Retracing Our Steps

The HPIES (horizontal electrometer pressure inverted echosounder) instrument at Slope Base. It measures the horizontal electrical field, the pressure due to the overlying ocean waters, and the vertical acoustic travel time from the seafloor to the sea surface. Photo Credit: UW/NSF-OOI/WHOI, V19

Up and down, up and down. Even when you’re on a ship at sea, deploying unique and advanced equipment in thousands of feet of water, the daily events can start to feel routine. Today was mainly spent in transit, starting with moving from the Axial Base to the Slope Base site (a 17 hour transit), and then multiple dives to 2900 meters (9500 feet).

Each trip to the deep means 2 hours down and 2 hours back up (plus the time required to complete the installation and recovery). Thanks to the professionalism and training of the ship’s crew, thee Jason team, and the UW engineers, technicians, and scientists, we managed to swap out multiple instrument packages at Slope Base (HPIES, CTD, and optical attenuation and absorption sensors).

We also were able to observe some interesting sea life, including “sea pigs” (a type of sea cucumber), burrowing sea anemones, flytrap anemones perched on a sponge stalk, and numerous rattail fish, which always show up to investigate any disturbance on the seafloor. They have an excellent sense of smell, so they can follow scent trails for miles, a critical skill in the deep ocean where the next meal is never guaranteed.

A rattail fish (aka Grenadier) at Slope Base with parasitic copepods attached to its back. Photo Credit: UW/NSF-OOI/WHOI, V19

One fish we saw had hitchhikers aboard: parasitic copepods that attach themselves to the sides of deep-sea fish, which is one way to make sure that you always have a bite to eat. But we couldn’t stop to admire the biology – there was work to do, and time is short.

Time at sea can be strangely dilated. At first it seemed that we had all the time in the world, but as we get closer to the end of this portion of the cruise, we have to make critical decisions about how to maximize the days we have left, while also allowing for changes in weather or other unforeseen events. Once we wrap up the operations at Slope Base later tonight, we will head back to Oregon Offshore for the last of the installations on this ‘leg’ of the cruise, and then back to the dock!