Lander Ho!

Happy 1^st day of the DSB2 Cruise aboard the RV Pt. Sur! I’m Jane Carrick, a postdoctoral fellow from the University of Rhode Island. Along with expert Dr. Andy Davies, I’m on the ship to deploy a benthic lander to the deep seafloor where it will record data for the next 11 days.

What is a benthic lander you might wonder? Well picture a moon lander but outfitted with a suite of highly specialized sensors that can capture environmental and biological activity. Also, swap out the moon for the deep, dark bottom of the seafloor. The lander we are deploying today is affectionately nicknamed WALL-E after the famous PIXAR robot, and stands at an impressive 8 feet tall and weighs in at nearly 2500 lbs. Though simple in its concept, our lander system is a complex matrix of hardware, custom parts, batteries, and specially designed equipment that has been painstakingly assembled in our workshop over several months. Everything must be precision-engineered in order for the lander to survive its drop to the seafloor and then withstand the high pressure and continuous saltwater exposure. Yet, this lander is the perfect tool to help understand the relationships between mesopelagic and benthic communities here from 370 m deep at our first site Viosca Knoll!

In order to both deploy and recover the lander, we use a system of acoustic transceivers that control mechanical latches when given the right signal, known as acoustic releases. As the lander is lowered down on the winch to the position over the seafloor we want to drop it, we send the signal for an acoustic release to open a latch holding the lander to the winch cable, and down goes WALL-E. A similar system keeps the lander on the seafloor until we are ready to recover it at the end of our cruise. We again send an acoustic command to a second acoustic release that is mounted onto the lander itself which will let go of a lead weight stack, allowing the rest of the lander and its sensors to float back up to the surface thanks to 15 glass floats that give it buoyancy. All this we can do from the back deck of the Pt. Sur with a dunker transducer and a few clicks of a button!

Anatomical labeling of WALL-E before deployment.

The lander is equipped with a scientific echosounder to detect fish and other marine life within the water column with the hope of capturing temporal patterns of mesopelagic species that have yet to be documented. Additional sensors on the lander will further measure time series of variables like temperature, salinity, dissolved oxygen, and current speed, among others. Finally, a camera mounted to the lander frame (along with LED lights—it’s pretty dark in the deep sea!) will record photos and videos every 15 minutes, and we are hoping to see some cool visitors!

Andy and I pushing the release button to drop the lander at 372 m!

With limited deck space and lots of large equipment, we had to get creative and stage the lander inside the MOCNESS pelagic sampler frame. Our biggest challenge today was to get the lander up and over the sides of the MOCNESS without hitting it and we didn’t have much wiggle room. But the weather was in our favor (minus the brutal heat!) and flat seas allowed everything to go just according to plan!

Bon voyage and see you soon WALL-E!