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The first dive (11/10/10)…

November 12, 2010

Prior to the first dive we had a slight delay in the recovery of the transponder assembly used in the navigation check because its acoustic release failed to activate. So, the ROV was launched to manually release the tower from its position on the sea floor some 500+ meters below the ship. It took about an hour for Jason to reach the sea floor. All we needed was some popcorn as a small group gathered to watch the flat screen monitor showing the live video feed from the ROV. This is one of the advantages of an ROV over a human-powered submersible — several scientists on board the ship can observe live video from the mission and gather data whereas there is no such feed on the typical 2- or 3-person sub.  Video from the descent showed only the occasional fish, squid, small shrimp, or other open water species, but once Jason reached the bottom, the “movie” contained a lot more action. Jason hovered just above the sea floor as it glided along searching for coral habitats. The pilot in the ROV “van” on the ship was at the physical controls but the scientists controlled where the ROV went, what it collected and which imaged were recorded.

At first, much of the sea bottom looked like soft sediments with ripple marks from undersea currents. There was also a noticeable rain of small particles falling through the water. This so-called “marine snow” is primarily organic debris from the ocean above and is an important food source for some deep ocean creatures. There were also streaks that moved in many directions — most likely copepods, small shrimp, or other invertebrates. Tonight there seemed to be little current — several squid moved through the view, and at least one released a cloud of ink which just hung in the water and slowly dissipated. I tried to imagine how a creature that lives at such depths reacts to this large “beast” with bright glowing “eyes” and jets of water coming out several sides.

After transiting across a flat sandy bottom between the transponder test site and the coral mounds, we saw some relief along the bottom in the form of coral rubble, live coral patches and what looked like small boulders. And with that came an increase in living things — small invertebrates, more squid, some fish. This shows the importance of structure as a habitat component and is one reason the cold-water coral mounds are so rich in biodiversity.

Jason pulled up to a small coral and one of the side arms brought a collection box (bio-box) into view. I was amazed at the dexterity of this machine and how adept the pilot was at picking up delicate samples. One arm has double pincer grips that can scoop or grab material; the other has been outfitted with a special claw-like grabber that can cradle and pinch off samples. The latter looks like a living creature on camera — a metal moray eel with a wide gape, capable of maneuvering into tight spaces in the coral thicket.

As the dive wore on, it was great to have experienced observers like Dr. Martha Nizinski, Jennie McClain-Courts and others sitting around to help interpret what we were seeing on screen. Listening to the call outs of names was a throw back to my graduate and SCUBA days — “crinoid, basket star, hydrozoan, gorgonian, squat lobster, crab, skate…” all part of the cast in this deep sea made-for-TV movie playing out before us.

Lophelia coral

Lophelia coral

The dive ended with a flurry of samples being collected on an impressive coral mound composed primarily of Lophelia, one of the main species of cold water coral found in this region. The branching thicket was composed of white living coral and brownish dead coral, both of which provide habitat for golden crabs, Galatheids, sponges, amphipods, as well as other coral species such as Stylaster and cup corals. It was beautiful. Jason delicately added samples to the remaining bio-boxes and the cylinders known as quivers on the front. It seemed  like a late night video game with the reward being a cache of important scientific data from an alien world. The screen went dark as the ascent began. For those of us who watched in fascination Jason’s deep sea journey, the real late night action will start when Jason surfaces. More on this in another post…

 

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