standardization of environmental data and information - International ...

?? Benthic currents: current meters on mooring lines.
?? Light transmission: transmissometers attached to mooring
systems.
?? Chemistry: Dissolved oxygen, alkalinity, nutrients (nitrate, nitrite and
silicate), dissolved trace metals and suspended solids.
(For details on methods and equipment, see appendix B at the end of
this volume.)
Results
Displaying a contour map generated from a hydrosweep of the area,
Ravindran said the researchers had accidentally discovered a possible
fracture zone, as well as some seamounts at 76° E and 12.5° S that
peaked at about 1000 m above the bottom.
From other results, scientists had generated graphs and profiles of
salinity, pH, dissolved oxygen (DO), PO4 and NO3. Vertical sections of
temperature and salinity had also been produced as part of the baseline
studies, along with sections of oxygen, nitrate, pH and phosphate.
For the benthic disturbance and impact studies, the area selected
was about 3000 m long and 200 m wide, with 26 tracks. The disturbance
had continued for nine days, for an effective time of 2850 minutes. It was
estimated that approximately 6000 m³ of sediment had been pumped up
by at least 5 m, over a distance of about 88.3 km. Each tow had run
approximately 4 km.
Pre-disturbance profiles had shown living organisms at the test site.
Post-disturbance images displayed distinct features of the disturber tracks
in some areas around the site, with the sediment disturbed and thrown to
the side. A thin layer of sediment had covered the undisturbed areas. After
five days, no sediment had been collected in the traps above 20 m from the
seafloor. At 7 m, there had been some plume suspension, but beyond 100
m from the track, nothing had been found in the sediment traps. These
were important results from the sediment trap and photographic
observations. Before the disturbance, the tracks and burrows of organisms
could be seen, but they had disappeared in the top 20 centimetres. Most of
the disturbance had been restricted to the upper 20 cm of the sediment in
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