Today started off with an excellent beginning, and as most days do; with breakfast, this one was different however, in that we had fresh tuna steaks. Gabe, one of the STAG technicians, had caught a fish a few days ago, the tuna is known as an “Ona”, which means delicious in Hawaiian, and it most certainly was. Also, the beginning of the day marked our arrival at Vailulu’u, an underwater volcano, known as a seamount. The area around Vailulu’u is around 5000 meters deep, whereas the highest points of the volcano itself are only 750 meters deep, and the interior crater is only about 1km at its deepest point. We will be studying the water in and around the seamount for a couple of days now, as it is a major point of interest, and the sole focus of several trips both before and after this one.

At 12:30 local time we also had our first fire and boat drills. During the fire drills, the scientists had to report to a central location for a head-count, and the crew prepared themselves to fight fires. During the abandon ship drill, everyone put on their lifejackets, which are in the staterooms. In addition, in the event of a real emergency, everyone would put on their protective dry suits, though one would probably not be necessary in the idyllic 85 degree Fahrenheit water. These are also located in our staterooms.

Today also marked the beginning of shifts, of which there are three; the 800-1600, 1600-2400 and 2400-800. The first shift began work using the CTD or Conductivity/Temperature/Depth, which actually tests much more than that. It is a large cage-like structure which is laden with instruments, it is then deployed over the side, and constantly sends back the readings to the ship, which logs them. Currently, we are sampling the inside of the volcano, for a full tidal cycle, therefore we are oscillating the depth of the CTD between 400m and 930m (almost the bottom), and collecting various data, one of the most interesting perhaps of which is one which indicates visibility. This is important because one of the interesting things about Vailulu’u is that the particulates given off by the hydrothermal venting is flushed out during each tidal cycle, by the surrounding water. By examining the CTD data, Stan Hart and Hubert Staudigel, the chief scientists on this cruise, hope to learn whether or not their hypothesis that cold water pours into the crater and displaces the warm hydrothermal water already in the crater, during a high tide.

The CTD itself is raised and lowered by a winch operator, who communicates with the scientists who views and captures all of the data the CTD sends back up to the ship. For the last 100m, or so, of lowering however, a different person, who is looking at a sonar transducer placed on the CTD instructs the winch operator on what to do, and tries to get the CTD as low as possible, without colliding with the ground, which can damage/skew instruments and data. This careful act is orchestrated with the help of an intercom, though at first a VHF radio was serving as intra-ship communication, but in order to keep the airwaves a little less cluttered, the intercom was adopted.

This whole enterprise was a learning process for the science crew, many of whom had not used a CTD before, much less were versed in the software and procedures used on this ship. However, at the same time it was fantastic to get real time data from a kilometer below the ocean’s surface, and try to finesse a few more meters towards the ocean floor.

Ryan Delaney onboard the R/V Kilo Moana.