Sulfur isotope analyses of individual aerosol particles B. Winterholler et al.

Introduction: Sulfur is a cosmochemically important element with four stable isotopes. It is the only element besides oxygen where a mass independent fractionation (MIF) has been observed both in nature [1-4] and the laboratory [4,5]. Unlike oxygen, where more than one process can produce MIF, sulfur MIF is exclusively of photochemical origin. Recently we have demonstrated a mass independent su...

The folding formalism for the nucleon-nucleus optical potential and inelastic form factor is applied to study elastic and inelastic proton scattering on 30−40S isotopes. A recently developed realistic density dependent M3Y interaction, well tested in the folding analysis of nucleus-nucleus elastic and inelastic scattering, is used as effective NN interaction. The nuclear ground state and transi...

Microbial sulfate reduction (MSR) utilizes sulfate as an electron acceptor and produces sulfide that is depleted in heavy isotopes of sulfur relative to starting sulfate. The fractionation of S-isotopes is commonly used to trace the biogeochemical cycling of sulfur in nature, but a mechanistic understanding of factors that control the range of isotope fractionation is still lacking. This thesis...

[1] Both sulfur and oxygen isotopes of sulfate preserved in ice cores from Greenland and Antarctica have provided information on the relative sources of sulfate in the ice and their chemical transformation pathways in the atmosphere over various time periods. The mass-independent fractionation in the oxygen isotopes of sulfate from the Vostok ice core from east Antarctica suggests that gas-phas...

Understanding the coupling of oxygen, carbon, and sulfur cycles in the past is critical for reconstructing the history of biogeochemical cycles, paleoclimatic variations, and oceanic chemistry. The abundance of sulfur isotopes (dS) in sulfate from ancient marine carbonates, or carbonate-associated sulfate (CAS), is commonly used, along with other archives (mainly evaporites and barite), to esti...

The determination of S by solution nebulization quadrupole inductively coupled plasma mass spectrometry (ICP-MS) is dif®cult because of interferences from oxygen dimer ions. The large O2 z ion current from the solvent water is a serious interference at S, the most abundant of the four isotopes, and precludes its measurement. The isotopic composition of S varies in nature as a consequence of nat...

Sulfur isotope signatures provide key information for the study of microbial activity in modern systems and the evolution of the Earth surface redox system. Microbial sulfate reducers shift sulfur isotope distributions by discriminating against heavier isotopes. This discrimination is strain-specific and often suppressed at sulfate concentrations in the lower micromolar range that are typical t...