node of only one member, while the newer viruses formed a distinct node. We detected no genetic recombination in the Thailand ZIKV. Five Thailand isolates discovered in 2006 were the second oldest ZIKV after the Malaysian prototype. Our result suggested two independent routes of ZIKV spread from Southeast Asia to Micronesia in 2007 and French Polynesia in 2013 before further spreading to South American countries. [ABSTRACT FROM AUTHOR]

Coral reefs are marine environments where calcium carbonate production and dissolution along with photosynthesis and respiration can have a large impact on the daily biogeochemical cycles of seawater dissolved inorganic carbon (DIC), total alkalinity (TA), oxygen (O 2), and major nutrients. Using seawater samples from Tetiaroa Atoll, French Polynesia, we apply isotope dilution thermal ionization mass spectrometry (ID-TIMS) to show that these daily cycles of variability extend to the dissolved seawater Sr/Ca ratio (Sr/Ca sw). Hourly measurements over a 27+ hour period indicate that Sr/Ca sw covaries with DIC and TA and exhibits up to a 2% relative difference compared to the regional Pacific Ocean source water Sr/Ca sw value of 8.53 mmol/mol. We hypothesize that the primary mechanism of hourly variability in Sr/Ca sw is carbonate precipitation/dissolution by corals and other marine calcifiers on the Tetiaroa reef, while sedimentary redox processes may significantly contribute to an apparent decoupling between net calcification rates estimated from TA compared to dissolved calcium [Ca] sw concentrations. Using a simple Rayleigh distillation model and a two-member mixing equation, we estimate the net partition coefficient of Sr (K D-Sr) for each hourly sample as a mixture of coral (aragonite; K D-Sr ∼ 1.06) and crustose coralline algae (high Mg-calcite; K D-Sr ∼ 0.39) contributions to the measured variability of [Ca] sw and Sr/Ca sw. As the high Mg-calcites of crustose coralline algae are (1) integral components to the structure and stability of the reef framework and (2) more soluble than aragonite under more acidic conditions, we propose that continued analyses of Sr/Ca sw within coral reef environments could be a useful tool for monitoring the ecological distribution and contributions of marine calcifiers on reefs as ocean warming and acidification intensify in response to anthropogenic climate change. Additionally, seasonal, interannual, and/or centennial-scale offsets between the Sr/Ca sw of open ocean source seawater and ambient reef seawater may have significant implications for interpreting past changes in sea surface temperatures derived from the coral Sr/Ca paleothermometer. [ABSTRACT FROM AUTHOR]

The introduction of biopollutant species challenge ecosystem health and economy in remote islands. Here we checked the advance of invasive fouling species in five French Polynesian islands. Expansion of invasive species (Acantophora spicifera , Bugula neritina , Chthamalus proteus , Dendostrea frons) was detected using individual barcoding (COI for animals, RBLC for algae), and metabarcoding on biofouling (COI and 18S sequences). They were especially abundant in Port Phaeton (Tahiti), Bora Bora and Rangiroa atoll. Chthamalus proteus is a vector of bacterial diseases and may harm native French Polynesian mollusks. Dendostrea frons is a vector of Perkinsus , a parasite to which black pearl oysters, the mainstay of the Polynesian economy, are susceptible. High ecological and epidemiological risks were estimated for C. proteus and D. frons , and ecological risks also for A. spicifera and especially for B. neritina. Strengthening marine biosecurity measures is highly recommended to conserve these unique ecosystems and their associated services. [Display omitted] • Biopollution is a threat for isolated ecosystems of remote islands. • DNA barcoding and metabarcoding biota inventory in French Polynesia ports. • A rapid advance of invasive species transported in fouling is detected. • Epidemiological and ecological risks of four biopollutants are considerable. • A higher control of ship hull fouling is urgently needed. [ABSTRACT FROM AUTHOR]

Shark conservation can be achieved through a combination of spatial protections, traditional fisheries regulations, and shark-based tourism development. The effectiveness of these approaches depends on stakeholder perception of the animals, and on the personal impacts legislation will have. We assessed stakeholder attitudes towards sharks in the French Polynesia sanctuary using the perception of (i) the risk that sharks pose to humans and (ii) the practice of shark feeding to support ecotourism. Despite few bites locally, about 50% of the people believed that sharks are potentially dangerous. Furthermore, 74% of people held a negative opinion about provisioning as potentially increasing the risk of bites or having negative effects on sharks. When crossed with the lack of compliance with the regulations of the sanctuary and the feeding, these results suggest the importance of local political decision-making to better integrate validated scientific data. These results could improve shark conservation and support for current efforts. [ABSTRACT FROM AUTHOR]

The South Pacific Superswell in Polynesia is associated with a large seismic mantle anomaly at depth, the Polynesian dome, and it is characterized by the volcanic activity of five different hotspots giving birth to the Marquesas, Society, Pitcairn-Gambier, Cook-Austral and Arago island chains. Here we present new isotopic and major and trace element data in basalts from two of these chains, the Society and Pitcairn-Gambier chains, in order to examine the similarities and differences of their mantle source regions. In the Society chain the entire geochemical diversity of the archipelago exists at the scale of individual islands with no systematic trend over time. In contrast, a clear geochemical dichotomy exists along the Pitcairn-Gambier chain between the old volcanoes (Muru basalts from Mururoa, Fangataufa, Gambier, >5 My) and their younger counterparts (Pitis basalts from Pitcairn Island and Seamounts, <1 My). The Muru group has high Nb N /Nb* and Ce/Pb, low 87Sr/86Sr and define a steep trend in Nd-Hf isotopic space, features that call for old eclogite in their mantle source. The unradiogenic Pb isotopic ratios of Muru basalts, well below the values observed in HIMU ("high µ", or high 238U/204Pb) localities, are not easily explained by varying the age and composition of the eclogite and may call for the involvement of Pacific lower mantle in the source region. In contrast, the Pitis basalts share with the Society basalts low Nb N /Nb* and radiogenic 87Sr/86Sr suggesting incorporation of continental material in their source region. While the Society source simply incorporates modern-like terrigenous sediments, the combination of low Ba/La, 143Nd/144Nd and 176Hf/177Hf and very high 208Pb*/206Pb* in Pitis basalts make the Pitis source unique and not sampled anywhere else on Earth. The Pitis source contains old, possibly Archean, material of unclear origin because it resembles neither modern lower continental crust nor modern pelagic sediments. Finally, the distribution of heterogeneities in the two mantle plumes is also very different: discrete filaments are randomly dispersed across the Society plume stem while eclogitic and continent-derived filaments are vertically separated under the Pitcairn-Gambier chain. By combining these results with those published for other Polynesian chains, we establish a snapshot of the composition, geometry and distribution of the crustal components present in the Polynesian dome. [ABSTRACT FROM AUTHOR]

This paper presents the new version of the operational code used at the Tsunami Warning Centers in French Polynesia and in mainland France. This nested multigrid code solves either the nonlinear shallow water or the weakly nonlinear Boussinesq equations in a spherical or Cartesian coordinates system. The objective is to simulate the propagation of tsunamis both in the context of tsunami early warning and in the context of research. The originality of this code is to simulate the tsunami propagation through a series of nested grids in which the numerical scheme is specified by the user. Three standard finite-difference methods and two finite volume schemes are available to take into account the dispersive nature of waves or to capture flow discontinuities. The performance of the five numerical schemes has been assessed through idealized 1D and 2D test cases. The convergence rate with grid refinement is evaluated for three of these tests. Diffusion and dispersion of the five schemes are evaluated through the 1D far-field propagation in a channel of constant depth. Finally, two-dimensional simulations of the 2011 Japanese tsunami are performed considering a homogeneous tectonic source. Coastal inundation is simulated in the bay of Kamaishi where run-up heights reached 10 m. The ability of the five schemes to propagate trans-Pacific tsunamis is evaluated through comparisons of time series between simulations and observations at DART buoys. In the context of tsunami early warning, numerical results show that standard finite-difference methods reproduce most of the observed time gauges and that numerical errors associated to these schemes are acceptable. • Tsunami simulation is performed both in a research and an operational context. • Three finite-difference methods and two finite volume schemes are presented. • The five numerical schemes are assessed through 1D and 2D numerical experiments. • The trans-Pacific propagation of the 2011 Japanese tsunami is simulated. • Standard finite-difference methods are acceptable in an operational context. [ABSTRACT FROM AUTHOR]

Massive dome-shaped coral Porites are the predominant choice for paleoclimate studies due to their consistent and reliable growth. When growing close to sea level, they become limited in their vertical growth and form so-called 'microatolls'. Microatolls have not yet been extensively explored for paleoclimate reconstruction. Here, we investigate how reliable modern Porites microatolls are against empirical sea-surface temperature using Sr/Ca, δ18O, Li/Mg and Sr U paleothermometry methods on samples from the Society Islands, French Polynesia. Our results show Sr/Ca ratios have the lowest Standard Error of the Inverse Prediction (SEIP) at 0.415 °C (N = 41) with a calibration of Sr/Ca (mmol mol−1) = −0.082 ± 0.006 SST (°C) + 11.256 ± 0.170 and with high reproducibility across multiple corals. The reproducibility of δ18O was less good, with SEIP increasing to 0.829 °C (N = 41). Considering methods directly from the literature, Li/Mg ratio empirically corrected for Sr/Ca had the best balance between bias and precision where no local calibration could be available. This study independently evaluates and confirms the suitability of Porites microatolls from well-flushed environments for paleoclimate studies. Fossil dome-shaped Porites grow anywhere between near-surface and roughly 20 m depths which inherently incorporates uncertainty into any sea surface temperature reconstruction. This uncertainty is significantly reduced for microatolls due to their well-constrained bathymetry. The study represents a fundamental step in paleoclimate research targeting consistently near the water-air interface bringing reliability and, especially when combined with their ability to reconstruct past sea-level changes, microatolls have the potential to be central for future paleoenvironmental studies. • Investigation into the potential of Porites microatolls for SST reconstruction. • Comparison between recent and more conventional coral paleoclimatology methods. • Application of Sr U and Li/Mg paleothermometer. • Accuracy and reproducibility of Sr/Ca proved to be the most suitable proxy for SST reconstruction. [ABSTRACT FROM AUTHOR]

French Polynesia is a territory extremely vulnerable to climate change and associated risks. Among these risks, the cyclonic risk impacts regularly and durably the Polynesian territory. The concept of resilience is particularly relevant in a dynamic of adaptation of territories and populations facing the increase of risks and uncertainties. However, it is complex to operationalize and measure. The methodology presented in this article is part of a larger project to design a spatial decision support system, built in the form of a risk and resilience observatory. This observatory is built around several bricks, one of which is intended to acquire various forms of data, and the other to involve local actors in the adaptation of their territory to climate risks. This paper develops a methodology to assess the social, technical and urban resilience during and after Hurricane Oli. It was built around qualitative data, acquired through interviews and questionnaires with inhabitants and local actors of three islands: Tubuai, Rurutu, Bora-Bora. This approach allowed us to identify different levels of resilience over the long term and according to the actors involved in the experience of cyclone Oli. Finally, this approach allowed for the long-term involvement of stakeholders in the evaluation and implementation of more resilient risk management strategies, both at the individual and collective levels. • Analysis and assessment of resilience to cyclonic risk over the long term in French Polynesia. • Developing a multi-methodological approach. • Developing participating approach with local stakeholders and inhabitants. • Construction of a spatial decision support system, in the form of a risk and resilience observatory. [ABSTRACT FROM AUTHOR]

• Food availability and mesoscale turbulence in the Marquesas jointly constrained larval dispersal, reducing its potential connectivity with other archipelagos in French Polynesia. • Settlement success is influenced by climatic ENSO cycles that drive ocean currents in the Pacific region. • Biophysical modelling refines management unit's definition in extremely fragmented archipelagos. Larval dispersal and connectivity are key processes that drive marine metapopulation dynamics, and therefore should be well characterized when designing effective management strategies. While temperature and food availability can structure marine species connectivity patterns, their contribution has not been thoroughly investigated in highly fragmented archipelagos. We used biophysical modeling of larval dispersal to explore the connectivity patterns of species with complex life-cycles across French Polynesia (FP), a territory formed by more than a hundred small, geographically isolated islands covering an area as large as Europe. We first simulated ten years of larval dispersal to investigate the spatial and temporal (seasonal and interannual) variability in larval dispersal pathways for different hypothetical species exhibiting a range of Larval Precompetency Period (LPP) values. Then, using the black-lip pearl oyster (Pinctada margaritifera) as a model species, we accounted for variability in the LPP induced by temperature and food availability, as derived from a Dynamic Energy Budget (DEB) model. The model showed that food availability and mesoscale turbulence (eddies) in the Marquesas jointly constrained larval dispersal, reducing its potential connectivity with other archipelagos in FP. The DEB simulations also revealed seasonal and interannual variability in connectivity driven by environmental conditions. However, accounting for food and temperature effects on larval development, barely changed the connectivity pattern at regional scale due to the remoteness of this archipelago. Our study thus provides appropriate management units definition at regional scale for the species across FP. [ABSTRACT FROM AUTHOR]

Marine megafauna feeding on fishery catches (depredation) or being incidentally caught on fishing gear (bycatch) have become important issues. Their socioeconomic and conservation stakes have been increasingly studied across the world fisheries. They remain understudied in the Pacific Ocean, where longline tuna fisheries reported such interactions. In this study, we provide the first assessment of bycatch and depredation by sharks and odontocetes on longlines in French Polynesia between 2000 and 2018, using data from observers reporting, captains' logbooks, questionnaires and additional monitoring by authors during three fishing trip. We found that less than 2% of the catch had been depredated, and that shark depredation was more common than odontocete depredation. Shark bycatch was important (20,000 sharks annually, 0.5 shark every 1000 hooks) and odontocete bycatch seemed low (13 occurrences in 18 years), though we identified clear reporting flaws. We discuss the range of uncertainty associated with our assessment, based on the current reporting systems, and the potential consequences of depredation and bycatch on tuna fisheries, as well as on shark and odontocete populations in French Polynesia. [ABSTRACT FROM AUTHOR]

Stonefish sting lethality in man has been scarcely documented since the middle of the 20th century. We report three clinical cases, including one fatality, emphasizing the cardiovascular toxicity of the Synanceia verrucosa venom, and its potentially lethal effects. All clinical data have been recently collected in New Caledonia and French Polynesia. • Stonefish sting is to be considered as a life-threatening event. • Envenomation may lead to acute pulmonary edema and/or cardiopulmonary arrest. • Prognosis relies on early cardiopulmonary resuscitation and on supportive respiratory care. • Stonefish antivenom is recommended in severe stonefish envenomation. [ABSTRACT FROM AUTHOR]

Ciguatera poisoning (CP), arising from ciguatoxins produced by toxic dinoflagellate Gambierdiscus , is one of the most common food-borne diseases in the South Pacific. Climate change as well as its related events have been hypothesized to a higher abundance and wider presence of toxic dinoflagellates, hence a higher risk of the disease. Yet existing studies assessing the relationship between climate factors and CP are limited or based on old data. In this study, we used prewhitened cross-correlation analysis and auto-regressive integrated moving-average (ARIMA) modeling to develop predictive models of monthly CP incidence in Cook Islands and French Polynesia, two ciguatera-endemic regions in the South Pacific, utilizing the latest epidemiological data. Results reveal the significant time-lagged associations between the monthly CP incidence rate and several indicators relating to sea surface temperature (SST). In particular, SST anomaly is proven to be a strong positive predictor of an increased ciguatera incidence for both countries. If these time-lags can be supported by more investigations, it will allow health authorities to take appropriate actions, to limit or avoid an epidemic risk, especially on high-risk climate scenarios. • Lags between sea surface temperatures and ciguatera incidence rate were estimated. • Predictions made by best-fit models were used to compare with the actual values. • Sea surface temperature anomaly is the most significant variable for prediction. • More investigations are recommended to confirm and explain the lagged correlations. [ABSTRACT FROM AUTHOR]

Gambierol is a marine polycyclic ether toxin, first isolated from cultured Gambierdiscus toxicus dinoflagellates collected in French Polynesia. The chemical synthesis of gambierol permitted the analyses of its mode of action which includes the selective inhibition of voltage-gated K+ (K V) channels. In the present study we investigated the action of synthetic gambierol at vertebrate neuromuscular junctions using conventional techniques. Gambierol was studied on neuromuscular junctions in which muscle nicotinic ACh receptors have been blocked with d-tubocurarine (postsynaptic block), or in junctions in which quantal ACh release has been greatly reduced by a low Ca2+–high Mg2+ medium or by botulinum neurotoxin type-A (BoNT/A) (presynaptic block). Results show that nanomolar concentrations of gambierol inhibited the fast K+ current and prolonged the duration of the presynaptic action potential in motor nerve terminals, as revealed by presynaptic focal current recordings, increased stimulus-evoked quantal content in junctions blocked by high Mg2+–low Ca2+ medium, and by BoNT/A, reversed the postsynaptic block produced by d-tubocurarine and increased the transient Ca2+ signals in response to nerve-stimulation (1–10 Hz) in nerve terminals loaded with fluo-3/AM. The results suggest that gambierol, which on equimolar basis is more potent than 3,4-diaminopyridine, can have potential application in pathologies in which it is necessary to antagonize pre- or post-synaptic neuromuscular block, or both. This article is part of a Special Issue entitled: Honoring Ricardo Miledi - outstanding neuroscientist of XX-XXI centuries. Unlabelled Image • The synthetic polyether toxin gambierol potently enhanced stimulus-evoked quantal transmitter release. • The presynaptic fast K+ current was inhibited and the synaptic delay prolonged by gambierol. • Gambierol reversed the postsynaptic block produced by d-tubocurarine. • Gambierol restored from complete paralysis neuromuscular transmission ex vivo in BoNT/A-poisoned mouse muscle. • Gambierol increased the transient Ca2+ signals in nerve terminals stimulated at 1 and 10 Hz. [ABSTRACT FROM AUTHOR]

• At least 22 cases of Angiostrongylus cantonensis infection have been reported in Europe to date. • Cases have mainly come from French Polynesia, Southeast Asia, and the Caribbean Islands. • Dominant suspected transmission is via the ingestion of prawns, shrimp, or salad. • Two-thirds of cases received benzimidazole treatment although this treatment is debated. • Suspect A. cantonensis in a patient with lasting headache returning from an endemic area. To describe and analyse the epidemiological and clinical characteristics of imported human angiostrongyliasis in Europe. A systematic literature review of cases of human angiostrongyliasis in Europe was performed. Seven databases were searched. The epidemiological and clinical characteristics were extracted from included records and simple summary statistics were performed on extracted data. Twenty-two cases reported between 1988 and 2019 were identified. They were mainly from French Polynesia, Southeast Asia, and the Caribbean Islands. The dominant suspected mode of transmission was ingestion of prawns, shrimp, or salad. For patients with data, 90% had a history of headache, often lasting, and half had paresthesia. Eighty-nine percent had eosinophilia, 93% had cerebrospinal fluid (CSF) eosinophilia, and 92% had elevated CSF protein. Central nervous system (CNS) imaging was normal in most cases. Two-thirds received albendazole or mebendazole treatment, although this is not currently recommended. We have increased previous numbers to 22 reported cases in total since 1988. Angiostrongyliasis should generally be suspected in patients with a lasting headache who have returned from Southeast Asia, China, the Caribbean Islands, Australia, or French Polynesia, as well as parts of North America and Tenerife, Spain, although one autochthonous case from mainland Europe has also been reported. A dietary history should focus on prawns, shrimp, and salad, whilst also including slugs and snails and other paratenic hosts where relevant. The clinical diagnosis is supported by the presence of blood eosinophilia, CSF eosinophilia, and elevated CSF protein. A definitive laboratory diagnosis should be sought, and CNS imaging should be used to support, not to rule out the diagnosis. The most up-to-date evidence should always be consulted before initiating treatment. Current recommendations include analgesics, corticosteroids, and periodic removal of CSF for symptom relief, while antihelminthic treatment is debated. [ABSTRACT FROM AUTHOR]

• Marine litter loads on French Polynesian beaches were classed as 'dirty'. • The majority of littered items originated from local land-based sources. • Some local abatement measures have shown to be effective. • Improved waste management infrastructure is still needed. Anthropogenic marine litter pollution is a serious issue facing oceans worldwide. Limited data exists on this pollution issue for South Pacific Island nations and for Small Island Developing States (SIDS) in general. This study presents the first extensive baseline survey of macro-sized marine litter on Mo'orea (0.75 items m−2) and Tahiti (0.95 items m−2), French Polynesia. Not unexpectedly, marine litter was dominated by plastics (58%); however, glass also made up a significant portion (21%). Sixty percent of recovered marine litter from both islands was derived from local land-based catchments, indicating that the bulk of the litter is from local sources. Measures to address the waste issue in French Polynesia will be discussed with a cash-for-container scheme for locally produced beer showing promising positive environmental results, and further strategies for waste management in SIDS raised. [ABSTRACT FROM AUTHOR]

Several successive arbovirus outbreaks have affected French Polynesia (FP) in the recent past years due to different dengue serotypes (DENV) present for several decades, Zika (ZIKV) (2013–2014) and chikungunya (CHIKV) (2014–2015) viruses with a potential impact on blood safety and blood supply due to the geographical isolation of these islands. This study reports an assessment of the impact of these outbreaks on blood products supply and infectious safety in FP and discuss the effectiveness of implemented preventive measures. To ensure the infectious safety of blood products during outbreaks, several measures have successively been introduced as the selection of donors suspected of infection, the nucleic acid testing (NAT) and the pathogen reduction of platelets and plasmas. The donor deferral rate increased by 6% between 2012 and 2014 without changes in the number of collected donations. NAT excluded five blood donations reactive for DENV RNA, 42 for ZIKV and 34 for CHIKV. As Zika screening could not been implemented before the third month of the outbreak, 36 blood products from ZIKV-infected donors were transfused to 26 recipients. However, no transfusion-transmitted arbovirus has been reported. The last past arboviruses outbreaks did not have a significant impact on blood supply in FP. The measures introduced to prevent arbovirus transmission by transfusion were able to maintain infectious safety for all blood products without impairing self-sufficiency. [ABSTRACT FROM AUTHOR]

• ZIKV negatively modulate the antiviral immune response, enhancing its replication. • Inflammation appears to be a promising therapeutic target for ZIKV infection. • Inflammation is the central point of neurological complications triggered by ZIKV. • Cardiotonic steroids as promising compounds in addition to ZIKV vaccines. Zika virus (ZIKV) is a mosquito-borne virus first reported from humans in Nigeria in 1954. The first outbreak occurred in Micronesia followed by an outbreak in French Polynesia and another in Brazil when the virus was associated with numerous cases of severe neurological manifestations such as Guillain-Barre syndrome in adults and congenital zika syndrome in fetuses, particularly congenital microcephaly. Innate immunity is the first line of defense against ZIKV through triggering an antiviral immune response. Along with innate immune responses, a sufficient balance between anti- and pro-inflammatory cytokines and the amount of these cytokines are triggered to enhance the antiviral responses. Here, we reviewed the complex interplay between the mediators and signal pathways that coordinate antiviral immune response and inflammation as a key to understanding the development of the underlying diseases triggered by ZIKV. In addition, we summarize current and new therapeutic strategies for ZIKV infection, highlighting cardiotonic steroids as antiviral drugs for the development of this agent. [ABSTRACT FROM AUTHOR]

Zika virus (ZIKV), a vector-borne infectious agent that has recently been associated with neurological diseases and congenital microcephaly, was first reported in the Western hemisphere in early 2015. A number of authors have reconstructed its epidemiological history using advanced phylogenetic approaches, and the majority of Zika phylogeography studies have used discrete diffusion models. Continuous space diffusion models make it possible to infer the possible origin of the virus in real space by reconstructing its ancestral location on the basis of geographical coordinates deduced from the latitude and longitude of the sampling locations. We analysed all the ZIKV complete genome isolates whose sampling times and localities were available in public databases at the time the study began, using a Bayesian approach for discrete and continuous phylogeographic reconstruction. The discrete phylogeographic analysis suggested that ZIKV emerged to become endemic/epidemic in the first decade of the 1900s in the Ugandan rainforests, and then reached Western Africa and Asia between the 1930s and 1950s. After a long period of about 40 years, it spread to the Pacific islands and reached Brazil from French Polynesia. Continuous phylogeography of the American epidemic showed that the virus entered in north-eastern Brazil in late 2012 and started to spread in early 2013 from two high probability regions: one corresponding to the entire north-east Brazil and the second surrounding the city of Rio de Janeiro, in a mainly northwesterly direction to Central America, the north-western countries of south America and the Caribbean islands. Our data suggest its cryptic circulation in both French Polynesia and Brazil, thus raising questions about the mechanisms underlying its undetected persistence in the absence of a known animal reservoir, and underline the importance of continuous diffusion models in making more reliable phylogeographic reconstructions of emerging viruses. • Discrete and continuous Zika virus phylogeography. • Importance of continuous phylogeography in the reconstructions of emerging viruses. • Importance of genome characterisation in the surveillance of emerging infections. [ABSTRACT FROM AUTHOR]

Distant swells produced by high latitude storms are poorly studied despite their significant impact on almost all major ocean basins. This article studies the consequences of extreme southern swells on the islands and atolls of French Polynesia by focusing on lagoon water filling. This phenomenon is a product of great water influx in the lagoon coming from waves breaking on the reef. This analysis is based on archives in Tahiti, and on surveys and interviews conducted in the Makemo Atoll (Tuamotu Archipelago) to identify the impacts of giant swells during August 2011 and July 1996. These swells have strongly affected all the archipelagos of the Western Pacific and have been strongly felt on the entire Pacific coastline of the American continent. In French Polynesia they caused a rise in the lagoons that reached 2.75 m (above the lowest astronomical tide), causing a major submersion event that strongly impacted the life of the inhabitants by destroying many resources on which they depended. Comparing the swells of 1996 and 2011, this article shows that the filling of the lagoon is largely determined by the duration of the intense wave event and not only by the maximum intensity reached by the swell. Finally, this article raises the question of how this phenomenon is taken into account in town / atoll planning, and the vulnerability of the coastlines of the intertropical zone to distant swells in the context of sea level rise and changes of atmospheric circulation. • Swells from high latitudes can produce strong flooding on tropical coastlines. • Distant swells can produce a rise of lagoon levels up to 2.75 m. • The rise of lagoon water levels is slowed down by lagoon filling inertia. • Longer-lasting swells produce higher lagoon levels. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Five new laxaphycins were isolated and fully characterised from the bloom forming cyanobacteria Anabaena torulosa sampled from Moorea, French Polynesia: three acyclic laxaphycin A-type peptides, acyclolaxaphycin A (1), [des-Gly11]acyclolaxaphycin A (2) and [des-(Leu10-Gly11)]acyclolaxaphycin A (3), as well as two cyclic ones, [ l -Val8]laxaphycin A (4) and [ d -Val9]laxaphycin A (5). The absolute configuration of the amino acids, established using advanced Marfey's analysis for compounds 2 – 5, highlights a conserved stereochemistry at the Cα carbons of the peptide ring that is characteristic of this family. To the best of our knowledge, this is the first report of acyclic analogues within the laxaphycin A-type peptides. Whether these linear laxaphycins with the aliphatic β-amino acid on the N -terminal are biosynthetic precursors or compounds obtained after enzymatic hydrolysis of the macrocycle is discussed. Biological evaluation of the new compounds together with the already known laxaphycin A shows that [ l -Val8]laxaphycin A, [ d -Val9]laxaphycin A and [des-Gly11]acyclolaxaphycin induce cellular toxicity whereas laxaphycin A and des-[(Leu10-Gly11)]acyclolaxaphycin A do not affect the cellular viability. An analysis of cellular death shows that the active peptides do not induce apoptosis or necrosis but instead, involve the autophagy pathway. [ABSTRACT FROM AUTHOR]

Dengue- (DENV) and Zika viruses (ZIKV) rely on their non-structural protein 5 (NS5) including a methyl-transferase (MTase) and a RNA-dependent RNA polymerase (RdRp) for capping and synthesis of the viral RNA, and the non-structural protein 3 (NS3) with its protease and helicase domain for polyprotein possessing, unwinding dsRNA proceeding replication, and NTPase/RTPase activities. Accumulation of data for DENV- and ZIKV NS3 and NS5 in solution during recent years provides information about their overall shape, substrate-induced alterations, oligomeric forms and flexibility, with the latter being essential for domain-domain crosstalk. The importance and differences of the linker regions that connect the two domains of NS3 or NS5 are highlighted in particular with respect to the different DENV serotypes (DENV-1 to −4) as well as to the sequence diversities between the DENV and ZIKV proteins. Novel mutants of the French Polynesia ZIKV NS3 linker presented, identify critical residues in protein stability and enzymatic activity. [ABSTRACT FROM AUTHOR]

Abstract French coastal policies have recently put greater emphasis on the need to better inform coastal populations about coastal risks in the context of climate change, in particular in French overseas territories that are nationally recognized as hotspots. It is therefore critical to further assess local populations' knowledge and perceptions of climate-related coastal risks. In this respect, we ran a social survey among inhabitants of two atolls of French Polynesia in the Pacific Ocean, using a questionnaire and semi-structured interviews largely based on images of landscapes. The results show that (1) coastal risks are not considered as a danger but only as a problem, and that (2) inhabitants have a very clear perception of the changes that have occurred locally over the last 70 years with respect to weather, climate, corals and beaches. (3) Interviewees generally show some knowledge about the notion of global climate change and its potential local impacts. (4) However, a multiple correspondence analysis distinguishes four groups (the 'informed', 'poorly informed, 'uninformed' and 'distant' groups) separated by age and gender, but also by levels of education and urbanization. The discussion therefore focuses on the most important drivers of climate change perception, showing a disconnection between atolls and generations: rural and older inhabitants present more sensitive mechanisms of risk perception and urban and younger interviewees more intellectual ones. A major challenge consists in bringing these dimensions closer by better integrating, on an intellectual level, local climate-related coastal risks into school programs, and by defining, on a more sensitive level, an ambitious cultural and environmental policy to allow young generations to keep contact with their original living environment. Highlighting the interest of this survey, risk management and adaptation policies now support the reactivation of local knowledge and practices. Highlights • We ran a survey on climate-related coastal risks' perception in French Polynesia. • People have perceived changes concerning weather, coral reefs, beaches for 70 years. • However, interviewees show contrasting knowledge about global climate change and its local impacts. • Risks' perception varies on atolls in relation to education and urbanization levels. • Policy must mix intellectual and sensitive approaches of climate change and coastal risks. [ABSTRACT FROM AUTHOR]

• Ostreopsis lenticularis has been reinvestigated from French Polyensia, its type locality. • 47 strains have been isolated and cultured from four archipelagos. • Morphology and LSU / ITS–5.8S rDNA sequences were identical for all strains and wild specimens. • From phylogenies, O. lenticularis clustered unambiguously within the clade Ostreopsis sp. 5. • No toxic effect was found on 19 strains tested using CBA-N2a and no PlTX-like molecules were detected in 4 analyzed strains. To date, the genus Ostreopsis comprises eleven described species, of which seven are toxigenic and produce various compounds presenting a major threat to human and environmental health. The taxonomy of several of these species however remains controversial, as it was based mostly on morphological descriptions leading, in some cases, to ambiguous interpretations and even possible misidentifications. The species Ostreopsis lenticularis was first described by Y. Fukuyo from French Polynesia using light microscopy observations, but without genetic information associated. The present study aims at revisiting the morphology, molecular phylogeny and toxicity of O. lenticularis based on the analysis of 47 strains isolated from 4 distinct locales of French Polynesia, namely the Society, Australes, Marquesas and Gambier archipelagos. Observations in light, epifluorescence and field emission scanning electron microscopy of several of these strains analyzed revealed morphological features in perfect agreement with the original description of O. lenticularis. Cells were oval, not undulated, 60.5–94.4 μm in dorso-ventral length, 56.1–78.2 μm in width, and possessed a typical plate pattern with thecal plates showing two sizes of pores. Phylogenetic analyses inferred from the LSU rDNA and ITS–5.8S sequences revealed that the 47 strains correspond to a single genotype, clustering with a strong support with sequences previously ascribed to Ostreopsis sp. 5. Clonal cultures of O. lenticularis were also established and further tested for their toxicity using the neuroblastoma cell-based assay and LC MS/MS analyses. None of the 19 strains tested showed toxic activity on neuroblastoma cells, while LC MS/MS analyses performed on the strains from Tahiti Island (i.e. type locality) confirmed that palytoxin and related structural analogs were below the detection limit. These findings allow to clarify unambiguously the genetic identity of O. lenticularis while confirming previous results from the Western Pacific which indicate that this species shows no toxicity, thus stressing the need to reconsider its current classification within the group of toxic species. [ABSTRACT FROM AUTHOR]

Abstract Coral reefs are highly productive ecosystems that typically exist in nutrient-poor waters, stimulating considerable research on the sources of nutrients that may support this productivity, including nutrient recycling. We examined the potential for resident herbivorous damselfish (Stegastes nigricans) to recycle nutrients within their territories by conducting an exclusion experiment on S. nigricans territories and measuring algal turf growth on shallow fringing reefs in Mo'orea, French Polynesia. A nutrient bioassay was used to evaluate whether the enhanced growth was due to increased nutrients. We chose 15 isolated damselfish territories for a caging experiment, with a large cage obstructing all fish access on one half of the territory (−Damselfish, −Herbivory) and a small low-profile cage allowing access but not herbivory to a portion on the other half (+Damselfish −Herbivory). Additionally, we measured turf in a randomly-chosen uncaged area within each territory where both damselfish and herbivory were present (+Damselfish +Herbivory). Behavioral observations confirmed damselfish rarely swam over the large-caged half of the territory, effectively eliminating their physical presence, but continued to interact with the other half. Over the 16-day experiment, time and treatment had a significant effect on turf growth. By day 16, the turf receiving the +Damselfish −Herbivory treatment experienced average net turf growth of 5.34 mm, which was significantly greater than turf growth within the territories receiving the −Damselfish −Herbivory (2.13 mm) and the +Damselfish +Herbivory (1.50 mm) treatments. The macroalgae in the nutrient bioassay grew 21% more on the side of the territory where damselfish were present compared to the side where they were excluded, supporting our conclusion that the mechanism that supported faster turf growth was increased nutrients. Thus, our study was the first to establish experimentally that the presence of damselfish increased algal growth by enhancing nutrient supplies via recycled waste products, a mechanism that has been advanced but never tested. Surveys established that damselfish territories covered 28–64% of the fringing reef flat along the north shore of Mo'orea, suggesting this increased productivity within territories could be a significant contribution to total reef productivity. These findings highlight the importance of continuing research into the long-term and spatial-scale effects of damselfish as nutrient recyclers on coral reefs. Highlights • Algal turf grew more in the presence of damselfish than in their absence. • Nutrient bioassay demonstrated faster algal turf growth due to increased nutrients. • This nutrient supplement may be important as territories cover large areas of reef. [ABSTRACT FROM AUTHOR]

Abstract Microplastics are ubiquitous throughout the oceans, yet few studies have documented their occurrence in marine organisms associated with coral reefs. Four genera of adult fish were sampled (Myripristis spp., Siganus spp., Epinephelus merra and Cheilopogon simus) from different trophic guilds around the tropical island of Moorea, French Polynesia. Digestive tracts from 133 adult fish were surveyed and microplastics were found in 28 tracts (21%). Abundance of ingested microplastic pieces per individual fish varied from 1 to 3 pieces, with an average of 1.25 ± 0.13 ingested microplastic pieces. Microplastics size ranged from 0.031 to 2.44 mm and 70% of microplastics did not exceed 0.3 mm in size. Overall, this study shows that the number and size of microplastic ingested per trophic groups are independent of trophic guild. Additional studies are needed to sample in other tropical regions in order to have a better assessment of microplastic occurrence in coral reefs. Highlights • This study highlights the presence of microplastics in four taxonomic genera of tropical fish from different trophic guild • 21% of the 133 fish ingested microplastics, with an average of 1.25 ± 0.13 microplastics pieces per fish that ingested microplastics • Microplastics size ranged from 0.031 to 2.44 mm and 70% of microplastics did not exceed 0.3mm in size • This study shows that the number and size of the microplastics ingested are independent of feeding habits [ABSTRACT FROM AUTHOR]

Abstract Submarine fresh groundwater discharge (SFGD) provides a pathway for dissolved nutrients and other solutes from land to the ocean. It connects pollution from anthropogenic land use with coastal marine waters. In case of the oligotrophic central South Pacific Ocean around Tahiti and Moorea, French Polynesia, nutrient concentrations are particularly low. Both islands are surrounded by tropical coral reefs, which are highly sensitive to nutrient concentrations in the ambient water so that a surplus of nutrients, e.g. from SFGD, could lead to the degradation of coral reef ecosystems. We examined nutrient contributions from different land cover classes to nutrient fluxes through SFGD by combining nutrient concentration data, spatial data, oxygen and hydrogen isotope ratios of water (δ18O H2O and δ2H H2O , respectively) and nitrogen and oxygen isotope ratios of nitrate (δ15N NO3- and δ18O NO3-). Undeveloped land provides measurable quantities of phosphate while nitrate concentrations are often below the detection limit. The bulk of the nutrient load in nutrient enriched groundwater is of anthropogenic origin. It enters the aquifer system at low altitudes, where catchments are characterized by anthropogenic land use. Elevated nitrate concentrations are mainly associated with septic waste/manure inputs in fresh water. This study elucidates sources of nutrients in the groundwater of two volcanic islands, highlighting the impact that even a small populated area along the coast of an island can have, as well as the differences in nutrient transport between these seemingly similar locations. Highlights • Human settlements and agriculture had a noticeable impact on nutrient concentrations in SFGD. • Although Tahiti and Moorea are geochemically and geologically similar, different processes dominate coastal nutrient fluxes. • Elevated nitrate concentrations are associated with septic/manure isotopic signal. [ABSTRACT FROM AUTHOR]

Abstract Few studies have examined the interaction of human geography, microbial community structure and obesity. We tested obese adult volunteers from France, Saudi Arabia, French Polynesia and from a traditional population in the village of Trois-Sauts in French Guiana by sequencing the V3-V4 region. We also sequenced homemade fermented cachiri beers that were obtained from the traditional Amazonian population and are highly consumed by this population. We found that French and Saudis had significantly less richness and biodiversity in their gut microbiota than Amazonians and Polynesians (p <0.05). Principle coordinate analysis of the overall composition of the genera communities revealed that the microbiomes of Amazonians clustered independently from the other obese individuals. Moreover, we found that Amazonians presented significantly stricter anaerobic genera than the Saudis, French and Polynesians (p < 0.001). Polynesians presented significantly lower relative abundance of Lactobacillus sp. than French (p 0.01) and Saudis (p 0.05). Treponema berlinense and Treponema succinifaciens were only present in the gut microbiome of Amazonians. The cachiri beers presented significantly more bacterial species in common with the gut microbiome of Amazonians (p < 0.005). Obese individuals with different origins present modifications in their gut microbiota, and we provide evidence that the cachiri beers influenced the gut microbiome of Amazonians. [ABSTRACT FROM AUTHOR]

• French Polynesia is a biodiversity hotspot for Gambierdiscus species. • Gambierdiscus polynesiensis is the main source of ciguatoxins in French Polynesia. • Herbivores and omnivores can be as toxic as carnivores in French Polynesia. • French Polynesia has a long-term epidemiological surveillance program on CP. • Cultural ramifications of CP have strong implications for risk management strategies. Ciguatera Poisoning (CP) is a seafood poisoning highly prevalent in French Polynesia. This illness results from the consumption of seafood contaminated with ciguatoxins (CTXs) produced by Gambierdiscus , a benthic dinoflagellate. Ciguatera significantly degrades the health and economic well-being of local communities largely dependent on reef fisheries for their subsistence. French Polynesia has been the site of rich and active CP research since the 1960′s. The environmental, toxicological, and epidemiological data obtained in the frame of large-scale field surveys and a country-wide CP case reporting program conducted over the past three decades in the five island groups of French Polynesia are reviewed. Results show toxin production in Gambierdiscus in the natural environment may vary considerably at a temporal and spatial scale, and that several locales clearly represent Gambierdiscus spp. "biodiversity hotspots". Current data also suggest the "hot" species G. polynesiensis could be the primary source of CTXs in local ciguateric biotopes, pending formal confirmation. The prevalence of ciguatoxic fish and the CTX levels observed in several locales were remarkably high, with herbivores and omnivores often as toxic as carnivores. Results also confirm the strong local influence of Gambierdiscus spp. on the CTX toxin profiles characterized across multiple food web components including in CP-prone marine invertebrates. The statistics, obtained in the frame of a long-term epidemiological surveillance program established in 2007, point towards an apparent decline in the number of CP cases in French Polynesia as a whole; however, incidence rates remain dangerously high in some islands. Several of the challenges and opportunities, most notably those linked to the strong cultural ramifications of CP among local communities, that need to be considered to define effective risk management strategies are addressed. [ABSTRACT FROM AUTHOR]

In remote and scattered islands, where space and resources for waste treatment are limited, the mismanagement of plastic waste gives rise to significant global environmental threats. Addressing this issue requires a clear understanding of how plastic waste accumulates over the year, particularly in areas heavily reliant on industries such as aquaculture. While the aquaculture sector is often of primary economic and social importance in these regions, it is also a major contributor to pollution due to its extensive use of plastic rearing structures. However, the extent of this contribution is often not accurately quantified. Our study aims to bridge this knowledge gap, focusing on the pearl farming industry in French Polynesia, which plays a vital economic and social role in the country. The surveys conducted among pearl farmers of three major Polynesian pearl farming islands revealed a wide diversity of practices. On this basis, we have developed an original methodology to estimate the potential plastic waste flow from this industry, taking into account these multiple practices. Our study showed that the pearl farming industry in French Polynesia may generate around 1603 tons of plastic waste annually. Moreover, this investigation raised concerns regarding unsustainable practices, revealing that 75% of the plastic waste generated is mismanaged, with half of it (46%) at risk of entering the ocean. In addition to structural waste management problems in these isolated islands, our work suggested that a lack of environmental awareness (expressed by 38% of surveyed pearl farmers) significantly contributes to this situation. These results highlight the urgent need to enhance waste management practices within the pearl farming industry in order to mitigate its environmental impact. Finally, the present work pioneers the quantification of plastic waste flows from a specific aquaculture industry characterized by multiple practices, establishing a foundation for future research in this field. [Display omitted] • New method to estimate plastic waste flow from multi-practice aquaculture. • First quantitative estimate of plastic waste flow from pearl farming. • Polynesian's pearl farming can generate 1603 tons of plastic waste annually. • Around half of this plastic waste is at risk of entering the ocean. • 38% of respondents lacked awareness regarding their environmental footprint. [ABSTRACT FROM AUTHOR]

This study is a first assessment of Metallic Trace Elements (MTE) contamination of four lagoons in French Polynesia, chosen because their main anthropic uses are potential sources of MTE (military, agriculture, maritime). We used the giant clam Tridacna maxima as a biointegrator of fifteen MTE to assess the environmental footprint of human activities. The study of organotropism showed that not only the kidney but also the gonad and digestive system (GDS) are accumulator organs of interest for ETM biomonitoring. This result confirms that heterotrophic feeding is the pathway of ETM accumulation. Here, T. maxima appeared to be a super-accumulator of Ni (2700 ppm.dw), but also revealed at Tubuai (As, Fe, Mn) and Arutua (Cd, Zn) the environmental footprint of agricultural and maritime activities. The concentration of Cd recorded in Arutua (5 ppm.dw) both in KID and GDS, also underline the need for better control of effluents resulting from human activities. • T. maxima is a biointegrator of metallic trace elements contamination. • Kidney but also gonad and digestive system are accumulator organs of interest. • T. maxima is a super-accumulator of Ni. • T. maxima can be used to monitor the environmental footprint of human activities. [ABSTRACT FROM AUTHOR]

Seawater temperature rise is damaging coral reef ecosystems. There is growing evidence for the negative impact of rising temperatures on the survival of adult corals and their reproductive success. However, the effect of elevated temperatures on gametes remains scarcely studied. Here we tested the effect of the thermal priming of gametes on the fertilization success in experimentally tested populations of Acropora cytherea corals in French Polynesia. As expected, a temperature of 30 °C (ambient +3 °C) reduces coral fertilization success. However, the thermal exposure of gametes to 30 °C after their release in seawater prior to fertilization limited fertilization failure, with a greater impact of oocytes in comparison to sperm. This temperature is similar to temperatures observed in nature under the changing climate. Our findings imply that the thermal priming of early life stages, such as gametes may play a role in maintaining the coral fertilization success in spite of increasing seawater temperature. [Display omitted] • Rising seawater temperatures reduce fertilization success in spawning corals. • We examined the understudied role of coral pelagic life stages in fertilization success. • Effect of experimental thermal pre-exposure of gametes was tested. • Coral gamete thermal priming improved fertilization success at high temperature. • Thermal priming of sperm or oocytes differentially restores fertilization success. [ABSTRACT FROM AUTHOR]

Atmospheric nuclear weapons tests carried out by the United States, the former Soviet Union, the United Kingdom, France and China between 1945 and 1980 resulted in radioactive fallout over the earth's surface of long-lived radionuclides, such as 137 Cs, 239+240 Pu and 238 Pu that could be detected more than 50 years after their production. In addition, the burnup in the upper atmosphere of a thermoelectric generator fueled by 238 Pu, SNAP-9A, contributed to the inventory of 238 Pu deposited on the ground. In order to estimate the deposition densities of 137 Cs, 239+240 Pu and 238 Pu in French Polynesia, we collected undisturbed soil samples up to 30 cm deep at eight sites in two islands (Hiva Oa, 139°W - 10°S and Raivavae, 148°W - 24°S) in 2015–2016. The top 0–10 cm of the soil cores were sliced into five 2-cm layers and the bottom 10–30 cm into four 5-cm layers for gamma spectrometry and alpha spectrometry measurements. We found that more than 50% of the radioactive inventories are still contained within the first 10 cm and that the average vertical migration velocities of 137 Cs and Pu are less than 0.2 cm y −1 . The average accumulated depositions, deduced from the profile measurements, are 236 ± 11 Bq.m −2 and 313 ± 39 Bq.m −2 for 137 Cs, 12.1 ± 1.5 Bq.m −2 and 22.1 ± 1.7 Bq.m −2 for 239+240 Pu, and 1.23 ± 0.46 Bq.m −2 and 1.58 ± 0.60 Bq.m −2 for 238 Pu, in Hiva Oa and Raivavae, respectively. The 238 Pu/ 239+240 Pu ratios are 0.102 ± 0.050 at Hiva Oa and 0.072 ± 0.033 at Raivavae. Both values are higher than the ratio in nuclear weapons tests fallout estimated to be 0.016 in 2016 (Hardy et al., 1973), because of the contribution of 238 Pu fallout from SNAP-9A, which is latitude dependent. The 137 Cs/ 239+240 Pu ratios, 19.5 ± 3.2 at Hiva Oa and 14.2 ± 2.8 at Raivavae are in the lower part of the range of values observed in other regions of the world. [ABSTRACT FROM AUTHOR]

The Marquesas Island chain in Polynesia is quite unusual because the alignment of the islands on the Pacific oceanic plate (N40°W) does not follow the plate motion in the region (N65°W). The exact location of the active hotspot is unknown but has been predicted to underlie the Marquesas Fracture Zone Ridge. Nevertheless, no concrete evidence exists. Here, we document the occurrence on this ridge of fresh tephrites dated at ~ 92 ka by the 40 Ar 39 Ar method. The lavas dredged on a small seamount have trace element contents and Sr, Nd, Pb isotopic compositions typical of the southwest Marquesas Islands, the Fatu Hiva group. This discovery demonstrates that the Marquesas plume is still active and it puts new constraints on its present location. It also supports McNutt et al.’s (1989) interpretation of the Marquesas Fracture Zone Ridge as a very young volcanic construction underlain by a hotspot. We suggest that the present location of the Marquesas plume is under the ridge, at its intersection with the isotopic divide known along the Marquesas chain. We attribute the presence of young volcanic products 190 km southwest of this location to preferential magma flow along the Marquesas Fracture lithospheric weakness zone. We also suggest that the puzzling general direction of the archipelago is the consequence of a persistent low magma flux over the past 5 Ma that could only find its way to the surface through multiple weak zones in the Pacific plate. [ABSTRACT FROM AUTHOR]

Black pearl farming is the second source of French Polynesia income after tourism, and Gambier Islands are the main farming sites. Gambier main lagoon contains several sub-lagoons critical for pearl oyster rearing and spat collecting (SC). The Rikitea lagoon, traditionally had good SC rates in the warm season which ensured steady supplies of oysters for black pearl production. However, since 2018, SC has abruptly decreased. To assess the factors affecting SC, Gambier lagoon hydrodynamics was investigated in 2019–2020 to calibrate a hydrodynamic model and simulate larval dispersal around the SC areas. The model shows the strong wind influence on larval dispersal and accumulation patterns and suggests that windy months in the warm season as it can occur during La Niña episodes can explain recent poor SC. Larval dispersal scenarios also informed on best locations to perform adult oyster restocking, a practice that can also enhance SC on the long term. • Gambier is the most important pearl farming site of French Polynesia. • Hydrodynamic conditions in Gambier are studied during the spat collection season. • A MARS3D hydrodynamical model is validated against in situ data. • The model is used to simulate pearl oyster larval dispersal. • The model identifies periods of low wind as critical for successful spat collection. [ABSTRACT FROM AUTHOR]

This paper increases by around 30% the sample of atoll reef islands studied from a shoreline change perspective, and covers an under-studied geographical area, i.e. the French Tuamotu Archipelago. It brings new irrefutable evidences on the persistence of reef islands over the last decades, as 77% of the 111 study islands exhibited areal stability while 15% and 8% showed expansion and contraction, respectively. This paper also addresses a key research gap by interpreting the major local drivers controlling recent shoreline and island change, i.e. tropical cyclones and seasonal swells, sediment supply by coral reefs and human activities. The 1983 tropical cyclones had contrasting impacts, depending on the shoreline indicator considered. While they generally caused a marked retreat of the stability line, the base of the beach advanced at some locations, as a result of either sediment reworking or fresh sediment inputs. The post-cyclone fair weather period was characterised by reversed trends indicating island morphological readjustment. Cyclonic waves contributed to island upwards growth, which reached up to 1 m in places, through the transfer of sediments up onto the island surface. However, the steep outer slopes of atolls limited sediment transfers to the reef flat and island system. We found that 57% of the study islands are disturbed by human activities, including ‘rural’ and uninhabited islands. Twenty-six percent of these islands have lost the capacity to respond to ocean-climate related pressures, including the ‘capital’ islands concentrating atolls' population, infrastructures and economic activities, which is preoccupying under climate change. [ABSTRACT FROM AUTHOR]

Food web structure is shaped by interactions within and across trophic levels. As such, understanding how the presence and absence of predators, prey, and competitors affect species foraging patterns is important for predicting the consequences of changes in species abundances, distributions, and behaviors. Here, we used plasma δ 13 C and δ 15 N values from juvenile blacktip reef sharks ( Carcharhinus melanopterus ) and juvenile sicklefin lemon sharks ( Negaprion acutidens ) to investigate how species co-occurrence affects their trophic interactions in littoral waters of Moorea, French Polynesia. Co-occurrence led to isotopic niche partitioning among sharks within nurseries, with significant increases in δ 15 N values among sicklefin lemon sharks, and significant decreases in δ 15 N among blacktip reef sharks. Niche segregation likely promotes coexistence of these two predators during early years of growth and development, but data do not suggest coexistence affects life history traits, such as body size, body condition, and ontogenetic niche shifts. Plasticity in trophic niches among juvenile blacktip reef sharks and sicklefin lemon sharks also suggests these predators are able to account for changes in community structure, resource availability, and intra-guild competition, and may fill similar functional roles in the absence of the other species, which is important as environmental change and human impacts persist in coral reef ecosystems. [ABSTRACT FROM AUTHOR]

This study was designed to identify in the pearl oyster Pinctada margaritifera , used as a bio-accumulator, molecular biomarkers for the presence of heavy metals in the lagoon environment. Pearl oysters were exposed to 2 concentrations (1 and 10 μg L − 1 ) of cadmium (Cd) and chromium (Cr) compared to a control. Twelve target genes encoding proteins potentially involved in the response to heavy metal contamination with antioxidant, detoxification or apoptosis activities were selected. P. margaritifera accumulated Cd but not Cr, and mortality was related to the amount of Cd accumulated in tissues. In response to Cd-Cr contamination, metallothionein (MT) was significantly up-regulated by Cd-Cr at both concentrations, while 7 others (SOD, CAT, GPX, GSTO, GSTM, CASP, MDR) were down-regulated. Based on the development of these molecular tools, we propose that the pearl oyster, P. margaritifera , could be used as a sentinel species for heavy metal contamination in the lagoons of tropical ecosystems. [ABSTRACT FROM AUTHOR]

This study tested the hypothesis that intraspecific morphological plasticity within a scleractinian coral elicits differential responses to elevated P CO2 and temperature. In Mo'orea, French Polynesia, two short-term laboratory experiments (21 and 14 days) were conducted to test the effects of P CO2 (400 vs. 700 μatm), and P CO2 (400 vs 1000 μatm) combined with temperature (27.0 vs. 29.8 °C), on branches and plates of Porites rus . Experiments employed two irradiances (~ 1000 vs 200 μmol photons m − 2 s − 1 ), which characterized the microenvironments on the shallow fringing reefs where branching and plating morphologies are common, respectively. Calcification of both morphologies was insensitive to P CO2 , as well as the combined effects of elevated P CO2 and temperature. Mean calcification rates were faster in high light than in low light for both morphologies, and biomass was greater in plates than branches in all treatments. Together, our results suggest P. rus is robust to increased P CO2 and high temperature within the constraints of the treatments applied. Morphological plasticity in this species does not mediate physiological resistance to low pH and high temperature. [ABSTRACT FROM AUTHOR]

Coconut (Cocos nucifera L.) is one of the world's most economically important tree species, and coconut palm plantations dominate many islands and tropical coastlines. However, the expansion of plantations to supply international markets threatens biodiversity. Therefore, monitoring the plantations is important not only for the food industry but also for evaluating and mitigating environmental impacts of the industry. However, the detection of coconut trees from space is challenging because the palms' crowns hold only limited pixels of high-resolution optical imagery. Here, we present an accurate and real-time COCOnut tree DETection method (COCODET) which uses satellite imagery to detect individual palms, comprising three components. First, an Adaptive Feature Enhancement (AFE) module is designed to improve both the capacity of representation at the highest level of the feature map and feature representation ability and help distinguish between coconut trees and other vegetation. Secondly, we modify a region proposal network to produce a Tree-shape Region Proposal Network (T-RPN) for producing coconut tree candidates. Finally, we create a Cross Scale Fusion (CSF) module for integrating multi-scale information to improve small tree detection; this fuses features of coconut crowns from different levels, connecting shallow and deep-level semantic features. We applied COCODET to detect coconut trees in four remote atolls from the Acteon Group in French Polynesia. The natural habitats on the islands were previously cleared for coconut plantations, many of which have since been abandoned. COCODET achieved an average F1 score of 86.5% using its real-time inference process, considerably outperforming other cutting-edge object detection algorithms (4.3 ∼ 12.0% more accurate). We detected 688 ha of coconuts and 182 ha of natural habitat on the islands, and within the coconut groves we detected 120,237 individuals. Our analyses indicate that deep learning approaches can be successfully applied to coconut palm detection, aiding efforts to understand human impacts on natural ecosystems and biodiversity. • We propose a new COCOnut tree crown DETection method named COCODET. • COCODET is an AI expert in detecting small coconut trees that are densely appearing. • COCODET identifies 120,237 coconut trees in four remote atolls of the Pacific Ocean. • The connections between coconut tree distribution and ecological functions in four remote atolls are quantified. [ABSTRACT FROM AUTHOR]

Ciguatera Fish Poisoning (CFP) is a non-bacterial seafood poisoning well characterized in the remote archipelagos of French Polynesia, yet poorly documented in the Society archipelago, most notably on Moorea, the second most populated island in French Polynesia, which counts a high proportion of fishermen fishing on a regular basis. To address this knowledge gap, a holistic study of the ciguatera issue was conducted on Moorea. First, ciguatera risk was analysed in terms of incidence rate, fish species most commonly involved and risk stratification in Moorea lagoon based on 2007–2013 epidemiological data. A mean incidence rate of 8 cases per 10,000 inhabitants for the study period and an average under-reporting rate of 54% were found. Taking into account hospitalization and medication fees, and loss of productive days, the health-related costs due to CFP were estimated to be USD $1613 and $749 for each reported and unreported case, respectively, with an overall cost of USD $241,847 for the study period. Comparison of the present status of CFP on Moorea with a risk map established in the late 1970’s showed that the spatial distribution of the risk has stayed relatively stable in time, with the north shore of the island remaining the most prone to ciguatera. Evaluation of the current knowledge on CFP among different populations groups, i.e. fishermen, residents and visitors, was also conducted through direct and indirect interviews. About half of the fishermen interviewed were actually able to identify risky fishing areas. While, overall, the CFP risk perception in the fishing community of Moorea seemed accurate, although not scientifically complete, it was sufficient for the safe practice of their fishing activities. This may be due in part to adaptive responses adopted by 36% of the fishermen interviewed, such as the avoidance of either high-risk fishing sites or toxic species. At the residents and visitors’ level, the study points out a striking lack of awareness of the CFP issue among visitors, as compared to local residents. Indeed, less than 25% of Moorea visitors vs. an average of 98% in residents were aware of CFP or of its presence on the island. Interestingly, evaluation of the fish consumption preferences showed that 70% of visitors do not consume lagoon fish during their stay, not for fear of CFP, but mainly due to the lack of availability of these species in recreational facilities or because they have nutritional preference for pelagic fish. This lack of awareness, along with the report by several CFP patients of the consumption of fish species yet banned for sale, stress the need for improved communication efforts on this critical issue among both residents and visitors on Moorea. The implementation of a public outreach strategy is proposed, based on both existing information networks and low-cost communication actions through information displays at various strategic locations, e.g. Tahiti-Faa’a international airport, the ferry boat station, recreational facilities, as well as the major trading points on Moorea Island. [ABSTRACT FROM AUTHOR]

Local thermal environment has a strong influence on the physiology of marine ectotherms. This is particularly relevant for tropical organisms living close to their thermal optimum, well exemplified by the increasing frequency of bleaching occurrence in shallow-water corals. Mesophotic Coral Ecosystems (MCEs) were suggested as potential oases, especially when they are submitted to internal waves inducing short-term cooling events. Indeed, probability of bleaching occurrence in scleractinians was reported to decrease with depth in Mo'orea as temperature variability increases. However, ecophysiological data are currently lacking to understand the cause of lower susceptibility/increased plasticity of deeper corals. A growing interest has been devoted the last decade to MCEs, but our understanding of the physiological performance of benthic organisms living in this environment remains relatively unexplored. To tackle that question, we first compared the metabolic responses (dark respiration, net photosynthesis and photosynthetic efficiency) of the depth-generalist scleractinian Pachyseris speciosa from two heterogeneous thermal environment (25 and 85 m depths) to acute heat stress to determine if the local thermal environment could predict coral response to warming. Then, we tested the thermal performance of two sympatric species (the scleractinian P. speciosa and the antipatharian Stichopathes sp.) to determine if there are inter-species differences in performances in species experiencing identical levels of temperature variability, at mesophotic depths (85 m). Results revealed broader thermal performances in the mesophotic P. speciosa compared to mid-depth ones, and constrained performances in the mesophotic antipatharian compared to the scleractinian species. We hypothesize that the high fluctuations in temperature due to internal waves in deeper areas contribute to the broader thermal performances of mesophotic P. speciosa. However, the constrained performances of the mesophotic antipatharian compared to P. speciosa suggests that other processes than the symbiosis with zooxanthellae also influence thermal performances of these mesophotic organisms. Our results supported that Stichopathes sp. lives close to its thermal optimum, suggesting a (relatively) cold thermal specialist strategy. In this context, composition of MCEs in the future is unlikely to shift to antipatharian-dominated landscape and will remain coral-dominated landscape. [Display omitted] • P. speciosa has broader thermal performance at 85 than 25 m. • Thermal regime likely explains depth-specific thermal performance for P. speciosa. • At 85 m depth, thermal performance is narrower for Stichopathes sp. than for P. speciosa. • Cooling events generated by internal waves do not always improve thermotolerance. • Stichopathes sp. at 85 m lives close to its thermal optimum. [ABSTRACT FROM AUTHOR]

Rivers have long been recognized for their ability to shape reef-bound volcanic islands. On the time-scale of glacial–interglacial sea-level cycles, fluvial incision of exposed barrier reef lagoons may compete with constructional coral growth to shape the coastal geomorphology of ocean islands. However, overprinting of Pleistocene landscapes by Holocene erosion or sedimentation has largely obscured the role lowstand river incision may have played in developing the deep lagoons typical of modern barrier reefs. Here we use high-resolution seismic imagery and core stratigraphy to examine how erosion and/or deposition by upland drainage networks has shaped coastal morphology on Tahaa, a barrier reef-bound island located along the Society Islands hotspot chain in French Polynesia. At Tahaa, we find that many channels, incised into the lagoon floor during Pleistocene sea-level lowstands, are located near the mouths of upstream terrestrial drainages. Steeper antecedent topography appears to have enhanced lowstand fluvial erosion along Tahaa's southwestern coast and maintained a deep pass. During highstands, upland drainages appear to contribute little sediment to refilling accommodation space in the lagoon. Rather, the flushing of fine carbonate sediment out of incised fluvial channels by storms and currents appears to have limited lagoonal infilling and further reinforced development of deep barrier reef lagoons during periods of highstand submersion. [ABSTRACT FROM AUTHOR]

An increasing number of geochemical studies looked for spatial organization of the isotopic variations along Pacific volcanic island chains (e.g., Hawaii, Marquesas, Samoa and Society Islands) in order to discuss the possible zoning of the plume conduits. Here, we reexamine the occurrence of isotopic stripes in the Society archipelago in French Polynesia, using new Sr–Nd–Hf–Pb isotope ratios of sixty-six lavas from six islands (Mehetia, Moorea, Maupiti, Huahine, Raiatea, Bora-Bora). We demonstrate that the Pb isotope variability observed using literature data is an analytical artifact related to the poor control of mass fractionation during Pb measurements by conventional TIMS technique. New MC-ICP-MS Pb data demonstrate that the isotopic stripes as previously defined disappear. They rather show that individual islands cover a significant part of the entire isotopic range of the chain. We suggest, therefore, that the dominant characteristic of the Society plume is small-scale heterogeneities, evenly distributed within the plume conduit. At a global scale, we show that some ocean island chains with similar geochemical and isotopic characteristics, such as Samoa and Society Islands, define different arrays when variations of Nd with high-precision Pb isotopes are considered. We proposed that this puzzling observation might record differences in recycling age of the basalt + sediment mixture subducted into the mantle and sampled by mantle plume. [ABSTRACT FROM AUTHOR]

The presence of fission products, which include numerous isotopes of lanthanides, can impact the isotopic ratios of these elements in the environment. A cloud point extraction (CPE) method was used as a preconcentration/separation strategy prior to measurement of isotopic ratios of three lanthanides (Nd, Sm, and Eu) by inductively coupled plasma tandem mass spectrometry (ICP-MS/MS). To minimise polyatomic interference, the combination of interferents removal by CPE, reaction/collision cell conditions in He and NH 3 mode and tandem quadrupole configuration was investigated and provided optimal results for the determination of isotopic ratio in environmental samples. Isotopic ratios were initially measured in San Joaquin soil (NIST-2709a), an area with little contamination of nuclear origin. Finally, samples collected from three sites with known nuclear activities (Fangataufa Lagoon in French Polynesia, Chernobyl and the Ottawa River near Chalk River Laboratory) were analysed and all exhibited altered isotopic ratios for 143/145 Nd, 147/149 Sm, and 151/153 Eu. These results demonstrate the potential of CPE and ICP-MS/MS for the detection of altered isotopic ratio in environmental samples collected in area subjected to nuclear anthropogenic contamination. The detection of variations in these isotopic ratios of fission products represents the first application of CPE in nuclear forensic investigations of environmental samples. [ABSTRACT FROM AUTHOR]

Shipboard multibeam survey is powerful tool to locate submarine volcanoes especially having small volume. Small submarine volcanoes may represent the initial stages of hotspot activity, but they may also form via lithospheric flexing, regional convection of the mantle, and the presence of fracture zones. Here we describe several volcanoes, flood lavas, and volcanic clusters in French Polynesia using data from archives of multibeam data. The clusters of small volcanoes are similar to petit-spots, and they are not considered to represent the initial stages of a hotspot as they are composed of both young and old edifices, and because the sites are located far from any known hotspot. These newly discovered submarine volcanoes are located in areas with low-velocity seismic shear waves at depths of 60 and 100 km. These lava fields will therefore facilitate geochemical mapping of the mantle in areas unrelated to hotspots, because these lavas may have developed from melts in the shallow mantle beneath French Polynesia. [ABSTRACT FROM AUTHOR]

Objectives: This is the first research article examining non-fatal suicidal behaviours (NFSB) in French Polynesia. The study was conducted in the frames of the WHO/START Study in 2008-2010. The main objective of the investigation was to obtain reliable data in order to develop evidence-based suicide prevention strategies.Method: Interviews with people presenting with NFSB at the Emergency Department (ED) of the French Polynesia Hospital (CHPF) were conducted by emergency and psychiatry departments' staff examining socio-demographic and clinical information and motives triggering suicidal behaviour. Odds ratios and rate ratios with 95% confidence intervals were calculated.Results: There were 556 presentations of NFSB by 515 persons at the ED of CHPF (ratio 1.08) with the average rate of 75 per 100,000 for those treated in the hospital. An estimate of cases occurring in remote islands might bring the rate for the whole French Polynesia around 94 per 100,000. NFSB was more prevalent in females; rates for both genders were highest in the age group 25-35 years and 15-24 years. The main suicide method was drug poisoning by psychotropic drugs. The most frequent psychiatric disorder was mood disorder (45.3%); however, 26% of subjects had no 'major' psychiatric disorders, with 14.5% without a psychiatric diagnosis or only reactive disorders (F43-11.7%). There was a high prevalence of previous NFSB (52.1%).Limitations: Study includes only NFSB seeking medical help from the biggest hospital in the country.Conclusion: Suicide prevention activities specific to the findings and the socio-cultural context of French Polynesia should be considered. [ABSTRACT FROM AUTHOR]

Pacific islands are particularly vulnerable to the effects of invasive species. After habitat destruction or modification, invasive species are responsible for more biological extinctions than any other cause. Further, the rate of extinction of native species has been higher on islands than anywhere else in the world. Invasive species have also degraded native ecosystems. In order to detect exotic intertidal mollusk species, an extensive sampling around Moorea Island, a more or less unspoiled island surrounded by a rich coral reef habitat, has been developed considering that sampled points have different characteristics in wave exposure, algae coverage, type of substrate, distance to ports, distance to freshwater, distance sewage and boat traffic. Samples were DNA barcoded for unequivocal species assignation. The presence of five NIS among 26 species seems an important signal of introduction of alien biota in Moorea Island coast. However they were represented by a total of 38 individuals among 1487 mollusks (2.55%). While the distance to relatively big ports influenced directly species richness, the intensity of maritime traffic measured as boat density near sampling points was significantly associated with the frequency of exotic species. Other environmental factors did not show significant correlation with the frequency of exotics, suggesting that in an environment without big discontinuities, with little habitat modification, local boat traffic is the most influential factor in the spread of exotic species. This could be mitigated relatively easily by reducing boat density in local zones of ecological interest. [ABSTRACT FROM AUTHOR]