Today was a mix of mechanical achievements and pure exploration—in one case unplanned—that led to the discovery of two surprisingly large deep coral habitats.
After the launch and long drive to the bottom, the day’s first task was to attach another oxygen sensor, this one at the NEPTUNE observatory’s only instrument package along the deepest axis of Barkley Canyon, 888 meters down. It’s the only instrument platform at this location because nobody was sure whether it was going to get buried in an underwater landslide at some point, but a few years out it seems like the spot is relatively safe.
Having an additional oxygen sensor there should prove especially helpful given that the first leg of this expedition returned with data suggesting that Barkley Canyon is a more important pathway than realized for the lower oxygen water that makes its way inshore.
Wally Washing
The next stop was a place they call Wallyland. That’s where a wired, robotic crawler called Wally lives. There are actually two Wallys and they measure a variety of oceanographic parameters like currents and temperature, and have two HD cameras. The Canadian team exchanges them about once a year. The vehicles have tracks like a tank, but made of rubber, and travel around at the commands of researchers in Canada, or Spain, or of the German team that built and maintains the vehicles.
This year, there was a problem with Wally 2, meaning Wally 1 has to stay on the bottom longer than usual. So, the ROPOS team paid him a visit and used a brush and the suction sampler blowing in reverse to give Wally a pretty thorough cleaning. His operators are already reporting that its instrumentation and cameras are performing better. “They seem to be very pleased with the carwash we did,” says Kim Juniper.
Coral Cruising
Another task on the day’s list was to connect a new current meter not far from Wallyland. This was where the unexpected exploration came in. The current meter was deployed by another ROV out here a few mongths ago, but there was a problem recording its exact position and it was about 600 meters from where the team thought.
In the process of searching, ROPOS cameras revealed a slope with a long line of black coral, hard bubblegum coral, and other species. “We knew there was coral there,” says Juniper, “But we had no idea of the extent. It was a bit of an eye opener.”
Once all the maintenance tasks were completed, we moved on to an area dubbed the Coral Cliffs. As the name suggests, the researchers knew there were some corals here as well, but they again found far more of them than expected because in the past they hadn’t had time to explore much of the area. “We started to define the perimeter but eventually gave up because it’s so big,” says Juniper.
Unlike the reefs in shallow water that people are more familiar with, deep corals tend to grow as individual branching colonies, each of which can take hundreds of years to grow. Knowing where they are, combined with all the data from the NEPTUNE observatory instruments, will help researchers to better understand what conditions are needed to support their growth.
Another job was spreading out an array of white cages that Neus Campanya Llovet will be using in some experiments this week aimed at figuring out what happens if you feed animals in the sediment extra food in the form of algae. Tomorrow we’ll explain more about how this is going to work.
