Emissions of carbon dioxide by industry is widely recognised as a driver of global climate change and ocean acidification. Carbon Capture and Storage (CCS) has been identified as an important way of reducing the amount of carbon dioxide released into the atmosphere and could be a key contributor to keeping the climate change derived temperature increase below the 2 degrees C target as outlined in European Commission Policy. Offshore storage of carbon dioxide in geological storage reservoirs, such as depleted oil and gas reservoirs and saline aquifers, is a promising option in the UK and worldwide. However, a key element of offshore carbon dioxide storage is the integrity assurance, which requires confidence that any leakage of the carbon dioxide into the marine environment (either from the storage complex or from pipelines) could be reliably detected. Recent experimental studies have shown that detection of a carbon dioxide leakage from the seafloor can be done with sensors mounted on either autonomous underwater vehicles (which can be very expensive) or on fixed installations (which require many installations to achieve broad spatial coverage). Recent technological developments have led to a low-cost hybrid system in between the autonomous underwater vehicles and the fixed installations, so called ‘flying nodes’. In this project we will show that the integration of chemical sensors and flying nodes is feasible and beneficial. To achieve this, we will define the technical and mechanical requirements for the integration, perform first hardware integration tests and perform a model exercise to specify the appropriate number and spacing of vehicles under different carbon dioxide monitoring scenarios.