Minerals Report - International Seabed Authority

initial mining, but that within a very short period of time, pioneering
communities come to re-colonize these areas of the seafloor.
Dr. Corbett said that based on the history of mining by De Beers in
the region, it has been able to implement a continuous monitoring
programme to gain more insight into the community structures on the sea
floor, and the severity of mining impacts on these communities.
He defined two types of mining impacts; direct disturbance of the
sea floor caused by mining tools that are actively extracting the gravel
from a given area, and the other as the disturbance caused by the
settlement of tailings plumes.
With regard to the condition of the seafloor after mining, Dr.
Corbett said that it appears as a series of overlapping circles of disturbed
ground caused by the large bore drills. He said however that based on the
science for studying these impacts; the approach to monitoring them is
with two basic techniques that follow conventional grab sampling.
He described as a major transformation of this approach the use of
the Jago submersible. He explained that during dives, the Jago provides
video transects that can be analysed in some detail. He said following
bottom grab sampling, control sites comprising undisturbed areas on the
soft seabed that are uninfluenced by mining and an area that has been
mined can be set up. Thereafter these sites can be used to deduce whether
there are differences due to mining or natural disturbances. At the same
time, he said that mined out areas have to be sampled over different time
intervals to look at the recovery of the community.
Dr. Corbett informed participants that Dr. Mark Gibbons, a
researcher at the University of Western Cape is in the process of
publishing a number of papers on this type of approach. He said that the
approach enables researchers to obtain a good analysis of the changes in
the seabed communities between the disturbed and undisturbed areas at a
much higher confidence level. He pointed out that with a grab, even if
equipped with a camera, one does not obtain a real context of the
sampling area whereas by flying over the area in a submersible, the
human brain is able to absorb the perspective. He also said that this
approach enables a researcher to create very specific sampling
programmes and to obtain results at a very high confidence level. He
stated that the approach has opened a new window on the marine
INTERNATIONAL SEABED AUTHORITY 658