C-DEBI Newsletter – June 16, 2014

Missed the last Networked Speaker Series seminar with Luke McKay on “Approaching the high temperature boundary for life in the hydrothermally altered sediments of Guaymas Basin”? Watch it now online.

C-DEBI’s next Networked Seminar Speaker is Dr. Jason Sylvan from the University of Southern California, Department of Biological Sciences:

Microbial life in old subseafloor basaltic crust
The aquifer in subseafloor basaltic crust is a massive, continuous microbial substrate, yet sparingly little is known about life in this habitat.  The work to date has focused largely on young crust at oceanic spreading regions and ridge flanks, where the basaltic crust is still porous and fluid flow through it is active.  Heat flow models predict that little fluid moves through subseafloor basalt >65 million years old, but recent work proves that seamounts, which are found throughout the seafloor, act as mid-plate conduits into and exits out of the subsurface aquifer for fluids and possibly microbes.  To determine if life does indeed exist in old subseafloor basaltic crust, I sampled 64-74 million year old extinct seamounts along the Louisville Seamount Chain in the southwest Pacific Ocean during Integrated Ocean Drilling Program Expedition 330. Newly developed methods for quantifying subsurface microbes were applied to these samples, providing the first quantification of microbes in cores retrieved from subseafloor basaltic crust. Analysis of community DNA indicated archaea are extremely rare in this setting.  The most abundant bacterial classes detected were Actinobacteria, Flavobacteria, Sphingobacteria, Bacilli, Clostridia, Alpha-, Beta and Gammaproteobacteria.  Genera putatively carrying out hydrocarbon oxidation and nitrogen, sulfur and metal redox processes were commonly detected in core samples as well as enrichment incubations started during the cruise.  This work shows that old subseafloor basalt is indeed home to microbial communities that may have a significant impact on marine biogeochemistry. I will discuss these results in more detail and put them in context with previous studies of microbiology in subseafloor basaltic crust. 
 

The Ninth International Symposium on Subsurface Microbiology (ISSM 2014) is a weeklong conference that will explore the link between microbiology, the subsurface environment, and microbial ecosystems. The conference will be held October 5-10, 2014, at Asilomar State Beach and Conference Grounds in Pacific Grove, California, U.S.A. The organizers are pleased to announce the Plenary Speakers for ISSM 2014:

• C-DEBI Sediment Steering Chair Peter Girguis, Ph.D., Harvard University, on “Hot-wired: The Nature and Extent of Extracellular Electron Transfer in Hydrothermal and Hydrocarbon Systems”
• Terry Hazen, Ph.D., University of Tennessee, on “Microbial Community Structure Predicts Groundwater Geochemistry”
• Rainer Meckenstock, Ph.D., Helmholtz Zentrum Muenchen, on “Microbial Life in Oil”
• Lars Peter Nielsen, Ph.D., Aarhus University, on “Tracking Electromicrobial Activity with Electric Potential Microsensors”
• Aaron Packman, Ph.D., Northwestern University, on “Ecological Connectivity between Surface and Groundwater Systems”
• Karsten Pedersen, Ph.D., Microbial Analytics Sweden AB, on “Cultivable and 16S rDNA Diversity of Archaea and Bacteria over Depth, Sample Site and Time in Hard Rock Aquifers”
• Timothy Scheibe, Ph.D., Pacific Northwest National Laboratory, on “Scale Challenges in Utilization of Microbial Metabolic Network Models in Application-Scale Simulations”
• Jack Schijven, Ph.D., National Institute of Public Health and the Environment (RIVM), on “QMRAcatch — A User-Friendly Computational Tool for Microbial Quality Simulations of Fresh Water Including Risk Assessment”

To learn more about the Plenary Speakers and other conference topics, please visit www.2014issm.com/presentations.html. 

Outreach