North Sea (UK Block 15/25, Witch Ground Basin), Skagerrak

Ammonium and ammonia concentration parameters in water bodies; Carbonate chemistry in sediment pore waters; Dissolved oxygen parameters for sediments; Dissolved organic carbon concentration in the water column; Vertical velocity of the water column (currents); Salinity of the water column; Horizontal velocity of the water column (currents); Redox potential in sediment; Seabed photography; Side-scan sonar; Stable isotopes in sediment; Temperature of the water column; Zoobenthos dry weight biomass; Zoobenthos taxonomic abundance; Zoobenthos taxonomy-related counts; Zoobenthos taxonomy-related wet weight biomass per unit area of the bed; Concentration of inorganic sulphur species in sediment; Concentration of inorganic sulphur species in sediment pore water; Total dissolved inorganic carbon (TCO2) concentration in the water column; Alkalinity, acidity and pH of the water column; Dissolved organic carbon concentrations in sediment pore waters; Stable isotopes in sediment pore waters; Bathymetry and Elevation; Carbon concentrations in sediment; Fauna abundance per unit area of the bed

Underwater cameras; discrete water samplers; unconsolidated sediment corers; CTD; current profilers; sidescan sonars; single-beam echosounders; rock dredges

The project is designed to study sulphide and methane based ecosystems and a large volume of data has been collected to facilitate this. Geophysical surveys have been made in the North Sea (Witch Ground Basin) and the Skagerrak. In the Witch Ground Basin surveys were carried out for shallow gas and seeps. Box core samples were taken to compare biomass and species composition of zoobenthos within pockmarks and on the flat sand bed. Measurements were made of dissolved gas concentrations in the water column within an area of gas seepage. In the Skagerrak surveys were carried out over an area where seepage is known to occur. A bathymetric map of the area has been produced with the aim of relating seepage areas to bottom topography. Sediment chemistry and zoobenthos in sediment cores have been compared in seep and non-seep areas. Estimates of the input of methane derived carbon into the zoobenthos have been made. Bottom photographs were taken.

Marine Biological Association of the United Kingdom
Citadel Hill
Plymouth
Devon
PL1 2PB
United Kingdom