Sulfur bacteria promote dissolution of authigenic carbonates at marine methane seeps

  • Beverly E Flood (Creator)
  • Dalton J Leprich (Creator)
  • Peter R Schroedl (Creator)
  • Elizabeth Ricci (Creator)
  • Jeffery J. Marlow (Creator)
  • Peter R. Girguis (Creator)
  • Jake Bailey (Creator)



Carbonate rocks at marine methane seeps are commonly colonized by sulfur-oxidizing bacteria that co-occur with etch pits that suggest active dissolution. We show that sulfur-oxidizing bacteria are abundant on the surface of an exemplar seep carbonate collected from Del Mar East Methane Seep Field, USA. We then used bioreactors containing aragonite mineral coupons that simulate certain seep conditions to investigate plausible in situ rates of carbonate dissolution associated with sulfur-oxidizing bacteria. Bioreactors inoculated with a sulfur-oxidizing bacterial strain, Celeribacter baekdonensis LH4, growing on aragonite coupons induced dissolution rates in sulfidic, heterotrophic, and abiotic conditions of 1773.97 (±324.35), 152.81 (±123.27), and 272.99 (±249.96) Mol CaCO3  cm-2  yr-1, respectively. Steep gradients in pH were also measured within carbonate-attached biofilms using pH-sensitive fluorophores. Together, these results show that the production of acidic microenvironments in biofilms of sulfur-oxidizing bacteria are capable of dissolving carbonate rocks, even under well-buffered marine conditions. Our results support the hypothesis that authigenic carbonate rock dissolution driven by lithotrophic sulfur-oxidation constitutes a previously unknown carbon flux from the rock reservoir to the ocean and atmosphere.

Assembled 16S rRNA gene iTag libraries of the microbial communities attached to a methane seep carbonate rock on the top surfaces vs. the bottom surface (in contact with sediments) subsampled 3 times.

Funding information
Sponsorship: NASA Exobiology (NNX-14AK20G); NSF (OCE-0826254); NASA (80NSSC18K1140); NSF (1542506)
Date made available2021
PublisherData Repository for the University of Minnesota
Date of data productionOct 15 2018

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