Consulta: subjectFacets:"Sediment traps"
Registros recuperados: 11
Data/hora: 11/06/2024 12:32:35

Downward fluxes of particulate organic matter in coastal and oceanic areas off Chile: The role of the OMZ and functional groups of the plankton
Provedor de dados: 72
Autores: González,H E; Daneri,G; Menschel,E; Marchant,M; Pantoja,S; Hebbeln,D; Barria,C; Vera,R; Iriarte,J.
Vertical fluxes of particles have been estimated during the last decade in coastal and oceanic systems off central-southern Chile. Free-drifting, cylindrical sediment traps have been deployed below the mixing layer from coastal areas, while automatic, cone-shaped sediment traps have been anchored in deep oceanic areas. Vertical fluxes toward 2300 m depth off Coquimbo were dominated by calcium carbonate (~70 mg m-2 d-1) instead of particulate organic carbon (POC ~7 mg m-2 d-1), where foraminifers (Neogloboquadrina pachyderma) and faecal pellets of Euphausia mucronata and Oikopleura spp, played important roles as vehicles for carbonate and carbon, respectively. In coastal upwelling systems, (i. e. Concepción), the dominant vertical flux was POC, mainly...
Tipo: Journal article
Palavras-chave: Particulate organic matter; Fluxes; Oxygen minimum zone; Zooplankton functional groups; Sediment traps; Central Chile.
Ano: 2006
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-65382006000300007

The fate of diatom valves in the Subantarctic and Polar Frontal Zones of the Southern Ocean: Sediment trap versus surface sediment assemblages
Provedor de dados: 5
Autores: Rigual-hernandez, Andres S.; Trull, Thomas W.; Bray, Stephen G.; Armand, Leanne K.
An array of deep ocean sediment traps was initiated in 1997 within the Australian sector of the Southern Ocean, and serviced annually for over a decade (the Subantarctic site is ongoing as part of the Southern Ocean Time Series). Here, we expand on previous findings obtained from the shallow traps (~ 1000 m depth) in the Polar Frontal Zone (PFZ) and Subantarctic Zone (SAZ) by examining the chemical composition and diatom assemblages collected by sediment traps deployed at bathypelagic depths in the PFZ (1500 m depth; years 1997–1998, 1999–2000 and 2003–2004) and SAZ (2000 and 3800 m; year 1999–2000). Additionally, the diatom assemblages of the surface sediments below the traps were analyzed to document how the seasonal signal is recorded in the sedimentary...
Tipo: Text
Palavras-chave: Diatoms; POC; Sediment traps; Surface sediments; Subantarctic Zone; Polar Frontal Zone.
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00341/45215/44642.pdf

Flux dynamics of planktic foraminiferal tests in the south-eastern Bay of Biscay (northeast Atlantic margin)
Provedor de dados: 5
Autores: Kuhnt, Tanja; Howa, Helene; Schmidt, Sabine; Marie, Louis; Schiebel, Ralf.
The temporal and water depth related dynamics of planktic foraminiferal fluxes in the south-eastern Bay of Biscay are discussed for a two year sampling period (June 2006-June 2008). Two sediment traps deployed at 800 m and 1700 m water depth at a mooring in 2000 m of water depth, were analyzed for the flux of planktic foraminiferal species &gt;150 mu m, in comparison with the total mass flux. Total flux of planktic foraminifera shows seasonal maxima in spring/early summer (&gt;2000 Ind.m(-2) d(-1)) and minima from late summer through winter (&lt;10 Ind.m(-2) d(-1)). The flux of planktic foraminiferal tests in the intermediate to deep water column at the inner Bay of Biscay comprises an intermittent and regionally variable signal of seasonal surface water...
Tipo: Text
Palavras-chave: Planktic foraminifera; Bay of Biscay; Sediment traps; Particulate mass flux; Pb-210; Seasonality; Lateral advection.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00125/23593/21785.pdf

Natural and anthropogenic trace metals in sediments of the Ligurian Sea (Northwestern Mediterranean)
Provedor de dados: 5
Autores: Heimbuerger, Lars-eric; Cossa, Daniel; Thibodeau, Benoit; Khripounoff, Alexis; Mas, Virginie; Chiffoleau, Jean-francois; Schmidt, Sabine; Migon, Christophe.
The magnitude and the chronology of anthropogenic impregnation by Hg and other trace metals of environmental concern (V, Cr, Ni, Cu, Zn, Ag, Cd and Pb, including its stable isotopes) in the sediments are determined at the DYFAMED station, a site in the Ligurian Sea (Northwestern Mediterranean) chosen for its supposed open-sea characteristics. The DYFAMED site (VD) is located on the right levee of the Var Canyon turbidite system, at the end of the Middle Valley. In order to trace the influence of the gravity current coming from the canyon on trace metal distribution in the sediment, we studied an additional sediment core (VA) from a terrace of the Var Canyon, and material collected in sediment traps at the both sites at 20 m above sea bottom. The patterns...
Tipo: Text
Palavras-chave: Marine sediments; Sediment traps; Mercury; Trace metals; Lead isotopes; Geochronology.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00073/18435/16125.pdf

Short scale (6 h) temporal variation of sinking fluxes of planktonic and terrigeneous lipids at 200 m in the NW Mediterranean Sea
Provedor de dados: 5
Autores: Mejanelle, L.; Dachs, J.
Drifting sediment trap measurements were carried out at high temporal frequency in the northwestern Mediterranean Sea in the course of the DYNAPROC 2 campaign, during the transition between late summer to autumn conditions. Molecular biomarkers were analyzed in selected subsets of consecutive samples collected for 6 h at 200 m depth. Fluxes of n-alkanes, long-chain alkenones, sterols and steroid ketones show high variability between consecutive 6-h samples, comparable in range to seasonal variability. n-Alkane export ranges from 1.4 to 29.7 mu g m(-2) d(-1), fluxes of C(37) alkenones varies from 0 to 14.2 mu g m(-2) d(-1). Fluxes of sterols, steroid ketones and C(30) alkane diol respectively range from 31 to 377, 2.2 to 46 and 0.3 to 9.3 mu g m(-2) d(-1)....
Tipo: Text
Palavras-chave: Long chain alkenones; North pacific ocean; Short term changes; Sediment traps; Fatty acids; Particulate matter; Alkyl diols; Alboran sea; Marine dinoflagellate; Organic geochemistry.
Ano: 2009
URL: https://archimer.ifremer.fr/doc/00210/32098/30555.pdf

Vertical particle flux in the northeast Atlantic Ocean (POMME experiment)
Provedor de dados: 5
Autores: Guieu, C; Roy-barman, M; Leblond, N; Jeandel, C; Souhaut, M; Le Cann, Bernard; Dufour, A; Bournot, C.
In the framework of the Programme Ocean Multidisciplinaire Meso Echelle (POMME) experiment, a 1.5 year record (February 2001-June 2002) of downward particle flux at 400 m and 1000 m was measured by sediment traps at four moorings located in the northeast Atlantic between 39 degrees-43 degrees N and 17 degrees-19 degrees W. Thorium-230 was used to estimate sediment trap efficiency, revealing values ranging from 18.5 to 55%. The lowest trapping efficiency was observed for the trap having experienced the highest currents. Significant interannual variability between 2001 and 2002 was clearly linked to the differences observed in the mixed layer depth. At some sites, particulate organic carbon (POC) export was higher (up to a factor of 1.6) during summer than...
Tipo: Text
Palavras-chave: Sediment traps; Carbon export; Biogenic and lithogenic tracers; Mesoscale circulation; Thorium isotopes.
Ano: 2005
URL: http://archimer.ifremer.fr/doc/00000/10982/7422.pdf

Sedimentation pathways in the Indian sector of the Southern Ocean during a production regime dominated by regeneration
Provedor de dados: 5
Autores: Cailliau, C; Belviso, S; Goutx, M; Bedo, A; Park, Y; Charriaud, E.
During summer 1994, the production regime at 2 sites located in the Indian sector of the Southern Ocean, one in the Permanent Open Ocean Zone (POOZ) at 52 degrees S, and a second in the Seasonal Ice Zone (SIZ) at 63 degrees S, was dominated by regeneration (0.3 &lt; f-ratio &lt; 0.4). Two time series, each of about 4 d, were performed over pre-determined time intervals of 4 h using a free-floating sediment trap set at 200 m at the 2 sites. Hourly variations of C, N, chlorophyll a (chl a) and its degradation products, taxon-specific pigments, lipid classes and dimethylsulfoniopropionate (DMSP) were measured simultaneously. Measurements in the water column were done during the sediment trap drifting. Fucoxanthin, a typical diatom pigment, was the major...
Tipo: Text
Palavras-chave: Antarctic; Austral ocean; Sediment traps; Diel cycles; Phytoplankton; Pigments; Lipids; DMSP; DMS.
Ano: 1999
URL: https://archimer.ifremer.fr/doc/00240/35083/33651.pdf

Variabilidad de los aportes a los sedimentos superficiales durante un ciclo anual en los Bancos de Salmedina
Provedor de dados: 20
Autores: Bernal, G.; Velásquez, A.; Vargas, I.; Agudelo, A.C.; Andrade, C.A.; Domínguez, J.G.; Ricaurte, C.; Mayo, G.
To understand sedimentation processes at Salmedina Reef Banks during the annual cycle, three cylindrical sediment traps were installed on the flat top of the reef Banks at mean depth of 8.5 m. Cylinders were collected monthly between July, 2003 and September, 2004. The trap content was analyzed by bulk composition and the composition of biogenic calcareous particles from the sand fraction. Results were compared with environmental parameters of the area trough the same time span. Sedimentological variables were analyzed with emphasis on terrigenous supply and relative percentages of calcareous components related to location and physical parameters. It was found that the totality of sedimentation, terrigenous contribution included, was concentrated during...
Tipo: Journal Contribution
Palavras-chave: Reefs; Sediment traps.
Ano: 2006
URL: http://hdl.handle.net/1834/1976

Electron microprobe analysis of suspended matter in the Angola Basin
Provedor de dados: 27
Autores: Bernard, P.; Eisma, D.; Van Grieken, R.
Electron microprobe analysis of suspended-matter samples collected at different water depths at ten stations in the Angola Basin indicated that at each station, from top to bottom, the elementary composition of the suspended matter was very similar and differed from the composition of the suspended matter at the adjacent stations. This indicates that the downward settling of the suspended matter is much faster than the horizontal transport and mixing by the currents. Assuming that the suspended matter settles in the form of flocs, or is scavenged by settling flocs, the suspended matter can indeed reach the bottom in a shorter period than needed for the currents to cover the distance between adjacent stations. Comparison with sediment trap data from the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Biochemical composition; Ocean basins; Sediment traps; Sedimentation; Suspended particulate matter.
Ano: 1999
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3977

Particle Fluxes and Bulk Geochemical Characterization of the Cabo Frio Upwelling System in Southeastern Brazil: Sediment Trap Experiments between Spring 2010 and Summer 2012
Provedor de dados: 42
Autores: ALBUQUERQUE,ANA LUIZA S.; BELÉM,ANDRÉ L.; ZULUAGA,FRANCISCO J.B.; CORDEIRO,LIVIA G.M.; MENDOZA,URSULA; KNOPPERS,BASTIAAN A.; GURGEL,MARCIO H.C.; MEYERS,PHILIP A.; CAPILLA,RAMSÉS.
Physical and biogeochemical processes in continental shelves act synergistically in both transporting and transforming suspended material, and ocean dynamics control the dispersion of particles by the coastal zone and their subsequent mixing and dilution within the shelf area constrained by oceanic boundary currents, followed by their gradual settling in a complex sedimentary scenario. One of these regions is the Cabo Frio Upwelling System located in a significantly productive area of Southeastern Brazil, under the control of the nutrient-poor western boundary Brazil Current but also with a wind-driven coastal upwelling zone, inducing cold-water intrusions of South Atlantic Central Water on the shelf. To understand these synergic interactions among...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Sediment traps; Bulk geochemical composition; Cabo Frio Upwelling System; Particle flux; Southeastern Brazilian shelf.
Ano: 2014
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652014000200601

A Model Analysis for the Design and Deployment of an Eulerian Sediment Trap Mooring Array in a Western Boundary Upwelling System from Southeast Brazil
Provedor de dados: 42
Autores: MENDOZA,URSULA; CANDELLA,ROGÉRIO N.; ASSAD,LUIZ P.F.; CASTILLO,FEDERICO V.; AZEVEDO,LAURA; KNOPPERS,BASTIAAN A.; ALBUQUERQUE,ANA LUIZA S.
This work addresses the design and configuration of a Eulerian sediment trap mooring array, which was deployed at the shelf edge (zm ≈ 140 m) 80 km off Cabo Frio, SE- Brazil (23° S). The site was subject to interplay between the Tropical Waters (TW) of the Brazil Current (BC), intrusions from the South Atlantic Central Waters (SACW), which are the source of upwelling in the region, and other oceanographic processes. Detailed computations were used to optimize the total weight, buoyancy balance, and maximum acceptable tilt to avoid hydrodynamic bias in the trapping efficiency and array adaptation to the local oceanographic conditions with the assistance of Matlab and Muringa programs and Modular Ocean Model 4.0 (MOM; i.e., to assert the vertical...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Design; Mooring array; Sediment traps; Trap efficiency; Cabo Frio upwelling; SE-Brazil.
Ano: 2014
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652014000200589