The NERC-funded QICS controlled CO2 release experiment (located offshore Oban, Scotland) mimics the formation of a new CO2 seep in the marine environment. At the site, CO2 is injected at an onshore well head, and a stainless steel pipe transports the CO2 under the seabed. Approximately 350 m offshore, the CO2 is released through a perforated screen into the 12 metres of overlying marine sediment, which is at approximately 10 metres water depth. During spring/summer 2012, 4.2 tonnes of CO2 was released at the QICS experimental site. CO2 bubbles emerged from the seafloor ~30m to the west of the site and individual plumes covered a total area of ~ 350m2. Bubble stream location was recording using audio (acoustic) and visual techniques (photography, video). Both techniques are useful for recording the general location of plumes. However their 2D nature made it hard to characterise individual plumes and their exact locations. The QICS1 experiment included 200 deployments/recoveries of instruments, collection of 1,300 samples, and installation of 1600 m of cable and placement of 24 cages of indicator species on the seabed. In order to aid planning and operation during potential further experiments at the site it would be beneficial to utilise a robust and accurate method of recording the locations of equipment, samples and CO2 bubble streams. In this review, the four main types of submarine geolocation technologies are detailed and compared, and best available models (as of June 2013) are detailed. Grant number: UKCCSRC-C1-31.
