Detailed visual seabed survey at drilling site 7218/11-1

5.2.3 Seashore algae and fishfalls
Theoffshoreenvironmentoften is perceivedto be a barrenenvironment,remotefrom the processes
which occur alongthe coast.However,often we find relatively fresh piecesof seaweedoriginating
from the shore, andthis indicatesa dynamictransport pathwayfrom the coastto the offshorestudy
areas.
Onlyoneobservationof macroalgaewasmade(position411675.2/ 8000871; not photographed).
5.3 Distribution maps and selected images
5.3.1 General overview
During the ROVsurvey1366 pictures were taken of the sea bottom. The bottom generallyhad a
smooth surfaceand the depth varied from appr. 310 – 335 m. Thedepth variationswere affecting
the angleof the ROVusingduringthe survey,resultingin a variationof angledpictures.Asa result,it
is difficult to make accuratecalculationsof the area of sediment present in each picture. A laser
beam is showinga distanceof 10 cm between the lines, but also the length of the beam varies
accordingto the angleof the ROV.
Further, during periods where fish shoalsare abundantnear the seafloor (from around 4 am and
towardsafternoon),the lights on the ROVattracted largeamountsof curiousfish duringthe survey,
mainly coalfish (Pollachiusvirens). Thesemadefilming of spongesdifficult becausethey stir up the
sedimentsurface.
Detailed site survey at PL531 Darwin
Akvaplan-niva AS Rapport 6051 - 1 27