Consulta: creatorFacets:"Sarthou, Geraldine"
Registros recuperados: 32
Data/hora: 04/06/2024 10:47:09

Mercury distribution and transport in the North Atlantic Ocean along the GEOTRACES-GA01 transect
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Cossa, Daniel; Heimburger, Lars-eric; Perez, Fiz F; Garcia-ibanez, Maria Isabel; Sonke, Jeroen E.; Planquette, Helene; Lherminier, Pascale; Boutorh, Julia; Cheize, Marie; Barraqueta, Jan Lukas Menzel; Shelley, Rachel; Sarthou, Geraldine.
We report here the results of total mercury (HgT) determinations along the 2014 GEOTRACES GEOVIDE cruise (GA01 transect) in the North Atlantic Ocean (NA) from Lisbon (Portugal) to the Labrador coast (Canada). Ninety-seven percent of the HgT concentrations of unfiltered samples (HgTUNF) ranged between 0.16 and 1.00 pmol L−1. The geometric mean was 0.51 pmol L−1 for the 535 samples analysed. The dissolved fraction (&lt; 0.45 μm) of HgT, determined on 141 samples, averaged 78 % of the HgTUNF for the whole water column. HgTUNF concentrations increased eastwards and with depth from Greenland to Europe and from sub-surface to bottom waters, respectively. The Hg distribution mirrored that of dissolved oxygen concentration, with highest HgTUNF levels associated...
Tipo: Text
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00412/52303/53071.pdf

Regional trends in the fractional solubility of Fe and other metals from North Atlantic aerosols (GEOTRACES cruises GA01 and GA03) following a two-stage leach
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Shelley, Rachel; Landing, William M.; Ussher, Simon J.; Planquette, Helene; Sarthou, Geraldine.
The fractional solubility of aerosol-derived trace elements deposited to the ocean surface is a key parameter of many marine biogeochemical models. Despite this, it is currently poorly constrained, in part due to the complex interplay between the various processes that govern the solubilisation of aerosol trace elements. In this study, we used a sequential two-stage leach to investigate the regional variability in fractional solubility of a suite of aerosol trace elements (Al, Ti, Fe, Mn, Co, Ni, Cu, Zn, Cd, and Pb) from samples collected during three GEOTRACES cruises to the North Atlantic Ocean (GA01, GA03-2010, and GA03-2011). We present aerosol trace element solubility data from two sequential leaches that provide a solubility window, covering a...
Tipo: Text
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00439/55041/56473.pdf

Introduction to the French GEOTRACES North Atlantic Transect (GA01): GEOVIDE cruise
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Sarthou, Geraldine; Lherminier, Pascale; Achterberg, Eric P.; Alonso-perez, Fernando; Bucciarelli, Eva; Boutorh, Julia; Bouvier, Vincent; Boyle, Edward A.; Branellec, Pierre; Carracedo, Lidia I.; Casacuberta, Nuria; Castrillejo, Maxi; Cheize, Marie; Pereira, Leonardo Contreira; Cossa, Daniel; Daniault, Nathalie; De Saint-leger, Emmanuel; Dehairs, Frank; Deng, Feifei; De Gesincourt, Floriane Desprez; Devesa, Jeremy; Foliot, Lorna; Fonseca-batista, Debany; Gallinari, Morgane; Garcia-ibanez, Maribel I.; Gourain, Arthur; Grossteffan, Emilie; Hamon, Michel; Heimburger, Lars Eric; Henderson, Gideon M.; Jeandel, Catherine; Kermabon, Catherine; Lacan, Francois; Le Bot, Philippe; Le Goff, Manon; Le Roy, Emilie; Lefebvre, Alison; Leizour, Stephane; Lemaitre, Nolwenn; Masque, Pere; Menage, Olivier; Barraqueta, Jan-lukas Menzel; Mercier, Herle; Perault, Fabien; Perez, Fiz F; Planquette, Helene; Planchon, Frederic; Roukaerts, Arnout; Sanial, Virginie; Sauzede, Raphaelle; Schmechtig, Catherine; Shelley, Rachel U.; Stewart, Gillian; Sutton, Jill; Tang, Yi; Tisnerat-laborde, Nadine; Tonnard, Manon; Treguer, Paul; Van Beek, Pieter; Zurbrick, Cheryl M.; Zunino Rodriguez, Patricia.
The GEOVIDE cruise, a collaborative project within the framework of the international GEOTRACES programme, was conducted along the French-led section in the North Atlantic Ocean (Section GA01), between 15 May and 30 June 2014. In this special issue (https://www.biogeosciences.net/special_ issue900.html), results from GEOVIDE, including physical oceanography and trace element and isotope cyclings, are presented among 18 articles. Here, the scientific context, project objectives, and scientific strategy of GEOVIDE are provided, along with an overview of the main results from the articles published in the special issue.
Tipo: Text
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00470/58178/60685.pdf

Inputs and processes affecting the distribution of particulate iron in the North Atlantic along the GEOVIDE (GEOTRACES GA01) section
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Gourain, Arthur; Planquette, Helene; Cheize, Marie; Lemaitre, Nolwenn; Menzel Barraqueta, Jan-lukas; Shelley, Rachel; Lherminier, Pascale; Sarthou, Geraldine.
The GEOVIDE cruise (May–June 2014, R/V Pourquoi Pas?) aimed to provide a better understanding on trace metal biogeochemical cycles in the North Atlantic. As particles play a key role in the global biogeochemical cycle of trace elements in the ocean, we discuss the distribution of particulate iron (PFe), in light of particulate aluminium (PAl), manganese (PMn) and phosphorus (PP) distributions. Overall, 32 full vertical profiles were collected for trace metal analyses, representing more than 500 samples. This resolution provides a solid basis for assessing concentration distributions, elemental ratios, size-fractionation, or adsorptive scavenging processes in key areas of the thermohaline circulation. Total particulate iron (PFe) concentrations ranged from...
Tipo: Text
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00485/59676/62747.pdf

Viral degradation of marine bacterial exopolysaccharides
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Lelchat, Florian; Mocaer, P Y; Ojima, T; Michel, G; Sarthou, Geraldine; Bucciarelli, Eva; Cérantola, S; Colliec-jouault, Sylvia; Boisset, Claire; Baudoux, A-c.
The identification of the mechanisms by which marine dissolved organic matter (DOM) is produced and regenerated is critical to develop robust prediction of ocean carbon cycling. Polysaccharides represent one of the main constituents of marine DOM and their degradation is mainly attributed to polysaccharidases derived from bacteria. Here, we report that marine viruses can depolymerize the exopolysaccharides (EPS) excreted by their hosts using 5 bacteriophages that infect the notable EPS producer, Cobetia marina DSMZ 4741. Degradation monitorings as assessed by gel electrophoresis and size exclusion chromatography showed that 4 out of 5 phages carry structural enzymes that depolymerize purified solution of Cobetia marina EPS. The depolymerization patterns...
Tipo: Text
Palavras-chave: Marine phage; EPS; Polysaccharidase; DOM; Ocean.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00499/61062/64512.pdf

The Ra-226-Ba relationship in the North Atlantic during GEOTRACES-GA01
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Le Roy, Emilie; Sanial, Virginie; Charette, Matthew A.; Van Beek, Pieter; Lacan, Francois; Jacquet, Stephanie H. M.; Henderson, Paul B.; Souhaut, Marc; Garcia-ibanez, Maribel I.; Jeandel, Catherine; Perez, Fiz F; Sarthou, Geraldine.
We report detailed sections of radium-226 (Ra-226, T-1/2 = 1602 years) activities and barium (Ba) concentrations determined in the North Atlantic (Portugal-Greenland-Canada) in the framework of the international GEO-TRACES program (GA01 section - GEOVIDE project, May-July 2014). Dissolved Ra-226 and Ba are strongly correlated along the section, a pattern that may reflect their similar chemical behavior. Because Ra-226 and Ba have been widely used as tracers of water masses and ocean mixing, we investigated their behavior more thoroughly in this crucial region for thermohaline circulation, taking advantage of the contrasting biogeochemical patterns existing along the GA01 section. We used an optimum multiparameter (OMP) analysis to distinguish the relative...
Tipo: Text
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00616/72790/72109.pdf

A rapid quantitative fluorescence-based bioassay to study allelochemical interactions from Alexandrium minutum
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Long, Marc; Tallec, Kevin; Soudant, Philippe; Lambert, Christophe; Le Grand, Fabienne; Sarthou, Geraldine; Jolley, Dianne; Hegaret, Helene.
Harmful microalgal blooms are a threat to aquatic organisms, ecosystems and human health. Toxic dinoflagellates of the genus Alexandrium are known to produce paralytic shellfish toxins and to release bioactive extracellular compounds (BECs) with potent cytotoxic, hemolytic, ichtyotoxic and allelopathic activity. Negative allelochemical interactions refer to the chemicals that are released by the genus Alexandrium and that induce adverse effects on the physiology of co-occurring protists and predators. Releasing BECs gives the donor a competitive advantage that may help to form dense toxic blooms of phytoplankton. However BECs released by Alexandrium minutum are uncharacterized and it is impossible to quantify them using classical chemical methods....
Tipo: Text
Palavras-chave: Harmful algal bloom; Alexandrium; Allelopathy; Cytotoxicity; PAM fluorometry; Bioassay.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00453/56424/58116.pdf

A call for refining the role of humic-like substances in the oceanic iron cycle
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Whitby, Hannah; Planquette, Helene; Cassar, Nicolas; Bucciarelli, Eva; Osburn, Christopher L.; Janssen, David J.; Cullen, Jay T.; González, Aridane G.; Völker, Christoph; Sarthou, Geraldine.
Primary production by phytoplankton represents a major pathway whereby atmospheric CO2 is sequestered in the ocean, but this requires iron, which is in scarce supply. As over 99% of iron is complexed to organic ligands, which increase iron solubility and microbial availability, understanding the processes governing ligand dynamics is of fundamental importance. Ligands within humic-like substances have long been considered important for iron complexation, but their role has never been explained in an oceanographically consistent manner. Here we show iron co-varying with electroactive humic substances at multiple open ocean sites, with the ratio of iron to humics increasing with depth. Our results agree with humic ligands composing a large fraction of the...
Tipo: Text
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00622/73388/72598.pdf

Effects of copper on the dinoflagellate Alexandrium minutum and its allelochemical potency
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Long, Marc; Holland, Aleicia; Planquette, Helene; Gonzalez Santana, David; Whitby, Hannah; Soudant, Philippe; Sarthou, Geraldine; Hégaret, Helene; Jolley, Dianne F.
The dinoflagellate Alexandrium minutum produces toxic compounds, including paralytic shellfish toxins, but also some unknown extracellular toxins. Although copper (Cu) is an essential element, it can impair microalgal physiology and increase their toxic potency. This study investigated the effect of different concentrations of dissolved Cu (7 nM, 79 nM and 164 nM) on A. minutum allelochemical potency, here defined as negative effects of a protist on competing protists through the release of chemicals. This was studied in relation to its physiology. The effects of Cu were assessed on A. minutum growth, reactive oxygen species level, photosynthesis proxies, lipid metabolism, exudation of dissolved organic compounds, allelochemical potency and on the...
Tipo: Text
Palavras-chave: Alexandrium; Copper; Toxicity; Allelopathy; Physiology; Exudate.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00484/59612/62629.pdf

High variability of particulate organic carbon export along the North Atlantic GEOTRACES section GA01 as deduced from 234Th fluxes
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Lemaitre, Nolwenn; Planchon, Frederic; Planquette, Helene; Dehairs, Frank; Fonseca-batista, Debany; Roukaerts, Arnout; Deman, Florian; Tang, Yi; Mariez, Clarisse; Sarthou, Geraldine.
In this study we report particulate organic carbon (POC) export fluxes for different biogeochemical basins in the North Atlantic as part of the GEOTRACES GA01 expedition (GEOVIDE, May–June 2014). Surface POC export fluxes were deduced by combining export fluxes of total Thorium-234 (234Th) with the ratio of POC to 234Th of sinking particles at the depth of export. Particles were collected in two size classes ( &gt; 53 and 1–53µm) using in situ pumps and the large size fraction was considered representative of sinking material. Surface POC export fluxes revealed latitudinal variations between provinces, ranging from 1.4mmolm−2d−1 in the Irminger basin, where the bloom was close to its maximum, to 12mmolm−2d−1 near the Iberian Margin, where the bloom had...
Tipo: Text
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00465/57664/59860.pdf

Contribution of electroactive humic substances to the iron-binding ligands released during microbial remineralisation of sinking particles
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Whitby, Hannah; Bressac, Matthieu; Sarthou, Geraldine; Ellwood, Michael J.; Guieu, Cécile; Boyd, Philip W.
Iron is a key micronutrient in seawater, but concentrations would be negligible without the presence of organic ligands. The processes influencing the ligand pool composition are poorly constrained, limiting our understanding of the controls on dissolved iron distributions. To address this, the release of iron and iron‐binding ligands during the microbial remineralisation of sinking particles was investigated by deploying in situ particle interceptor/incubator devices at subsurface sites in the Mediterranean Sea and Subantarctic. Analyses revealed the pool of released ligands was largely dominated by electroactive humic substances (74 ± 28%). The release of ligands during remineralisation ensured that concurrently released iron remained in solution, which...
Tipo: Text
Palavras-chave: Iron; Ligand; Humic; Remineralisation; Particle; Degradation.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00618/72981/72055.pdf

Pervasive sources of isotopically light zinc in the North Atlantic Ocean
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Lemaitre, Nolwenn; De Souza, Gregory F.; Archer, Corey; Wang, Ruo-mei; Planquette, Helene; Sarthou, Geraldine; Vance, Derek.
In this study, we report seawater dissolved zinc (Zn) concentration and isotope composition (Zn) from the GEOTRACES GA01 (GEOVIDE) section in the North Atlantic. Across the transect, three subsets of samples stand out due to their isotopically light signature: those close to the Reykjanes Ridge, those close to the sediments, and those, pervasively, in the upper ocean. Similar to observations at other locations, the hydrothermal vent of the Reykjanes Ridge is responsible for the isotopically light Zn composition of the surrounding waters, with an estimated source Zn of -0.42 ‰. This isotopically light Zn is then transported over a distance greater than 1000 km from the vent. Sedimentary inputs are also evident all across the trans-Atlantic section,...
Tipo: Text
Palavras-chave: Zinc isotopes; North Atlantic; Zinc sources; GEOTRACES; GEOVIDE.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00618/73035/72166.pdf

Atmospheric aerosoldeposition fluxes over the Atlantic Ocean: A GEOTRACES case study
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Menzel Barraqueta, Jan-lukas; Klar, Jessica K.; Gledhill, Martha; Schlosser, Christian; Shelley, Rachel; Planquette, Helene; Wenzel, Bernhard; Sarthou, Geraldine; Achterberg, Eric P.
Atmospheric deposition is an important source of micronutrients to the ocean, but atmospheric deposition fluxes remain poorly constrained in most ocean regions due to the limited number of field observations of wet and dry atmospheric inputs. Here we present the distribution of dissolved aluminium (dAl), as a tracer of atmospheric inputs, in surface waters of the Atlantic Ocean along GEOTRACES sections GA01, GA06, GA08, and GA10. We used the surface mixed layer concentrations of dAl to calculate atmospheric deposition fluxes using a simple steady state model. We have optimized the aerosol Al fractional solubility, dAl residence time within the surface mixed layer and depth of the surface mixed layer for each separate cruise to calculate the atmospheric...
Tipo: Text
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00485/59675/62745.pdf

The GEOTRACES Intermediate Data Product 2014
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Mawji, Edward; Schlitzer, Reiner; Dodas, Elena Masferrer; Abadie, Cyril; Abouchami, Wafa; Anderson, Robert F.; Baars, Oliver; Bakker, Karel; Baskaran, Mark; Bates, Nicholas R.; Bluhm, Katrin; Bowie, Andrew; Bown, Johann; Boye, Marie; Boyle, Edward A.; Branellec, Pierre; Bruland, Kenneth W.; Brzezinski, Mark A.; Bucciarelli, Eva; Buesseler, Ken; Butler, Edward; Cai, Pinghe; Cardinal, Damien; Casciotti, Karen; Chaves, Joaquin; Cheng, Hai; Chever, Fanny; Church, Thomas M.; Colman, Albert S.; Conway, Tim M.; Croot, Peter L.; Cutter, Gregory A.; De Baar, Hein J. W.; De Souza, Gregory F.; Dehairs, Frank; Deng, Feifei; Huong Thi Dieu,; Dulaquais, Gabriel; Echegoyen-sanz, Yolanda; Edwards, R. Lawrence; Fahrbach, Eberhard; Fitzsimmons, Jessica; Fleisher, Martin; Frank, Martin; Friedrich, Jana; Fripiat, Francois; Galer, Stephen J. G.; Gamo, Toshitaka; Solsona, Ester Garcia; Gerringa, Loes J. A.; Godoy, Jose Marcus; Gonzalez, Santiago; Grossteffan, Emilie; Hatta, Mariko; Hayes, Christopher T.; Heller, Maija Iris; Henderson, Gideon; Huang, Kuo-fang; Jeandel, Catherine; Jenkins, William J.; John, Seth; Kenna, Timothy C.; Klunder, Maarten; Kretschmer, Sven; Kumamoto, Yuichiro; Laan, Patrick; Labatut, Marie; Lacan, Francois; Lam, Phoebe J.; Lannuzel, Delphine; Le Moigne, Frederique; Lechtenfeld, Oliver J.; Lohan, Maeve C.; Lu, Yanbin; Masque, Pere; Mcclain, Charles R.; Measures, Christopher; Middag, Rob; Moffett, James; Navidad, Alicia; Nishioka, Jun; Noble, Abigail; Obata, Hajime; Ohnemus, Daniel C.; Owens, Stephanie; Planchon, Frederic; Pradoux, Catherine; Puigcorbe, Viena; Quay, Paul; Radic, Amandine; Rehkaemper, Mark; Remenyi, Tomas; Rijkenberg, Micha J. A.; Rintoul, Stephen; Robinson, Laura F.; Roeske, Tobias; Rosenberg, Mark; Van Der Loeff, Michiel Rutgers; Ryabenko, Evgenia; Saito, Mak A.; Roshan, Saeed; Salt, Lesley; Sarthou, Geraldine; Schauer, Ursula; Scott, Peter; Sedwick, Peter N.; Sha, Lijuan; Shiller, Alan M.; Sigman, Daniel M.; Smethie, William; Smith, Geoffrey J.; Sohrin, Yoshiki; Speich, Sabrina; Stichel, Torben; Stutsman, Johnny; Swift, James H.; Tagliabue, Alessandro; Thomas, Alexander; Tsunogai, Urumu; Twining, Benjamin S.; Van Aken, Hendrik M.; Van Heuven, Steven; Van Ooijen, Jan; Van Weerlee, Evaline; Venchiarutti, Celia; Voelker, Antje H. L.; Wake, Bronwyn; Warner, Mark J.; Woodward, E. Malcolm S.; Wu, Jingfeng; Wyatt, Neil; Yoshikawa, Hisayuki; Zheng, Xin-yuan; Xue, Zichen; Zieringer, Moritz; Zimmer, Louise A.
The GEOTRACES Intermediate Data Product 2014 (IDP2014) is the first publicly available data product of the international GEOTRACES programme, and contains data measured and quality controlled before the end of 2013. It consists of two parts: (1) a compilation of digital data for more than 200 trace elements and isotopes (TEls) as well as classical hydrographic parameters, and (2) the eGEOTRACES Electronic Atlas providing a strongly inter-linked on-line atlas including more than 300 section plots and 90 animated 3D scenes. The IDP2014 covers the Atlantic, Arctic, and Indian oceans, exhibiting highest data density in the Atlantic. The TEI data in the IDP2014 are quality controlled by careful assessment of intercalibration results and multi-laboratory data...
Tipo: Text
Palavras-chave: GEOTRACES; Trace elements; Isotopes; Electronic atlas.
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00308/41910/41190.pdf

Processes Driving Iron and Manganese Dispersal From the TAG Hydrothermal Plume (Mid-Atlantic Ridge): Results From a GEOTRACES Process Study
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: González-santana, David; Planquette, Helene; Cheize, Marie; Whitby, Hannah; Gourain, Arthur; Holmes, Thomas; Guyader, Vivien; Cathalot, Cecile; Pelleter, Ewan; Fouquet, Yves; Sarthou, Geraldine.
Hydrothermal vents are a recognized source of trace elements to the ocean inventory. Nevertheless, the contribution of slow-spreading ridges remains poorly resolved. To address this, high-resolution dissolved (&lt;0.45 μm) iron (dFe) and manganese (dMn) samples were collected during the GEOTRACES HERMINE GApr07 process study at the Mid Atlantic Ridge. Samples were collected at nine stations, from the TAG vent site to 75 km south-southwest following the neutrally buoyant plume. Concentrations of dMn and dFe ranged from 71 ± 6 and 51 ± 2 nmol kg–1 right above the vent site to 0.43 ± 0.01 and 1.56 ± 0.02 nmol kg–1 at the most distal station, respectively. Using a 5-box model coupled with our data, we show that as the plume traveled away from the vent,...
Tipo: Text
Palavras-chave: Iron; Manganese; Hydrothermal; TAG; Mid Atlantic Ridge; GEOTRACES.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00643/75530/76431.pdf

The GEOTRACES Intermediate Data Product 2017
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Schlitzer, Reiner; Anderson, Robert F.; Dodas, Elena Masferrer; Lohan, Maeve; Geibere, Walter; Tagliabue, Alessandro; Bowie, Andrew; Jeandel, Catherine; Maldonado, Maria T.; Landing, William M.; Cockwell, Donna; Abadie, Cyril; Abouchami, Wafa; Achterberg, Eric P.; Agather, Alison; Aguliar-islas, Ana; Van Aken, Hendrik M.; Andersen, Morten; Archer, Corey; Auro, Maureen; De Baar, Hein J.; Baars, Oliver; Baker, Alex R.; Bakker, Karel; Basak, Chandranath; Baskaran, Mark; Bates, Nicholas R.; Bauch, Dorothea; Van Beek, Pieter; Behrens, Melanie K.; Black, Erin; Bluhm, Katrin; Bopp, Laurent; Bouman, Heather; Bowman, Katlin; Bown, Johann; Boyd, Philip; Boye, Marie; Boyle, Edward A.; Branellec, Pierre; Bridgestock, Luke; Brissebrat, Guillaume; Browning, Thomas; Bruland, Kenneth W.; Brumsack, Hans-juergen; Brzezinski, Mark; Buck, Clifton S.; Buck, Kristen N.; Buesseler, Ken; Bull, Abby; Butler, Edward; Cai, Pinghe; Camara Mor, Patricia; Cardinal, Damien; Carlson, Craig; Carrasco, Gonzalo; Casacuberta, Nuria; Casciotti, Karen L.; Castrillejo, Maxi; Chamizo, Elena; Chance, Rosie; Charette, Matthew A.; Chaves, Joaquin E.; Cheng, Hai; Chever, Fanny; Christl, Marcus; Church, Thomas M.; Closset, Ivia; Colman, Albert; Conway, Tim M.; Cossa, Daniel; Croot, Peter; Cullen, Jay T.; Cutter, Gregory A.; Daniels, Chris; Dehairs, Frank; Deng, Feifei; Dieu, Huong Thi; Duggan, Brian; Dulaquais, Gabriel; Dumousseaud, Cynthia; Echegoyen-sanz, Yolanda; Edwards, R. Lawrence; Ellwood, Michael; Fahrbach, Eberhard; Fitzsimmons, Jessica N.; Flegal, A. Russell; Fleisher, Martin Q.; Van De Flierdt, Tina; Frank, Martin; Friedrich, Jana; Fripiat, Francois; Froellje, Henning; Galer, Stephen J. G.; Gamo, Toshitaka; Ganeshram, Raja S.; Garcia-orellana, Jordi; Garcia-solsona, Ester; Gault-ringold, Melanie; George, Ejin; Gerringa, Loes J. A.; Gilbert, Melissa; Godoy, Jose M.; Goldstein, Steven L.; Gonzalez, Santiago R.; Grissom, Karen; Hammerschmidt, Chad; Hartman, Alison; Hassler, Christel S.; Hathorne, Ed C.; Hatta, Mariko; Hawco, Nicholas; Hayes, Christopher T.; Heimburger, Lars-eric; Helgoe, Josh; Heller, Maija Iris; Henderson, Gideon M.; Henderson, Paul B.; Van Heuven, Steven; Ho, Peng; Horner, Tristan J.; Hsieh, Yu-te; Huang, Kuo-fang; Humphreys, Matthew P.; Isshiki, Kenji; Jacquot, Jeremy E.; Janssen, David J.; Jenkins, William J.; John, Seth; Jones, Elizabeth M.; Jones, Janice L.; Kadko, David C.; Kayser, Rick; Kenna, Timothy C.; Khondoker, Roulin; Kim, Taejin; Kipp, Lauren; Klar, Jessica K.; Klunder, Maarten; Kretschmer, Sven; Kumamoto, Yuichiro; Laan, Patrick; Labatut, Marie; Lacan, Francois; Lam, Phoebe J.; Lambelet, Myriam; Lamborg, Carl H.; Le Moigne, Frederic A. C.; Le Roy, Emilie; Lechtenfeld, Oliver J.; Lee, Jong-mi; Lherminier, Pascale; Little, Susan; Lopez-lora, Mercedes; Lu, Yanbin; Masque, Pere; Mawji, Edward; Mcclain, Charles R.; Measures, Christopher; Mehic, Sanjin; Barraqueta, Jan-lukas Menzel; Van Der Merwe, Pier; Middag, Rob; Mieruch, Sebastian; Milne, Angela; Minami, Tomoharu; Moffett, James W.; Moncoiffe, Gwenaelle; Moore, Willard S.; Morris, Paul J.; Morton, Peter L.; Nakaguchi, Yuzuru; Nakayama, Noriko; Niedermiller, John; Nishioka, Jun; Nishiuchi, Akira; Noble, Abigail; Obata, Hajime; Ober, Sven; Ohnemus, Daniel C.; Van Ooijen, Jan; O'Sullivan, Jeanette; Owens, Stephanie; Pahnke, Katharina; Paul, Maxence; Pavia, Frank; Pena, Leopoldo D.; Petersh, Brian; Planchon, Frederic; Planquette, Helene; Pradoux, Catherine; Puigcorbe, Viena; Quay, Paul; Queroue, Fabien; Radic, Amandine; Rauschenberg, S.; Rehkamper, Mark; Rember, Robert; Remenyi, Tomas; Resing, Joseph A.; Rickli, Joerg; Rigaud, Sylvain; Rijkenberg, Micha J. A.; Rintoul, Stephen; Robinson, Laura F.; Roca-marti, Montserrat; Rodellas, Valenti; Roeske, Tobias; Rolison, John M.; Rosenberg, Mark; Roshan, Saeed; Van Der Loaff, Michiel M. Rutgers; Ryabenko, Evgenia; Saito, Mak A.; Salt, Lesley A.; Sanial, Virginie; Sarthou, Geraldine; Schallenberg, Christina; Schauer, Ursula; Scher, Howie; Schlosser, Christian; Schnetger, Bernhard; Scott, Peter; Sedwick, Peter N.; Semiletov, Igor; Shelley, Rachel; Sherrell, Robert M.; Shiller, Alan M.; Sigman, Daniel M.; Singh, Sunil Kumar; Slagter, Hans A.; Slater, Emma; Smethie, William M.; Snaith, Helen; Sohrin, Yoshiki; Sohst, Bettina; Sonke, Jeroen E.; Speich, Sabrina; Steinfeldt, Reiner; Stewart, Gillian; Stichel, Torben; Stirling, Claudine H.; Stutsman, Johnny; Swarr, Gretchen J.; Swift, James H.; Thomas, Alexander; Thorne, Kay; Till, Claire P.; Till, Ralph; Townsend, Ashley T.; Townsend, Emily; Tuerena, Robyn; Twining, Benjamin S.; Vance, Derek; Velazquez, Sue; Venchiarutti, Celia; Villa-alfageme, Maria; Vivancos, Sebastian M.; Voelker, Antje H. L.; Wake, Bronwyn; Warner, Mark J.; Watson, Ros; Van Weerlee, Evaline; Weigand, M. Alexandra; Weinstein, Yishai; Weiss, Dominik; Wisotzki, Andreas; Woodward, E. Malcolm S.; Wu, Jingfeng; Wu, Yingzhe; Wuttig, Kathrin; Wyatt, Neil; Xiang, Yang; Xie, Ruifang C.; Xue, Zichen; Yoshikawa, Hisayuki; Zhang, Jing; Zhang, Pu; Zhao, Ye; Zheng, Linjie; Zheng, Xin-yuan; Zieringer, Moritz; Zimmer, Louise A.; Ziveri, Patrizia; Zunino, Patricia; Zurbrick, Cheryl.
The new IDP2017 is a significant improvement over the earlier IDP2014 and roughly doubles the number of included cruises, stations, samples and parameters. The IDP2017 is a truly international product containing data from 326 researchers from 25 countries. The IDP2017 provides data for the Pacific Ocean, and the Mediterranean and Black seas, in addition to Atlantic, Arctic and Indian Oceans that were already represented in the previous data product. For the first time, the IDP2017 contains significant amounts of biogeochemistry data as well as TEI data for aerosols and rain. As before, users can obtain complete IDP2017 data sets as bulk downloads. Alternatively, there is now a customisable online data extraction service that allows data selections by...
Tipo: Text
Palavras-chave: GEOTRACES; Trace elements; Isotopes; Electronic atlas; IDP2017.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00442/55362/56877.pdf

Aluminium in the North Atlantic Ocean and the Labrador Sea (GEOTRACES GA01 section): roles of continental inputs and biogenic particle removal
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Barraqueta, Jan-lukas Menzel; Schlosser, Christian; Planquette, Helene; Gourain, Arthur; Cheize, Marie; Boutorh, Julia; Shelley, Rachel; Pereira, Leonardo Contreira; Gledhill, Martha; Hopwood, Mark J.; Lacan, Francois; Lherminier, Pascale; Sarthou, Geraldine; Achterberg, Eric P.
The distribution of dissolved aluminium (dAl) in the water column of the North Atlantic and Labrador Sea was studied along GEOTRACES section GA01 to unravel the sources and sinks of this element. Surface water dAl concentrations were low (median of 2.5 nM) due to low aerosol deposition and removal by phytoplankton. However, surface water dAl concentrations were enhanced on the Iberian and Greenland shelves (up to 30.9 nM) due to continental inputs (rivers, glacial flour and ice melt). A negative correlation was observed between dAl in surface waters and primary production, phytoplankton community structure and biogenic opal production. The abundance of diatoms exerted a significant (p &lt; 0.01) control on the surface particulate Al (pAl) to dAl ratios by...
Tipo: Text
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00422/53359/54197.pdf

Atmospheric deposition fluxes over the Atlantic Ocean: a GEOTRACES case study
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Menzel Barraqueta, Jan-lukas; Klar, Jessica K.; Gledhill, Martha; Schlosser, Christian; Shelley, Rachel; Planquette, Helene; Wenzel, Bernhard; Sarthou, Geraldine; Achterberg, Eric P.
Atmospheric deposition is an important source of micronutrients to the ocean, but atmospheric deposition fluxes remain poorly constrained in most ocean regions due to the limited number of field observations of wet and dry atmospheric inputs. Here we present the distribution of dissolved aluminium (dAl), as a tracer of atmospheric inputs, in surface waters of the Atlantic Ocean along GEOTRACES sections GA01, GA06, GA08, and GA10. We used the surface mixed-layer concentrations of dAl to calculate atmospheric deposition fluxes using a simple steady state model. We have optimized the Al fractional aerosol solubility, the dAl residence time within the surface mixed layer and the depth of the surface mixed layer for each separate cruise to calculate the...
Tipo: Text
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00491/60227/63598.pdf

Early winter barium excess in the Southern Indian Ocean as an annual remineralisation proxy (GEOTRACES GIPr07 cruise)
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Van Horsten, Natasha René; Planquette, Helene; Sarthou, Geraldine; Ryan-keogh, Thoams James; Mtshali, Thato Nicholas; Roychoudhury, Alakendra; Bucciarelli, Eva.
The Southern Ocean is of global importance and processes such as mesopelagic remineralisation that impact the efficiency of the biological carbon pump in this region is of substantial interest. During this study the proxy barium excess which is utilised to shed light on mesopelagic remineralisation was measured at seven stations along 30° E in the Southern Indian Ocean during early austral winter of 2017. To our knowledge this is the first reported winter study utilising this proxy in the Southern Ocean. Concentrations of 59 to 684 pmol L−1 were comparable to those observed throughout other seasons, indicating that this proxy has a longer timescale than previously thought. Background barium excess values observed in deep waters were also similar to...
Tipo: Text
Ano: 2021
URL: https://archimer.ifremer.fr/doc/00683/79485/82077.pdf

Tracing water masses with 129I and 236U in the subpolar North Atlantic along the GEOTRACES GA01 section
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Castrillejo, Maxi; Casacuberta, Nuria; Christl, Marcus; Vockenhuber, Christof; Synal, Hans-arno; Garcia-ibanez, Maribel; Lherminier, Pascale; Sarthou, Geraldine; Garcia-orellana, Jordi; Masque, Pere.
Pathways and timescales of water mass transport in the subpolar North Atlantic Ocean (SPNA) have been investigated by many studies due to their importance for the meridional overturning circulation and thus for the global ocean. In this sense, observational data on geochemical tracers provide complementary information to improve the current understanding of the circulation in the SPNA. To this end, we present the first simultaneous distribution of artificial 129I and 236U in 14 depth profiles and in surface waters along the GEOVIDE section covering a zonal transect through the SPNA in spring 2014. Our results show that the two tracers are distributed following the water mass structure and that their presence is largely influenced by the global fallout (GF)...
Tipo: Text
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00457/56873/58725.pdf

Seasonal depletion of the dissolved iron reservoirs in the sub‐Antarctic zone of the Southern Atlantic Ocean
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Mtshali, T.n.; Horsten, N.r.; Thomalla, S.j.; Ryan‐keogh, T.j.; Nicholson, S.‐a.; Roychoudhury, A.n.; Bucciarelli, Eva; Sarthou, Geraldine; Tagliabue, A.; Monteiro, P.m.s.
Seasonal progression of dissolved iron (DFe) concentrations in the upper water column were examined during four occupations in the Atlantic sector of the Southern Ocean. DFe inventories from euphotic and aphotic reservoirs decreased progressively from July to February, while dissolved inorganic nitrogen (DIN) decreased from July to January with no significant change between January and February. Results suggest that between July and January, DFe loss from both euphotic and aphotic reservoirs were predominantly in support of phytoplankton growth (Iron to carbon (Fe:C) uptake ratio of 16±3 μmol mol‐1) highlighting the importance of the “winter DFe‐reservoir” for biological uptake. During January to February, excess loss of DFe relative to DIN (Fe:C uptake...
Tipo: Text
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00487/59914/63095.pdf

Particulate barium tracing of significant mesopelagic carbon remineralisation in the North Atlantic
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Lemaitre, Nolwenn; Planquette, Helene; Planchon, Frederic; Sarthou, Geraldine; Jacquet, Stephanie; Garcia-ibanez, Maria Isabel; Gourain, Arthur; Cheize, Marie; Monin, Laurence; Andre, Luc; Laha, Priya; Terryn, Herman; Dehairs, Frank.
The remineralisation of sinking particles by prokaryotic heterotrophic activities is important for controlling oceanic carbon sequestration. Here, we report mesopelagic particulate organic carbon (POC) remineralisation fluxes in the North Atlantic along the GEOTRACES-GA01 section (GEOVIDE cruise; May–June 2014) using the particulate biogenic barium (excess barium; Baxs) proxy. Important mesopelagic (100–1000 m) Baxs differences were observed along the transect depending on the intensity of past blooms, the phytoplankton community structure and the physical forcing, including downwelling. The subpolar province was characterized by the highest mesopelagic Baxs content (up to 727 pmol L−1), which was attributed to an intense bloom averaging 6 mg Chl-a m−3...
Tipo: Text
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00412/52308/53075.pdf

Dissolved Pb and Pb isotopes in the North Atlantic from the GEOVIDE transect (GEOTRACES GA-01) and their decadal evolution
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Zurbrick, Cheryl M.; Boyle, Edward A.; Kayser, Richard J.; Reuer, Matthew K.; Wu, Jinfeng; Planquette, Helene; Shelley, Rachel; Boutorh, Julia; Cheize, Marie; Contreira, Leonardo; Barraqueta, Jan-lukas Menzel; Lacan, Francois; Sarthou, Geraldine.
During the 2014 GEOVIDE transect, seawater samples were collected for dissolved Pb and Pb isotope analysis. These samples provide a high-resolution "snapshot" of the source regions for the present Pb distribution in the North Atlantic Ocean. Some of these stations were previously occupied for Pb from as early as 1981, and we compare the 2014 data with these older data, some of which are reported here for the first time. Lead concentrations were highest in subsurface Mediterranean Water (MW) near the coast of Portugal, which agrees well with other recent observations by the US GEOTRACES program (Noble et al., 2015). The recently formed Labrador Sea Water (LSW) between Greenland and Nova Scotia is much lower in Pb concentration than the older LSW found in...
Tipo: Text
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00456/56760/58607.pdf

Regulation of the Phytoplankton Heme b Iron Pool During the North Atlantic Spring Bloom
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: 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 (&lt; 1 pmol L-1) in iron limited phytoplankton in cultures and in the field. Here, we determined heme b in marine particulate material (&gt; 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

Measurement of the isotopic composition of dissolved iron in the open ocean
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Lacan, F.; Radic, A.; Jeandel, C.; Poitrasson, F.; Sarthou, Geraldine; Pradoux, C.; Freydier, R.
This work demonstrates for the first time the feasibility of the measurement of the isotopic composition of dissolved iron in seawater for a typical open ocean Fe concentration range (0.1-1 nM). It also presents the first data of this kind. Iron is preconcentrated using a Nitriloacetic Acid Superflow resin and purified using an AG1x4 anion exchange resin. The isotopic ratios are measured with a MC-ICPMS Neptune, coupled with a desolvator (Aridus II), using a Fe-57-Fe-58 double spike mass bias correction. Measurement precision (0.13%, 2SD) allows resolving small iron isotopic composition variations within the water column, in the Atlantic sector of the Southern Ocean (from delta Fe-57 = -0.19 to +0.32 parts per thousand). Isotopically light iron found in...
Tipo: Text
Palavras-chave: MC ICP MS; Chelating resin; Southern ocean; Fractionation; Seawater; Earth; Separation; Accuracy; Pacific; FE(III).
Ano: 2008
URL: https://archimer.ifremer.fr/doc/00202/31374/29781.pdf

Trace element behaviour at cold seeps and the potential export of dissolved iron to the ocean
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Lemaitre, Nolwenn; Bayon, Germain; Ondreas, Helene; Caprais, Jean-claude; Freslon, Nicolas; Bollinger, Claire; Rouget, Marie-laure; De Prunele, Alexis; Ruffine, Livio; Olu-le Roy, Karine; Sarthou, Geraldine.
Seawater samples were collected by submersible above methane seeps in the Gulf of Guinea (Regab and Baboon pockmarks) in order to investigate the behaviour of iron (Fe), manganese (Mn) and rare earth elements (REE) during fluid seepage. Our aim was to determine whether cold seeps may represent potential sources of dissolved chemical species to the ocean. Dissolved (&lt;0.45 μm filtered samples) and total dissolvable (unfiltered samples) concentrations were determined over ∼50 m long vertical transects above the seafloor and at various discrete locations within the pockmarks. We show that substantial amounts of Fe and Mn are released into seawater during seepage of methane-rich fluids. Mn is exported almost quantitatively in the dissolved form (more than...
Tipo: Text
Palavras-chave: Iron; Rare earth elements; Cold seeps; Seawater; Organic ligands; Iron-sulfide nanoparticles.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00211/32190/30704.pdf

The Solomon Sea: its circulation, chemistry, geochemistry and biology   explored during two oceanographic cruises
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Ganachaud, Alexandre; Cravatte, Sophie; Sprintall, Janet; Germineaud, Cyril; Alberty, Marion; Jeandel, Catherine; Eldin, Gerard; Metzl, Nicolas; Bonnet, Sophie; Benavides, Mar; Heimburger, Lars-eric; Lefevre, Jerome; Michael, Susanna; Resing, Joseph; Queroue, Fabien; Sarthou, Geraldine; Rodier, Martine; Berthelot, Hugo; Baurand, Francois; Grelet, Jacques; Hasegawa, Takuya; Kessler, William; Kilepak, Moyep; Lacan, Francois; Privat, Emilien; Send, Uwe; Van Beek, Pieter; Souhaut, Marc; Sonke, Jeroen E.
The semi-enclosed Solomon Sea in the southwestern tropical Pacific is on the pathway of a major oceanic circuit connecting the subtropics to the equator via energetic western boundary currents. Waters transiting through this area replenish the Pacific Warm Pool and ultimately feed the equatorial current system, in particular the equatorial undercurrent. In addition to dynamical transformations, water masses undergo nutrient and micronutrient enrichment when coming in contact with the coasts, impacting the productivity of the downstream equatorial region. Broadscale observing systems are not well suited for describing the fine-scale currents and water masses properties in the Solomon Sea, leaving it relatively unexplored. Two multidisciplinary oceanographic...
Tipo: Text
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00390/50185/50808.pdf

Iron budgets for three distinct biogeochemical sites around the Kerguelen Archipelago (Southern Ocean) during the natural fertilisation study, KEOPS-2
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Bowie, A. R.; Van Der Merwe, P.; Queroue, Fabien; Trull, Thomas; Fourquez, M.; Planchon, F.; Sarthou, Geraldine; Chever, Fanny; Townsend, A. T.; Obernosterer, I.; Sallee, Jean-baptiste; Blain, S.
Iron availability in the Southern Ocean controls phytoplankton growth, community composition and the uptake of atmospheric CO2 by the biological pump. The KEOPS-2 (KErguelen Ocean and Plateau compared Study 2) "process study", took place around the Kerguelen Plateau in the Indian sector of the Southern Ocean. This is a region naturally fertilised with iron on the scale of hundreds to thousands of square kilometres, producing a mosaic of spring blooms which show distinct biological and biogeochemical responses to fertilisation. This paper presents biogeochemical iron budgets (incorporating vertical and lateral supply, internal cycling, and sinks) for three contrasting sites: an upstream high-nutrient low-chlorophyll reference, over the plateau and in the...
Tipo: Text
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00276/38726/37233.pdf

High variability in dissolved iron concentrations in the vicinity of the Kerguelen Islands (Southern Ocean)
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Queroue, Fabien; Sarthou, Geraldine; Planquette, Helene; Bucciarelli, Eva; Chever, Fanny; Van Der Merwe, P.; Lannuzel, Delphine; Townsend, A. T.; Cheize, Marie; Blain, S.; D'Ovidio, F.; Bowie, A. R.
Dissolved Fe (dFe) concentrations were measured in the upper 1300 m of the water column in the vicinity of the Kerguelen Islands as part of the second KErguelen Ocean Plateau compared Study (KEOPS2). Concentrations ranged from 0.06 nmol L-1 in offshore, Southern Ocean waters to 3.82 nmol L-1 within Hillsborough Bay, on the north-eastern coast of the Kerguelen Islands. Direct island runoff, glacial melting and resuspended sediments were identified as important inputs of dFe that could potentially fertilise the northern part of the plateau. A significant deep dFe enrichment was observed over the plateau with dFe concentrations increasing up to 1.30 nmol L-1 close to the seafloor, probably due to sediment resuspension and pore water release. Biological uptake...
Tipo: Text
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00274/38482/36942.pdf

Allelochemicals from Alexandrium minutum induce rapid inhibition of metabolism and modify the membranes from Chaetoceros muelleri
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Long, Marc; Tallec, Kevin; Soudant, Philippe; Le Grand, Fabienne; Donval, Anne; Lambert, Christophe; Sarthou, Geraldine; Jolley, Dianne F.; Hegaret, Helene.
Allelochemical interactions are likely to be a contributing factor explaining the success of large blooms of the harmful marine dinoflagellate Alexandrium, however, the physiological mechanisms of allelochemical interactions remain poorly described. Here we investigated the sub-lethal effects (on an hourly scale) of a filtrate containing allelochemicals from Alexandrium minutum on the physiology of the common diatom Chaetoceros muelleri. The filtrate induced deleterious effects to the diatom physiology within only 30 min of exposure. Esterase activity and photosynthesis were drastically inhibited, with up to 34% of the population being metabolically inactive and up to 30% reduction in photosystem II quantum yield when exposed to the filtrate. In addition,...
Tipo: Text
Palavras-chave: Allelopathy; Alexandrium; Metabolism; Photoinhibition; Lipids; Pigments.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00460/57133/59748.pdf

Revisiting the distribution of oceanic N-2 fixation and estimating diazotrophic contribution to marine production
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Tang, Weiyi; Wang, Seaver; Fonseca-batista, Debany; Dehairs, Frank; Gifford, Scott; Gonzalez, Aridane G.; Gallinari, Morgane; Planquette, Helene; Sarthou, Geraldine; Cassar, Nicolas.
Marine N-2 fixation supports a significant portion of oceanic primary production by making N-2 bioavailable to planktonic communities, in the process influencing atmosphere-ocean carbon fluxes and our global climate. However, the geographical distribution and controlling factors of marine N-2 fixation remain elusive largely due to sparse observations. Here we present unprecedented high-resolution underway N-2 fixation estimates across over 6000 kilometers of the western North Atlantic. Unexpectedly, we find increasing N-2 fixation rates from the oligotrophic Sargasso Sea to North America coastal waters, driven primarily by cyanobacterial diazotrophs. N-2 fixation is best correlated to phosphorus availability and chlorophylla concentration. Globally,...
Tipo: Text
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00484/59564/62548.pdf

Particulate Trace Element Export in the North Atlantic (GEOTRACES GA01 Transect, GEOVIDE Cruise)
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Lemaitre, Nolwenn; Planquette, Helene; Dehairs, Frank; Planchon, Frederic; Sarthou, Geraldine; Gallinari, Morgane; Roig, Stéphane; Jeandel, Catherine; Castrillejo, Maxi.
Vertical export of particulate trace elements (pTEs) is a critically underconstrained aspect of their biogeochemistry. Here, we combine elemental analyses on large (&gt;53 μm) particles and 234Th measurements to determine downward export fluxes from the upper layers (40–110 m) of pTEs (Al, Cd, Co, Cu, Fe, Mn, Ni, P, Ti, V, Zn) and mineral phases (lithogenic, Fe- and Mn-oxides, calcium carbonate, and opal) in the North Atlantic along the GEOVIDE transect (Portugal–Greenland–Canada; GEOTRACES GA01 cruise). The role of lithogenic particles in controlling TE fluxes is obvious at proximity of the Iberian margin where the highest pTE export fluxes were estimated (up to 3912 μg/m2/d for pFe). However, high lithogenic and pTE fluxes are also observed up to 1700 km...
Tipo: Text
Palavras-chave: Particulate trace elements; Export fluxes; Multiple carrier phases; Residence times; GEOTRACES.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00656/76810/78174.pdf