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| Registros recuperados: 369 | |
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| Fripiat, Francois; Corvaisier, Rudolph; Navez, Jacques; Elskens, Marc; Schoemann, Veronique; Leblanc, Karine; Andre, Luc; Cardinal, Damien. |
| Regional and seasonal variability of the Si dissolution: production ratios in the surface ocean have not been well assessed. Here, we propose a new method for determining these rates, using the Si-30-isotopic dilution technique with a high-resolution sector field inductively coupled plasma mass spectrometer (HR-SF-ICP-MS). Relative analytical precision of the isotopic measurement is better than 1%, similar to that obtained by thermal ionization-quadrupole mass spectrometry (TIMS). Accuracy and reproducibility of the isotopic measurements have been checked on artificial and natural solutions by intercomparison between two HR-SF-ICP-MS instruments and one TIMS. Measurements of real Si production and dissolution rates are illustrated for two contrasted... |
| Tipo: Text |
Palavras-chave: Isotopic fractionation; Southern ocean; Acid uptake; Waters; Phytoplankton; Environments; Biosilica; Recovery; Balance; Tracer. |
| Ano: 2009 |
URL: https://archimer.ifremer.fr/doc/00205/31607/30033.pdf |
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| Lefebvre, Alain; Devreker, David. |
| The first quantitative and comprehensive assessment of the eutrophication status from coastal to offshore French waters was performed within the Marine Strategy Framework Directive (MSFD descriptor 5) for the English Channel, the southern bight of the North Sea, the Celtic Seas, the Bay of Biscay and the Western Mediterranean Sea. Based on a combination of different data sources (in situ, satellite, and modeling products), a fully-integrated dataset was generated over the period 2010–2016. Using the best available knowledge on the eutrophication process and definition, the assessment procedure was implemented considering nutrient pressures, and direct and indirect effects of excessive inputs. The different steps of the assessment were: (i) Establishment of... |
| Tipo: Text |
Palavras-chave: Eutrophication; Assessment; Marine Strategy Framework Directive (MSFD); Water Framework Directive (WFD); Oslo and Paris Convention (OSPAR); English Channel; Celtic Seas; Bay of Biscay; Mediterranean Sea; Nutrients; Chlorophyll; Oxygen; Turbidity; Phytoplankton; Macro-algae. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00641/75350/76083.pdf |
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| Belin, Catherine; Raffin, Bernard. |
| This document presents the results obtained through the French Phytoplankton and Phycotoxins Monitoring Network (REPHY), concerning the presence of toxic and harmful phytoplankton species along the French coast, from 1984 to 1995. The network REPHY is briefly described. Then the different species, and their associated events, are reviewed : first, species toxic to shellfish consumers, e.g. Dinophysis spp. and Alexandrium minutum, which respectively produce diarrheic and paralytic toxins ; then, species which are toxic or harmful for marine fauna (fish, shellfish). The monitoring results are preceded by the main knowledge on taxonomy, distribution, biology, ecology and toxicity of the concerned species. A final synthesis illustrates the distribution of... |
| Tipo: Text |
Palavras-chave: Phytoplancton; Phycotoxines; Surveillance; Espèces toxiques; Espèces nuisibles; Dinophysis; Alexandrium; DSP; PSP; Secteurs fermés; Phytoplankton; Phcotoxins; Monitoring; Toxic species; Harmful species; Dinophysis; Alexandrium; DSP; PSP; Closed areas. |
| Ano: 1998 |
URL: http://archimer.ifremer.fr/doc/00094/20514/18184.pdf |
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| Gohin, Francis; Van Der Zande, Dimitry; Tilstone, Gavin; Eleveld, Marieke A.; Lefebvre, Alain; Andrieux-loyer, Francoise; Blauw, Anouk N.; Bryère, Philippe; Devreker, David; Garnesson, Philippe; Hernandez Farinas, Tania; Lamaury, Yoann; Lampert, Luis; Lavigne, Héloïse; Menet-nedelec, Florence; Pardo, Silvia; Saulquin, Bertrand. |
| The variability of the phytoplankton biomass derived from daily chlorophyll-a (Chl-a) satellite images was investigated over the period 1998–2017 in the surface waters of the English Channel and the northern Bay of Biscay. Merged satellite (SeaWiFS-MODIS/Aqua-MERIS-VIIRS) Chl-a was calculated using the OC5 Ifremer algorithm which is optimized for moderately-turbid waters. The seasonal cycle in satellite-derived Chl-a was compared with in situ measurements made at seven coastal stations located in the southern side of the English Channel and in the northern Bay of Biscay. The results firstly showed that the satellite Chl-a product, derived from a suite of space-borne marine reflectance data, is in agreement with the coastal observations. For compliance with... |
| Tipo: Text |
Palavras-chave: Satellite remote-sensing; Ocean colour; Phytoplankton; Chlorophyll-a; English Channel; Bay of Biscay; Eutrophication assessment; European marine strategy framework directive. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00513/62514/66811.pdf |
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| Guillaud, Jean-francois; Andrieux-loyer, Francoise; Menesguen, Alain. |
| As part of the French National Programme for Coastal Oceanography, this paper focuses on improvement of biogeochemical modelling in the: Bay of Seine (Eastern Channel), by introducing phosphorus in nutrient cycles. The Bay of Seine receives the Seine river, which exhibits very high nutrient concentrations, and this coastal zone constitutes a typical case of eutrophication in a river plume area. In terms of analyses, sequential extraction and analysis of sedimentary phosphorus were used in order, to measure various forms of particulate phosphorus in suspended matter and sediment (calcium-bound phosphate, Fe/Al-bound phosphate, exchangeable phosphate and organic phosphorus). In the modelling approach, the Bay is divided into 42 boxes and a two-layer,... |
| Tipo: Text |
Palavras-chave: Bay of Seine; Phytoplankton; Phosphorus; River plume; Biological two layer box model. |
| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/2000/publication-462.pdf |
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| Labry, Claire; Youenou, Agnes; Delmas, Daniel; Michelon, Pascale. |
| The speciation of particulate phosphorus (TPP) into inorganic (PIP) and organic phosphorus (POP), has been scarcely investigated in suspended particulate matter (SPM), contrary to numerous sediment studies. This work evaluates the actual capacity of methods for TPP, POP and PIP determination in SPM to measure efficiently and specifically each pool. Methods were tested on a range of plankton-associated organic and inorganic P compounds, on microalgal cultures and estuarine samples. Then results are specifically discussed reviewing P speciation in phytoplankton. For TPP analysis, the method of Solorzano and Sharp (1980) is recommended compared with that of Aspila et al. (1976), originally dedicated to sediment, as there is one step less, the protocol is more... |
| Tipo: Text |
Palavras-chave: Phosphorus; Speciation; Waters; Phytoplankton; HTC; CWO. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00149/26046/26385.pdf |
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| Trottet, Aurore; Leboulanger, Christophe; Vidussi, Francesca; Pete, Romain; Bouvy, Marc; Fouilland, Eric. |
| The importance of heterotrophic bacteria relative to phytoplankton in the uptake of ammonium and nitrate was studied in Mediterranean coastal waters (Thau Lagoon) during autumn, when the Mediterranean Sea received the greatest allochthonous nutrient loads. Specific inhibitors and size-fractionation methods were used in combination with isotopic N-15 tracers. NO3 (-) and NH4 (+) uptake was dominated by phytoplankton (60 % on average) during the study period, which included a flood event. Despite lower biomass specific NH4 (+) and NO3 uptake rates, free-living heterotrophic bacteria contributed significantly (> 30 %) to total microbial NH4 (+) and NO3 (-) uptake rates in low chlorophyll waters. Under these conditions, heterotrophic bacteria may be... |
| Tipo: Text |
Palavras-chave: Bacteria; Phytoplankton; Inhibitors; Size fractionation; Nitrogen uptake; Dissolved inorganic nitrogen. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00314/42497/41907.pdf |
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| Alzieu, Claude. |
| The necessity to combat oil slicks makes it necessary to assess the relative effectiveness and toxicity of dispersal agents used. This is usually done by using individual or groups of indicator organisms. The theory behind the various approaches is outlined, and some considerations are listed for the choice of technique. 2 organisms were chosen - the Portuguese oyster (Crassostrea), and the phytoplankton alga Phaeodactylum tricornutum Bohlin, on which if feeds - and the oyster closing reaction, and level of inhibition of growth under the influence of irritant products was measured. Methods are described, and the results shown for emulsifying, agglomerating and precipitating products. The results are discussed, and the mode of interference of the products... |
| Tipo: Text |
Palavras-chave: Choice of technique; Phytoplankton; Organisms; Toxicity; Oil spills; Pollution. |
| Ano: 1972 |
URL: http://archimer.ifremer.fr/doc/1972/publication-2073.pdf |
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| Mudie, Peta J.; Marret, Fabienne; Mertens, Kenneth; Shumilovskikh, Lyudmila; Leroy, Suzanne A. G.. |
| We present the first comprehensive taxonomic and environmental study of dinoflagellate cysts in 185 surface sediment samples from the Black Sea Corridor (BSC) which is a series of marine basins extending from the Aegean to the Aral Seas (including Marmara, Black, Azov and Caspian Seas). For decades, these low-salinity, semi-enclosed or endorheic basins have experienced large-scale changes because of intensive agriculture and industrialisation, with consequent eutrophication and increased algal blooms. The BSC atlas data provide a baseline for improved understanding of linkages between surface water conditions and dinoflagellate cyst (dinocyst) distribution, diversity and morphological variations. By cross-reference to dinocyst occurrences in sediment cores... |
| Tipo: Text |
Palavras-chave: Phytoplankton; Harmful algae; Biodiversity; Paleoceanography; Surface samples. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00387/49824/50408.pdf |
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| Cozic, Amandine. |
| A sensitive, precise and rapid analytical method was elaborated to measure simultaneously 5 volatile reduced sulfur compounds (VRSC) ; hydrogen sulfide (H2S), carbonyl sulfide (OCS), methane thiol (MeSH), dimethyl sulfide (DMS), dimethyl disulfide (DMDS). The study of VRSC in the Bay of Quiberon highlights seasonal and interannual variations of concentrations in epibenthic zone. H2S analyzed near the sediment water interface (anoxic microzones), is more elevated in summer. The OCS distribution is consistent with a predominant photodegradation in winter and a sedimentary source in summer. The variations of MeSH, DMS and DMDS are correlated with the Dinophyceae abundance. In the Seine estuary, the absence of volatile H2S in the up estuary is explained by the... |
| Tipo: Text |
Palavras-chave: Phytoplankton; Metal speciation; DMS; Sulfur; Phytoplancton; Spéciation métallique; DMS; Soufre. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/these-2687.pdf |
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| Belin, Catherine; Amzil, Zouher. |
| Toxin monitoring is carried out along the coasts of France by a national network, REPHY, which is the National Monitoring Network for Phytoplankton and Phycotoxins. Sampling strategy differs according to the type of zone coastal or offshore and to the family of toxins. For PSP and ASP toxins, monitoring is based on the detection of toxic phytoplankton species. For lipophilic toxins, a systematic analysis of toxins is performed in risk areas during high risk periods. Experimental monitoring for palytoxins has also been conducted along the Mediterranean coast since 2007. The total number of toxin analyses is in the order of 2500 to 3000 per year. The detailed results for each family of toxins showed that the most frequent toxic events for the period from... |
| Tipo: Text |
Palavras-chave: Monitoring; Phytoplankton; Toxin; Sampling; Shellfish; French coasts. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00077/18821/16398.pdf |
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| Schapira, Mathilde; Seuront, Laurent. |
| Despite ample evidence of micro- and small-scale (i.e., millimeter- to meter-scale) phytoplankton and zooplankton patchiness in the ocean, direct observations of nutrient distributions and the ecological importance of this phenomenon are still relatively scarce. In this context, we first describe a simple procedure to continuously sample nutrients in surface waters, and subsequently provide evidence of the existence of microscale distribution of ammonium in the ocean. We further show that ammonium is never homogeneously distributed, even under very high conditions of turbulence. Instead, turbulence intensity appears to control nutrient patchiness, with a more homogeneous or a more heterogeneous distribution observed under high and low turbulence... |
| Tipo: Text |
Palavras-chave: Nutrient patchiness; Turbulence; Phytoplankton; Surge uptake; Nutrient depletion; Turbulent history. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00643/75527/76435.pdf |
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| Louropoulou, Evangelia; Gledhill, Martha; Browningi, Thomas J.; Desai, Dhwani K.; Barraqueta, Jan-lukas Menzel; Tonnard, Manon; Sarthou, Geraldine; Planquette, Helene; Bowie, Andrew R.; Schmitz, Ruth A.; Laroche, Julie; Achterberg, Eric P.. |
| Heme b is an iron-containing co-factor in hemoproteins. Heme b concentrations are low (< 1 pmol L-1) in iron limited phytoplankton in cultures and in the field. Here, we determined heme b in marine particulate material (> 0.7 mu m) from the North Atlantic Ocean (GEOVIDE cruise - GEOTRACES section GA01), which spanned several biogeochemical regimes. We examined the relationship between heme b abundance and the microbial community composition, and its utility for mapping iron limited phytoplankton. Heme b concentrations ranged from 0.16 to 5.1 pmol L-1 (median = 2.0 pmol L-1, n = 62) in the surface mixed layer (SML) along the cruise track, driven mainly by variability in biomass. However, in the Irminger Basin, the lowest heme b levels (SML: median =... |
| Tipo: Text |
Palavras-chave: Heme b; North Atlantic; Phytoplankton; Diatoms; Iron; Limitation; GEOTRACES; GEOVIDE. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00508/61940/66029.pdf |
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| Strady, Emilie; Harmelin-vivien, Mireille; Chiffoleau, Jean-francois; Veron, Alain; Tronczynski, Jacek; Radakovitch, Olivier. |
| The transfer of 210Po and 210Pb in the food web of small pelagic fishes (from phytoplankton and zooplankton to anchovy Engraulis encrasicolus and sardine Sardina pilchardus) is investigated in the Gulf of Lion (GoL). We present original data of 210Po and 210Pb activity concentrations, C and N stable isotope ratios, measured (i) from different size classes of phytoplankton and zooplankton during spring and winter in different environments of the GoL, and (ii) in two fish species. Significant spatial patterns based on 210Po, 210Pb activity concentrations and 210Po/210Pb ratios in the different plankton size classes are evidenced by hierarchical clustering, both in spring and winter. This variability, also observed for C and N stable isotopes ratios, is... |
| Tipo: Text |
Palavras-chave: Po-210; Pb-210; Phytoplankton; Zooplankton; Pelagic fishes; Mediterranean Sea. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00255/36609/35264.pdf |
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| Registros recuperados: 369 | |
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