Subseafloor Life


Exploring Subseafloor Life With the Integrated Ocean Drilling Program
Oct. 3-5, 2006, Vancouver, British Columbia, Canada

An international workshop sponsored by

Workshop Description

This workshop will bring together microbiologists, biogeochemists, geologists, and other scientists to consider how greater understanding of subseafloor life can be advanced through the Integrated Ocean Drilling Program. Workshop objectives: to outline major science questions, identify possible scientific drilling targets in the ocean floor, discuss required protocols and technology developments, and develop collaborative relationships.

Held in Vancouver, British Columbia, Oct. 3-5, 2006, the workshop can accommodate approximately 60 participants, with some spaces designated for graduate students and early career scientists. Interested persons from all countries are encouraged to apply. Selected participants will be notified by the Steering Committee.


Workshop Background and Purpose

As one of its many scientific accomplishments, the Ocean Drilling Program (ODP) provided the first evidence of abundant microbes and diverse microbial activities deep beneath the seafloor. This exciting discovery set the stage for further exploration of the extraordinary ecosystem beneath the seafloor using drilling technology. Such exploration will undoubtedly yield many unexpected results. For this reason, exploration of subseafloor life is highlighted as one of IODP's three main scientific themes.

Seawater migrates through sediments and actively circulates through faults, fractures, and other permeable conduits in the ocean crust and underlying mantle; in doing so, it redistributes heat, alters rock, forms massive mineral deposits, and influences the chemical composition of the oceans. This massive and dynamic plumbing system cycles the entire volume of the ocean through the subseafloor every one million years. Over a surprisingly broad range of subsurface depths, temperatures, and pressures, the subseafloor ocean hosts an extensive microbial population. By some estimates, as much as two-thirds of Earth's microbial biomass may live beneath the ocean floor. How microbial communities survive in such a seemingly inhospitable environment with little or no input from photosynthetic organisms poses basic questions for biogeochemistry, microbial physiology, and microbial ecology. The subseafloor life also represents a unique natural laboratory that offers new and barely explored opportunities to examine the ecological and evolutionary processes that drive microbial diversity, community organization, and microbial interactions.

Workshop participants will examine the current state of knowledge regarding the subseafloor life, and will be challenged to identify the first-order science questions in exploring subseafloor life and its interaction mechanisms with the subseafloor ocean. Participants will be encouraged to develop strategies to address these science questions by combining observations, sample and remote and in situ data collection, laboratory experiments, and modeling. To foster the participation of a wide community of international scientists, science community, participants will also have the opportunity to learn about the IODP proposal process and current proposed drilling projects that focus on biology themes.


Workshop Structure
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The workshop will alternate plenary sessions with smaller breakout activities. There will be a limited number of keynote talks and reports on recent activities with evening poster sessions.

The workshop steering committee has identified the following topical groups and associated questions as the focus of the workshop:

Group A: Genes, Cells, Populations, and Communities

  • What, if anything, is unique about microbes in this environment? What would one measure to define the uniqueness-and commonality-of the deep microbial biosphere?
  • What are the genomic adaptations that permit survival and proliferation in this environment? What are the drivers of diversity in this environment? What minimum density of cells can persist in subseafloor environments and their unique sets of adaptive challenges? Is this environment radically different with regard to evolutionary history, rates of gene transfer and other adaptive genetic properties because of the unique challenges it imposes on microbial life?
  • Do subseafloor microbial communities have special attributes that shape planetary evolution over geological time scales?
  • What questions can be asked in ecosystems that contain only microbes and possibly viruses? What constrains the representation of different phyla or different metabolic types? How stable is the community structure? What causes cell death?
  • How correlated are microbial physiology/community structures and the physical/chemical environment? If one is known, can the other be predicted?
  • How should one interpret the co-occurrence of microbes found in an individual sample?
  • Are there endemic subseafloor species? Are there two separate communities in a given location- one fixed in place, and another that moves with water flow? If so, do they interact? What is the relationship of cells to each subseafloor physical environment? What interactions among cells create subseafloor communities?

Group B: Habitability

Habitability refers to those environments that we consider to be suitable for life. As such, it is defined in terms of biogeochemical and physical parameters without regard to the specifics of the molecular machinery. Assessing habitability is largely based upon examination of life in the most extreme earthly environments. 

  • What combinations of chemical constituents, energy sources, physical conditions (e.g., liquidity of water, temperature, etc.), and stability make an environment habitable? What is the range of habitable subseafloor environments? What is their relevance for habitability on other worlds, e.g., on Mars, on Europa? How do oceanographic and geologic processes establish and modify habitability of subseafloor environments?
  • What are the possible ways that energy can be supplied to biological systems? Can life's fundamental energy requirements (flux, quanta) be defined and quantified? How can quantitative thermodynamic and kinetic models for energy flow and biological systems be applied to subseafloor ecosystems? How much energy is available?
  • How do microorganisms and/or ecosystems respond as their environment approaches a habitability limit? How do microorganisms and/or ecosystems "fail" as their environment moves beyond a habitability limit (e.g., a limit in temperature; availability of water, nutrients or energy; environmental stability)? What is the importance of endogenous versus exogenous biota in restoring biological activity to intermittently habitable subseafloor environments?
  • To what extent and under what conditions can deep subseafloor environments be regarded as more stable than (for example) surface ocean environments? How does this affect habitability?

Group C: Biogeography

  • What unique opportunities do subseafloor environments provide to examine questions related to the biogeography of microbes?
  • Can microbial biogeography be predicted to a first order from existing geochemical and geophysical data, and can such predictions be used to suggest future needs in IODP?
  • What is the extent of the life in different subseafloor environments? How and to what extent do biosignatures in subseafloor environments provide information on past communities and microbial processes versus extant communities and processes?
  • How can we define microbial diversity in the subseafloor environment (or in any environment)?
  • Can microbiology in the subseafloor life progress with a preponderance of single site studies, or is it necessary to plan studies drawing on site-to-site comparisons? Can both be accommodated within the IODP?

Group D: Technology issues

  • What technology issues must be considered to successfully address challenges of exploring subseafloor ecosystems, such as cultivation requirements, low cell numbers, low rates of microbial activities, contamination? Which of these issues have specific implications for drilling strategies?
  • Broadly speaking, what technical issues, such as facilities, funding, etc must be dealt with? What are the basic requirements for the work? What is already in place? What needs to be made available?
  • Consider the advantages and disadvantages of conducting dedicated 'microbiology' cruises versus addition of microbial studies to existing cruises. How can operators maximize success of expeditions using cruises of opportunity?

Steering Committee

Steven D'Hondt (co-chair)
University of Rhode Island
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Fumio Inagaki (co-chair)
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Bo Barker Joergensen
Max-Planck Institute - Bremen
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Kenji Kato
Shizuoka University
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Paul Kemp
SUNY Stony Brook
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Patricia Sobecky
Georgia Institute of Technology
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Mitchell Sogin
Marine Biological Laboratory
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Ken Takai
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White Papers

All members of the scientific and engineering community are invited to submit one or more white papers to the steering committee. These papers will be used in developing the detailed program for the workshop and will be available to participants and to the community prior to the workshop. A white paper may address any topic of relevance to the workshop. We particularly seek white papers that discuss important objectives regarding studies of subseafloor life, locations where IODP should consider drilling to address these important objectives, long-term drilling strategies, or key measurements that can be made in conjunction with IODP drilling.


Meeting Logistics

The workshop will be held at Renaissance Vancouver Hotel in downtown Vancouver , British Columbia. Vancouver International airport is 18 km from the Renaissance Hotel and a shuttle cost approximately $14.00 CAD; taxi $30.00 CAD. There are direct flights to YVR from Narita, Osaka, Frankfurt and many US cities. Vancouver has a cosmopolitan population of about 2 million - residents and visitors alike take advantage of the mild climate, exquisite natural scenery, and relaxed, outdoor lifestyle.

Earlier Planning Documents