standardization of environmental data and information - International ...

the tendency was to think of the system as working primarily from the top
down, with most of the organisms in the mesopelagic and bathypelagic
realms deriving their primary food source from the particulates and detritus
sinking through the water column. However, while most of the food came
from the surface rather than from the bottom up, Smith had pointed out
research that had identified releases, reproductive products and other
things rising from the seabed up to the surface. The question deserved
further examination, as little work had been done on it
Smith said his gut feeling was that the surface water impacts would
probably not lead to species extinction, at least not on the same scale as at
the bottom. However, the volume of water to be discharged would not stay
as a cube and sink to the bottom of the ocean. It would mix in the upper
ocean and it was qualitatively much different from surface waters.
According to the earlier modelling efforts that Charles Morgan had cited
(see chapter 4 above), it would generate a standing plume of 85 by 20 km.
It was reasonable to expect enhanced productivity and altered food web
dynamics in that plume. This was not a large part of the ocean and there
would probably not be a devastating impact, but there would be some
impact and it almost certainly would be visible from a satellite, so that the
public would be aware of it. Whether or not that was acceptable was
another issue.
Nevertheless, the discharge would be into the deep water at a depth
to be defined, not on the surface, a participant countered. No current
design contemplated discharging at the surface.
Smith acknowledged that he had presented a worst-case scenario
with discharge at the surface. He thought that, for minimal impact, the best
idea might be to discharge at 10 m above the bottom, into the environment
that was already disturbed.
Koslow reiterated his view that the project would be much more
acceptable to everybody if the deepwater and sediment tailings were put
back into deep water.
Asked whether enough was known to make reasonable predictions
about the bathypelagic zone (4000-5000 m) where the discharge might
occur, Koslow said nothing was known about that zone. All the work he
knew about had been carried out mostly in the epipelagic zone, with some
in the mesopelagic. There was some knowledge about the distribution of
copepods, euphausids and other planktonic groups, and people had worked
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