Preface The expedition ARK XIX/3 with the German icebreaking RV ...

A. 4.4.3 Biogeoprocesses along the Giant Mound transect
Berov, D., Wheeler, A., Roberts, M.
One of the small mounds up slope from the "Giant mound" directly overlies a
boundary fault and, on the basis of information from the Petroleum Affairs Division of
the Irish Department of Communication, Marine and Natural Resources, was the most
likely mound to show evidence of gas seepage. On inspection this was not the case.
In contrast, this mound showed evidence of seabed erosion. The summit of the mound
was dominated by a hardground on which various fauna were living. Strong current
activity had eroded away the soft sediment on top of the mound until it had reached
the hard lithified (cemented) layers beneath. There was also evidence that erosion
had continued with some less well cemented layers eroded, causing the overlying
hardground to topple. This chaotic seabed provided a number of holes and crevasses
in which fish were hiding. In order to find out the age of these hardgrounds, a large
section (63cm long x 46cm wide x 13cm thick) was recovered by "Victor 6000" and
brought back to the surface.
This recovered specimen was examined and found to be composed of heavily bored
and cemented marl with numerous organisms encrusting the surface. A small live
Lophelia colony was recovered with several sponges attached at the base of the coral.
Also present was an erect stylasterid as well as several soft bodied anemones.
molluscs occurred, hiding in the burrows in the hardground.
Box-cores
A series box-cores were also collected from the site for sedimentological analysis and
are logged below.
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