DAPI-stained cells in white flocculent material from the Subway snowblower vent and orange flocculent material from the seafloor. From Meyer et al. 2013.

Research Overview

Research Goals

The global ocean comprises the Earth’s largest biome, with microorganisms playing a dominant biogeochemical role. C-DEBI researchers have provided compelling evidence suggesting that the microbial abundance in subseafloor sediments equals that in the overlying ocean. C-DEBI researchers have also demonstrated that the microbial cell counts in marine sediments vary by many orders of magnitude from ocean margins to ocean gyres, and from the sediment-water interface to the deep subsurface. However, it remains unknown what environmental properties and processes control observed variations, what limits the extent and variety of life in the subseafloor, and how physiologically and phylogenetically diverse these sediment communities are.

Despite the magnitude of these scientific unknowns, another marine biome may prove to be even more astonishing—the igneous crust. Researchers have shown that the igneous crust below the oceans and sediments is the largest aquifer system on Earth, extending across >300 million km2. Most of this system is hydrologically active, with a vast flow of fluid exchanging between ocean basins and crustal reservoirs. This fluid carries heat, solutes, genetic material, microorganisms, spores, and viruses. Furthermore, the deep crustal biosphere appears to be very different from its counterpart in marine sediments, which, in turn, is very different from that in the overlying ocean.

Given the connectivity of these three enormous biomes:

The central scientific goal of C-DEBI is to resolve the extent, function, dynamics, and implications of the subseafloor biosphere through an integrated, multidisciplinary, and multi-institutional distributed infrastructure.

C-DEBI research in the initial phase primarily focused on exploration and discovery of subseafloor ecosystems anchored firmly in three major field programs: Juan de Fuca Ridge Flank (JdF), South Pacific Gyre (SPG), and North Pond (NP). The overall goal was to investigate microbial life, geochemistry, and hydrology in the sediment and igneous crust of the subseafloor, beginning with a small set of focused study sites. These studies relied on a variety of truly innovative methods and tools, capitalizing on the unprecedented scheduling of three ocean drilling expeditions within 18 months of each other, all with subseafloor microbiology as a major focus. In addition, C-DEBI supported research at other compelling subseafloor settings, nurtured a growing multidisciplinary scientific community, and coordinated a broad range of complementary activities in research and training.

Based on the insights and understandings gained in the initial phase, C-DEBI researchers will in the current phase conduct multi-disciplinary studies to develop an integrated understanding of subseafloor microbial life at the molecular, cellular, and ecosystem scales. The current phase will comprise a transition from exploration-dominated investigations to projects that balance discovery with hypothesis testing, data integration, and ecosystem modeling. It will maintain our multi-disciplinary approach of microbiology, geochemistry, oceanography, and hydrology, but will be weighted more strongly towards microbiology. This shift is clearly reflected in C-DEBI’s Phase II research themes, and also in the expertise of the scientific leadership and our plans for generating and interpreting large data sets.

We will create knowledge of those traits of microbial life that are distinctive to the subseafloor environment, and address fundamental questions such as:

  • What are the key sources and minimum fluxes of metabolic energy to support and maintain subseafloor life?
  • What are the principles that govern physical, chemical, and biological interactions in ecosystems that experience long-term isolation or minimal connectivity?
  • What are the molecular and physiological features of slow-growing microorganisms and how do they coordinate their metabolisms?

Answers to these questions will provide, for the first time, a foundational understanding of the molecular and physiological features of subseafloor life, using C-DEBI’s Phase II Research Themes as a framework.

See also:

Research Themes Field Sites

Research Support

C-DEBI is the community-initiated means of providing the collaborative framework and support that we believe is needed for new research projects to be developed in the deep subsurface biosphere.

Since C-DEBI’s inception in 2010, we supported calls for proposals for our Research Grants and Graduate and Postdoctoral Fellowships. We are now in the final years of C-DEBI where NSF funding for all STCs scales back substantially.

2018 represented the last round of the Research Grants and Fellowships programs; we now move towards synthesis activities and continue to support community workshops, research exchanges and bioinformatic projects.

Research Exchange Program
C-DEBI facilitates scientific coordination and collaborations by supporting student, postdoctoral, and faculty exchanges to build, educate and train the deep subseafloor biosphere community. We award small research exchange grants for Center participants. These grants may be used to support research, travel for presenting C-DEBI research at meetings, or travel exchanges to other partner institutions or institutions that have new tools and techniques that can be applied to C-DEBI research.

Community Workshop Support
C-DEBI invites proposals for for community workshops that will help to advance C-DEBI’s central research agenda: to investigate the subseafloor biosphere deep in marine sediment and oceanic crust, and to conduct multi-disciplinary studies to develop an integrated understanding of subseafloor microbial life at the molecular, cellular, and ecosystem scales.

Bioinformatic Help Desk
Members of the C-DEBI community can contact C-DEBI Bioinformatic Specialist, Dr. Benjamin Tully (tully.bj@gmail.com), for services such as access to the C-DEBI computational server, minor questions regarding bioinformatics tools, workflows and coding challenges, and more.