Organic sulfur fluxes and geomorphic control of sulfur isotope ratios in rivers

Evaluating the multiple sulfur isotope signature of Eoarchean rocks from the Isua Supracrustal Belt (Southwest‐Greenland) by MC‐ICP‐MS: Volcanic nutrient sources for early life

“…Across the range of external and in‐house consistency standards with δ 34 S values ranging from −34‰ to 22‰, our method agrees well with previous literature (Böttcher et al., 2007; Brand et al., 2014; Burke et al., 2019; Kemeny et al., 2021; Paris et al., 2013; Present et al., 2015, Figure 5, Table 1). For each standard, the average of the full procedural replicates is within two standard deviations of the previously reported values.…”

Arctic Permafrost Thawing Enhances Sulfide Oxidation

“…Furthermore, the oxidation of low valent sulfur species back to $${{\text{SO}}_{4}}^{2-}$$ can incorporate environmental oxygen and alter $${\delta }^{18}{\mathrm{O}}_{{\text{SO}}_{4}}$$ values without necessarily changing $${\delta }^{34}{\mathrm{S}}_{{\text{SO}}_{4}}$$ values (Mills et al., 2016). Microbial processes have previously been suggested to increase fluvial $${\delta }^{34}{\mathrm{S}}_{{\text{SO}}_{4}}$$ and $${\delta }^{18}{\mathrm{O}}_{{\text{SO}}_{4}}$$ values in permafrost settings and other landscapes (Joo et al., 2022; Jones et al., 2020), but there is also evidence that $${\delta }^{34}{\mathrm{S}}_{{\text{SO}}_{4}}$$ (Kemeny et al., 2021b) and $${\delta }^{18}{\mathrm{O}}_{{\text{SO}}_{4}}$$ (Burt et al., 2021) can behave conservatively in river systems.…”

“…The fitting was performed 10.1029/2022GB007644 10 of 36 in MATLAB as an optimization to minimize proportional misfit, with the contributions from reference spectra constrained to be positive and without constraint on their sum, and with equal weighting for all points between 2,470 eV and 2,490 eV where the relative fluorescence response was ≥0.1 (Manceau & Nagy, 2012;Prietzel et al, 2011). The normalized fractional contributions of the disulfide, thiol, and sulfoxide reference spectra were then summed to reach the statistic F red , which approximately reflects the fractional importance of reduced sulfur moieties to each spectrum (Kemeny et al, 2021b;Torres et al, 2020).…”

The Hydrochemical Signature of Incongruent Weathering in Iceland

“…In some past work on weathering in Iceland, it has been assumed that silicate weathering processes release solutes in similar ratios to bulk basalts (Gíslason et al., 1996; Jacobson et al., 2015; Kemeny et al., 2021; Stefánsson et al., 2001) or some mixture of bulk basalts and bulk rhyolites (Louvat et al., 2008). The assumption of congruent solute release (i.e., similar elemental ratios for rivers as in bulk rocks) may be reasonable for catchments where volcanic glass weathering dominates as experiments show the congruent release of major cations from basaltic glass (Gislason & Eugster, 1987).…”