Minerals Report - International Seabed Authority

diversity within the Benguela Ecosystem and resulted in the creation of a
very important data set for De Beers for environmental management of
mining operations, and for other users of marine resources such as the
fisheries community.
Dr. Corbett said that the work conducted by De Beers with the Jago
submersible has allowed it to interact extensively with the scientific
community. He said De Beers donates a number of dives to various
members of that community for their own research dives whenever it uses
the Jago.
In summary, Dr. Corbett said that De Beers is producing unique
data sets based on the Jago submersible and grab sampling. He said that
this approach allows De Beers to look at local scale, short-term changes.
He also said that De Beers has learnt that mining alters the habitat on the
sea floor, but that the response is different for different animals. With
regard to the long-term perspective, Dr. Corbett said that it is only through
long-term baseline datasets that one can really start to understand the
impact of mining and the disposal of sterile material originally recovered
from the seabed back to the seabed, He said that one of the things that has
been found is that when the material is dumped over board, it can create
what is termed by some Canadian scientists as environmental
enhancement. He noted that in parts of Canada on the Scotia shelf, this
process has been able to regenerate the lobster stocks through aggregate
extraction, which creates breeding ground scenarios where formerly the
lobsters were at risk. In this regard, he asked whether in fact De Beers is
enhancing the environment in a way that could, for example, enhance the
fisheries stocks in Namibia?
He emphasized that it is to be appreciated that the Benguela
ecosystem is a dynamic environment with natural variability both in time
and space. Dr. Corbett said that in 1997 employees at De Beers were able
to witness a 2 to 3 metres swell operating directly on the sea floor in 126 to
128 metres of water. He said that employees were able to watch a natural
event where vast volumes of the very fine silts on the sea floor were
picked up and suspended in a column, that was about 50 or 60 metres
thick. He noted that this event had never been witnessed by anybody
previously. He said that this event showed that there are very large-scale
perturbations in the natural system that may be caused by internal waves
impinging on the continental shelf. He also said that these natural events
have the capacity to create low oxygen conditions over vast areas of the
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