As above, so below…

14 May 2019

Looks like our luck is back and stronger than ever as we round off another full day of surveying with some fascinating new finds. After spending the night away from the experimental site we returned this morning to redeploy our old favourite Freya, the Gavia AUV. Although initially reluctant to dive she eventually spent a few hours patrolling the site collecting sidescan sonar and sub-bottom data.

Launch of the AUV Gavia, aka Freya, with the Goldeneye platform on the horizon

The sub-bottom data is created by sending out a series of high frequency sound waves into the seabed and observing the strength of the sound waves reflected back, like sonar. However, unlike sonar, the sound waves actually travel into the underlying sediment and reflect off the interior layers in the sediment, allowing us to see what is under the surface. Today’s sub-bottom survey was particularly exciting as it revealed the exact position of the gas pipe we’ve been using in the experiment, and shows our gas escaping from it just as we planned.

Sub-bottom profile data showing the position of the pipe (black dot) and – to the trained eye – the gas escape above it (the fuzzy bit!)

That’s not the only thing going on today though – the sensors team is hard at work processing the data from their landers. Despite the rate of bubble release being relatively low, less than 30ml/min, they’re already seeing distinct changes in the chemical properties of the water and the sediment in response. We’re so pleased with these results we’ve decided to roll onto the next phase of the experiment, upping the flow of CO2 from the tank to increase the rate of bubble release. Stay tuned to find out what happens over the next few days…

PS – How cool is this? Footage from the ROV of CO2 gas bubbling out of the seafloor sediments at the experiment site!

Almost as cool as the STEMM-CCS beanie hats that the team is sporting today…

Everyone is working hard – clockwise from top left: Isabella, Rudi, Paul & Chris, and Dirk. Team beanie hats abound today!

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