Strategies, methods, and technologies adopted on the R.V. G.O. Sars MAR-ECO expedition to the Mid-Atlantic Ridge in 2004

The MAR-ECO project aimed to gather information on mid-ocean ridge macro- and megafaunal assemblages and their distribution patterns in relation to the abiotic environment, and the target area extended from Iceland to the Azores, comprising waters associated with the Mid-Atlantic Ridge. Strategies and methods adopted on the 2004 international expedition on the R.V. G.O. Sars and M.S. Loran were selected in order to maximise data and sample collection in all pelagic and benthic habitats to a maximum depth of 3500 m, spanning the organism size range from mm to metres. The approach selected was to combine (1) Continuous sampling along the shipʹs track; (2) Point observations using a pre-defined set of samplers at pre-determined sites; and (3) Opportunistic sampling to study particular phenomena or carry out exceptional tasks. range of nets and mid-water and bottom trawls were mobilised in order to collect biological samples. Hull-mounted, lowered and towed optical and acoustical instruments collected data and images. Two remotely operated vehicles (ROVs) were used for pelagic and demersal studies, and moored echosounders and cameras on benthic landers collected vessel-independent information. Observation of whales and seabirds were made from a custom-built observation area on top of the wheelhouse. Using a range of technologies from the same platform efficiently provided comprehensive results and enhanced the potential for new discoveries at the organism, community, and ecosystem levels.