| 1. |
- Breitbarth, E., et al.
(författare)
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Iron biogeochemistry across marine systems : progress from the past decade
- 2010
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Ingår i: Biogeosciences. - : Copernicus GmbH. - 1726-4170 .- 1726-4189. ; 7:3, s. 1075-1097
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Tidskriftsartikel (refereegranskat)abstract
- Based on an international workshop (Gothenburg, 14-16 May 2008), this review article aims to combine interdisciplinary knowledge from coastal and open ocean research on iron biogeochemistry. The major scientific findings of the past decade are structured into sections on natural and artificial iron fertilization, iron inputs into coastal and estuarine systems, colloidal iron and organic matter, and biological processes. Potential effects of global climate change, particularly ocean acidification, on iron biogeochemistry are discussed. The findings are synthesized into recommendations for future research areas
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| 2. |
- Breitbarth, Eike, et al.
(författare)
-
Iron biogeochemistry across marine systems – progress from the past decade
- 2010
-
Ingår i: Biogeosciences. - 1726-4170. ; 7, s. 1075-1097
-
Forskningsöversikt (refereegranskat)abstract
- Based on an international workshop (Gothenburg, 14–16 May 2008), this review article aims to combine interdisciplinary knowledge from coastal and open ocean research on iron biogeochemistry. The major scientific findings of the past decade are structured into sections on natural and artificial iron fertilization, iron inputs into coastal and estuarine systems, colloidal iron and organic matter, and biological processes. Potential effects of global climate change, particularly ocean acidification, on iron biogeochemistry are discussed. The findings are synthesized into recommendations for future research areas.
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| 3. |
- Plathe, K. L., et al.
(författare)
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The role of nanominerals and mineral nanoparticles in the transport of toxic trace metals: Field-flow fractionation and analytical TEM analyses after nanoparticle isolation and density separation
- 2013
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Ingår i: Geochimica et Cosmochimica Acta. - : Elsevier BV. - 0016-7037. ; 102, s. 213-225
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Tidskriftsartikel (refereegranskat)abstract
- Nanominerals and mineral nanoparticles from a mining-contaminated river system were examined to determine their potential to co-transport toxic trace metals. A recent large-scale dam removal project on the Clark Fork River in western Montana (USA) has released reservoir and upstream sediments contaminated with toxic trace metals (Pb, As, Cu and Zn), which had accumulated there as a consequence of more than a century and a half of mining activity proximal to the river's headwaters near the cities of Butte and Anaconda. To isolate the high-density nanoparticle fractions from riverbed and bank sediments, a density separation with sodium polytungstate (2.8g/cm3) was employed prior to a standard nanoparticle extraction procedure. The stable, dispersed nanoparticulate fraction was then analyzed by analytical transmission electron microscopy (aTEM) and flow field-flow fractionation (FlFFF) coupled to both multi-angle laser light scattering (MALLS) and high-resolution, inductively coupled plasma mass spectrometry (HR-ICPMS). FlFFF analysis revealed a size distribution in the nano range and that the elution profiles of the trace metals matched most closely to that for Fe and Ti. aTEM confirmed these results as the majority of the Fe and Ti oxides analyzed were associated with one or more of the trace metals of interest. The main mineral phases hosting trace metals are goethite, ferrihydrite and brookite. This demonstrates that they are likely playing a significant role in dictating the transport and distribution of trace metals in this river system, which could affect the bioavailability and toxicity of these metals. © 2012 Elsevier Ltd.
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| 4. |
- Plathe, K. L., et al.
(författare)
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Using FlFFF and aTEM to determine trace metal–nanoparticle associations in riverbed sediment
- 2010
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Ingår i: Environmental Chemistry. - 1448-2517. ; 7:1, s. 82-93
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Tidskriftsartikel (refereegranskat)abstract
- Analytical transmission electron microscopy (aTEM) and flow field flow fractionation (FlFFF) coupled to multi-angle laser light scattering (MALLS) and high-resolution inductively coupled plasma mass spectroscopy (HRICPMS) were utilised to elucidate relationships between trace metals and nanoparticles in contaminated sediment. Samples were obtained from the Clark Fork River (Montana, USA), where a large-scale dam removal project has released reservoir sediment contaminated with toxic trace metals (namely Pb, Zn, Cu and As) which had accumulated from a century of mining activities upstream. An aqueous extraction method was used to recover nanoparticles from the sediment for examination; FlFFF results indicate that the toxic metals are held in the nano-size fraction of the sediment and their peak shapes and size distributions correlate best with those for Fe and Ti. TEM data confirms this on a single nanoparticle scale; the toxic metals were found almost exclusively associated with nano-size oxide minerals, most commonly brookite, goethite and lepidocrocite.
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| 5. |
- Dubascoux, S., et al.
(författare)
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Field-flow fractionation and inductively coupled plasma mass spectrometer coupling: History, development and applications
- 2010
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Ingår i: Journal of Analytical Atomic Spectrometry. - : Royal Society of Chemistry (RSC). - 0267-9477 .- 1364-5544. ; 25, s. 613-623
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Tidskriftsartikel (refereegranskat)abstract
- Field-Flow Fractionation (FFF) is now recognised as a versatile pool of techniques allowing particle size or molar mass to be obtained in a wide variety of samples covering numerous applications in the fields of environment, materials or biology. In the same time, Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) has an indisputable place in the field of elemental detectors and the coupling between FFF and ICP-MS can be considered as an emerging technique capable to reach relevant physico-chemical information at sub-micrometre scale and trace element concentration level. This paper gives some key elements of FFF-based fractionation linking theory and practical analytical aspects, from injection and preconcentration to analysis. The different components of the coupling are described. Summary tables of the main operating conditions of FFF-ICP-MS coupling are presented and operating conditions such as carrier composition, flow and nebulizers are discussed. Special attention is given to the FFF-ICP-MS interface. Qualitative and quantitative analysis is also discussed. Applications in the fields of environment, bioanalysis and nanoparticles are presented in order to illustrate the potentialities of such coupling.
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| 6. |
- Gelting, Johan, et al.
(författare)
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Fractionation of iron species and iron isotopes in the Baltic Sea euphotic zone
- 2010
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Ingår i: Biogeosciences. - : Copernicus GmbH. - 1726-4170 .- 1726-4189. ; 7:8, s. 2489-2508
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Tidskriftsartikel (refereegranskat)abstract
- To indentify sources and transport mechanisms of iron in a coastal marine environment, we conducted measurements of the physiochemical speciation of Fe in the euphotic zone at three different locations in the Baltic Sea. In addition to sampling across a salinity gradient, we conducted this study over the spring and summer season. Moving from the riverine input characterized low salinity Bothnian Sea, via the Landsort Deep near Stockholm, towards the Gotland Deep in the Baltic Proper, total Fe concentrations averaged 114, 44, and 15 nM, respectively. At all three locations, a decrease in total Fe of 80-90% from early spring to summer was observed. Particulate Fe (PFe) was the dominating phase at all stations and accounted for 75-85% of the total Fe pool on average. The Fe isotope composition (δ 56Fe) of the PFe showed constant positive values in the Bothnian Sea surface waters (+0.08 to +0.20‰). Enrichment of heavy Fe in the Bothnian Sea PFe is possibly associated to input of aggregated land derived Fe-oxyhydroxides and oxidation of dissolved Fe(II). At the Landsort Deep the isotopic fractionation of PFe changed between -0.08‰ to +0.28‰ over the sampling period. The negative values in early spring indicate transport of PFe from the oxic-anoxic boundary at ∼80 m depth. The average colloidal iron fraction (CFe) showed decreasing concentrations along the salinity gradient; Bothnian Sea 15 nM; Landsort Deep 1 nM, and Gotland Deep 0.5 nM. Field Flow Fractionation data indicate that the main colloidal carrier phase for Fe in the Baltic Sea is a carbon-rich fulvic acid associated compound, likely of riverine origin. A strong positive correlation between PFe and chl-a indicates that cycling of suspended Fe is at least partially controlled by primary production. However, this relationship may not be dominated by active uptake of Fe into phytoplankton, but instead may reflect scavenging and removal of PFe during phytoplankton sedimentation.
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| 7. |
- Hoffmann, L. J., et al.
(författare)
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Influence of trace metal release from volcanic ash on growth of Thalassiosira pseudonana and Emiliania huxleyi
- 2012
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Ingår i: Marine Chemistry. - : Elsevier BV. - 0304-4203. ; 132-133, s. 28-33
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Tidskriftsartikel (refereegranskat)abstract
- Recent studies demonstrate that volcanic ash has the potential to increase phytoplankton biomass in the open ocean. However, besides fertilizing trace metals such as Fe, volcanic ash contains a variety of potentially toxic metals such as Cd, Cu, Pb, and Zn. Especially in coastal regions closer to the volcanic eruption, where ash depositions can be very high, toxic effects are possible. Here we present the first results from laboratory experiments, showing that trace metal release from different volcanic ashes can have both fertilizing and toxic effects on marine phytoplankton in natural coastal seawater. The diatom Thalassiosira pseudonana generally showed higher growth rates in seawater that was in short contact with volcanic ash compared to the controls without ash addition. In contrast to that, the addition of volcanic ash had either no effect or significantly decreased the growth rate of the coccolithophoride Emiliania huxleyi. It was not possible to attribute the effects to single trace metals, however, our results suggest that Mn plays an important role in regulating the antagonistic and synergistic effects of the different trace metals. This study shows that volcanic ash can lead to changes in the phytoplankton species composition in the high fall-out area of the surface ocean.
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| 8. |
- Stolpe, Björn, 1974, et al.
(författare)
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Size and composition of colloidal organic matter and trace elements in the Mississippi River, Pearl River and the northern Gulf of Mexico, as characterized by flow field-flow fractionation
- 2010
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Ingår i: Marine Chemistry. - : Elsevier BV. - 0304-4203. ; 118:3-4, s. 119-128
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Tidskriftsartikel (refereegranskat)abstract
- The continuous colloidal size spectra (0.5–40 nm) of chromophoric and fluorescent organic matter, Fe, P, Mn, Cu, Zn, Pb, and U, were determined by on-line coupling of flow field-flow fractionation (FFF) to detectors including UV-absorbance, fluorescence, and ICP-MS, in samples from the lower Mississippi River, the Atchafalaya River, the Pearl River, and from marine stations in the northern Gulf of Mexico. The colloidal size spectra showed the presence of 3–4 colloid populations; 0.5–4 nm CDOM-colloids, binding most elements, 3–8 nm protein-like colloids, binding P in seawater, and 5–40 nm Fe-rich colloids, binding P, Mn, Zn, and Pb. Moreover, protein-like colloidal matter, Fe, P, Mn and Pb were largely found in the > 40 nm fraction. We hypothesize that the CDOM-colloids represent terrestrial fulvic acid, and that the protein-like colloids are mostly derived from in situ biological production, while the iron-rich colloids are largely inorganic and contain Fe(III)-hydroxide/oxyhydroxide. The colloidal concentrations, determined by both FFF and ultrafiltration, were generally much higher in the Pearl River than in the other rivers, and decreased seaward in the Gulf of Mexico. The colloidal size distribution of protein-like organic matter, Fe-rich colloids and associated elements were shifted to larger sizes in the Mississippi and Atchafalaya Rivers compared with the Pearl River.
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