The benthic environment of the north sea (56 deg to 61 deg n)
The benthic environment of the north sea (56 deg to 61 deg n)D. BASFORD AND A. ELEFTHERIOU
Marine Laboratory, P.O. Box 101, Victoria Road, Aberdeen
AB9 8DB
In an attempt to describe the physical and chemical
characteristics of the sediments as an environment
for the invertebrate benthos, a total of 273 stations
covering the sector from 56 deg N to 61 deg N in the
North Sea was sampled. The sediment samples which
were collected by grab and corer were analysed for
particle size (as well as silt-clay content and sorting,),
organic carbon, plant pigments and trace metals (Cd,
Pb, Zn, Ni, Co, Cu). On a smaller scale a few stations
were sampled for redox potential, pH and pesticides.
Taking into account the geological history and the on-going
hydrographic processes, explanations for the formation
of the sedimentary provinces in the North Sea were
provided. The sediments were predominantly fine to
medium sand, but there was a depth-related gradient
with the finer grades, organic carbon and, to a lesser
extent, plant pigment being found in the deeper sedimentation
basins of the Fladen Grounds and Norwegian Trench.
Trace metals and pesticide contaminants associated with
the finer organic and inorganic fractions were higher
in the sediments of the above deeper areas as well
as in the vicinity of estuaries. It could be concluded
that despite the enhanced concentrations of Cd, Ni,
Pb and Co, at the cast of Shetland, which were due
to a geochemical anomaly, there was no evidence of
any important or large-scale contamination of the North
Sea as a whole.
J mar. biol. Ass. U.K. (1988), 68, 125-141