Gouvernement de la Nouvelle-Calédonie

Humid heat stress and heatwaves pose significant risks for living organisms, from humans and wildlife to insects. These threats have wide-ranging health, ecological, and socio-economic impacts that are expected to worsen with climate change. How large-scale climate modes drive the week-to-month variability of humid heat remains poorly understood at the global scale. This limitation hinders the development of accurate forecasts necessary for risk-management measures, notably in the heavily populated and ecologically fragile regions of the tropics and subtropics. With forecast lead times up to several weeks, the Madden-Julian Oscillation (MJO), a global-scale intraseasonal tropical atmospheric disturbance circumnavigating earth in around 30-60 days, provides considerable predictability for weather conditions, and meteorological and oceanic extremes. Here we show that the MJO, and the associated boreal summer intraseasonal oscillation (BSISO), have a significant influence on humid heat and heatwaves over much of the tropics and subtropics across all seasons, both over terrestrial and marine regions. Humid heatwave likelihood can double or halve, depending on the MJO phase, in large areas of the Earth. The MJO/BSISO's influence on wet-bulb temperature is primarily via specific humidity rather than dry-bulb temperature anomalies. In the subtropics and other regions where we typically do not find a strong signal of the convection, we find that intraseasonal anomalies of specific humidity and dry-bulb temperature are influenced by horizontal advection in the planetary boundary layer. Particularly in the subtropics where advection of the climatological moisture and temperature gradient by MJO-related anomalous winds is an important term.

The genus Parsonsia R.Br. in New Caledonia is partially revised to solve different taxonomic and nomenclatural issues, and describe four new species. An updated key of the genus is given for New Caledonia. The species complex Parsonsia flexuosa / P. terminaliifolia is discussed, and a new circumscription of two species is provided, with P. carnea and P. rigida as the new accepted names in order to avoid future confusions for field botanists. The species complex P. franchetii / P. brachiata is also analysed so that both names are lumped as one sclerophyllous forest species, but another name, P. hienghenensis, is reinstated as a distinct species, growing in calcareous forests. The application of the name P. edulis is clarified. The nomenclature and taxonomy of P. scabra is revised. A detailed morphological study revealed that P. effusa was in fact made up of two different taxa; a new separate species, P. crucifera is therefore described. Three other new species are also described following new gatherings in the field and/or reexamination of older herbarium specimens: P. bogotensis from the Bogota peninsula, P. tiebaghiensis from the Tiebaghi and Ouazangou massifs, and P. urceolata from the Poum massif. Finally, several lectotypifications are discussed and proposed.

Le 16 avril 2014, le ferry Sewol sombre au Sud de la Corée, en direct à la télévision. Il fait 304 victimes, pour la plupart des lycéens en voyage de classe. Le pays entier est sous le choc. Au lieu de remettre en scène l’événement ou de critiquer ses causes (comme nombre d’auteurs après le drame), Choi Eun-young choisit de porter son attention sur les conséquences concrètes et les émotions vécues au quotidien par les Coréens. Une manière de saisir l’ampleur des dégâts et de dépasser le traumatisme.

Abstract QuestionsHigh species richness is observed in certain shrublands on infertile substrates. Mineral nutrients are likely to be the primary limiting resources in these ecosystems, and below‐ground plant interactions may be crucial to understanding their diversity. Using ionomics, we investigated whether there were nutritional variations between plant species that coexist in a shrubland located in an edaphically extreme environment.LocationNew Caledonia.MethodsWe set up a 20 m × 20 m plot in a diverse shrubland (“maquis”) on ultramafic (infertile) substrate, in which we sampled all 475 plants taller than 1 m and characterized their ionome (22 elements).ResultsIn our study, 37 species were identified in the plot, representing all major forms of mycorrhizal symbioses, as well as nitrogen‐fixing plants, cluster rooted and parasitic plants. Notably, both nickel hyperaccumulating and manganese hyperaccumulating species were present. Hypervolume approaches were used to assess ionome overlap among the nine most abundant species, with the results revealing limited overlap. Moreover, it was observed that the rarest species in the plot also had the most functionally distinct features.ConclusionsDifferent nutritional strategies were present in the plot, as demonstrated by the variety of root symbioses and leaf ionomes. Our findings indicate coexistence of multiple species within this infertile shrubland may be achieved by species partitioning into different highly specialized biogeochemical niches.

SummaryBackgroundPacific Islanders are underrepresented in vaccine efficacy trials. Few studies describe their immune response to COVID-19 vaccination. Yet, this characterization is crucial to re-enforce vaccination strategies adapted to Pacific Islanders singularities.MethodsWe evaluated the humoral immune response of 585 adults self-declaring as Melanesians, Europeans, Polynesians or belonging to other communities to Pfizer BNT162b2 vaccine. Anti-Spike and anti-Nucleoprotein IgG levels, capacity to neutralize SARS-CoV-2 variants and capacity to mediate Antibody-Dependent Cellular Cytotoxicity (ADCC) were assessed across communities at one and three months post-second dose or one and six months post-third dose.Results61.3% of the sera tested contained anti-Nucleoprotein antibodies, evidencing mostly a hybrid immunity resulting from vaccination and SARS-CoV-2 infection. Anti-Spike IgG levels and capacity to mediate Omicron neutralization and ADCC were equivalent across the four ethnic communities at one-month post-immunization, during follow-up and at six months post-third dose, regardless of the infection status. Obese individuals (BMI>30 kg/m²) had significantly higher anti-Spike IgG levels at one-month post-immunization (+0.26 (0.04; 0.48) AU in LuLISA assay,pvalue = 0.017). Odds of Omicron neutralization at six months after the third dose decreased significantly in the 40-64 years and ≥65 years groups (OR (95% CI) 0.48 (0.24-0.90) and 0.29 (0.14-0.58) respectively,p-value = 0.003).ConclusionsOur study evidenced Pacific Islander’s robust humoral immune response to Pfizer BNT162b2 vaccine, which is pivotal to re-enforce vaccination deployment in a population at risk for severe COVID-19 (clinicaltrials.gov:NCT05135585).summaryEthnicity has little impact on Pacific Islanders’ hybrid humoral immune response to BNT162b2 vaccination and SARS-CoV-2 infection. Anti-Spike IgG levels, capacity to neutralize Omicron variants and capacity to mediate Antibody-Dependent Cellular Cytotoxicity are equivalent across Pacific communities following BNT162b2 vaccination.

Northern Zealandia is a continent submerged for more than 90% under the water of the southwest Pacific Ocean and separated from Australia by the Tasman Sea ocean basin. Its absolute position since its drift form Australia in the Cretaceous is determined by means of global absolute plate motion models, as local paleomagnetic constraints are completely missing. We present new absolute paleolatitudes for northern Zealandia using paleomagnetic data from sediments drilled in International Ocean Discovery Program Sites U1507 and U1511 (Expedition 3711,2). After correcting for paleomagnetic inclination shallowing, typical of sediments, we derived five paleolatitude estimates that provide a trajectory of northern Zealandia past position from the middle Eocene to early Miocene, spanning geomagnetic polarity chrons C21n to C5Er (~48–18 Ma). Generally, our results support previous works on global absolute plate motion, including a rapid 6° northward migration of northern Zealandia between the early Oligocene–early Miocene. However, paleomagnetic-determined absolute paleolatitude is systematically lower, and this difference is significant in the Bartonian and Priabonian (C18n–C13r). This discrepancy may be explained by some degree of true polar wander, a solid Earth rotation with respect to the spin axis that can be resolved only using paleomagnetic data. These new paleomagnetic dataset anchors past latitudes of Zealandia to Earth’s spin axis, with implications not only for global geodynamics, but for addressing paleoceanographic problems, which generally require precise paleolatitude placement of proxy data3.Figure 1. Present-day map of northern and southern Zealandia, enveloped respectively by the yellow and orange dashed line. The yellow stars indicate the location of International Ocean Discovery Program Sites U1507 (26.4886°S, 166.5286°E) and U1511 (37.5611°S, 160.3156°E). Solid and dashed white lines indicate active and inactive subduction zones, respectively, with arrows lying on the overriding plate. LHR = Lord Howe Rise, NCT = New Caledonia trough, NR = Norfolk Ridge, RB = Reinga basin.(1) Sutherland, R. et al. Proc. Int. Ocean Discov. Progr. 371, 1–33 (2019); (2) Dallanave, E. & Chang, L. Newsletters Stratigr. 53, 365–387 (2020); (3) Dallanave, E. et al. J. Geophys. Res. Solid Earth 127, 1–19 (2022).