NE Pacific Expedition Day 5

A report from Dr. M while he is at sea in the northeast Pacific. You can follow the expedition here.

Our first day in the water.  The sea is calm and tremendously blue.  Of course blue clear water means little primary production at the ocean’s surface. Through the 3.5km of transparent water column, the ROV Doc Ricketts, only its 77th time to descend to the seafloor, descended on lava flows dating to the early nineties. We start the dive on a very steep talus slope, dropping nearly one meter in depth for every horizontal meter.  It is thought that the immense amount of lava rubble here was formed when the flow fell off the cliff face and simply rolled down the hill.  We then proceeded to conduct biological transects, five in total, along two nearby volcanic cones covered in volcanic pillows. Some had burst open and we were able to see the remnants of their volcanic viscera scattered nearby.

In the nearly 15 years since this lava cooled, it appears few organisms have colonized. Randomly placed crinoids, small corals barely a tenth of their full height potential, a few asteroids (with one extremely rare to science), translucent enteropneusts and holothurians with only their well-filled guts visible, dot the blackened substrate.  The highlight of the trip was a lone wolf predator, an octopus from the Opisthoteuthids, that was intrigued by this large heavily lighted robot in this otherwise jet black world.  It examines us with a watchful eye as we do the same.

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