Open AccessSpeciation of sulfur from filamentous microbial mats from sulfidic cave springs using X‐ray absorption near‐edge spectroscopy
Author(s) -
Engel Annette Summers,
Lichtenberg Henning,
Prange Alexander,
Hormes Josef
Publication year - 2007
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2006.00600.x
Subject(s) - sulfur , environmental chemistry , microbial mat , sulfur cycle , xanes , sulfate , genetic algorithm , x ray absorption spectroscopy , chemistry , ecology , biology , bacteria , spectroscopy , absorption spectroscopy , organic chemistry , paleontology , cyanobacteria , physics , quantum mechanics
Most transformations within the sulfur cycle are controlled by the biosphere, and deciphering the abiotic and biotic nature and turnover of sulfur is critical to understand the geochemical and ecological changes that have occurred throughout the Earth's history. Here, synchrotron radiation‐based sulfur K‐edge X‐ray absorption near‐edge structure (XANES) spectroscopy is used to examine sulfur speciation in natural microbial mats from two aphotic (cave) settings. Habitat geochemistry, microbial community compositions, and sulfur isotope systematics were also evaluated. Microorganisms associated with sulfur metabolism dominated the mats, including members of the Epsilonproteobacteria and Gammaproteobacteria . These groups have not been examined previously by sulfur K‐edge XANES. All of the mats consisted of elemental sulfur, with greater contributions of cyclo ‐octasulfur (S 8 ) compared with polymeric sulfur (S μ ). While this could be a biological fingerprint for some bacteria, the signature may also indicate preferential oxidation of S μ and S 8 accumulation. Higher sulfate content correlated to less S 8 in the presence of Epsilonproteobacteria . Sulfur isotope compositions confirmed that sulfur content and sulfur speciation may not correlate to microbial metabolic processes in natural samples, thereby complicating the interpretation of modern and ancient sulfur records.