standardization of environmental data and information - International ...

Abrasion with nodules usually destroyed the fauna; therefore, further
trawling was abandoned, in the knowledge that this would result in a gap of
information desired for both its intrinsic value and for the determination of
species.
1.5.1.1. Ocean Floor Observation System (OFOS)
1.5.1.1.1. General description
The Ocean Floor Observation System, built by Preussag Marine
Technology, consists of an onboard unit and an underwater unit. By means
of the onboard unit, different functions of the underwater unit can be
controlled, and warning lamps indicate malfunctions, e.g. empty batteries or
interruption of the data-transmission line. The underwater unit is a metal
frame containing batteries, television and photographic cameras, lamps,
flashes and a navigation transponder. The instrument is towed a few
metres above the seafloor.
1.5.1.1.2. Photo system
The underwater flashes are activated by turning on the
corresponding switches. Two control lamps serve as charging controls for
the flashes. The red "Wait" lamp indicates that the flashes are being
charged and the green "Ready" lamp is on when the flashes are ready for
the next underwater photograph. Premature release of the flashes is
possible, but then the flash energy is lower and consequently the
photograph is darker. The flashes are released by pressing the "Actuate"
button or using the hand-held trigger. A counter on the onboard unit shows
the number of frames taken at a station or along a profile. Up to 800
exposures can be made during one operation, before the battery package
has to be recharged and the camera reloaded. The lower left corner of each
frame contains additional information on the distance to the bottom and
the time the photograph was taken. Colour slides can be developed aboard
the ship, employing the E6 process, and are available for evaluation only a
few hours after the end of operation. The film used was Kodak Ektachrome
200 Professional.
1.5.1.1.3. TV system
Four spotlights and two floodlights are installed in the instrument
housing of the underwater unit. They can be switched on and off
separately, and the brightness can be varied by adjusting the dimmer
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