An international team of scientists have published results of the first ever sub-sea carbon dioxide impact, detection and monitoring experiment relevant to Carbon dioxide Capture and Storage (CCS) in sub-seabed storage reservoirs in Nature Climate Change.

The study was designed to understand how marine life on the seabed and in the water above might react to a real-life leakage, as well as determine methods for detection and monitoring of a small-scale carbon dioxide (CO2) leak event. The research found that, for a leak of this scale, the environmental damage was limited; restricted to a small area and with a quick recovery of both the chemistry and biology.

The Quantifying and Monitoring Potential Ecosystem Impacts of Geological Carbon Storage (QICS) project was led by Plymouth Marine Laboratory’s (PML) Jerry Blackford and funded by the Research Councils UK, the Natural Environment Research Council, the Scottish and Japanese Governments. A number of UK and Japanese institutes collaborated with the experimental controlled release of CO2 undertaken in Ardmucknish Bay, (near Oban) Scotland in 2012; the experiment was co-ordinated by the Scottish Association for Marine Science (SAMS).

4.2 tonnes of CO2 (less than the annual CO2 emission of a gas-heated UK home*) was injected over 37 days from a land-based lab via a borehole drilled through rock to the release site, 350 meters from the shore and 11 meters below the seabed (see illustration below). Scientists initially monitored how the CO2 moved through the sediment and the 12 meters of water above. Over the following 12 months the impact on the chemistry and biology of the surrounding area was assessed using a combination of techniques, including chemical sensors, listening for bubbles and diver-mediated sampling.

A combination of chemical sensors and bubble acoustic techniques are shown to provide the optimal monitoring technology to detect leakage or give assurance of no leakage.

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Source: Carbon Capture Journal, 16 Oct 2014