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Registros recuperados: 27
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Effects of copper on the dinoflagellate Alexandrium minutum and its allelochemical potency ArchiMer
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
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Processes Driving Iron and Manganese Dispersal From the TAG Hydrothermal Plume (Mid-Atlantic Ridge): Results From a GEOTRACES Process Study ArchiMer
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 (<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
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The Transpolar Drift as a Source of Riverine and Shelf-Derived Trace Elements to the Central Arctic Ocean ArchiMer
Charette, Matthew A.; Kipp, Lauren E.; Jensen, Laramie T.; Dabrowski, Jessica S.; Whitmore, Laura M.; Fitzsimmons, Jessica N.; Williford, Tatiana; Ulfsbo, Adam; Jones, Elizabeth; Bundy, Randelle M.; Vivancos, Sebastian M.; Pahnke, Katharina; John, Seth G.; Xiang, Yang; Hatta, Mariko; Petrova, Mariia V.; Heimbürger-boavida, Lars-eric; Bauch, Dorothea; Newton, Robert; Pasqualini, Angelica; Agather, Alison M.; Amon, Rainer M.w.; Anderson, Robert F.; Andersson, Per S.; Benner, Ronald; Bowman, Katlin L.; Edwards, R. Lawrence; Gdaniec, Sandra; Gerringa, Loes J.a.; González, Aridane G.; Granskog, Mats; Haley, Brian; Hammerschmidt, Chad R.; Hansell, Dennis A.; Henderson, Paul B.; Kadko, David C.; Kaiser, Karl; Laan, Patrick; Lam, Phoebe J.; Lamborg, Carl H.; Levier, Martin; Li, Xianglei; Margolin, Andrew R.; Measures, Chris; Middag, Rob; Millero, Frank J.; Moore, Willard S.; Paffrath, Ronja; Planquette, Helene; Rabe, Benjamin; Reader, Heather; Rember, Robert; Rijkenberg, Micha J.a.; Roy-barman, Matthieu; Rutgers Van Der Loeff, Michiel; Saito, Mak; Schauer, Ursula; Schlosser, Peter; Sherrell, Robert M.; Shiller, Alan M.; Slagter, Hans; Sonke, Jeroen E.; Stedmon, Colin; Woosley, Ryan J.; Valk, Ole; Van Ooijen, Jan; Zhang, Ruifeng.
A major surface circulation feature of the Arctic Ocean is the Transpolar Drift (TPD), a current that transports river‐influenced shelf water from the Laptev and East Siberian Seas toward the center of the basin and Fram Strait. In 2015, the international GEOTRACES program included a high‐resolution pan‐Arctic survey of carbon, nutrients, and a suite of trace elements and isotopes (TEIs). The cruises bisected the TPD at two locations in the central basin, which were defined by maxima in meteoric water and dissolved organic carbon concentrations that spanned 600 km horizontally and ~25‐50 m vertically. Dissolved TEIs such as Fe, Co, Ni, Cu, Hg, Nd, and Th, which are generally particle‐reactive but can be complexed by organic matter, were observed at...
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Ano: 2020 URL: https://archimer.ifremer.fr/doc/00620/73223/72435.pdf
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High variability of particulate organic carbon export along the North Atlantic GEOTRACES section GA01 as deduced from 234Th fluxes ArchiMer
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 ( > 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...
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Ano: 2018 URL: https://archimer.ifremer.fr/doc/00465/57664/59860.pdf
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Inputs and processes affecting the distribution of particulate iron in the North Atlantic along the GEOVIDE (GEOTRACES GA01) section ArchiMer
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...
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Ano: 2019 URL: https://archimer.ifremer.fr/doc/00485/59676/62747.pdf
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Particulate barium tracing of significant mesopelagic carbon remineralisation in the North Atlantic ArchiMer
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...
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Ano: 2018 URL: https://archimer.ifremer.fr/doc/00412/52308/53075.pdf
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Ironing Out Fe Residence Time in the Dynamic Upper Ocean ArchiMer
Black, Ee; Kienast, Ss; Lemaitre, N; Lam, Pj; Anderson, Rf; Planquette, Helene; Planchon, Frederic; Buesseler, Ko.
Although iron availability has been shown to limit ocean productivity and influence marine carbon cycling, the rates of processes driving iron's removal and retention in the upper ocean are poorly constrained. Using 234Th‐ and sediment‐trap data, most of which were collected through international GEOTRACES efforts, we perform an unprecedented observation‐based assessment of iron export from and residence time in the upper ocean. The majority of these new residence time estimates for total iron in the surface ocean (0‐250 m) fall between 10 and 100 days. The upper ocean residence time of dissolved iron, on the other hand, varies and cycles on sub‐annual to annual timescales. Collectively, these residence times are shorter than previously thought, and the...
Tipo: Text Palavras-chave: Thorium-234<; /AUTHOR_KEYWORD>; Iron<; /AUTHOR_KEYWORD>; Export<; /AUTHOR_KEYWORD>; GEOTRACES<; /AUTHOR_KEYWORD>; Residence time<; /AUTHOR_KEYWORD>.
Ano: 2020 URL: https://archimer.ifremer.fr/doc/00644/75632/76493.pdf
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A call for refining the role of humic-like substances in the oceanic iron cycle ArchiMer
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...
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Ano: 2020 URL: https://archimer.ifremer.fr/doc/00622/73388/72598.pdf
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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 ArchiMer
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...
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Ano: 2018 URL: https://archimer.ifremer.fr/doc/00439/55041/56473.pdf
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Dissolved Pb and Pb isotopes in the North Atlantic from the GEOVIDE transect (GEOTRACES GA-01) and their decadal evolution ArchiMer
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...
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Ano: 2018 URL: https://archimer.ifremer.fr/doc/00456/56760/58607.pdf
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Revisiting the distribution of oceanic N-2 fixation and estimating diazotrophic contribution to marine production ArchiMer
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,...
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Ano: 2019 URL: https://archimer.ifremer.fr/doc/00484/59564/62548.pdf
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Particulate Rare Earth Element behavior in the North Atlantic (GEOVIDE cruise) ArchiMer
Lagarde, Marion; Lemaitre, Nolwenn; Planquette, Helene; Grenier, Mélanie; Belhadj, Moustafa; Lherminier, Pascale; Jeandel, Catherine.
Particulate concentrations of the fourteen Rare Earth Elements (PREE), yttrium and 232-thorium have been measured in two hundred samples collected in the epipelagic (ca. 0–200 m) and the mesopelagic (ca. 200–1000 m) zones of the North Atlantic, during the GEOVIDE cruise (May/June 2014, R/V Pourquoi Pas ?, GEOTRACES GA01). Particulate cerium (PCe) concentrations vary from 0.2 pmol L−1 to 16 pmol L−1, particulate neodymium (PNd) ones from 0.09 pmol L−1 to 6.1 pmol L−1 and particulate ytterbium (PYb) ones from 0.01 pmol L−1 to 0.5 pmol L−1. PREE concentrations are higher close to the Iberian margin and on the Greenland shelf, where PREE concentrations normalized to Post Archean Australian Shale (PAAS) display a positive Ce anomaly between 0.3 and 3, and a...
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Ano: 2020 URL: https://archimer.ifremer.fr/doc/00601/71323/69750.pdf
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Regulation of the Phytoplankton Heme b Iron Pool During the North Atlantic Spring Bloom ArchiMer
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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Mercury distribution and transport in the North Atlantic Ocean along the GEOTRACES-GA01 transect ArchiMer
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 (< 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...
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Ano: 2018 URL: https://archimer.ifremer.fr/doc/00412/52303/53071.pdf
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Introduction to the French GEOTRACES North Atlantic Transect (GA01): GEOVIDE cruise ArchiMer
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.
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Ano: 2018 URL: https://archimer.ifremer.fr/doc/00470/58178/60685.pdf
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Pervasive sources of isotopically light zinc in the North Atlantic Ocean ArchiMer
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
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Investigating the microbial ecology of coastal hotspots of marine nitrogen fixation in the western North Atlantic ArchiMer
Wang, Seaver; Tang, Weiyi; Delage, Erwan; Gifford, Scott; Whitby, Hannah; González, Aridane G.; Eveillard, Damien; Planquette, Helene; Cassar, Nicolas.
Variation in the microbial cycling of nutrients and carbon in the ocean is an emergent property of complex planktonic communities. While recent findings have considerably expanded our understanding of the diversity and distribution of nitrogen (N2) fixing marine diazotrophs, knowledge gaps remain regarding ecological interactions between diazotrophs and other community members. Using quantitative 16S and 18S V4 rDNA amplicon sequencing, we surveyed eukaryotic and prokaryotic microbial communities from samples collected in August 2016 and 2017 across the Western North Atlantic. Leveraging and significantly expanding an earlier published 2015 molecular dataset, we examined microbial community structure and ecological co-occurrence relationships associated...
Tipo: Text Palavras-chave: Element cycles; Marine biology.
Ano: 2021 URL: https://archimer.ifremer.fr/doc/00685/79677/82454.pdf
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Impact of inorganic particles of sedimentary origin on global dissolved iron and phytoplankton distribution ArchiMer
Beghoura, H.; Gorgues, Thomas; Aumont, Olivier; Planquette, Helene; Tagliabue, A.; Auger, P.‐a..
Iron is known to be the limiting nutrient for the phytoplankton growth over ~40% of the global ocean and to impact the structure of marine ecosystems. Dissolved iron (DFe) is assumed to be the only form available to phytoplankton while particulate iron (PFe) has mostly been considered for its role in the biogenic iron remineralization and induced scavenging. Therefore, most studies focused on the nature of DFe external sources to the ocean (i.e. aeolian dust, riverine fluxes, hydrothermal sources and sediment) and their quantification, which still remain uncertain. Among these external sources, the sedimentary sources have been shown to be underestimated. Moreover, the iron supply from sediments has been documented to be often larger in the particle...
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Ano: 2019 URL: https://archimer.ifremer.fr/doc/00591/70270/68330.pdf
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Particulate Trace Element Export in the North Atlantic (GEOTRACES GA01 Transect, GEOVIDE Cruise) ArchiMer
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 (>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
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Cadmium in the waters off South Morocco: Nature of particles hosting Cd and insights into the mechanisms fractionating Cd from phosphate ArchiMer
Waeles, Mathieu; Planquette, Helene; Afandi, Imane; Delebecque, Nina; Bouthir, Fatimazohra; Donval, Anne; Shelley, Rachel U.; Auger, Pierre-amael; Riso, Ricardo D.; De Morais, Luis Tito.
In this study, we report the distributions of total dissolvable cadmium and particulate cadmium from 27 stations in southern Moroccan coastal waters (22°N–30°N), which is part of the North-West African upwelling system. These distributions were predominantly controlled by upwelling of the North Atlantic Central Waters (NACWs) and uptake by primary production. Atmospheric inputs and phosphogypsum slurry inputs from the phosphate industry at Jorf Lasfar (33°N), recently estimated as an important source of dissolved cadmium (240 t Cd yr−1), are at best of minor importance for the studied waters. Our study provides new insights into the mechanisms fractionating cadmium from phosphate. In the upper 30 m, the anomalies observed in terms of Cd:P ratios in both...
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Ano: 2016 URL: https://archimer.ifremer.fr/doc/00334/44520/44216.pdf
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