Haklang SERPENT visit report

The SERPENT project made two visits to the Transocean Leader semisubmersible drilling rig to study seabed disturbance at the Statoil operated Haklang prospect in the Norwegian Sea in the autumn of 2008. Seabed depth at Haklang was 1250m and the water temperature was -1⁰C. Using the Oceaneering Magnum ROV seabed disturbance was assessed by visual observations and sediment sampling immediately after drilling impact. Megafaunal community observations were used to determine the ecological changes. Video showed a cuttings pile with complete coverage of the seabed and absence of megafauna extending 25-55m from the well. Beyond this seabed coverage was heterogeneous with cuttings visible to at least 100m to the north west. Mean megafaunal abundance was low to a distance of 40 m. Cerianthids were the dominant organisms and were present closer to the well than other taxa, perhaps because of their burrowing habit. The longer term effects of this disturbance are unclear. In addition specimens of the invertebrate megafauna were collected at Haklang.