Impact of a CO2 leak on the release of major and trace elements according to groundwater flow conditions in a shallow freshwater carbonate aquifer: In-situ experiments and modelling
To investigate the role of hydrogeological conditions on the release of major and trace elements during CO2 leakage occurring in shallow freshwater aquifers in a CO2 Capture and Storage context, this paper compares the results of two in-situ CO2 leakage experiments. These experiments were carried out in a shallow freshwater carbonated aquifer located in Saint-Emilion, France, during both low and high-water levels periods. In both experiments, 200 L of carbonated water were injected into a well and groundwater monitoring was carried out downstream. Due to the physical heterogeneity of the aquifer at a small scale, the CO2-rich water plume did not follow the same flow path between the two hydrogeological periods, thus highlighting preferential pathways. It was observed that geochemical changes were not of the same intensity. The concentrations of Ca2+, HCO3−, Mg2+, Fe, Mn, As, Co, Cu, Ba, Sr and V increased during the low-water level experiment while the measured concentrations only reflected the dilution of the gasified water injected during the high-water level period.
(International Journal of Greenhouse Gas Control. vol. 132, n° 1750-5836, pp. 104042, 01/02/2024)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IFPEN
Persistent organic pollutants and trace metals in selected marine organisms from the Akanda National Park, Gabon (Central Africa)
Akanda National Park (ANP) is composed of mangrove ecosystems bordering Libreville, Gabon's capital. The contamination of aquatic resources from the ANP by persistent organic pollutants (POPs) and trace metals (TMs) was never evaluated. To provide a basis for their monitoring in the ANP, five species (two fish, two mollusks, and one crustacean) were analyzed from three sampling sites in 2017. Contamination levels for POPs and TMs were below maximum acceptable limits for seafood, including Cd and Pb. No DDT was found in any sample. Inter-specific differences were more obvious than the differences among sites, although the results may be biased by an unbalanced sampling design. The oyster Crassostrea gasar was the most contaminated species, making this species a good candidate to assess environmental contamination in the area. The studied species also contained essential elements, such as Fe, Zn and Mn at interesting levels in a nutritional point of view.
(Marine Pollution Bulletin. vol. 199, n° 0025-326X, pp. 116009, 01/02/2024)
IRD, LEMAR, IRD, IFREMER, UBO EPE, CNRS, SFA, SOS, CENAREST, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UMR MARBEC, IRD, IFREMER, CNRS, UM
Sedimentary Records in the Lesser Antilles Fore‐Arc Basins Provide Evidence of Large Late Quaternary Megathrust Earthquakes
The seismic potential of the Lesser Antilles subduction zone is poorly known and highly debated. Only two damaging earthquakes have been reported in the historical period, in 1839 and 1843, but their sources and magnitude are still uncertain. Global Navigation Satellite Systems and coral data contradict each other, and no conclusion has been reached on the coupling ratio of the plate interface. Given the threat posed by the possible occurrence of a large megathrust earthquake, it is crucial to gain information on prehistorical events. We present the results of a submarine paleoseismological study that covers an exceptional ∼120 Kyr‐long period. We studied the sediments sampled in six up to 26 m‐long piston cores collected in deep fore‐arc basins located over the epicentral region of the 1843 earthquake. Using a multiproxy approach combining geophysical, geochemical, and sedimentological analysis, biostratigraphy and radiocarbon dating, we identified, characterized, and dated numerous event deposits that we then correlated with the sampled basins over an up to 160 km‐long area. We show that at least 33 earthquakes likely triggered these sediment remobilizations in the last 120 Kyr. Four of these events promoted exceptional deposits of turbidites + homogenites. From peak ground acceleration calculated for potential earthquakes occurring on various faults, and the absence of deposits linked to the historical earthquakes, we propose that the sources are likely megathrust earthquakes. Over the last 60 Kyr, we inferred at least three 15–25 Kyr‐long seismic cycles in which the recurrence times of earthquakes shortens from ∼5 to ∼2 Kyr.
(Geochemistry, Geophysics, Geosystems. vol. 25, pp. e2023GC011152, 31/01/2024)
IPGP - UMR_7154, INSU - CNRS, IGN, UR, IPG Paris, CNRS, UPCité, LDEO, GEOAZUR 7329, INSU - CNRS, UniCA, CNRS, IRD [Occitanie], UniCA, ISTerre, IRD, INSU - CNRS, USMB [Université de Savoie] [Université de Chambéry], CNRS, Fédération OSUG, UGA, GEO-OCEAN, UBS, IFREMER, INSU - CNRS, UBO EPE, CNRS, UBO EPE, MNHN, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CEOAS, OSU, LOCEAN-VOG, LOCEAN, MNHN, IRD, INSU - CNRS, SU, CNRS, IPSL (FR_636), ENS-PSL, UVSQ, CEA, INSU - CNRS, X, CNES, SU, CNRS, UPCité, ISMER, UQAR, iSTeP, INSU - CNRS, SU, CNRS, RDT, IFREMER, LOG, INSU - CNRS, ULCO, CNRS, IRD [Ile-de-France]
Response of vegetative and reproductive organs of Cucurbita pepo L. Subsp pepo ‘Allegria’ exposed to aged dieldrin contamination in regards to soil concentration and plant development
Aims Dieldrin is an Organochlorine Pesticides (OCPs) which, due to its persistence in agricultural soils, continues to be a source of contamination for crops, especially Cucurbita pepo L. subsp pepo ( C. pepo L.). The latter are able to absorb dieldrin from contaminated soils and transfer it from the roots to the shoots. However, dieldrin allocation has been partially studied, especially in the shoots. This study aims at characterizing dieldrin distribution in the different plant organs according to soil contamination and plant growth. Methods This was achieved by growing C. pepo L. ‘Allegria’ in soil mixtures presenting 5 levels of dieldrin concentration (< 1 to 145 µg kg −1 ) and by harvesting them after different exposure periods (30, 90 and 140 d after transplant). Results The results showed (i) the predominance of the root impregnation path, (ii) that dieldrin concentration in the vegetative organs of C. pepo L. ‘Allegria’ increased with soil concentration while (iii) it stabilized for reproductive organs at soil concentrations exceeding 50 µg kg −1 DW. The bioconcentration factors (BCFs) for vegetative organs were classified as follows: stems (70) > roots (47) > leaves (19). Furthermore, the mass distribution of dieldrin was more dependent on variations in organ mass fraction with plant development than variations of dieldrin concentration in the different organs. Conclusions These results are of main importance for (i) the identification of dieldrin contaminated agricultural plots using phytoscreening methods as well as for (ii) their phytomanagement providing crucial allocation information for phytoextraction purposes.
(Plant and Soil. vol. 499, n° 0032-079X, pp. 655 - 669, 23/01/2024)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, BioGeCo, UB, INRAE
Copper Speciation in Wine Growing-Drain Waters: Mobilization, Transport, and Environmental Diffusion
Copper (Cu) has been used to treat vines for a long time, which has led to its accumulation in vineyard soils. In the present work, the mobilization of copper from these soils and its transport, and diffusion outside the plots by drain water were investigated. For this, the distribution of copper between the dissolved and colloidal phases, and within the colloidal phase, of these waters was determined using an investigation strategy based on the coupling between a size separation technique, asymmetric flow field-flow fractionation, and several detectors. First, the total copper concentrations in water from different drains were monitored over a period of 2 years: Cu was mainly found in the fraction of < 450 nm. Then, the distribution of copper on the size continuum was more closely studied in water from one of the drains, sampled over a winter period. Between 45 and 75% of Cu was found in the 2–450 nm colloidal fraction. The <450 nm colloidal phase of the drain waters was found to be mainly composed of humic acids (~15 to 60 mg L−1) and clay-rich particles (~100 to 650 mg (Al) L−1). These particles also contained (hydr)oxides of iron and manganese. The concentrations of Fe and Mn were approximately 100 to 200 times lower than those of Al. The majority of humic acids had an apparent molar mass of ≤ 10 kDa. They were distributed along the size continuum: (i) in a population with an average size of ~20 nm, probably consisting of supramolecular entities, and (ii) associated with clay-rich particles with a size of ~120–200 nm. Copper was found to be complexed with humic acids and associated with clays via clay-humic complexes. Copper mobilization from the soil to the water and its transport to the drain water appeared governed by the soil humidity level and the rainfall.
(Environments. vol. 11, n° 2076-3298, pp. 19, 19/01/2024)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IPREM, UPPA, INC-CNRS, CNRS
Secular shoreline response to large-scale estuarine shoal migration and welding
The 14.5-km North-Médoc coast, southwest France, is a high-energy mesoto macro-tidal environment adjacent to the largest estuary in Europe. Over the last centuries, this coastline has locally suffered periods of severe erosion, threatening coastal infrastructures and requiring the progressive implementation of coastal structures and, more recently, localized beach nourishments. This contribution combines 84 years (1937-2021) of shoreline data from various sources, 118 years (1903-2021) of shallow water bathymetric surveys and historical photographs. Results show that, averaged in both time and space, the coast eroded by-0.6 m/yr over the last 84 years, but with a large alongshore and temporal variability. Erosion is locally peaking at-5.2 m/yr, while accretion is restricted to a remote 2.5-km and locally peaks at 5.4 m/yr. A salient characteristic of shoreline evolution is the alternation of rapid erosion (<-5 m/yr) and dramatic accretion (> 20 m/yr) periods over relatively short intervals (≈ 10 years) and across limited alongshore distances (e.g. couple of
(Geomorphology. vol. 445, n° 0169-555X, pp. 108972, 15/01/2024)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, BRGM
Hot carbonates deep within the Chicxulub impact structure
Abstract Constraining the thermodynamic conditions within an impact structure during and after hypervelocity impacts is extremely challenging due to the transient thermal regimes. This work uses carbonate clumped-isotope thermometry to reconstruct absolute temperatures of impact lithologies within and close to the ∼66 Myr old Chicxulub crater (Yucatán, México). We present stable oxygen (δ18O), carbon (δ13C), and clumped-isotope (Δ47) data for carbonate-bearing impact breccias, impact melt rock, and target lithologies from four drill cores on a transect through the Chicxulub structure from the northern peak ring to the southern proximal ejecta blanket. Clumped isotope-derived temperatures (T(Δ47)) are consistently higher than maximum Late Cretaceous sea surface temperatures (35.5°C), except in the case of Paleogene limestones and melt-poor impact breccias outside of the crater, confirming the influence of burial diagenesis and a widespread and long-lived hydrothermal system. The melt-poor breccia unit outside the crater is overlain by melt-rich impact breccia yielding a much higher T(Δ47) of 111 ± 10°C (1 standard error [SE]), which likely traces the thermal processing of carbonate material during ejection. Finally, T(Δ47) up to 327 ± 33°C (1 SE) is determined for the lower suevite and impact melt rock intervals within the crater. The highest temperatures are related to distinct petrological features associated with decarbonation and rapid back-reaction, in which highly reactive CaO recombines with impact-released CO2 to form secondary CaCO3 phases. These observations have important climatic implications for the Cretaceous–Paleogene mass extinction event, as current numerical models likely overestimate the release of CO2 from the Chicxulub impact event.
(PNAS Nexus. vol. 3, n° 2752-6542, 11/01/2024)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Co-infection of two eukaryotic pathogens within clam populations in Arcachon Bay
The parasitic species Perkinsus olseni (= atlanticus ) (Perkinsea, Alveolata) infects a wide range of mollusc species and is responsible for mortality events and economic losses in the aquaculture industry and fisheries worldwide. Thus far, most studies conducted in this field have approached the problem from a “one parasite-one disease” perspective, notably with regards to commercially relevant clam species, while the impact of other Perkinsus species should also be considered as it could play a key role in the disease phenotype and dynamics. Co-infection of P. olseni and P. chesapeaki has already been sporadically described in Manila clam populations in Europe. Here, we describe for the first time the parasitic distribution of two Perkinsus species, P. olseni and P. chesapeaki , in individual clam organs and in five different locations across Arcachon Bay (France), using simultaneous in situ detection by quantitative PCR (qPCR) duplex methodology. We show that P. olseni single-infection largely dominated prevalence (46–84%) with high intensities of infection (7.2 to 8.5 log-nb of copies. g −1 of wet tissue of Manila clam) depending on location, suggesting that infection is driven by the abiotic characteristics of stations and physiological states of the host. Conversely, single P. chesapeaki infections were observed in only two sampling stations, Ile aux Oiseaux and Gujan, with low prevalences 2 and 14%, respectively. Interestingly, the co-infection by both Perkinsus spp., ranging in prevalence from 12 to 34%, was distributed across four stations of Arcachon Bay, and was detected in one or two organs maximum. Within these co-infected organs, P. olseni largely dominated the global parasitic load. Hence, the co-infection dynamics between P. olseni and P. chesapeaki may rely on a facilitating role of P. olseni in developing a primary infection which in turn may help P. chesapeaki infect R. philippinarum as a reservoir for a preferred host. This ecological study demonstrates that the detection and quantification of both parasitic species, P. olseni and P. chesapeaki , is essential and timely in resolving cryptic infections and their consequences on individual hosts and clam populations.
(Frontiers in Microbiology. vol. 14, n° 1664-302X, pp. 1250947, 08/01/2024)
LEMAR, IRD, IFREMER, UBO EPE, CNRS, CRIOBE, UPVD, EPHE, PSL, CNRS, SBR, SU, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ASIM, IFREMER
Remotely sensing potential climate change tipping points across scales
AbstractPotential climate tipping points pose a growing risk for societies, and policy is calling for improved anticipation of them. Satellite remote sensing can play a unique role in identifying and anticipating tipping phenomena across scales. Where satellite records are too short for temporal early warning of tipping points, complementary spatial indicators can leverage the exceptional spatial-temporal coverage of remotely sensed data to detect changing resilience of vulnerable systems. Combining Earth observation with Earth system models can improve process-based understanding of tipping points, their interactions, and potential tipping cascades. Such fine-resolution sensing can support climate tipping point risk management across scales.
(Nature Communications. vol. 15, n° 2041-1723, 06/01/2024)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Offshore evidence of historic and prehistoric tsunamis on the north shore of Tutuila (American Samoa)
Although research dealing with the geological evidence of past tsunamis has increased significantly in the last two decades, studies of tsunami deposits emplaced during the backwash phases are still underrepresented. Here, we provide the first investigation of tsunami backwash deposits all around an island (Tutuila Island, American Samoa), in the southwest of the Pacific Ring of Fire. We decipher the sedimentary record preserved offshore an open bay (Fagafue) and within a sheltered bay (Masefau) on the north shore of Tutuila. Backwash deposits of three historic tsunamis, namely the 2009 South Pacific, 1960 Valdivia and 1917 Tonga Trench tsunamis, were identified in sediment cores, based on sedimentological, geochemical and chronological data. Deposits were characterized by a geochemical terrestrial signature (Ti/Ca and K), while the grain size characteristics differed, being finer offshore the open bay and coarser within the sheltered bay. The 2009 South Pacific and the 1960 Valdivia tsunamis are recorded on both the north (Masefau and off Fagafue bays) and south (Pago Pago Bay) shores of Tutuila, providing the first correlation of tsunami backwash deposits all around an island. Furthermore, the present study presents the first geological evidence of backwash associated with a large 15-16th century tsunami, which also affected many parts of the South Pacific, as well as that of an older event between the 11th and 14th century. Studies of tsunami backwash deposits provide means to extend the geological record of these high energy events, due to the generally good preservation potential of the deposits.
(Sedimentary Geology, n° 0037-0738, pp. 106572, 05/01/2024)
LIENSs, INSU - CNRS, ULR, CNRS, BEES, UNSW, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS