Science success before the storm

On the 13 September, just before the stormy weather came in, the first survey Autosub6000, our AUV (Autonomous Underwater Vehicle: a robotic submarine that can be programmed to scan the seabed with a side-scan sonar for 24 hours, without pilot supervision), was completed.

The sonar maps the seafloor, highlighting particular structures such as cold-water coral reefs. This has led to the discovery of some new mounds, extending our knowledge regarding the distribution of the Darwin Mounds!

Eight years ago, we deployed some scientific equipment in the area, and attached settlement plates a few meters above the seabed. With these plates, we aimed to see whether coral settlement occurred via the flow of larvae conveyed by the bottom currents. After using the HyBIS to recover the equipment, we realised that not only the plates but also the buoys were entirely covered by deep-sea animals such as barnacles, brittle stars, small bivalves, predatory worms, sea urchins, overall supporting a whole little community. To our surprise, even some species of coral settled onto the buoys. Several colonies of the coral Lophelia pertusa that originated the Darwin Mounds were also found. This is a critical observation in order to assess if the recovery of the Darwin Mounds can take place after the bottom trawling damage.

For the interested readers, a 3D model of the buoy has been uploaded online so you can inspect the buoy interactively as we did onboard (https://skfb.ly/6NuBA).

In the afternoon the crew celebrated the birthday of our colleague Tim Le Bas. This was really a special event since Tim was part of the scientific crew that discovered the Darwin Mounds back in 1998. The mounds were then further characterised by Brian Bett, also onboard for the current expedition.

Following the pessimistic weather forecast we mentioned in the last post, this weekend we were sheltering off the coast of Stornoway due to the stormy weather. Seven metre waves were predicted in our study area! We will be back at the Darwin Mounds on Monday around 4 am. There, we will run another CTD cast, continue with the box coring, and deploy our AUV again.

We will carry on with our surveying and keep you posted about the new incoming activities in the DY108/109 cruise!