COBALT-RICH FERROMANGANESE CRUSTS
31
Defining characteristics of
biodiversity of cobalt-rich
ferromanganese crusts
3.4
The faunal communities associated with ferromanganese
crusts have been described in detail in the preceding section
on habitats and ecosystems. There are some key characteris-
tics that need to be considered specifically for this environ-
ment when assessing potential impacts:
• The dominant benthic fauna on seamounts are often ses-
sile corals and sponges. These may include species with a
wide distribution as well as those that are endemic or only
occur in a small region. Their slow growth rates and high
longevity make recovery from disturbance either unlikely or
very long-term.
• It is uncertain whether seamounts with ferromanganese
crusts have different fauna from non-ferromanganese-crust
features. This uncertainty needs to be addressed. If there is
no difference, then mining sites and protected sites should
be relatively easy to select. If there are distinct communities
specific to seamounts with ferromanganese crusts, then con-
servation strategies will need more detailed evaluation.
• Faunal composition changes with water depth, and sea-
mounts have a large depth range. As the species compo-
sition and abundance change, so too do the vulnerability/
resilience of benthic communities. Therefore, the depth of
an extractive activity must be considered when developing
management plans or designing for conservation.
• Knowledge of the biodiversity associated with ferromanga-
nese crusts is poor, and considerable basic data need to
be collected during the exploration phase of any mineral
development.
