The abyssal giant sinkholes of the Blake Bahama Escarpment: evidence of focused deep-ocean carbonate dissolution
This study reports the discovery of abyssal giant depressions located at the toe of the Bahamian carbonate platform, along the Blake Bahama structurally-controlled Escarpment (BBE) that exhibits up to 4 km of submarine elevation above the San Salvador Abyssal Plain (SSAP). Analysis of seismic reflection and bathymetric data collected during the CARAMBAR 2 cruise revealed the presence of 29 submarine depressions; their water depths range from 4584 m to 4967 m whereas their negative reliefs are elliptical in shape, range in diameter from 255 m to 1819 m, and in depth from 30 m to 185 m. The depression alignment trends are parallel to the BBE as well as to structural lineaments of the area, exclusively between 2200 and 5000 m from its toe, and overlies a buried carbonate bench in which a high-amplitude seismic anomaly has been detected. The depression density interestingly increases where the recognized structural lineaments intersect the BBE. Based on their physical attributes (i.e. location, jagged morphologies, water depths), we interpret these depressions as collapse sinkholes rather than pockmarks or plunge pools. The aforementioned observations suggest an atypical relationship between the spatial occurrence of the giant abyssal sinkholes, the carbonate platform tectonic structures, the buried carbonate bench that underlies the hemipelagites in the SSAP and the geomorphology of the area. According to the wider literature that reports fluid seepages along submarine carbonate escarpments, we propose that the ground water entrance during low sea-level stands, the dissolution of evaporites by meteoric water, the platform-scale thermal convection and the seawater entrance at the platform edge most probably collectively act in concert to favor the circulation of brines and therefore the corrosion within the Bahamian carbonate platform. These mechanisms are particularly efficient along the structural heterogeneities (e.g. the Sunniland Fracture Zone, SFZ) which act as fluid conduits localizing the dissolution and control the physiography of the area by maintaining the location of the sedimentary pathways. The dense fluids would migrate along the faults towards the BBE free edge and are subsequently trapped into the buried carbonate bench that laterally disappears below the low-permeability deep-sea hemipelagites of the SSAP. In consequence, the trapped corrosive fluids dissolve the carbonates preferentially along the tectonic structures such as the SFZ. They are this way at the origin of the BBE curvature and generate collapse-structures in the overlying fine-grained deposits finally resulting in the formation of giant abyssal sinkholes. This structurally-directed process of dissolution seems efficient to provide a brines density head to move out down to >4.5 km of water depth and is believed to have played a major role in the BBE 5-6 km erosional retreat.
(Geomorphology. vol. 398, n° 0169-555X, 13/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Ideas and perspectives: Sea-level change, anaerobic methane oxidation, and the glacial-interglacial phosphorus cycle
The oceanic phosphorus cycle describes how phosphorus moves through the ocean, accumulates with the sediments on the seafloor, and participates in biogeochemical reactions. We propose a new two-reservoir scenario of the glacial-interglacial phosphorus cycle. It relies on diagenesis in methane hydrate-bearing sediments to mobilize sedimentary phosphorus and transfer it to the oceanic reservoir during times when falling sea level lowers the hydrostatic pressure on the seafloor and destabilizes methane hydrates. The stock of solid phase phosphorus mobilizable by this process is of the same order of magnitude as the dissolved phosphate inventory of the current oceanic reservoir. The potential additional flux of phosphate during the glacial period is of the same order of magnitude as pre-agricultural, riverine dissolved phosphate fluxes to the ocean. Throughout the cycle, primary production assimilates phosphorus and inorganic carbon into biomass, which, upon settling and burial, returns phosphorus to the sedimentary reservoir. Primary production also lowers the partial pressure of CO2 in the surface ocean, potentially drawing down CO2 from the atmosphere. Concurrent with this slow "biological pump", but operating in the opposite direction, a "physical pump" brings metabolic CO2-enriched waters from deep-ocean basins to the upper ocean. The two pumps compete, but the direction of the CO2 flux at the air-sea interface depends on the nutrient content of the deep waters. Because of the transfer of reactive phosphorus to the sedimentary reservoir throughout a glaciation cycle, low-phosphorus and high-CO2 deep waters reign at the beginning of a deglaciation, resulting in rapid transfer of CO2 to the atmosphere. The new scenario provides another element to the suite of processes that may have contributed to the rapid glacial-interglacial climate transitions documented in paleo-records.
(Biogeosciences. vol. 19, n° 1726-4170, pp. 1421-1434, 13/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
NiONPs-induced alteration in calcium signaling and mitochondrial function in pulmonary artery endothelial cells involves oxidative stress and TRPV4 channels disruption
In New Caledonia, anthropic activities, such as mining, increase the natural erosion of soils in nickel mines, which in turn, releases nickel oxide nanoparticles (NiONPs) into the atmosphere. Pulmonary vascular endothelial cells represent one of the primary targets for inhaled nanoparticles. The objective of this in vitro study was to assess the cytotoxic effects of NiONPs on human pulmonary artery endothelial cells (HPAEC). Special attention will be given to the level of oxidative stress and calcium signaling, which are involved in the physiopathology of cardiovascular diseases. HPAEC were exposed to NiONPs (0.5–150 μg/cm2) for 4 or 24 h. The following different endpoints were studied: (i) ROS production using CM-H2DCF-DA probe, electron spin resonance, and MitoSOX probe; the SOD activity was also measured (ii) calcium signaling with Fluo4-AM, Rhod-2, and Fluo4-FF probes; (iii) inflammation by IL-6 production and secretion and, (iv) mitochondrial dysfunction and apoptosis with TMRM and MitoTracker probes, and AnnexinV/PI. Our results have evidenced that NiONPs induced oxidative stress in HPAEC. This was demonstrated by an increase in ROS production and a decrease in SOD activity, the two mechanisms seem to trigger a pro-inflammatory response with IL-6 secretion. In addition, NiONPs exposure altered calcium homeostasis inducing an increased cytosolic calcium concentration ([Ca2+]i) that was significantly reduced by the extracellular calcium chelator EGTA and the TRPV4 inhibitor HC-067047. Interestingly, exposure to NiONPs also altered TRPV4 activity. Finally, HPAEC exposure to NiONPs increased intracellular levels of both ROS and calcium ([Ca2+]m) in mitochondria, leading to mitochondrial dysfunction and HPAEC apoptosis.
(Nanotoxicology. vol. 16, n° 1743-5390, pp. 29-51, 13/04/2026)
CRCTB, UB, CHU Bordeaux, INSERM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CHU Bordeaux, BIC, UB, INSERM, CNRS, ICMCB, UB, INC-CNRS, CNRS
New cosmogenic nuclide constraints on Late Glacial and Holocene glacier fluctuations in the sub-Antarctic Indian Ocean (Kerguelen Islands, 49°S)
Cosmogenic nuclide dating of glacial landforms on the Kerguelen Archipelago (49°S, 69°E) gives the opportunity to study multi-millennial glacier fluctuations within the sub-Antarctic sector of the Indian Ocean. We here dated such geomorphic features to provide time constraints over the last 17,000 years using in situ-produced 36Cl in three glacial valleys: Val Travers valley, Ampere Glacier valley and Arago Glacier valley. For the first time, a combination of in situ-produced 36Cl and 10Be dating and 26Al/10Be ratios analysis was performed in the quartz-bearing syenite boulders of the Arago Glacier site. In addition, a Bayesian approach was computed to obtain a better constraint on moraine dating. Glacial advances occurred during the Late Glacial at 16.0 ± 1.9 ka and at 12.9 ± 1.7 ka in Val Travers, and at 13.6 ± 1.8 ka in Arago Glacier valley, probably linked to the Heinrich Stadial 1 and/or Antarctic Cold Reversal events, respectively. This suggests that all glaciers at this latitude were broadly sensitive to the large-scale climatic signal of the Antarctic Cold Reversal. So far, no Early nor Mid-Holocene moraines have been found in the glacial valleys on Kerguelen, indicating that the glaciers had probably receded significantly during these periods. This is in agreement with previously determined 14C ages from peat bogs, which suggest extensive deglaciation during several millennia of the Holocene period. Samples from glacially-polished bedrock surfaces (ranging from ~4.4 ka to ~14 ka) at Ampere Glacier site also suggest that this valley was ice free for several millennia during the Holocene. Finally, glaciers seem to have re-advanced only during the Late Holocene, especially within the last millennium, at ~1 ka, ~430 yr and ~300 yr. A comparison of this new dataset with the available 10Be ages from other southern mid latitude regions during the Holocene allows the identification of three different glacier evolution patterns. We suspect that variations of Kerguelen glaciers, which are located in the Southern Indian Ocean, were controlled by the combined effects of sea surface temperature related to the variations of the Antarctic Polar Front and fluctuations of precipitation related to long-term variations of the Southern Annular Mode.
(Quaternary Science Reviews. vol. 283, n° 0277-3791, pp. 107461, 13/04/2026)
CEREGE, IRD, AMU, CdF (institution), INSU - CNRS, CNRS, INRAE, GEOPS, INSU - CNRS, CNRS, CRPG, INSU - CNRS, UL, CNRS, UL, ELI, UCLouvain, IGE, IRD, INSU - CNRS, CNRS, Fédération OSUG, UGA, Grenoble INP, UGA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ULaval, LGL-TPE, ENS de Lyon, UCBL, INSU - CNRS, UJM, CNRS, UJM, LGP, UP1, UPEC UP12, CNRS
NiONP-Induced Oxidative Stress and Mitochondrial Impairment in an In Vitro Pulmonary Vascular Cell Model Mimicking Endothelial Dysfunction
The development and use of nanomaterials, especially of nickel oxide nanoparticles (NiONPs), is expected to provide many benefits but also has raised concerns about the potential human health risks. Inhaled NPs are known to exert deleterious cardiovascular side effects, including pulmonary hypertension. Consequently, patients with pulmonary hypertension (PH) could be at increased risk for morbidity. The objective of this study was to compare the toxic effects of NiONPs on human pulmonary artery endothelial cells (HPAEC) under physiological and pathological conditions. The study was conducted with an in vitro model mimicking the endothelial dysfunction observed in PH. HPAEC were cultured under physiological (static and normoxic) or pathological (20% cycle stretch and hypoxia) conditions and exposed to NiONPs (0.5–5 μg/cm2) for 4 or 24 h. The following endpoints were studied: (i) ROS production using CM-H2DCF-DA and MitoSOX probes, (ii) nitrite production by the Griess reaction, (iii) IL-6 secretion by ELISA, (iv) calcium signaling with a Fluo-4 AM probe, and (v) mitochondrial dysfunction with TMRM and MitoTracker probes. Our results evidenced that under pathological conditions, ROS and nitrite production, IL-6 secretions, calcium signaling, and mitochondria alterations increased compared to physiological conditions. Human exposure to NiONPs may be associated with adverse effects in vulnerable populations with cardiovascular risks
(Antioxidants. vol. 11, n° 2076-3921, pp. 847, 13/04/2026)
CRCTB, UB, CHU Bordeaux, INSERM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, DER, ANSES, CHU Bordeaux
Stratigraphy in the Greenland/ Iceland/Norwegian (GIN) seas: A multiproxy approach on Pleistocene sediments
A multiproxy sedimentological study was conducted on five sediment cores retrieved between 67 and 79°N in the Greenland/Iceland/Norwegian seas in order to infer a common chronostratigraphic model for the selected cores. This model is based on the use of a series of geochemical, physical and micropaleontological proxies which are routinely measured in sedimentological investigations of marine sediment cores: the major and minor element content derived from X-Ray Fluorescence (XRF) core scanner analyses; the lightness and color of the sediment derived from spectrophotometry analyses; the magnetic susceptibility of the sediment; the distribution of planktonic foraminiferal assemblages combined to coccolith stratigraphy (acme zones) providing preliminary stratigraphic tie points. All those proxies are correlated independently between the five sediment cores. Our results demonstrate that high resolution studies using those standard paleoceanographical tools are powerful for establishing core-to-core correlation. A chronostratigraphical framework is proposed based on the correlation of the planktonic δ 18 O isotopic record obtained in core M17KC03 with the LR04 benthic δ 18 O reference stack. A comparison between the M17KC03 stratigraphy and other dated cores from the sub-polar North Atlantic confirms the robustness of the approach. Our study suggests that XRF core scanner-derived elemental ratios (especially those related to Ca), the lightness L* and the coccolith-based biostratigraphy provide robust stratigraphic tie-points at the scale of the whole Greenland/Iceland/Norwegian seas. The elemental ratio Sr/sum, the magnetic
(13/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, M2C, UNICAEN, NU, INSU - CNRS, UNIROUEN, NU, CNRS, SHOM
Genetic and epigenetic interplay allows rapid transgenerational adaptation to metal pollution in zebrafish
Despite still being a matter of debate, there is growing evidence that pollutant-induced epigenetic changes can be propagated across generations. Whereas such modifications could have long-lasting effects on organisms and even on population, environmentally relevant data from long-term exposure combined with follow-up through multiple generations remain scarce for non-mammalian species. We performed a transgenerational experiment comprising four successive generations of zebrafish. Only fish from the first generation were exposed to an environmentally realistic concentration of cadmium (Cd). Using a whole methylome analysis, we first identified the DNA regions that were differentially methylated in response to Cd exposure and common to fish of the first two generations. Among them, we then focused our investigations on the exon 3 (ex3) of the cep19 gene. We indeed recorded transgenerational growth disorders in Cd-exposed fish, and a mutation in this exon is known to cause morbid obesity in mammals. Its methylation level was thus determined in zebrafish from all the four generations by means of a targeted and base resolution method. We observed a transgenerational inheritance of Cd-induced DNA methylation changes up to the fourth generation. However, these changes were closely associated with genetic variations, mainly a single nucleotide polymorphism. This single nucleotide polymorphism was itself at the origin of the creation or deletion of a methylation site and deeply impacted the methylation level of neighboring methylation sites. Cd-induced epigenetic changes were associated with different mRNA transcripts and an improved condition of Cd fish. Our results emphasize a tight relationship between genetic and epigenetic mechanisms and suggest that their interplay and pre-existing diversity can allow rapid adaptation to anthropogenic environmental changes.
(Environmental Epigenetics. vol. 8, n° 2058-5888, 13/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UMS POREA, INSU - CNRS, CNRS, INRAE, CBIB, GeT-PlaGe, GET, GENOTOUL, UT3, ENVT, INSERM, CNRS, Toulouse INP, INRAE, INRAE, IBGC, UB, CNRS
Wave Dissipation and Mean Circulation on a Shore Platform Under Storm Wave Conditions
While wave processes on shore platforms have been recently advanced by a number of field-based studies, few attention has been paid to the role of bed roughness on wave dissipation and wave setup dynamics in these environments. This study reports on a new field experiment conducted under storm wave conditions on a gently sloping shore platform which was instrumented from 10 m water depth up to the shoreline. Data analyses are complemented with numerical simulations performed with a 3D fully coupled modeling system using a vortex force formalism to represent the effects of short waves on the mean circulation. An accurate representation of wave dissipation by both depth-induced breaking and bottom friction is found essential to reproduce the transformation of short waves across the platform and the resulting wave setup. Wave energy dissipation by bottom friction is dominant in the subtidal part of the platform and contributes to about 40% of the total wave energy dissipation. The enhanced wave bottom friction on the platform decreases the wave height before breaking, which reduces the contribution of wave forces to the wave setup compared to a smooth bottom (mechanism 1). Conversely, an idealized analysis of the cross-shore momentum balance reveals that the wave-induced circulation increases the wave setup, this process being enhanced on a rough bottom (mechanism 2). The contribution of mechanism 2 increases with the bottom slope, accounting for up to 26% of the wave setup for a 1:20 sloping shore platform, and overcoming mechanism 1.
(Journal of Geophysical Research: Earth Surface. vol. 127, n° 2169-9003, pp. 105319, 13/04/2026)
LIENSs, INSU - CNRS, ULR, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Ammonium and sulfate assimilation is widespread in benthic foraminifera
(Frontiers in Marine Science, n° 2296-7745, 13/04/2026)
LPG, UM, UA, INSU - CNRS, CNRS, Nantes univ - UFR ST, Nantes Univ, EPFL, ENTROPIE [Réunion], IRD, UR, CNRS, WHOI, CAGE, UiT, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UNIL
Impacts des produits phytopharmaceutiques sur la biodiversité et les services écosystémiques. Synthèse de l’expertise scientifique collective
Impacts des produits phytopharmaceutiques sur la biodiversité et les services écosystémiques Synthèse de l'expertise scientifique collective-Mai 2022 Direction de l'expertise scientifique collective, de la prospective et des études (DEPE)
(pp. 136 p., 13/04/2026)
DEPE, INRAE, ECOSYS, INRAE, RiverLy, INRAE, IFREMER, AQUA, INRAE, ISA, UNS, CNRS, INRAE, UniCA, LMGE, CNRS, UCA, UMR BAGAP, ESA, INRAE, Institut Agro, LPED, IRD, AMU, SEBIO, INERIS, URCA, ULH, NU, URCA, CNRS, INERIS, EMMAH, AU, INRAE, MET, ENVL, INRAE, CRIOBE, UPVD, EPHE, PSL, CNRS, CNELIAS, ENS de Lyon, EHESS, AU, AMU, CNRS, LBBE, UCBL, VAS, CNRS, UB, UBFC, INRAE, Institut Agro, LCE, CNRS, UFC, UBFC, UMR SAVE, UB, Bordeaux Sciences Agro, INRAE, DECOD, IFREMER, INRAE, Institut Agro, Institut Agro, OFB, GREDEG, UNS, CNRS, UniCA, LEREPS, UT Capitole, Comue de Toulouse, UT2J, Comue de Toulouse, ENSFEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UMR Eco&Sols, Cirad, IRD, INRAE, Institut Agro, IODE, UR, CNRS, UPR HORTSYS, Cirad, Cirad-PERSYST, Cirad, UMR MARBEC, IRD, IFREMER, CNRS, UM, DipSO, INRAE, AMURE, IRD, IFREMER, UBO EPE, CNRS, UR EABX, INRAE, IMBE, AU, AMU, CNRS, ICRA, UdG, BRM, IFREMER, URAFPA, UL, INRAE, UR HYCAR, INRAE