Farris Willingham and Tamar Hallerman
GHG Monitor
07/06/12
Researchers examining the effects of a simulated underwater CO2 leak on marine life ecosystems off the west coast of Scotland are calling initial release operations a “success,” reporting that the CO2 behaved as the team expected. The project is led by the Plymouth Marine Laboratory, and though researchers have now turned off the CO2 stream, data collection and analysis work remain ongoing and the site will be continually monitored until at least September. “Following a complex drilling operation, the injection of CO2 from a shore-based laboratory into shallow marine sediments is allowing scientists to determine whether (and how) such a leak from a CCS sub-seabed storage site would adversely affect marine life. The experiment is also enabling the assessment of various ways of monitoring for CO2 leakage,” a Plymouth Marine Laboratory release said.
Researchers began piping more than four and a half tonnes of CO2 through a borehole into shallow sediments in Scotland’s Ardmucknish Bay in mid-May to examine how CO2 disperses through the sediment and water and affects marine life and the surrounding ecosystems. In an interview this week with GHG Monitor, experiment coordinator Henrik Stahl of the Scottish Association for Marine Science said that divers observing the site have found that the impact of the experiment has been very localized, and that some nearby marine life was affected by the experiment, while others remained unaltered. “We’re still processing much of the data,” Stahl said. “What we’ve seen initially is that we could see the gas seeping through the sediment surface quite quickly. Surprisingly, there was a large number of gas bubbles. We’re still calculating how much is coming out as CO2, and we’re still calculating the pH level. But some animals seemed to suffer from the low PH, while other animals seemed to cope better.” In particular, Stahl said that sea urchins were negatively affected, while crabs appeared to be attracted to the site where the gaseous bubbles were forming. He said a surprise result was that the CO2 being released from the sea bed was being affected by the tides—more carbon would flow out during low tide.
Most European CO2 Storage Projects Offshore
Stahl said that even though researchers simulated the leak on a small testing area, the experiment will help provide insight into any potential leaks that could occur underwater in the future. “This experiment tests how the [surrounding environment and marine life] was affected in the short-term, but even within this time period, some animals seemed to suffer,” Stahl said. “We could compute that our experiment worked, and it worked very well.”
The simulated leakage project is part of a larger four-year research effort to better understand how the U.K.’s marine environments react to potential leaks from underwater carbon storage operations, as well as to develop technology to help monitor marine environments for leakage. The effort is a particularly relevant one for Europe, where most of the continent’s CO2 storage projects are slated for offshore development. Norway’s Statoil currently runs two of world’s oldest CO2 storage projects, both offshore at Sliepner and Snøhvit. More recently, the Netherlands barred all onshore CO2 storage, while the U.K. said it will only accept entries into its CCS demonstration program that plan to inject CO2 into offshore saline aquifers or depleted oil and gas reservoirs.
