After my brief stint on the R/V Rachel Carson, I catch a flight to the East coast and arrive in Woodshole to meet UW’s larger ship, the R/V Thomas G Thompson. The boat is docked all the way at the end of town, but I can see the mast towering high above the buildings as I walk down the street. This small, coastal town is a major hub for Oceanography, and essentially is built around and consists of the Woodshole Oceanographic Institution. I can overhear people discussing their research while walking down the street. There are flyers for a plankton exhibit taped on store fronts. Everyone sports shades of blue.
The Thompson is enormous. It can house about thirty crew and thirty scientists. There are four different science labs, a library, a lounge, a gym. It is much larger and more stable than any other ship I have ever sailed on. When we leave the dock, there are no sudden movements or strange noises. So, it’s only when I look up and out the porthole and see the masts of other ships going by that I realize we are underway. Out we go, to the continental shelf!
About one hundred miles off the coast of New England, the oceanic plate dives under the continental plate, resulting in a sudden drop from relatively shallow coastal shelf to deep ocean. The Gulf Stream runs northward along this boundary, and every so often, the inner edge of the stream catches and peels off in massive eddies. In the main lab across the passageway, a satellite image is displayed on the projector screen. Shades of the rainbow illustrate where the warm water from the Gulf brushes against the cold, nutrient-rich shelf water. To the south of Woodshole is a massive swirl of red that is unmatched in size by any other feature on the screen. A warm core eddy. By its side is a bright blue ribbon that snakes out into the open ocean. The scientists point and call it the streamer.
Although this whole region has been widely sampled and studied, scientists have yet to thoroughly examine and quantify the streamer itself. The science party on board is an interdisciplinary group, made up of labs all over the country. They have come together to seek out this streamer and learn everything they can about it. To do this, they have brought an arsenal of instruments on board with them. As one of the technicians, one of the largest aspects of the job is to assist in the safe deployment and recovery of these instruments. My first deployment on board is with the Video Plankton Recorder (VPR) which looks like a small black fixed-wing plane. In its nose is a strobe light and in the starboard wing is a camera, so as the instrument is towed behind the ship, it takes images of an area the size of a cubic centimeter. It essentially acts as an underwater microscope, which can communicate a live feed of images to us up in the lab as it “flies” through the water. On board is also one of the Remote Environment Monitoring UnitS (REMUS) from the Woodshole Institution of Oceanography. This robot comes with its own team of technicians that are responsible for programming, communicating, and troubleshooting REMUS. Although it looks like a glider, REMUS has a propeller on its tail, which gives it greater control over its movement and a greater range of travel throughout its mission. The deployment is a bit more complicated, since the robot will be free floating, we lift the 700 lb REMUS up into the air with our crane, then slowly lead it overboard and out into the water. As it hit the surface of the water, we pull a line that releases a pin mechanism on the bridle of the instrument, and the robot is free.
During our cruise, REMUS unexpectedly aborted one of its missions. Communication with the instrument while it is underwater is limited to echo sounding, which only works when the instrument is within range. To “talk” to REMUS while it is close by, but underwater, the team has a hand-held transducer that can be lowered just over the rail and into the water. There are a variety of commands that can be communicated through a series of clicks. Judson holds the transducer up to my ear and sets the dial to “Abort”. I hear it crisp and clear; click, click, click-click-click. He sets the dial to the next setting “Run”. Click, click, click-click-click. I can’t tell the difference at all. Judson is all smiles. Clearly excited, he explains that the commands may all sound the same to the human ear, but REMUS can differentiate between them and respond accordingly. However, when the robot aborted its mission, the transducer wasn’t even in the water. By some sort of miracle, that exact series of clicks was generated by something somewhere out in the ocean, and REMUS heard.
When the data from all of the instruments and sensors are combined, we are able to see the ocean in a rare and beautiful light. Instead of just a satellite surface layer image, the screen now flashes through 3D graphics of the streamer with red and blue and green swirls indicating temperature fronts, high and low salinity, blooms of phytoplankton, areas with oxygen, areas without. To the average person, this swath of sea would appear desolate and lifeless. Perhaps a few would notice amber fronds of sargassum floating by; maybe others would spot a storm petrel riding the high pressure wind under the crest of a wave. But for the most part, the North Atlantic, to the naked eye, is an endless blue desert. So if you are lucky enough to tag along with group of thirty oceanographers at sea, do not hesitate, for they will reveal to you a world that is teeming with diversity and incredible forms of life.
