RRS Charles Darwin Cruise 112C, 19 May-24 Jun 1998. Atlantic Margin Environmental Survey: seabed survey of deep-water areas (17th round Tranches) to the north and west of Scotland

This cruise formed part of the Atlantic Margin Environmental Survey (AMES) 1998. The primary objective of the cruise was to carry out a large-scale seabed sampling survey of six areas of continental slope variously located north and west of Shetland and west of the Hebrides. In total over 100 seabed stations were sampled using either megacorer, box corer or Day grab, generating samples for the subsequent analysis of macrobenthos, hydrocarbons, heavy metals, particle size, total organic carbon and nitrogen and geology. Additional survey operations included photographic observation of the seafloor using still and video cameras mounted on the SOC WASP and epibenthic sledge vehicles and limited sampling with a gravity corer (British Geological Survey). The cruise also re-sampled (primarily for macrobenthos) a bathymetric transect of stations to the west of Shetland previously established during RRS Charles Darwin Cruise 112 C leg 2 (AMES 1996). Shipboard observations of seabed samples and video footage collected in the various survey areas are summarised in the report. Other general observations include (a) the effects of deep-sea trawling, observed to the west of Shetland and the Hebrides; (b) the widespread and mass occurrence of phytodetritus in the deeper waters of the Rockall Trough; (c) numerous observations of, frequently dense, populations of xenophyophores (Syringammina fragilissima) at around 1000 m depth in the Rockall Trough; and (d) the discovery of a field of coral (Lophelia pertusa) topped seabed mounds in the Rockall Trough immediately to the south of the Wyville-Thomson Ridge.