59615 résultat(s)
Hasenhündl Martin, Talling Peter j., Pope Ed l., Baker Megan l., Heijnen Maarten s.expand

Submarine canyons and channels are globally important pathways for sediment, organic carbon, nutrients and pollutants to the deep sea, and they form the largest sediment accumulations on Earth. However, studying these remote submarine systems comprehensively remains a challenge. In this study, we used the only complete-coverage and repeated bathymetric surveys yet for a very large submarine system, which is the Congo Fan off West Africa. Our aim [...]

Honfo Kodjo Jules, Chaigneau Alexis, Morel Yves, Duhaut Thomas, Marsaleix Patrickexpand

Seasonal water circulation and residence times in the large (150 km2) and shallow (1.3 m average dry season depth) Nokoué Lagoon (Benin) are analyzed by means of numerical simulations using the three-dimensional SYMPHONIE model. The average circulation during the four primary hydrological periods throughout the year are studied in detail. Despite the lagoon's shallowness, significant disparities between surface and bottom conditions are observed. [...]

Haubrock Phillip j., Soto Ismael, Ahmed Danish a., Ansari Ali r., Tarkan Ali Serhanexpand

Biological invasions pose a rapidly expanding threat to the persistence, functioning and service provisioning of ecosystems globally, and to socio-economic interests. The stages of successful invasions are driven by the same mechanism that underlies adaptive changes across species in general-via natural selection on intraspecific variation in traits that influence survival and reproductive performance (i.e., fitness). Surprisingly, however, the r [...]

Whitaker James Andrew, Armstrong Chelsey Geralda, Odonne Guillaume

This chapter examines perceptions and ontologies concerning climatic changes in the Makushi villages of Surama and Yupukari and in the Akawaio village of Kamarang/Warawatta in Guyana. In 2021, these villages experienced reportedly unprecedented flooding that severely disrupted cassava-based agriculture and was attributed by many villagers to climate change. In addition to flooding, villagers also report recent seasonal irregularities, such as unp [...]

Buck Clifton, Fietz Susanne, Hamilton Douglas, Ho Tung-Yuan, Perron Morganeexpand

The international GEOTRACES program has allowed unprecedented access to aerosols in the remote marine environment, moved the community toward standardized methodologies, and contributed to expanding research capabilities around the globe. A key aspect of GEOTRACES aerosol research is the quantification of deposition fluxes of trace elements and isotopes to the surface ocean as a source for biolimiting nutrients and anthropogenic contaminants. New [...]

This study investigates spatiotemporal dynamics in metal sedimentation in the North American Great Lakes and their underlying biogeochemical controls. Bulk geochemical and isotope analyses of n = 72 surface and core sediment samples show that metal (Cu, Zn, Pb) concentrations and their isotopic compositions vary spatially across oligotrophic to mesotrophic settings, with intra-lake heterogeneity being similar or higher than inter-lake (basin-scal [...]

It is commonly assumed that beach seining (BS) is more sustainable than bottom trawling because it involves non-motorized operations and limited fishing power. However, no scientific evidence supports this assumption. To address this gap, we evaluated the impact of beach seining, taking a small-scale shrimp fishery in northeast Brazil. Data collected monthly from December 2016 to November 2017 and in literature, were assessed (BS 31,001 individua [...]

Auguin Erwan, Guinet Christophe, Mourier Johann, Clua Eric, Gasco Nicolasexpand

Intra-population heterogeneity in the behavioural response of predators to changes in prey availability caused by human activities can have major evolutionary implications. Among these activities, fisheries, while extracting resources, also provide new feeding opportunities for marine top predators. However, heterogeneity in the extent to which individuals have responded to these opportunities within populations is poorly understood. Here, we use [...]

Yang Xinyu, Li Tao, Chen Tianyu, Zheng Jianfan, Li Wei

Knowledge of silicic acid concentrations at the surface Southern Ocean helps better understand the role of the biological pump in regulating atmospheric CO2 concentrations in the past. While the silicon isotope compositions of diatom provide a measure of Si utilization efficiency, proxies on surface silicic acid concentration are not yet available. Here we determined the diatom frustule Al/Si ratio and dust flux to constrain the surface silicic a [...]

Junqueira Tassiane p., Vriens Bas, Leybourne Matthew i., Harrison Anna l., Sullivan Kaj v.expand

Zinc (Zn) is an essential trace element that is involved in both biotic and abiotic processes in Earth's surface environments. Over the last 20 years, advances in mass spectrometry instrumentation have enabled unprecedented high-precision Zn isotope abundance ratio determinations in natural and anthropogenic samples. Supported by a solid theoretical background inherited from the traditional non-metal stable isotopes (C, N, H, O, S), the understan [...]

Huguet Antoine, Petitgas Pierre, Dorand Marine, Ozanam Baptiste

Ce livrable présente les travaux effectués sur le golfe de Gascogne concernant la dynamique de plusieurs variables environnementales sur une vingtaine d’années. Les travaux ont porté sur la température et la chlorophylle a. Deux méthodologies ont été employées, l’une utilisant les fonctions empiriques orthogonales, l’autre les modèles linéaires dynamiques. Ces deux approches et les résultats associés sont décrits dans les résumés ci-dessous. Dyna [...]

Depuis 2008, le paramètre « macroalgues subtidales » est surveillé sur 3 stations de la masse d’eau FRFC11 « Côte basque ». Dans le cadre du 2ème cycle de suivi DCE, depuis 2014, des métriques complémentaires sont calculées, comme pour l'ensemble de la façade Manche/Atlantique. Ces métriques ont été mesurées pour la quatrième fois en 2023 et ont pour objectif d'optimiser les informations collectées pour évaluer l'état écologique des masses d'eau [...]

Verrez-Bagnis Véronique, Silva Helena, Mendes Rogério

Seafood product fraud, involving the addition of “foreign” proteins by substituting all or part of a seafood species for another seafood species or for non-seafood proteins, has attracted much attention because it is widespread throughout the world and may have serious consequences in terms of public health and major economic losses. Therefore, there is a great need for methods to detect illegal substitutions, whether full or partial, or adultera [...]

Les données OBSDEB, collectées sur la base d’un plan d’échantillonnage aléatoire sont analysées par des méthodes issues de la théorie des sondages. La méthodologie de collecte et d’estimation est décrite dans le document Weiss J., Demaneche S., Guyader O., 2020 disponible en accès libre sur Archimer: https://archimer.ifremer.fr/doc/00471/58281/ En Martinique, le programme OBSDEB a démarré en 2008. Jusqu’en 2017, il s’appliquait à l’ensemble des n [...]

Dauvin Jean-Claude, Zarrouki Assia, Boutet Martial, Bennis Anne-Claire

The aim of this study is to analyse and model the dispersal of Ampelisca, a benthic genus of amphipod crustaceans, in the fine sand community of the Bay of Morlaix (western English Channel), during their nocturnal migration in the water column. Based on sampling of the suprabenthos (in the water column adjacent to the bottom) and surface plankton on 17 June 1994, Dauvin and Zouhiri (1996) studied the vertical distribution of Ampelisca during a sp [...]

Barhdadi Mohammed, Mouret Aurélia, Barras Christine, Schmidt Sabine, Maillet Grégoire m.expand

The study of manganese (Mn) and iron (Fe) cycling in early diagenetic processes in estuaries is crucial for understanding the functioning of these vital ecosystems and predicting their responses to environmental change. The present study investigates the dynamic interplay of Mn and Fe in early diagenetic processes at highly contrasted hydrosedimentary conditions in the Loire estuary, which is very rare and allows a comprehensive framework to unde [...]

Les masses d’eau de transition (MET) font l’objet de suivi de macroalgues qui constituent l’un des éléments de qualité biologique pour définir l’état écologique d’une masse d’eau au sens de la Directive Cadre sur l’Eau (DCE). Ce suivi comprend les macroalgues de substrats durs et les banquettes à Vaucheria des substrats meubles de la zone intertidale. Sur la côte basque, la masse d’eau de transition suivie est la partie aval de l’Adour FRF07 « Ad [...]

Depuis de nombreuses années, l’Ifremer assure le suivi de la coquille Saint-Jacques. Afin d’établir un diagnostic annuel sur l’état du stock de coquilles Saint-Jacques de la baie de Seine, une évaluation directe de la ressource est menée chaque année. Les données recueillies lors des campagnes annuelles d'évaluation directe COMOR sont à la base de l'expertise. Les résultats obtenus permettent à la profession et à l’Administration des pêches d’avo [...]