This dataset is comprised of carbon isotopic composition and concentration of samples from stable isotope pulse chase tracer experiments. Data are available for sediment macrofauna, dissolved inorganic carbon in overlying water, and phospholipid fatty acids (PLFAs) in the sediment. Experiments were conducted onboard RRS James Cook (JC055) from 13/01/2011 to 22/02/2011 at three sites in the Bransfield Strait, Antarctica. Two of the sites lay on raised edifices, known as Hook Ridge and Middle Sister along the axis of the basin and included a diffuse hydrothermal site. A third site labelled as 'Off-Vent' others without hydrothermal vents was located along the north side of the basin, and was sampled as a control site. Sediment cores were recovered using a multiple corer for isotope tracing experiments. Duplicate cores were subject to two treatments; the 'algae' treatment with added algal detritus (simulating photosynthetic carbon) and the 'bicarbonate' treatment to simulate a substrate for benthic carbon fixation. Overlying water samples were analysed for concentration and isotopic composition of dissolved inorganic carbon. Frozen sediment samples were freeze dried and analysed for phospholipid fatty acids (PLFAs). Sediment horizons between 0 and 10cm preserved in formalin were sieved and macrofauna were extracted. This work was carried out by Clare Woulds, James Bell, and Louise Brown at the University of Leeds, Adrian Glover at the Natural History Museum, and Steven Bouillon at KU Leuven. It was funded by the NERC Discovery Science project Tracer Studies of Biological Carbon Cycling in Chemosynthetic Communities of the Southern Ocean (grant reference NE/J013307/1) active from March 1, 2012 to February 28, 2015.