standardization of environmental data and information - International ...

SUMMARY OF DISCUSSION
Impact of disturber track
Referring to the damage caused directly by passage of the mining
vehicle across the seafloor, a participant said he had learned, from
research into deforestation in rain forests, that the effect on soil fauna
depended hugely on how deforestation was carried out. If cutters walked in
and took the trees away after cutting them down, the damage to the soil
fauna was not particularly great. If a bulldozer was used, however, there
was a huge impact on the biodiversity of the soil fauna, because the weight
of the machine seemed to do something horrible to the environment,
looked at from a nematode’s or termite’s point of view.
Mr. Fukushima responded that, unfortunately during the Japanese
trial, samples had not been taken from the disturber’s tow track. In a new
project initiated in 1999, such sampling would be done at a depth of 200
m.
Chlorophyll distribution
Discussing why graphs on vertical distribution of chlorophyll showed
a maximum concentration at 100 m and not nearer to the surface (see
figure 4 above), a participant explained that those profiles had been
recorded before any impact. They were the natural chlorophyll profiles,
typical for oligotrophic waters, in which the chlorophyll maximum was
usually at depths of 75-100 m or so because the nutricline was at those
depths. Shade-adapted or low-light adapted phytoplankton lived at the
depths near where they were able to obtain nutrients.
Effects on meiofauna and megafauna
To a question about the response of meiofauna and megafauna to
the JET experiment, Mr. Fukushima said suspension feeders had not
decreased significantly but deposit feeders had declined. The reason, in his
opinion, was that the impact from the DSSR had been temporary for the
former but not for the latter, because organic carbon in sediment had
remained low after two years. This meant that deposit feeders had suffered
for two years while suspension feeders had been affected for only one
month. The same results had been obtained for macrofauna and
218 INTERNATIONAL SEABED AUTHORITY