Fate of sulfide in the Frasassi cave system and implications for sulfuric acid speleogenesis

Daniel S. Jones, Lubos Polerecky, Sandro Galdenzi, Brian A. Dempsey, Jennifer L. Macalady

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


The oxidation of hydrogen sulfide (H2S) has led to the formation of some of the world's largest caves through a process known as sulfuric acid speleogenesis (SAS). Here we present a multi-year study of the large, sulfidic, and actively-forming Frasassi cave system, Italy. We show that despite the presence of abundant sulfide-oxidizing biofilms in Frasassi streams, H2S(g) degassing to the cave atmosphere was the major sink for dissolved sulfide. Degassing rates ranged from 0.9 to 80μmolm-2s-1, whereas microbial oxidation rates were between 0.15 and 2.0μmolm-2s-1. Furthermore, microsensor measurements showed that sulfuric acid is not a major end product of microbial sulfide oxidation in the streams. Our results suggest that subaerial SAS will be important for karstification, and more important than subaqueous SAS, wherever ground waters with high sulfide concentrations emerge as flowing streams in contact with cave air.

Original languageEnglish (US)
Pages (from-to)21-27
Number of pages7
JournalChemical Geology
StatePublished - Sep 2 2015

Bibliographical note

Publisher Copyright:
© 2015 Elsevier B.V.


  • Cave
  • Geomicrobiology
  • Hydrogen sulfide
  • Karst
  • Sulfur-oxidizing bacteria
  • Sulfuric acid


Dive into the research topics of 'Fate of sulfide in the Frasassi cave system and implications for sulfuric acid speleogenesis'. Together they form a unique fingerprint.

Cite this