An experiment to test what would happen if carbon dioxide (CO2) leaked from underground storage reservoirs beneath the seabed has been hailed a success.
A team lead by Plymouth Marine Laboratory drilled and then injected CO2 over 30 days from a shore-based laboratory into shallow marine sediments to see what would happen to marine life in the event of a leak.
The experiment, which the group says is a world’s first, was carried out 350 metres from the shore off Ardmucknish Bay, near Oban, and 12 metres beneath the seabed. It will continue to be monitored into late September.
Project coordinator Dr Henrik Stahl said: “CO2 gas has been bubbling out of the sediments over the last few weeks and we have seen a clear but localised drop in the pH in the sediments and overlying water in the bubble zone, as expected.
“Some animals, such as sea-urchins living in the sediments, seem to react negatively to the increase in CO2 whereas others, such as crabs, seem to be attracted or unaffected by the bubbles; so there could be both winners and losers in a real-life situation.
“The next step is to turn off the gas flow and continue to study the recovery of the affected area.”
CO2 storage in depleted hydrocarbon reservoirs would be used in Carbon Capture and Storage (CCS), a process to capture carbon dioxide at fossil fuel power stations and store it at depth beneath the ground.
CCS is, however, still at a developmental stage. Shell, with SSE, is work on the Peterhead Carbon Capture and Storage project, which would be the first large-scale CCS operation of its kind in the UK.
The Quantifying and Monitoring Potential Ecosystem Impacts of Geological Carbon Storage (QICS) project was funded by RCUK/NERC and led by Plymouth Marine Laboratory in collaboration with the Scottish Association for Marine Science and four other institutions.
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