Application of Fe isotopes to tracing the geochemical and biological cycling of Fe

Fractionation of iron species and iron isotopes in the Baltic Sea euphotic zone

“…Following this model, the suspended phase in the Bothnian Sea is dominated by oxyhydroxides. If the regression line (Fig 6b) extrapolated to the average crust Fe/Ti value (10.2), δ 56 Fe is approximately −0.07‰, a value close to what has been measured in the Kalix river during spring flood (Ingri et al, 2006), but not similar to the composition of the average crust, which have a δ 56 Fe = 0.09 ± 0.05 relative the IRMM-014 standard (Beard et al, 2003). The filters analyzed in this study were clogged to collect some of the colloidal Fe, which likely consists of the Fe-carbon rich phase and the Fe-oxyhydroxide phase (Lyvén et al, 2003).…”

“…10b and 11). A PFe phase with a Fe/Ti value close to average crust ratio would be regarded as mainly composed of lithogenic particles and is predicted to have a δ 56 Fe of 0.09 (Beard et al, 2003). This was not the case here and thus the use of elemental ratios should be carefully evaluated.…”

“…Beard et al, 2003;Bergquist and Boyle, 2006;de Jong et al, 2007). In particular, significant fractionation of Fe isotopes has been demonstrated during oxidation and reduction reactions, suggesting that Fe isotopes are also useful tracers of Fe redox cycling (e.g.…”

Fe isotope exchange between Fe(II)aq and nanoparticulate mackinawite (FeSm) during nanoparticle growth

“…Experimental data on aqueous Fe species, Fe-oxides and Fe-carbonates have been documented and demonstrate that the largest Fe isotope fractionations are produced during redox reactions in both biologically mediated (Brantley et al, 2001Anbar, 2004;Johnson et al, 2004;Beard et al, 1999Beard et al, ,2003Icopini et al, 2004;Croal et al, 2004) and abiotic systems (Anbar et al, 2000;Skulan et al, 2002Brantley et al, 2004Welch et al, 2003;Matthews et al, 2004;Teutsch et al, 2005;Jang et al, 2008, Handler et al, 2009McAnena, 2009, Beard et al, 2010. Smaller, but significant fractionations have been seen in abiotic non-redox reactions (Wiesli et al, 2004;Wiedehold et al, 2006;Dideriksen et al, 2008;Mikutta et al, 2009), including the ligand-exchange process involved in mackinawite (FeS m ) formation (Butler et al, 2005).…”

Evaluation of the Analytical Capability of NIR Femtosecond Laser Ablation-Inductively Coupled Plasma Mass Spectrometry

“…Recent studies on Fe isotopes have revealed that natural isotopic fractionation of Fe is common on the Earth. The overall variation so far observed in natural samples is about 4‰ 59,60 In order to detect a small level of isotopic fractionation, an ICP-mass spectrometer equipped with a multiple collector array (MC-ICPMS) was employed. The ablation pit sizes produced by the ArF excimer laser and fs-laser were 20 and 15 μm, respectively.…”