Introduction to the preliminary version (1991)
This report is part of the project "Deep-sea environmental
protection - Examination of existing (imagery) material" ("Tiefsee-Umweltschutz
- Auswertung vorhandenen Materials") funded by the German Federal
Ministry for Research and Technology (BMFT = Bundesministerium für
Forschung und Technologie). Photo- and video-material of the first cruise
(SONNE 61) of the DISCOL-experiment have been examined.
In 1989 the Institute of Hydrobiology and Fishery Science (Institut für
Hydrobiologie und Fischereiwissenschaft) of the University of Hamburg
started a "DISturbance and reCOLonization experiment in the South
Pacific" (DISCOL) to contribute knowledge to the environmental effects
of deep-sea-(manganese nodule)-mining (Foell et al. 1990, Schriever 1990,
Thiel & Schriever 1989). The DISCOL experimental area (DEA) is located
south of the Galapagos Islands near a mining claim of the German AMR (=
Arbeitsgemeinschaft meerestechnisch gewinnbarer Rohstoffe) consortium.
The DEA is circular with a diameter of ca. 2 nmi (= 3 754m), corresponding
to an area of 3.14 nmi² (= 10.8 km²). The central position is
07o 04.4'S and 88o 27.6'W. The area and its surroundings were mapped by
SEABEAM charting (8 x 12 nmi area). The water depth is between 3 950 -
4 500m.
The photos in this megafauna atlas were made by the 35mm camera unit of
the Ocean Floor Observation System (OFOS) used by the DISCOL investigators
to monitor the sea floor of the DEA during the experiment. The OFOS is
built by the German firm PREUSSAG AG - Marine Technology. It is a towed
unit equipped with real-time television and photo-on-command capabilities.
The video and photo cameras are fixed to a metal frame, together with
batteries, lamps, strobes and a navigation transponder.
The photo system contains a BENTHOS survey camera with a NIKONOS 28mm
lens. The film used was KODAK Ektachrome 200 professional. During a single
deployment, up to 800 photos can be taken before the battery package has
to be recharged and the camera reloaded. Information about the time and
the distance of OFOS above the sea bottom are added into the frame data
chamber by a data encoder. The TV system contains a low level underwater
camera, which sends black and white signals via coaxial cable to the shipboard
unit. Aboard the ship the incoming signals are recorded on VHS tapes.
On the videotapes the date and time are added. The OFOS is towed 3 - 5
m above the sea floor. The videosequences are used for better interpretation
of the three-dimensional appearence of faunal individuals. Together with
the 35mm slides, abundance values for the megafauna of this area can be
determined.
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