|
|
|
| Registros recuperados: 118 | |
|
| |
|
| |
|
|
| Djeghri, Nicolas; Pondaven, Philippe; Stockenreiter, Maria; Behl, Stephan; Huang, Jessica Y. T.; Hansen, Thomas; Patris, Sharon; Ucharm, Gerda; Stibor, Herwig. |
| Mixotrophic organisms are increasingly recognized as important components of ecosystems, but the factors controlling their nutrition pathways (in particular their autotrophy–heterotrophy balance) are little known. Both autotrophy and heterotrophy are expected to respond to density‐dependent mechanisms but not necessarily in the same direction and/or strength. We hypothesize that the autotrophy–heterotrophy balance of mixotrophic organisms might therefore be a function of population densities. To investigate this relationship, we sampled mixotrophic jellyfish holobionts (host, Mastigias papua etpisoni; symbiont, Cladocopium sp.) in a marine lake (Palau, Micronesia) on six occasions (from 2010 to 2018). Over this period, population densities varied ~100... |
| Tipo: Text |
Palavras-chave: Density dependence; Jellyfish; Marine lakes; Mixotrophy; Stable isotopes; Symbiosis; Zooxanthellae. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00663/77469/79159.pdf |
| |
|
|
| Trystram, Clément; Roos, David; Guyomard, David; Jaquemet, Sébastien. |
| Understanding drivers of trophic partitioning at the community level is an essential prerequisite to the establishment of ecosystem-based management of fisheries. In this study, we identify drivers of trophic partitioning within a community of epipelagic fish and a community of deep-water fishes off Reunion Island. Effects of intrinsic (species identity, etc.) and environmental variables (fishing zone, month) on stomach content composition and stable isotope ratios were tested using regression trees and linear models respectively. Our results demonstrated firstly an independence of both communities, with very few common prey although they occurred in similar localities, and secondly, very different patterns of resources partitioning among each community.... |
| Tipo: Text |
Palavras-chave: Trophic partitioning; Deep-sea; Epipelagic; Predator; Stable isotopes; Stomach contents. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00353/46440/46184.pdf |
| |
|
|
| Le Bourg, B.; Banaru, Daniela; Saraux, Claire; Nowaczyk, A.; Le Luherne, E.; Jadaud, Angelique; Bigot, Jean-louis; Richard, P.. |
| Increasing abundance of non-commercial sprats and decreasing biomass and landings of commercial anchovies and sardines justify the need to study the feeding ecology and trophic niche overlap of these planktivorous species in the Gulf of Lions. Their diet has been investigated on the basis of stomach content and stable isotope analyses in 2011 and 2012 according to different depths and regions in the study area. The main prey were Corycaeidae copepods, Clauso/Paracalanus, Euterpina acutifrons and Microsetella, for sprats and small copepods, such as Microsetella, Oncaea and Corycaeidae, for anchovies and sardines. This is the first time that the diet of sprats is described in the Gulf of Lions. Sprats fed on a larger size spectrum of prey and seem to be more... |
| Tipo: Text |
Palavras-chave: Anchovies; Sardines; Sprats; North-western Mediterranean sea; Stomach contents; Stable isotopes. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00272/38314/38625.pdf |
| |
|
|
| Andersen, Nils; Lauterbach, Stefan; Erlenkeuser, Helmut; Danielopol, Dan L.; Namiotko, Tadeusz; Huels, Matthias; Belmecheri, Soumaya; Dulski, Peter; Nantke, Carla; Meyer, Hanno; Chapligin, Bernhard; Von Grafenstein, Ulrich; Brauer, Achim. |
| The so-called 8.2 ka event represents one of the most prominent cold climate anomalies during the Holocene warm period. Accordingly, several studies have addressed its trigger mechanisms, absolute dating and regional characteristics so far. However, knowledge about subsequent climate recovery is still limited although this might be essential for the understanding of rapid climatic changes. Here we present a new sub-decadally resolved and precisely dated oxygen isotope (5180) record for the interval between 7.7 and 8.7 ka BP 10(3) calendar years before AD 1950), derived from the calcareous valves of benthic ostracods preserved in the varved lake sediments of pre-Alpine Mondsee (Austria). Besides a clear reflection of the 8.2 ka event, showing a good... |
| Tipo: Text |
Palavras-chave: Holocene; Palaeoclimatology; Europe; Stable isotopes; 8.2 ka event; Lake sediments. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00504/61597/65876.pdf |
| |
|
|
| Day, Louise; Kopp, Dorothee; Robert, Marianne; Le Bris, Hervé. |
| Human activities affect continental shelves, especially due to the harvest of living marine resources. Understanding their functioning and dynamics has become a growing concern in recent decades, especially through use of trophic modelling approaches. Studying the feeding ecology of key component species also improves this understanding by providing accurate information on trophic processes, particularly the dependence on trophic pathways. This study focuses on the trophic ecology of four large gadiforms (cod, haddock, whiting and hake) found on the continental shelf of the Celtic Sea. The study combines information on recently ingested prey (gut content analysis) and a more integrated indicator of food sources (stable isotope analysis). Two size classes... |
| Tipo: Text |
Palavras-chave: Celtic Sea; Feeding; Gut content; Stable isotopes; Ontogeny; Habitat comparison. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00486/59742/62839.pdf |
| |
|
|
| Bauch, Henning A.; Erlenkeuser, Helmut. |
| Sediment cores from the Norwegian Sea were studied to evaluate interglacial climate conditions of the marine isotope stage 5e (MIS 5e). Using planktic forminiferal assemblages as the core method, a detailed picture of the evolution of surface water conditions was derived. According to our age model, a step-like deglaciation of the Saalian ice sheets is noted between ca. 135 and 124.5 Kya, but the deglaciation shows little response with regard to surface ocean warming. From then on, the rapidly increasing abundance of subpolar forminifers, concomitant with decreasing iceberg indicators, provides evidence for the development of interglacial conditions sensu stricto (5e-ss), a period that lasted for about 9 Ky. As interpreted from the foraminiferal records,... |
| Tipo: Text |
Palavras-chave: Holocene; Last interglacial; Nordic seas; Palaeoceanography; Planktic foraminifers; Stable isotopes. |
| Ano: 2008 |
URL: https://archimer.ifremer.fr/doc/00237/34811/33316.pdf |
| |
|
|
| Cresson, Pierre; Ruitton, Sandrine; Ourgaud, Melanie; Harmelin-vivien, Mireille. |
| A large complex of artificial reefs was deployed in the Bay of Marseilles, North-Western Mediterranean, for the enhancement of commercial fisheries stocks. Carbon and nitrogen stable isotope and stomach content analyses were performed on 23 fish species collected on the artificial reefs to assess their trophic position and feeding behaviour. Results indicated that fish diets were not modified on the artificial reefs compared to natural environments, nor was the structure of their trophic network. Artificial reefs, with their complex design, provide diverse and abundant food sources for fishes. Ranges of delta C-13 and delta N-15 of artificial reef fishes were comparable to those recorded in natural Mediterranean environments, with a similar trophic... |
| Tipo: Text |
Palavras-chave: Artificial reefs; Fish diet; NW Mediterranean; Stable isotopes; Stomach content; Trophic level. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00186/29708/28188.pdf |
| |
|
|
| Gueguen, Bleuenn; Rouxel, Olivier; Ponzevera, Emmanuel; Bekker, Andrey; Fouquet, Yves. |
| Although initial studies have demonstrated the applicability of Ni isotopes for cosmochemistry and as a potential biosignature, the Ni isotope composition of terrestrial igneous and sedimentary rocks, and ore deposits remains poorly known. Our contribution is fourfold: (a) to detail an analytical procedure for Ni isotope determination, (b) to determine the Ni isotope composition of various geological reference materials, (c) to assess the isotope composition of the Bulk Silicate Earth relative to the Ni isotope reference material NIST SRM 986 and (d) to report the range of mass-dependent Ni isotope fractionations in magmatic rocks and ore deposits. After purification through a two-stage chromatography procedure, Ni isotope ratios were measured by MC-ICP-MS... |
| Tipo: Text |
Palavras-chave: Nickel; Stable isotopes; MC-ICP-MS; Geological reference materials; Bulk Silicate Earth; Abiotic fractionation. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00159/27069/25332.pdf |
| |
|
| |
|
| |
|
| |
|
|
| Delaygue, G; Bard, E; Rollion, C; Jouzel, J; Stievenard, M; Duplessy, Jc; Ganssen, G. |
| We analyze the surface sigma O-18 - salinity relationships of the Bay of Bengal and the Arabian Sea, in the northern Indian Ocean, known for their contrasting hydrological conditions. New measurements of these tracers show a very low sigma O-18 - salinity slope associated with the strong dilution in the Bay of Bengal, but a slope more typical of this latitude in the Arabian Sea. Although this region is marked by a complex monsoonal regime, numerical modeling using a box model and a general circulation model is able to capture the sigma O-18 - salinity slope and its geographical variation. Both models clearly show that the low sigma O-18 - salinity slope is due to the evaporation-minus-precipitation balance, with an important contribution of the continental... |
| Tipo: Text |
Palavras-chave: Indian Ocean; Ocean/atmosphere interactions; Paleoclimatology; Stable isotopes. |
| Ano: 2001 |
URL: https://archimer.ifremer.fr/doc/00221/33225/31800.pdf |
| |
|
| |
|
| |
|
| |
|
|
| Guillermic, Maxence; Lalonde, Stefan; Hendry, Katharine R.; Rouxel, Olivier. |
| Although dissolved concentrations of germanium (Ge) and silicon (Si) in modern seawater are tightly correlated, uncertainties still exist in the modern marine Ge cycle. Germanium stable isotope systematics in marine systems should provide additional constraints on marine Ge sources and sinks, however the low concentration of Ge in seawater presents an analytical challenge for isotopic measurement. Here, we present a new method of pre-concentration of inorganic Ge from seawater which was applied to measure three Ge isotope profiles in the Southern Ocean and deep seawater from the Atlantic and Pacific Oceans. Germanium isotopic measurements were performed on Ge amounts as low as 2.6 ng using a double-spike approach and a hydride generation system coupled to... |
| Tipo: Text |
Palavras-chave: Stable isotopes; Germanium; Silicon; Sponges; Southern Ocean; Chemical oceanography. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00388/49956/50529.pdf |
| |
|
|
| Ritt, Benedicte; Duperron, Sebastien; Lorion, Julien; Lazar, Cassandre; Sarrazin, Jozee. |
| Recently, small Idas-like mussels have been discovered living on carbonate crusts associated with cold-seeps in the Marmara Sea. These mussels, here referred to as Idas-like nov. sp., differ morphologically and genetically from another species identified as Idas aff. modiolaeformis, living in the same type of ecosystem in the Nile Deep-Sea Fan (eastern Mediterranean Sea). A phylogenetic analysis confirms the distinction between the two species, which belong to highly divergent lineages. Carbon stable isotope values, as well as the detection of thiotroph-related bacteria in the gill tissue, support the presence of a symbiotic, thiotroph-derived nutrition. In contrast, Idas aff. modiolaeformis displays six different types of symbionts. Finally our... |
| Tipo: Text |
Palavras-chave: Mytilidae; Idas-like; Cold-seeps; Marmara Sea; Phylogeny; Symbiosis; Stable isotopes. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00098/20915/19672.pdf |
| |
|
|
| Issac, Pierre; Robert, Marianne; Le Bris, Hervé; Rault, Jonathan; Pawlowski, Lionel; Kopp, Dorothee. |
| We used stable isotope ratio and gut content analyses to determine and compare the feeding ecology of two commercially important predator species, Lophius piscatorius and Lophius budegassa in the Celtic sea, where data concerning their trophic ecology remain sparse. This study included two areas and two size-classes, showing that anglerfish in the Celtic sea are mainly piscivorous top predators as observed in other marine waters. However, a substantial part of the diet of the fish in the small size classes consists of benthic macro-invertebrates, mainly Crustaceans. Despite the common knowledge that they are opportunistic predators that display a low degree of prey selectivity, our results suggest that the two species have different trophic niches when... |
| Tipo: Text |
Palavras-chave: Lophius; Gut content; Stable isotopes; Trophic niche; Trophic segregation; Top predator. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00395/50614/51326.pdf |
| |
| Registros recuperados: 118 | |
|
|
|
