Leaving Newport, the R/V Thompson was partially hidden in fog as we steamed to the Slope Base Site near the foot of the continental margin. Onboard we have a new group of 9 undergraduate and graduate students from the UW College of the Environment, School of Oceanography, and Earth and Space Sciences Department, as well as from the College of Engineering. On our steam out to Slope Base, the fog horn routinely welcomed old timers, as well as new sailors, to the ship.
Leg 4 is dedicated to completing a few seafloor installations at the Slope Base Site, installing all of the infrastructure at Southern Hydrate Ridge, and installing (for the first time) the shallow winched profiler and instrument platform on the two-legged mooring at the Oregon Offshore Site — a very busy Leg it will be/already is.
We arrived at Slope Base at ~1900 PDT and installed the final seafloor instrument, the HPIES, and the connecting extension cable, thus completing the seafloor installation. Here, the students got to experience their first CTD and watch in the ROPOS control room. The R/V Thompson then transited a couple hours east to Southern Hydrate Ridge where we completed cable-route surveys for three cables that will connect short-period seismometers on a follow-on dive.
Near the end of the dive, we saw a spectacular "farm" of Neptunea snails. Hundreds of the snails were sitting on egg stalks that form beautiful yellow spirals on top of which sit the "tender" snails. The snails build their egg stalks, which are reminiscent of woven yellow lines, on small carbonate cobbles. The babysitter snails, as they are often called, lay their eggs and then die and fall off the stalks, littering the surrounding nursery.