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Title: Iron in north-east Pacific waters,
Description: Although Fe is an element of great biological 1 and geochemical 2 importance, little is known about its distribution in the sea. The reasons for this are: (1) contamination is extremely difficult to avoid during sampling and laboratory procedures, not only because of man's wide use of this element, but also because it is fourth most abundant element in the Earth's crust (5.63%) 3; (2) the chemistry of Fe is very complex, and its form (or forms) in seawater is poorly known, hence whether one preconcentration technique will work for existing species is questionable. Iron also appears to be very insoluble 4 in oxygenated ocean water, and most (90%) 5 precipitates out in association with dissolved organics during estuarine mixing processes 5-8. Indeed, some argue that truly dissolved Fe does not exist in seawater and that the fraction found in filtrates is totally colloidal 9. We have been attempting oceanic dissolved Fe measurements for the past four years and report here three vertical Fe profiles (Fig. 1) that have the following features in common: Fe is severely depleted (0.15-0.30 nmol kg -1) in surface waters; Fe maxima (up to 2.6 nmol kg -1) occur in association with oxygen minima; and, Fe levels appear to vary little in mid-depth waters (0.5-1.0 nmol kg -1)., Cited By (since 1996):33, ,
Author: Gordon, Martin, Knauer
Date: 1982-01-01T00:00:00Z

Title: Cobalt in north-east Pacific waters,
Description: Significant understanding has been gained recently about the biogeochemical cycling of trace metals in the ocean. This knowledge has mostly resulted from the accurate measurement of dissolved species in oceanic water columns. We report here that cobalt's vertical distribution is similar to that exhibited 1-3 by Mn; that is, its surface enrichment/deep depletion (Fig. 1). However, amounts of Co (1-7 ng 1 -1) are ∼10-20 times less than those for Mn (Table 1), as might be expected from crustal abundance estimates 4 for these elements (Mn=950; Co=25 μg per g). The similarity between Mn and Co profiles implies the same biogeochemical pathways. The Co excess in nearshore surface waters probably results from continental weathering input processes, as suggested by the remarkable Co-salinity mirror-image relationship shown in Fig. 1, and the Co-salinity scatter diagram in Fig. 2a. The steady decrease in Co concentrations also indicates that Co is usually scavenged rather than regenerated at depth, as is the case with Mn (Fig. 1; Table 1). © 1982 Nature Publishing Group., Cited By (since 1996):47 Oceanography, ,
Author: Knauer, Martin, Gordon
Date: 1982-01-01T00:00:00Z

Title: Mytilus californianus as a bioindicator of trace metal pollution: Variability and statistical considerations,
Description: Trace metal variability was evaluated in two populations of Mytilus californianus through the analysis of individual specimens. Samples were collected for two areas in the Southern California Bight and analysed for their Al, Cd, Cr, Cu, Fe, Ni, Pb and Zn content. Analysis of the data revealed that population variability was not the same between the two sites, indicating that variability may need to be evaluated for each population (site) studied. In general, the analysis of 10 to 30 individuals was necessary to yield maximum resolution in terms of trace metal concentrations between population means while maintaining cost effectiveness., Cited By (since 1996):29, CODEN: MPNBA, ,
Author: Gordon, Knauer, Martin
Date: 1980-01-01T00:00:00Z

Title: Silver distributions and fluxes in north-east Pacific waters,
Description: In recent years, significant knowledge has been gained about the oceanic distributions of several trace elements 1,2. However, relatively little is known about amounts of Ag in the ocean, and how this element cycles through it. We report here that Ag levels are relatively low near the surface (∼1 pmol kg -1), and that concentrations more or less steadily increase with depth; for example, 23 pmol kg -1 at 2,440 m, the deepest sample we collected. In general, Ag depth profiles are similar to those observed for Cu (Fig. 1). The near-surface cycles of Ag appears to be involved with particulate organic matter uptake-sinking-regeneration processes. © 1983 Nature Publishing Group., Cited By (since 1996):39, Oceanography, ,
Author: Martin, Knauer, Gordon
Date: 1983-01-01T00:00:00Z

Title: The distribution and behavior of dissolved and particulate iron and zinc in the Ross Sea and Antarctic circumpolar current along 170°W,
Description: Dissolved and particulate iron and zinc were measured in water samples collected from the Antarctic Circumpolar Current (ACC) region and the Ross Sea during the US JGOFS Antarctic Environment Southern Ocean Process Study (AESOPS). Dissolved and particulate zinc showed strongly seasonal variation, indicating efficient recycling in the upper 150 m of the water column in both regions. Seasonal zinc utilization is 21-118 μmol m-2 in the ACC and 134-192 μmol m-2 in the Ross Sea. Only 10-25% of the particulate zinc is exported below 150 m. Generally low dissolved (<0.05 nmol kg -1) and particulate iron concentrations (<0.2 nmol kg -1) were observed in the mixed layer year-around in the ACC region whereas seasonal depletion of dissolved iron and relatively high particulate iron (>1 nmol kg-1) were found in the Ross Sea. Seasonal iron utilization is 7-45 μmol m-2 in the ACC and 450-938 μmol m -2 in the Ross Sea, which yields an estimated Fe/C ratio of 15 and 100 (μmol Fe:mol C) for the ACC and the Ross Sea, respectively. More than 50% of the total iron production is exported below 150 m in the ACC region. Iron input through vertical mixing was minimal, in contrast to the vertical input of dissolved zinc and macronutrients in the ACC region. Upwelling may supply 50% of the export production of iron near the Southern ACC Front. In the Ross Sea, more iron is available due to the variety of inputs, in contrast to the ACC region. In addition to the input of dissolved and particulate iron from melting sea-ice, there is substantial input of particulate iron from the suspended materials of sediments. © 2004 Elsevier Ltd. All rights reserved., Cited By (since 1996):42, Oceanography, CODEN: DRORE, Antarctica, ,
Author: Coale, Gordon, Wang
Date: 2005-01-01T00:00:00Z