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| Registros recuperados: 14 | |
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| 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 |
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| Schneider,Wolfgang; Fuenzalida,Rosalino; Garcés-Vargas,José; Bravo,Luis; Lange,Carina. |
| Recent high-resolution hydrographic measurements (1976-2001) from the eastern South Pacific (ESP) were employed combined with high-resolution data from the World Ocean Circulation Experiment to evaluate the vertical and horizontal extension of the OMZ (oxygen minimum zone, < 20 µmol kg-1) there. Of the six permanent hypoxic regions in the world oceans, the ESP OMZ is volumetrically the fourth largest, occupying 2.74 x 10(6) km³ and accounting for ~11% globally. Examples of variability in the vertical position of the OMZ in the water-column and also in its intensity offshore central Chile will be addressed. We conclude that the OMZ in the ESP is partly based on old, low-oxygen waters from intermediate depths of the North Pacific Ocean, which were further... |
| Tipo: Journal article |
Palavras-chave: Oxygen minimum zone; Dissolved oxygen; Coastal upwelling; Eastern South Pacific; Peru; Chile. |
| Ano: 2006 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-65382006000300016 |
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| Ulloa,Osvaldo; Belmar,Lucy; Farías,Laura; Castro-González,Maribel; Galán,Alexander; Lavín,Paris; Molina,Verónica; Ramírez,Salvador; Santibáñez,Francisco; Stevens,Heike. |
| In recent years, our group has been studying the microbial communities of the water column associated with the oxygen minimum zone (OMZ) off northern Chile and Peru, trying to understand who the main players are in the OMZ biogeochemical cycles and which metabolic strategies they are using. For that, we are combining flow cytometry, molecular techniques and biogeochemical approaches. Most of our work, so far, has focused on microbes capable of doing oxygenic photosynthesis, such as the cyanobacteria, and those involved in the nitrogen cycle, such as the denitrifying, nitrifying and anammox bacteria. We have also started to look at the more general microbial abundance and diversity. In each case, we are finding that the OMZ holds distinct microbial... |
| Tipo: Journal article |
Palavras-chave: Oxygen minimum zone; Microbial diversity; Nitrogen cycle. |
| Ano: 2006 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-65382006000300018 |
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| Domke, Lia; Lacharite, Myriam; Metaxas, Anna; Matabos, Marjolaine. |
| Megafaunal diversity in the deep sea shows a parabolic pattern with depth. It can be affected by factors such as low oxygen concentration, which suppresses diversity, or the presence of submarine canyons, which enhances it. Barkley Canyon, located off the west coast of British Columbia, Canada, is a submarine canyon that extends from the continental margin (200 m) into the deep ocean (2,000 m). This canyon receives drift kelp from shoreline kelp forests and contains an oxygen minimum zone (OMZ) at 500 to 1,500 m depth. Our study investigated the abundance and diversity of epibenthic megafauna over a range of depths (200–2,000 m) and oxygen concentrations (0.5–5.0 ml/L) within Barkley Canyon, as well as changes in abundance near detrital kelp. Video was... |
| Tipo: Text |
Palavras-chave: Barkley Canyon; Benthic surveys; British Columbia; Kelp detritus; Oxygen minimum zone; Submarine canyon. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00416/52773/56793.pdf |
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| Pizarro-koch, Matias; Pizarro, Oscar; Dewitte, Boris; Montes, Ivonne; Ramos, Marcel; Paulmier, Aurelien; Garcon, Veronique. |
| We investigate the seasonal variability of the southern tip (30 degrees-38 degrees S) of the eastern South Pacific oxygen minimum zone (OMZ) based on a high horizontal resolution (1/12 degrees) regional coupled physical-biogeochemical model simulation. The simulation is validated by available in situ observations and the OMZ seasonal variability is documented. The model OMZ, bounded by the contour of 45 mu M, occupies a large volume (4.5x10(4) km(3)) during the beginning of austral winter and a minimum (3.5x10(4) km(3)) at the end of spring, just 1 and 2 months after the southward transport of the Peru-Chile Undercurrent (PCUC) is maximum and minimum, respectively. We showed that the PCUC significantly impacts the alongshore advection of dissolved oxygen... |
| Tipo: Text |
Palavras-chave: Oxygen minimum zone; Eddy fluxes; Peru-Chile Undercurrent; Oxygen budget; Eastern South Pacific. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00688/79991/82948.pdf |
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| Heller, Maija Iris; Lam, Phoebe J.; Moffett, James W.; Till, Claire P.; Lee, Jong-mi; Toner, Brandy M.; Marcus, Matthew A.. |
| Oxygen minimum zones (OMZs) have been proposed to be an important source of dissolved iron (Fe) into the interior ocean. However, previous studies in OMZs have shown a sharp decrease in total dissolved Fe (dFe) and/or dissolved Fe(II) (dFe(II)) concentrations at the shelf-break, despite constant temperature, salinity and continued lack of oxygen across the shelf-break. The loss of both total dFe and dFe(II) suggests a conversion of the dFe to particulate form, but studies that have coupled the reduction-oxidation (redox) speciation of both dissolved and particulate phases have not previously been done. Here we have measured the redox speciation and concentrations of both dissolved and particulate forms of Fe in samples collected during the U.S. GEOTRACES... |
| Tipo: Text |
Palavras-chave: Oxygen minimum zone; Oxygen deficient zone; OMZ; ODZ; Fe redox cycling; Synchrotron XAS. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00386/49714/50242.pdf |
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| Ohkushi, K.; Kennett, J. P.; Zeleski, C. M.; Moffitt, S. E.; Hill, T. M.; Robert, Cyril; Beaufort, L.; Behl, R. J.. |
| The oxygen minimum zone (OMZ) of the late Quaternary California margin experienced abrupt and dramatic changes in strength and depth in response to changes in intermediate water ventilation, ocean productivity, and climate at orbital through millennial time scales. Expansion and contraction of the OMZ is exhibited at high temporal resolution (107-126 year) by quantitative benthic foraminiferal assemblage changes in two piston cores forming a vertical profile in Santa Barbara Basin (569 m, basin floor; 481 m, near sill depth) to 34 and 24 ka, respectively. Variation in the OMZ is quantified by new benthic foraminiferal groupings and new dissolved oxygen index based on documented relations between species and water-mass oxygen concentrations.... |
| Tipo: Text |
Palavras-chave: Oxygen minimum zone; Foraminifera; Ventilation; Oxygen index; Pacific; Hypoxia. |
| Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00264/37489/35811.pdf |
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| Blanchet, C. L.; Kasten, S.; Vidal, L.; Poulton, S. W.; Ganeshram, R.; Thouveny, N.. |
| In order to evaluate the influence of diagenetic and post-sampling processes on the stable oxygen and carbon isotope compositions of biogenic carbonates, we conducted a multiproxy study of organic-rich sediments from the eastern Pacific oxygen minimum zone. Core MD02-2520, which was retrieved from the Gulf of Tehuantepec (Mexico), has seasonal laminations and covers the last 40 kyr. Together with the presence of gypsum crystals and inorganic calcite aggregates, the occurrence of large excursions in the stable oxygen and carbon isotope records of both planktonic and benthic foraminifera (as large as +3 parts per thousand in delta O-18 and -5 parts per thousand in delta C-13) point to significant secondary transformations. Storage-related gypsum... |
| Tipo: Text |
Palavras-chave: Diagenesis; Gypsum; Inorganic calcite; Laminations; Oxygen minimum zone; Sulfur reoxidation. |
| Ano: 2012 |
URL: https://archimer.ifremer.fr/doc/00139/25049/23173.pdf |
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| Neira, Carlos; Gad, Gunnar; Arroyo, Nina L.; Decraemer, Wilfrida. |
| Glochinema bathyperuvensis sp. n., the first record of Epsilonematidae from bathyal muddy sediments of the oxygen minimum zone (OMZ) off Callao, Peru (eastern Pacific Ocean) is described. The new species belongs to the subfamily Glochinematinae and is characterized by the possession of more than 8 pairs of subdorsal thorns asymmetrically arranged and a single dorsal one in the pharyngeal region, as well as by the presence of ten to thirteen blade-like cuticular protrusions forming a latero-dorsal palisade around the posterior head region and anterior cervical region. In addition, G. bathyperuvensis is characterized by its large size, more than 240 cuticular annules, provided with an extremely dense „hairy“ body ornamentation and, four rows of ambulatory... |
| Tipo: Article / Letter to the editor |
Palavras-chave: Glochinema bathyperuvensis sp. n.; Nematoda; Epsilonematidae; Bathyal sediments; Oxygen minimum zone; El Niño; Peru. |
| Ano: 2001 |
URL: http://www.repository.naturalis.nl/record/534382 |
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| TAPIA,RAÚL; LANGE,CARINA B; MARCHANT,MARGARITA. |
| This study examines onshore-offshore and vertical distribution of living (Rose Bengal stained) benthic foraminifera (> 180 μm fraction) from three sediment stations along a bathymetric transect off Concepción, Chile (station 18 = 88 m water depth, station 26 = 120 m, station 40 = 1,030 m), within and below the oxygen minimum zone. All cores were collected in austral winter. Calcareous foraminifera dominated the three stations. The species composition, living foraminifera density, and vertical distribution patterns within the sediment changed in accordance with bottom water dissolved oxygen concentration and food availability. Onshore-offshore pattern revealed overall highest living foraminiferal densities at shelf stations 18 and 26 where... |
| Tipo: Journal article |
Palavras-chave: Benthic foraminifera; Sediments; Oxygen minimum zone; Concepción; Chile. |
| Ano: 2008 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2008000300009 |
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| Registros recuperados: 14 | |
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