Abstract:
Diverse microbial communities and numerous energy-yielding activities
occur in deeply buried sediments of the eastern Pacific Ocean. Distributions
of metabolic activities often deviate from the standard model. Rates of
activities, cell concentrations, and populations of cultured bacteria vary
consistently from one subseafloor environment to another. Net rates of
major activities principally rely on electron acceptors and electron donors
from the photosynthetic surface world. At open-ocean sites, nitrate and
oxygen are supplied to the deepest sedimentary communities through the
underlying basaltic aquifer. In turn, these sedimentary communities may
supply dissolved electron donors and nutrients to the underlying crustal
biosphere.
