Cadmium, copper, iron, nickel and zinc in the north-east Atlantic Ocean (original) (raw)
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Cadmium, copper and nickel distributions at four stations in the eastern central and south Atlantic
Mar Chem, 1995
Distributions of cadmium, copper and nickel at four stations in the eastern part of the Atlantic Ocean from 30 ° S to 34 ° N are described based on analytical results from three laboratories. The Cd and Ni profiles show nutrient-like distributions with concentrations in the deep waters increasing from north to south. Copper profiles all show gradual increases from surface to bottom with the highest concentrations occurring near bottom on the most northerly station.Variations in the deep-water Cd and Ni concentrations can be understood in terms of mixing of southern source waters with high concentrations with lower concentration northern source waters. The deep-water Cu distributions indicate a significant near-bottom source to the northern end of the section.Cadmium vs. phosphate relationships show features that result from both regeneration and mixing. Higher Cd:PO4 ratios are seen in the southern source waters than in the northern waters, thus discounting the suggestion that the inflection in the global Cd:PO4 relationship at PO4 ≈ 1.3 μM originates in the southern ocean. Differential regeneration of Cd and PO4 is seen through the equatorial oxygen minimum.
Marine Chemistry, 1982
Spencer, M.J., Betzer, P.R. and Piotrowicz, S.R., 1982. Concentrations of cadmium, copper, lead and zinc in surface waters of the northwest Atlantic Ocean --a comparison of Go-rio and teflon water samples. Mar. Chem., 11: 403--410.
The determination of Cd, Cu, Fe, Ni, Pb and Zn in Baltic Sea water
Marine Chemistry, 1980
Zn in Baltic Sea water. Mar. Chem., 8: 231--244. Cd, Cu, Fe, Ni, Pb and Zn were determined in 123 samples from the Baltic Sea proper. The trace metals were extracted directly on board the vessel, using a dithiocarbamate--Freon procedure. Final analyses of the extracts are performed onshore by atomic absorption spectrometry. Similar trace-metal concentrations are found in different areas of the Baltic proper. Most values fall in the following ranges: Cd, 30--60 ng 1-1 ; Cu, 0.6--1.0/lgll-l ; Fe, 0.3--0.9 pg 1-1 ; Ni, 0.6 -0.9 pg 1-1 ; Pb, 0.05--0.2 pg l -l ; and Zn, 1.5--3.5 pg l-. The metalconcentrations are generally independent of depth. However, copper exhibits a small but significent decrease in concentration below 80 m. Filtration did not affect trace-metal concentrations, with the exception of iron in waters from lower layers. Similarly, storage under acid conditions was shown to affect only the concentration of iron. An electro-chemical technique was also used to determine Cu in some samples.
Continental Shelf Research, 1993
Open ocean studies have shown that dissolved manganese, cobalt and lead exhibit vertical profiles that reflect external sources and short residence times due to scavenging on to particle surfaces. In contrast, dissolved cadmium, copper, nickel and zinc mirror, to different degrees, the profiles of the nutrients. The work reported here for three cruises (November-December 1985, May and July-August 1986) in a shallow shelf sea shows that seasonal variations are shown by metals of the scavenged group, whereas the metals whose cycling in the open ocean parallels those of the nutients, do not show these correlations and, in fact, show no measurable seasonal variability. Concentrations of manganese increased progressively from winter to summer [2.3 -+ 0.7 (mean + lo) to 5.0 + 3.0 nmol 1-1]. A surface enrichment in the upper mixed layer of the western Channel during summer was also observed. Concentrations of cobalt increased from winter to spring (from -<0.02-0.50 to 0.08-0.71 nmol 1-1), paralleling those of manganese, but then decreased into summer (to -<0.08-0.56 nmol l-1). The regional distribution of lead changed during the spring, possibly reflecting removal by diatoms and decreased river inputs, although overall mean concentrations remained similar throughout the year (0.22 nmol 1-1). Concentrations of cadmium (0.20 nmol l-I), copper (3.2 nmol l-1), nickel (3.8 nmol l-1 ) and zinc (7.6 nmol I 1 ), and their regional distributions, remained relatively uniform over the period of the observations. 944 A.D. TAPPIbl et al. b z~ e-, ©
Analytica Chimica Acta, 1979
Sea-water samples collected by a variety of clean sampling techniques yielded consistent results for copper, cadmium, zinc, and nickel, which implies that representative, uncontaminated samples were obtained. A dithiocarbamate extraction method coupled with atomic absorption spectrometry and electro,thermal atomization is described which is essentially 100% quantitative for each of the four metals studied, has lower blanks and detection limits, and yields better precision than previously published techniques. A more precise and accurate determination of these metals in sea water at their natural ng 1-l concentration levels is therefore possible. Samples analyzed by this procedure and by concentration on Chelex-100 showed similar results for cadmium and zinc. Both copper and nickel appeared to be inefficiently removed from sea water by Chelex-100. Comparison of the organic extraction results with other pertinent investigations showed excellent agreement.
The distribution of dissolved zinc in the Atlantic sector of the Southern Ocean
Deep Sea Research Part II: Topical Studies in Oceanography, 2011
The distribution of dissolved zinc (Zn) was investigated in the Atlantic sector of the Southern Ocean in the austral autumn of 2008 as part of the IPY GEOTRACES expedition ZERO & DRAKE. Research focused on transects across the major frontal systems along the Zero Meridian and across the Drake Passage. There was a strong gradient in surface zinc concentrations observed across the Antarctic Polar Front along both transects and high zinc levels were found in surface waters throughout the Southern Ocean. Vertical profiles for dissolved Zinc showed the presence of local minima and maxima in the upper 200 m consistent with significant uptake by phytoplankton and release by zooplankton grazing, respectively. Highest deep water zinc concentrations were found in the centre of the Weddell Gyre associated with Central Intermediate Water (CIW), a water mass which is depleted in O 2 , elevated in CO 2 and is regionally a CFC minimum. Our data suggests that the remineralization of sinking particles is a key control on the distribution of Zn in the Southern Ocean. Disappearance ratios of zinc to phosphate (Zn:P) in the upper water column increased southwards along both transects and based on laboratory studies they suggest slower growth rates of phytoplankton due to iron or light limitation. Zinc and silicate were strongly correlated throughout the study region but the disappearance ratio (Zn:Si) was relatively uniform overall except for the region close to the ice edge on the Zero Meridian.
The marine geochemistry of trace metals
1976
The marine geochemical cycles of iron, copper, nickel, and cadmium were studied in order to provide a basis for oceanographic models for trace metals. Copper, nickel, and cadmium can be determined in a 100 ml seawater sample using cobalt pyrrolidine di thiocarbamate chelate coprecipi tat ion and graphite atomizer atomic absorption spectrometry. Concentration ranges likely to be encountered and estimated (10) analytical precisions are copper, 1 to 6 nanomole/kg (10.1); nickel, 3 to 12 nanomole/kg (i 0. 3); and cadmium, o. 0 to 1.1 nanomole/kg (i 0. l). The technique may be applied to freshwater samples with slight modification.-5-ACKNOWLEDGEMENT S I am grateful to John M. Edmond for being my advisor and friend and for providing a stimulating environment in which to do and learn research.
Trace metals in the eastern part of the North Sea: 1: Analyses and short-term distributions
Advanced analysis procedures for dissolved and particulate trace metals in sea water have been developed and tested in international intercalibration exercises. Since these tests gave evidence that reliable data could be produced with such methods, trace metal distributions in the coastal waters of the eastern North Sea were studied. The spatial distributions of most dissolved and particulate trace metals are, at least qualitatively, similar. Their concentrations decrease with distance from the coast and the mouth of the Scheldt estuary ( particulates much stronger than dissolved species). The salinity gradient is similar (but opposite) to the trace metals and turbidity gradients. The five trace metals studied can be subdivided into two groups on the basis of their KD ratios (particulate metal concentration to dissolved metal concentration). Hg and Pb are strongly associated with particulate matter (KD from 0.5 to1.5 offshore and from 7.9 to 40 in the coastal area), while Cd, Cu and...
Marine Chemistry, 1995
Dissolved" ( < 0.4 /*rn filtered) and "total dissolvable" (unfiltered) trace element samples were collected using "clean" sampling techniques from four vertical profiles in the eastern Atlantic Ocean on the first IOC Trace Metals Baseline expedition. The analytical results obtained by 9 participating laboratories for Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb, and Se on samples from station 4 in the northeast Atlantic have been evaluated with respect to accuracy and precision (intercomparability). The data variability among the reporting laboratories was expressed as 2 X SD for a given element and depth, and was comparable to the 95% confidence interval reported for the NASS seawater reference standards (representing analytical variability only). The discrepancies between reporting laboratories appear to be due to inaccuracies in standardization (analytical calibration), blank correction, and/or extraction efficiency corrections.
Marine Chemistry, 2007
Dissolved Fe, Mn and Al concentrations (dFe, dMn and dAl hereafter) in surface waters and the water column of the Northeast Atlantic and the European continental shelf are reported. Following an episode of enhanced Saharan dust inputs over the Northeast Atlantic Ocean prior and during the cruise in March 1998, surface concentrations were enhanced up to 4 nmol L − 1 dFe, 3 nmol L − 1 dMn and 40 nmol L − 1 dAl and returned to 0.6 nmol L − 1 dFe, 0.5 nmol L − 1 dMn and 10 nmol L − 1 dAl towards the end of the cruise three weeks later. A simple steady state model (MADCOW, [Measures, C.I., Brown, E.T., 1996. Estimating dust input to the Atlantic Ocean using surface water aluminium concentrations. In: Guerzoni. S. and Chester. R. (Eds.), The impact of desert dust across the Mediterranean, Kluwer Academic Publishers, The Netherlands, pp. 301-311.]) was used which relies on surface ocean dAl as a proxy for atmospheric deposition of mineral dust. We estimated dust input at 1.8 g m − 2 yr − 1 (range 1.0-2.9 g m − 2 yr − 1 ) and fluxes of dFe, dMn and dAl were inferred. Mixed layer steady state residence times for dissolved metals were estimated at 1.3 yr for dFe (range 0.3-2.9 yr) and 1.9 yr for dMn (range 1.0-3.8 yr). The dFe residence time may have been overestimated and it is shown that 0.2-0.4 yr is probably more realistic. Using vertical dFe versus Apparent Oxygen Utilization (AOU) relationships as well as a biogeochemical two end member mixing model, regenerative Fe:C ratios were estimated respectively to be 20 ± 6 and 22 ± 5 μmol Fe:mol C. Combining the atmospheric flux of dFe to the upper water column with the latter Fe:C ratio, a 'new iron' supported primary productivity of only 15% (range 7%-56%) was deduced. This would imply that 85% (range 44-93%) of primary productivity could be supported by regenerated dFe. The open ocean surface data suggest that the continental shelf is probably not a major source of dissolved metals to the surface of the adjacent open ocean. Continental shelf concentrations of dMn, dFe, and to a lesser extent dAl, were well correlated with salinity and express mixing of a fresher continental end member with Atlantic Ocean water flowing onto the shelf. This means probably that diffusive benthic fluxes did not play a major role at the time of the cruise.