Does parasitism influence sediment stability? Evaluation of trait-mediated effects of the trematode Bucephalus minimus on the key role of cockles Cerastoderma edule in sediment erosion dynamics
In coastal environments, bioturbators greatly influence the physical and biogeochemical properties of sediments with consequences for central ecological processes such as erosion dynamics. In addition to their direct impact on sediment stability, bioturbators can have an impact on sediment erosion processes by modulating the growth of microphytobenthic organisms that stabilise the surface layer of sediments. The direct and indirect influences of bioturbators on sediment dynamics depend on the magnitude of their activity and inherently on their physiological state. Bioturbators are infected by various parasites, which have a substantial impact on their physiology and behaviour. However, the knock-on effects of parasites on key ecosystem functions like sediment dynamics remain poorly studied. We conducted flume experiments to investigate the indirect influence of the trematode Bucephalus minimus parasitising the common cockle Cerastoderma edule on the dynamics of sandy sediments enriched or not with microphytobenthos (MPB). Cockles modified bed roughness, sediment surface erodibility and hence destabilised sandy sediments. In sediments not enriched with MPB, both unparasitised and parasitised organisms had a similar impact on the stability of sandy sediments. In contrast, parasitism slightly reduced the destabilisation effect of cockles in MPB-enriched sediments. In the latter, parasitised cockles did not interfere with MPB growth whereas unparasitised organisms constrained the microalgae development. However, the enrichment of the surface layers of sandy sediments with MPB did not modulate the erosion dynamics of these environments. Thus, the lower destabilisation effect of parasitised cockles was not here linked to a stabilisation effect of MPB. When standardised for length, parasitised cockles were lighter than unparasitised organisms. Weakened cockles may have had a lower bioturbation potential than unparasitised conspecifics. If so, the influence parasitised cockles had on sediment erodibility and sediment roughness may have been reduced. The absence of a parasitism effect on the dynamics of MPB-unenriched sediments remains nonetheless unclear.
(Science of the Total Environment. vol. 733, n° 0048-9697, pp. 139307, 02/09/2026)
BOREA, UNICAEN, NU, MNHN, IRD, SU, CNRS, UA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CHRU Besançon
Contrasting responses of different functional groups stabilize community responses to a dominant shrub under global change
Changes in precipitation regimes and nitrogen deposition levels due to global change are altering terrestrial ecosystems worldwide. Most attempts at understanding how biotic interactions affect plant species and community responses to global change have focused on biotic interactions measured at the community level. However, these approaches ignore that communities include functionally dissimilar species that might respond differently to changes in the effects of dominant neighbours along environmental gradients. We test the hypothesis that plant species with differences in functional traits may exhibit contrasting interactions with a dominant shrub species within a single community, thereby stabilizing community-level responses to the effects of global change. We manipulated water and nitrogen applications in a semi-arid dune community in northern China, quantified the biomass of herbaceous species occurring below the dominant shrub, Artemisia ordosica, and in adjacent open patches (without the shrub), and measured herbaceous species height and leaf dry matter content. The effects of A. ordosica were quantified at the species, group and community levels using the relative interaction index (RII). Redundancy analysis was performed on species traits and the RII values to assess the relationships between functional differences in species and plant–plant interactions. Species were then grouped using a cluster analysis and the RII values were recalculated at the group level. The redundancy analysis showed that species height and leaf dry matter content were significantly correlated to the changes in species' responses to the effect of A. ordosica along treatments. The four groups of species identified by the cluster analysis showed contrasting variations in competitive or facilitative responses depending on species traits and environmental treatments. However, the interactions measured at the group level balanced the community-level responses, as we found no significant changes in the effects of A. ordosica along treatments for community biomass, richness and functional diversity indices. Synthesis. Our findings indicate that species with different functional strategies within a community exhibit contrasting responses to a dominant shrub along environmental gradients. These contrasting changes in plant–plant interactions of functionally different species may balance the responses of community-level metrics. This suggests that functional differences between species groups and the balance of plant–plant interactions stabilize community responses to global change. © 2021 British Ecological Society
(Journal of Ecology. vol. 109, n° 0022-0477, pp. 1676-1689, 02/09/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Seismo‐Turbidites in Aysén Fjord (Southern Chile) Reveal a Complex Pattern of Rupture Modes Along the 1960 Megathrust Earthquake Segment
Grainsize analysis and end-member modeling of a long sediment core from Aysen Fjord (southern Chile) allows to identify over 25 seismo-turbidites in the last 9,000 years. Considering the shaking intensities required to trigger these turbidites (V1/2-VI1/2), the majority can be related to megathrust earthquakes. Multiple studies in south-central Chile have aimed at finding traces of giant, tsunamigenic megathrust earthquakes leading to the current 5,500-year-long paleoseismological record of the Valdivia segment. However, none of these cover the southern third of the segment. Aysen Fjord allows to fill this data gap and presents the first, crucial paleoseismic data to demonstrate that the 1960 event was not unique for the Valdivia segment, yielding a recurrence rate of 321 116 years in the last two millennia. Moreover, the oldest identified events in Aysen Fjord date back to 9,000 cal years BP and, thus, also extend the regional paleoseismological record in time. We infer a large temporal variability in rupture modes, with successions of full-segment ruptures alternating with partial and cascading ruptures. The latter seems to significantly postpone the occurrence of another full rupture when consecutively occurring in different parts of the segment. Additionally, one outstanding period of seismic quiescence-during which no megathrust earthquake evidence has been found at any paleoseismic site-occurred after a full rupture in AD similar to 745 that presents an unusual uplift/subsidence pattern. Such variability makes it highly speculative to anticipate the rupture mode of the next megathrust earthquake along the Valdivia segment.
(Journal of Geophysical Research : Solid Earth. vol. 125, n° 2169-9313, 02/09/2026)
UGent, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, CLIMAG, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, GEOPS, INSU - CNRS, CNRS, UB
Organotropism and biomarker response in oyster Crassostrea gigas exposed to platinum in seawater
Platinum (Pt) is a technology critical element (TCE) for which biogeochemical cycles are still poorly understood. This lack of knowledge includes Pt effects on marine organisms, which proved to be able to bioconcentrate this trace element. Oysters Crassostrea gigas were exposed to stable Pt isotope spiked daily in seawater for 35 days. Seawater was renewed daily and spiked (with Pt(IV)) to three nominal Pt concentrations (50, 100, and 10,000 ng L−1) for two replicate series. Organotropism study revealed that gills, and to a lesser extent mantle, are the key organs regarding Pt accumulation, although a time- and concentration-dependent linear increase in Pt levels occurred in all the organs investigated (i.e., digestive gland, gonads, gills, mantle, and muscle). In oysters exposed to Pt concentrations of 10,000 ng L−1, significant biomarker impairments occurred, especially at cellular levels. They reflect altered lipofuscin and neutral lipid contents, as well as intralysosomal metal accumulation. These observations were attributed to activation of excretion/detoxification mechanisms, including Pt elimination through feces and clearly support the importance of the digestive gland in the response to direct Pt exposure. Despite relatively constant condition index, the integrative biological response (IBR) index suggests a generally decreasing health status of oysters
(Environmental Science and Pollution Research. vol. 27, n° 0944-1344, pp. 3584-3599, 02/09/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UPV / EHU
Foraminiferal community response to seasonal anoxia in Lake Grevelingen (the Netherlands)
Over the last decades, hypoxia in marine coastal environments has become more and more widespread, prolonged and intense. Hypoxic events have large consequences for the functioning of benthic ecosystems. In severe cases, they may lead to complete anoxia and the presence of toxic sulfides in the sediment and bottom-water, thereby strongly affecting biological compartments of benthic marine ecosystems. Within these ecosystems, benthic foraminifera show a high diversity of ecological responses, with a wide range of adaptive life strategies. Some species are particularly resistant to hypoxia-anoxia, and consequently it is interesting to study the whole foraminiferal community as well as species-specific responses to such events. Here we investigated the temporal dynamics of living benthic foraminiferal communities (recognised by CellTracker™ Green) at two sites in the saltwater Lake Grevelingen in the Netherlands. These sites are subject to seasonal anoxia with different durations and are characterised by the presence of free sulfide (H 2 S) in the uppermost part of the sediment. Our results indicate that foraminiferal communities are impacted by the presence of H 2 S in their habitat, with a stronger response in the case of longer exposure times. At the deepest site (34 m), in summer 2012, 1 to 2 months of anoxia and free H 2 S in the surface sediment resulted in an almost complete disappearance of the foraminiferal community. Conversely, at the shallower site (23 m), where the duration of anoxia and free H 2 S was shorter (1 month or less), a dense foraminiferal community was found throughout the year except for a short period after the stressful event. Interestingly, at both sites, the foraminiferal community showed a delayed response to the onset of anoxia and free H 2 S, suggesting that the combination of anoxia and free H 2 S does not lead to increased mortality , but rather to strongly decreased reproduction rates. At the deepest site, where highly stressful conditions prevailed for 1 to 2 months, the recovery time of the community takes about half a year. In Lake Grevelingen, Elphidium selseyense and Elphidium magellanicum are much less affected by anoxia and free H 2 S than Ammonia sp. T6. We hypothesise that this is not due to a higher tolerance for H 2 S, but rather related to the seasonal availability of food sources, which could have been less suitable for Ammonia sp. T6 than for the elphidiids.
(Biogeosciences. vol. 17, n° 1726-4170, pp. 1415-1435, 02/09/2026)
LPG-ANGERS, LPG, UA, UN UFR ST, UN, INSU - CNRS, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LPG, UA, UN UFR ST, UN, INSU - CNRS, CNRS, NIOZ
Pour un hommage au Professeur Sergueï Gorchkov et une introduction à la géoécologie russe
Cet article est à la fois un témoignage concernant le parcours de vie du professeur Sergei Gorchkov (1932-2018), l’un des pionniers de la géoécologie russe, et l’essai de finalisation d’un article scientifique qu’il avait laissé inachevé. Les deux premières parties, biographiques, révèlent des anecdotes inédites sur la vie de Sergueï Gorchkov, qu’il a lui-même racontées aux auteurs, et elles mettent l’accent sur ses missions de terrain en Sibérie, qui furent le point de départ de ses réflexions sur l’unicité et la globalité de l’environnement géographique. A l’instar de la pédologie pour Dokoutchaev, la science du pergélisol est devenue pour Sergueï Gorchkov le creuset de toutes les composantes environnementales. Pour comprendre l’évolution de la cryolithozone sibérienne, ce géomorphologue intégra les recherches en climatologie, en biogéographie et en hydrologie. Sa collaboration scientifique avec ses collègues géologues le conduisit à étudier les échelles de temps les plus longues et à se passionner pour les paléo-environnements. La troisième partie, directement scientifique, s’attache aux conséquences de la tendance au remplacement de la croûte océanique par la croûte continentale. Ainsi, les sphères inorganiques et biogéniques évoluent en sens opposé. La première se débarrasse de l’excès d’énergie cristallochimique contenue dans la matière inerte du manteau terrestre. La seconde, tout en se complexifiant, augmente son potentiel énergétique lié aux associations minérales du socle métamorphique et à sa couverture sédimentaire riche en énergie solaire accumulée par les facteurs biogéniques. Si l’on considère que la géoécologie doit reposer sur une meilleure compréhension de l’homéostasie de la biosphère, il convient d’étudier ce qui peut-être considéré comme une sorte de résilience du plus haut niveau d’organisation, d’échelle mondiale, à ceci près que la résilience au sens strict conduit à un retour à l’équilibre initial, tandis que l’homéostasie mène à un nouvel équilibre. Par son échelle globale, la fonction homéostatique de biofiltration productive de l’océan domine toutes les autres. Grâce à elle, le rayonnement solaire pénètre dans l’océan. Cette réserve de chaleur est transférée par advection aux masses d’air, qui se déchargent de leur humidité au-dessus des continents et augmentent ainsi la biomasse des écosystèmes terrestres. Les grands fleuves reçoivent et transportent plus de matière organique vers les mers et le cycle continue. La combinaison de la densité du couvert végétal sur les continents, de la production primaire de phytoplancton et de la filtration du zooplancton océanique est au cœur de la fonction homéostatique de la biosphère. Géographiquement, c’est cette zone de contact qui représente l’interface planétaire majeure. Du point de vue de la géomorphologie continentale, il s’agit du milieu marin sous l’influence des embouchures fluviales ; du point de vue de l’océanographie, c’est le filtre marginal (tel que déterminé par l’océanologue russe Lisitsyn). S. Gorchkov écrivait que le « signal intégré » des écosystèmes terrestres et océaniques se trouvait dans ces mers épicontinentales. Cet article y ajoute une comparaison de l’importance des apports en éléments nutritifs par les upwellings et par les grands bassins fluviaux à dense couverture végétale.
(Dynamiques Environnementales - Journal international des géosciences et de l’environnement. vol. 46, n° 1968-469X, pp. 148-183., 02/09/2026)
CEDETE, UO
Oxythermal window drastically constraints the survival and development of European sturgeon early life phases
Oxythermal window drastically constraints the survival and development of European sturgeon early life phases
(Environmental Science and Pollution Research. vol. 27, n° 0944-1344, pp. np, 02/09/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UB, INRA, ONEMA, UR EABX, INRAE, PAnTher, Oniris VetAgroBio, INRAE
Transfer and Transcriptomic Profiling in Liver and Brain of European Eels ( Anguilla anguilla ) After Diet‐borne Exposure to Gold Nanoparticles
A nanometric revolution is underway, promising technical innovations in a wide range of applications and leading to a potential boost in environmental discharges. The propensity of nanoparticles (NPs) to be transferred throughout trophic chains and to generate toxicity was mainly assessed in primary consumers, whereas a lack of knowledge for higher trophic levels persists. The present study focused on a predatory fish, the European eel (Anguilla anguilla) exposed to gold NPs (AuNPs; 10 nm, polyethylene glycol–coated) for 21 d at 3 concentration levels in food: 0 (NP0), 1 (NP1), and 10 (NP10) mg Au kg−1. Transfer was assessed by Au quantification in eel tissues, and transcriptomic responses in the liver and brain were revealed by a high‐throughput RNA‐sequencing approach. Eels fed at NP10 presented an erratic feeding behavior, whereas Au quantification only indicated transfer to intestine and kidney of NP1‐exposed eels. Sequencing of RNA was performed in NP0 and NP1 eels. A total of 258 genes and 156 genes were significantly differentially transcribed in response to AuNP trophic exposure in the liver and brain, respectively. Enrichment analysis highlighted modifications in the immune system–related processes in the liver. In addition, results pointed out a shared response of both organs regarding 13 genes, most of them being involved in immune functions. This finding may shed light on the mode of action and toxicity of AuNPs in fish.
(Environmental Toxicology and Chemistry. vol. 39, n° 0730-7268, pp. 2450-2461, 02/09/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IRSN/PRP-ENV/SERIS/LECO, IRSN/PRP-ENV/SERIS, IRSN, GENOTOUL, UT3, Comue de Toulouse, ENVT, Toulouse INP, INSERM, CNRS, Toulouse INP, Comue de Toulouse, INRAE, MIAT INRAE, INRAE, INRAE, GET, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS, ICMCB, UB, INC-CNRS, CNRS
Collateral diseases: Aquaculture impacts on wildlife infections
Aquaculture is a promising source of fish and other aquatic organisms to ensure human food security but it comes at the price of diverse environmental impacts. Among others, these include diseases which often thrive under the conditions in aquaculture settings and can cause high economic losses. These diseases may also affect wildlife, however, the impacts of aquaculture on disease dynamics in wild species in surrounding ecosystems are poorly understood. In this Review, we provide a conceptual framework for studying the effects of aquaculture on wildlife diseases, and illustrate the different mechanisms identified with examples from the literature. In addition, we highlight further research needs and provide recommendations for management and policy. We identified five potential means by which farmed populations may alter wildlife disease dynamics: (a) farmed species may co-introduce parasites to the new environment, which infect wild conspecifics without infecting other species (intraspecific parasite spillover); (b) these co-introduced parasites from farmed species may infect other wild host species potentially leading to emerging diseases (interspecific parasite spillover); (c) parasites from other wild host species may infect farmed species, amplifying parasite numbers and increasing parasite infections when spilling back to wild hosts (interspecific parasite spillback); (d) farmed species may acquire parasites from wild conspecifics, increasing parasite population size and subsequently raising infection loads in the wild host population (intraspecific parasite spillback); and (e) farmed species may be neither hosts nor parasites, but affect the transmission of parasites between wild host species (transmission interference). Although these mechanisms can alter wildlife disease dynamics, we found large knowledge gaps regarding collateral disease impacts and strong biases in terms of production countries, aquaculture practices and host taxa. Synthesis and applications. The strong potential for aquaculture to affect the dynamics of diseases in wildlife populations calls for the consideration of collateral disease impacts in risk assessments and biosecurity protocols regarding aquaculture. In particular, comprehensive parasite inventories of both farmed and wild hosts as well as disease monitoring in wildlife surrounding farms will be necessary to increase our knowledge on aquaculture impacts on wildlife disease and to develop adequate prevention and mitigation measures. © 2020 The Authors. Journal of Applied Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society
(Journal of Applied Ecology. vol. 58, n° 0021-8901, pp. 453-464, 02/09/2026)
NIOZ, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Health indicators and contaminant levels of a critically endangered species in the Gironde estuary, the European sturgeon
The European sturgeon, Acipenser sturio, is a highly endangered species that almost disappeared in the last decades. Thanks to yearly restocking of the population, this species is still found in the Gironde estuary (France), where juveniles grow during several years before leaving to the ocean. The aims of this study were to evaluate the pressure exerted on these fish by known organic and inorganic contaminants during their stay at the Gironde estuary, and to get information on the fish's health in this context. Monthly captures over the year 2014 provided 87 fish from the cohorts 2012 and 2013 mainly, and from cohorts 2008, 2009, and 2011, all fish born in hatchery. We report the very first analyses of contaminant levels and of biological markers measured in the blood of these fish.
(Environmental Science and Pollution Research. vol. 27, n° 0944-1344, pp. 3726-3745, 02/09/2026)
UR EABX, INRAE, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LEESA, UB, CNRS, LEFE, INEE-CNRS, CNRS, UT3, Comue de Toulouse, CNRS, Toulouse INP, Comue de Toulouse