Content-Length: 238312 | pFad | https://archimer.ifremer.fr
Variation in reproductive success is a fundamental prerequisite for sexual selection to act upon a trait. Assessing such variation is crucial in understanding a species’ mating system and offers insights into population growth. Parentage analyses in cetaceans are rare, and the underlying forces of sexual selection acting on their mating behaviours remain poorly understood. Here, we combined 25 years of photo-identification and genetic data to ass [...]
Marine aerosol observations from 6 shipborne campaigns carried out in 2021 and 2023 in the southwest Indian Ocean are presented. A set of aerosol instruments is used to study the spatial and temporal variability of the aerosol size distribution, cloud condensation nuclei (CCN), activation diameters, and hygroscopicity (κ). Total number of aerosols (Na) shows concentration above 1500 cm-3 in polluted areas, and between 100–1500 cm-3 in the open oc [...]
Fish spawning aggregations (FSAs) are critical events in the life cycle of many commercially and ecologically important species, yet FSAs are often exploited and highly vulnerable to fishing due to their predictability in time and space. Although FSAs are increasingly recognized as a conservation and management priority, monitoring these ephemeral dynamic events remains challenging. Here, we assessed the ability of remote underwater video (RUV) t [...]
Humans are exposed to toxic methylmercury mainly by consuming marine fish, in particular top predator species like billfishes or tunas. In seafood risk assessments, mercury is assumed to be mostly present as organic methylmercury in predatory fishes; yet high percentages of inorganic mercury were recently reported in marlins, suggesting markedly different methylmercury metabolism across species. We quantified total mercury and methylmercury conce [...]
We investigated MP ingestion in lanternfishes (Myctophidae), one of the most abundant vertebrates in the world, using archived specimens from museum collections from 1999 to 2017. Microplastics were detected in 55% of the 1167 specimens analysed (0.95 ±1.22 MP individual-1). Global plastic production has increased by about 53% during this period. Interestingly, almost half of the lanternfishes analysed contained at least one particle in the gastr [...]
In polar and temperate regions seasonality in environmental conditions is an important driver of animal phenology. In tropical systems, where the environment is relatively homogeneous year-round, the link between phenology and seasonality is weakened, and many species breed asynchronously or even year-round. This leads to the question of how these species adapt to seasonal changes, which remain present albeit to a lesser extent. To assess relatio [...]
The environmental DNA (eDNA) technique characterizes spatio-temporal fish diversity patterns along estuarine habitats, such as hard-to-reach mangroves, yet it has rarely been applied in West Africa. In this study conducted over two seasons (dry and rainy) in coastal Guinea Bissau, fish eDNA was extracted from water samples collected in three habitats with distinct human uses. These habitats included site-specific mangroves, rice fields, and trans [...]
In this study, we investigated the role of atmospheric and oceanographic variability in shaping surface Marine Heatwaves (MHWs) in the Northern Humboldt Current System (NHCS) over the last two decades. Through a series of pluriannual hydrodynamic model simulations, we highlighted the importance of considering at least high-frequency atmospheric variability to accurately reproduce the observed MHW characteristics. On the contrary, when synoptic at [...]
Les peptidases TET sont des aminopeptidases géantes présentes dans les trois domaines du vivant. Elles sont supposées intervenir dans la protéolyse intracellulaire, en aval du protéasome. Des études structurales ont montré que ces enzymes forment des complexes tétraédriques dodécamériques creux. Chez les Archées, les peptidases TET ont principalement été étudiées chez des espèces de l’ordre des Thermococcales, révélant quatre types distincts de T [...]
Report of the EuroGOOS DataMEQ Working Group Meeting, hybrid meeting hosted by INGV, Bologna
Since 2011, massive strandings of Sargassum (brown alga) have significantly affected Caribbean islands causing major health, environmental and economic problems. Amongst them, the degradation of algae releases corrosive gases, hydrogen sulphide (H2S) and ammonia (NH3) which causes an accelerated corrosion of the metallic structures of these coastal areas. The aim of this study was to quantify the impact of Sargassum strandings on the corrosion of [...]
Phytoplankton supports food webs in all aquatic ecosystems. Ecological studies highlighted the links between environmental variables and species successions in situ. However, the role of life cycle characteristics on phytoplankton community dynamics remains poorly characterized. In diatoms, sexual reproduction creates new genetic combinations and prevents excessive cell size miniaturisation. It has been extensively studied in vitro but seldom in [...]
The Kuroshio Current significantly influences the exchange of physical, chemical, and biological properties in the western Pacific Ocean, while its strength and path in the Okinawa Trough during the Holocene remains unclear. Previous studies have not established consistent conclusions due to the existence of multiple solutions for sediment provenance proxies, but these inconsistencies can potentially be addressed by identifying early diagenetic e [...]
Understanding the mechanisms underlying nutrient (nitrogen and phosphorus) and carbon cycling in reefs is critical for effective management. Research on reef nutrient and carbon cycling needs to account for (i) the contributions of multiple organisms, (ii) abiotic and biotic drivers, and (iii) a social-ecological perspective. In this paper, we review the mechanisms underlying nutrient and carbon cycling in reef social-ecological systems and analy [...]
The comparability of methods applied to environmental DNA (eDNA) samples across laboratories remains a significant challenge for biodiversity monitoring on a global scale. Performance differences between protocols can jeopardize effective conservation strategies across regions and focal species. To address potential discrepancies amongst four international partners within a collaborative eDNA initiative, an inter-laboratory comparison (i.e., ring [...]
Given the significant ecosystem services provided by benthic communities, monitoring their biodiversity enable to better understand how global changes would affect their structure in a context of biodiversity loss. Using underwater video transect, we characterize alpha and beta diversity of epibenthic communities, their structure and forcing factors in St. Pierre Bank; an area where marine benthos is still poorly documented. Video monitoring enab [...]
Le projet DEFIPEL s’est déroulé entre septembre 2019 et juillet 2024. Il s’agit d’un projet de recherche ayant pour but d’analyser la structure et la dynamique de la filière française des petits pélagiques, en intégrant les composantes habitat, ressource (sardine et anchois principalement), pêcheries et filière aval avec notamment l’industrie de la conserve. C’est un projet national qui s’est intéressé aux 3 façades maritimes métropolitaines : la [...]
La compréhension du fonctionnement des écosystèmes est importante pour prédire, gérer et protéger les écosystèmes dans lesquels nous vivons et dont nous dépendons. Cette thèse y apporte une contribution en scrutant le compartiment zooplanctonique, qui joue un rôle crucial – quoiqu’encore largement méconnu – dans le fonctionnement des écosystèmes marins, et plus particulièrement les cycles biogéochimiques et le transfert trophique. La présente thè [...]
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