Minerals Report - International Seabed Authority

zooplankton at the upper boundary of hydrothermal plumes in the northeast
Pacific indicate that plume productivity may feed plankton food chains in the
water column 8 ; this remains to be quantified.
3 Vent Ecosystems
Mid-ocean ridges reveal an astonishing diversity of styles of seafloor
spreading and associated geology and biology. One of the key variables that
affect spreading style is the plate divergence rate: slow spreading ridges have
very different characteristics from fast spreading ridges. Readers are referred
to a theoretical paper 9 for detailed consideration of the relation between
seafloor spreading rate, vent habitat frequency and vent faunal diversity. This
section will briefly compare vent ecosystems on two parts of the ridge system
that have formed the basis of much of our understanding: the East Pacific Rise
(EPR), between 8° 30’ N and 13° 30’ N, which is spreading at approximately
100 mm/yr; and the Mid-Atlantic Ridge (MAR) between 33° N and 38° N,
which is spreading at about a quarter of that rate.
3.1 EPR Vent Ecosystems
A schematic representation of the general appearance of vent
ecosystems on the northern EPR is shown in Figure 3.
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