In May, 2019, a comprehensive controlled release experiment was carried out in the Oslo Fjord. During the experiment, CO2 was released both in gas phase (bubbles) and in dissolved phase (local seawater manipulated by adding CO2). The CO2 was released from a leak frame at the seabed at 62 m water depth, and the response to this simulated leak was measured using a range of chemical and acoustic sensors mounted on various platforms. The experiment lasted 6 weeks.
Key parameters that were measured include the chemical response and spatial footprint of the controlled CO2 release, acoustic properties of CO2 bubbles measured using different active acoustic sensors (echo sounders and sonars), and the rise height of CO2 bubbles at different leak rates. In addition to stationary seabed templates instrumented with suitable sensors, the controlled release was monitored using sensors mounted on the Simrad Echo R/V, the HUGIN AUV, and the SeaExplorer glider.