Methods for analyzing the concentration and speciation of major and trace elements in marine particles

Lam, Phoebe J.; Twining, Benjamin S.; Jeandel, Catherine; Roychoudhury, Alakendra N.; Santschi, Peter H.; Anderson, Robert F.

doi:10.1016/j.pocean.2015.01.005

Cited by 42 publications

(21 citation statements)

References 130 publications

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“…However, the concentrations of both pCo and pMn were low and tend to decrease from the surface to the deep sea, with an exception at the bottom depth ( Figure 7). Moreover, MnO 2 concentrations, estimated by following Lam et al [2015] method (MnO 2 = (pMn À (pTi * 0.13)), were extremely low along the section except in the Alboran Sea (Figure 7c). These observations probably indicate that only a small fraction of DCo might be removed by MnOx pathway.…”

Section: Dco Fluxes At the Sicily Channelmentioning

confidence: 99%

The biogeochemistry of cobalt in the Mediterranean Sea

Dulaquais

Planquette

L’Helguen

et al. 2017

Global Biogeochemical Cycles

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The soluble (sCo < 0.02 μm), dissolved (DCo < 0.2 μm), colloidal (cCo, as DCo minus sCo), and the particulate (pCo > 0.2 μm) fractions of cobalt were investigated along the GEOTRACES-A04 section. Our results show that sCo was the predominant form (90%) of the DCo in the Mediterranean Sea and that cCo and pCo generally followed the same distribution, suggesting a biogeochemical link between these two fractions. In the Mediterranean Sea, DCo displayed an overall scavenged-like profile in the different sub-basins, with high concentrations (up to 350 pM) in surface and quasi-uniformed low concentrations of DCo (~45 pM) in the deep sea. However, the decoupling between the surface and the deep reservoirs suggested that the transfer of Co from dissolved to particulate pools during the sink of particles may not be the only process governing DCo distribution. High-surface Co inputs, stabilization of DCo in a soluble form, and the extremely high regeneration rate of biogenic pCo all lead to the accumulation of DCo in surface. Conversely, low pCo export from the surface waters, low remineralization of biogenic pCo, and slow but efficient removal of DCo by scavenging including colloid aggregation into particles prevented its accumulation in the intermediate and deep sea. Moreover, Mediterranean circulation prevented the exchanges between the DCo-rich surface and the DCo-poor deep layers enhancing the scavenged-like profile of DCo. Finally, tentative DCo budgets were balanced at basin scale and showed the strong imprint of the surface inputs at Gibraltar Strait on the Mediterranean cobalt biogeochemistry.

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Section: Dco Fluxes At the Sicily Channelmentioning

confidence: 99%

The biogeochemistry of cobalt in the Mediterranean Sea

Dulaquais

Planquette

L’Helguen

et al. 2017

Global Biogeochemical Cycles

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“…Future work should thus strive towards a more chemically-relevant approach to marine Fe speciation studies, by employing techniques that directly probe functional group chemistry (e.g. the characterisation, concentration (density), saturation and binding affinity of Fe-binding sites) of organic colloids, and the mineralogy and surface chemistry properties of inorganic colloids (see a recent review by Lam et al, 2015).…”

Section: Future Workmentioning

confidence: 99%

A review of colloidal iron partitioning and distribution in the open ocean

Heyden

Roychoudhury

2015

Marine Chemistry

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“…Few tools are available to examine in situ cellular metal concentrations and accumulation rates, and each has unique advantages and disadvantages. Measurements of total bulk particulate metals provide precise particulate metal concentration data, but these include unknown lithogenic contributions that must be corrected (reviewed by Lam et al, 2015). Metal quotas of single cells have been reported using synchrotron X-ray fluorescence, but this method is resource and technically intensive and is currently undertaken by only one group (e.g., Twining et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Using 67Cu to Study the Biogeochemical Cycling of Copper in the Northeast Subarctic Pacific Ocean

et al. 2016

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Microbial copper (Cu) nutrition and dissolved Cu speciation were surveyed along Line P, a coastal to open ocean transect that extends from the coast of British Columbia, Canada, to the high-nutrient-low-chlorophyll (HNLC) zone of the northeast subarctic Pacific Ocean. Steady-state size fractionated Cu uptake rates and Cu:C assimilation ratios were determined at in situ Cu concentrations and speciation using a 67 Cu tracer method. The cellular Cu:C ratios that we measured (∼30 μmol Cu mol C −1 ) are similar to recent estimates using synchrotron x-ray fluorescence (SXRF), suggesting that the 67 Cu method can determine in situ metabolic Cu demands. We examined how environmental changes along the Line P transect influenced Cu metabolism in the sub-microplankton community. Cellular Cu:C assimilation ratios and uptake rates were compared with net primary productivity, bacterial abundance and productivity, total dissolved Cu, Cu speciation, and a suite of other chemical and biological parameters. Total dissolved Cu concentrations ([Cu] d ) were within a narrow range (1.5-2.8 nM), and Cu was bound to a ∼5-fold excess of strong ligands with conditional stability constants (K cond 2 ) of ∼10 14 .CuL,Cu + Free Cu 2+ concentrations were low (pCu 14.4-15.1), and total and size fractionated net primary productivity (NPP ; g C L −1 d −1 V μ ) were negatively correlated with inorganic Cu concentrations ([Cu ]). We suggest this is due to greater Cu drawdown by faster growing phytoplankton populations. Using the relationship between [Cu ] drawdown and NPP V , we calculated a regional photosynthetic Cu:C drawdown export ratio between 1.5 and 15 μmol Cu mol C −1 , and a mixed layer residence time (2.5-8 years) that is similar to other independent estimates (2-12 years). Total particulate Cu uptake rates were between 22 and 125 times faster than estimates of Cu export; this is possibly mediated by rapid cellular Cu uptake and efflux by phytoplankton and bacteria or the effects of grazers and bacterial remineralization on dissolved Cu. These results provide a more detailed understanding of the interactions between Cu speciation and microorganisms in seawater, and suggest that marine phytoplankton modify Cu speciation in the open ocean.

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Methods for analyzing the concentration and speciation of major and trace elements in marine particles

Cited by 42 publications

References 130 publications

The biogeochemistry of cobalt in the Mediterranean Sea

The biogeochemistry of cobalt in the Mediterranean Sea

A review of colloidal iron partitioning and distribution in the open ocean

Using 67Cu to Study the Biogeochemical Cycling of Copper in the Northeast Subarctic Pacific Ocean

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