OVERALL SUMMARY OF DEEP LIFE
Deep Life exerts a vital influence on Earth's subsurface carbon fluxes and reservoirs. It
exploits Earth's deep energy at the intersection between abiotic and biotic realms. The
Deep Life Community will map the abundance and diversity of subsurface marine and
continental microorganisms in time and space as a function of their phylogenomic and
biogeochemical properties, and their interactions with deep carbon. By integrating in situ
and in vitro assessments of biomolecules, cells, communities, process rates and subsurface
habitats using advanced measurement, imaging, and cultivation technologies, we will
describe the environmental limits to deep life, its survival, metabolism and reproduction.
The resulting data will inform experiments and models that seek to measure Deep Life’s
impact on the carbon cycle, to constrain biologically-mediated structural alteration of deep
reservoirs of carbon and other elements, and to define the deep biosphere’s relation to the
surface world.
DECADAL GOALS:
The Deep Life Community will explore the evolutionary and functional diversity of
Earth’s deep biosphere and its interaction with the carbon cycle.
I. Determine the processes that define the diversity and distribution of deep life as it
relates to the carbon cycle. Examples of research focus include:
 Conduct a global 3-D census over time of biological diversity (Bacteria, Archaea,
Eukarya, viruses) in continental and marine deep subsurface environments.
 Investigate whether specific mechanisms govern microbial evolution and dispersal
in the deep biosphere.
 Determine what ecological rules explain deep microbial community structure, e.g.
spatial and temporal scales of community turnover, the role of the rare biosphere,
and the effects of limited dispersal.
II. Determine the environmental limits of deep life. For example we will:
 Probe and test life’s response to physical and chemical extremes using observation,
experimentation in the laboratory and in the field, and modeling.
 Explore what genomes can tell us about the limits and possible origins of life.
 Establish a bio-energetic framework for understanding the limits and adaptation of
life in the deep subsurface.
III. Determine the interactions between deep life and carbon cycling on Earth. For
example we will:
 Determine the principal pathways of carbon transformations in the subsurface and
quantify the rates of these reactions.
 Characterize transitions between abiotic and biotic realms.
 Quantify how these processes interact with the surface world.