Fungal Diversity Associated with an Active Deep Sea Volcano: Vailulu'u Seamount, Samoa

Abstract

Active undersea volcanoes generate complex hydrothermal environments that provide microbial habitats rich in reduced metals. These habitats harbor a substantial microbial communities functionally capable of Fe(II) and Mn(II) oxidation. The role of eukaryotes in these settings remains largely unknown. We explored the presence of fungi in actively growing Fe-oxide mats and basalt rock surfaces from the active volcano, Vailulu'u seamount (Samoan chain). Here we document the presence of a diverse fungal community including eight yeasts and yeast-like fungal species isolated from cold hydrothermal environments and basalt rock surfaces. Many of the isolates produce siderophores, a class of molecules used to acquire and utilize Fe (III), and one isolate, Rhodotorula graminis oxidizes Mn(II). These results suggest that fungi may also play a functional role in seafloor alteration and biomineralization processes.

Keywords:

• Fe-oxide mats
• fungi
• hydrothermal
• Vailulu'u
• yeast

We thank M. Iszard, K. Clegg, M. Jani, L. Mayhew, and New England Math & Science Upward Bound students for laboratory assistance. Field sampling by the Pisces V submersible was funded by the NOAA Explorations program and executed by Terry Kirby and his first-rate team of professional engineers and pilots. Furthermore, we thank the remaining science team of the 2005 Vailulu'u expeditions, in particular L. Sudek, B. Bailey, S. Hart, A. Koppers, B. Tebo and C. Young. This work was partially supported by the Agouron Foundation and the National Science Foundation grant OCE-0433692. Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the opinions of the funding agencies.