Unexpected sightings

Wednesday, August 06, 2014
Bathylychnops or a Paralepidid at Axial Base
Big rattail and nodes

A large rattail swims beside LJ03A and LV03A at the Axial Base site (2600 meters deep).

Photo Credit: NSF-OOI/UW/CSSF, Dive 1738, V14

HPIES Deployed At Axial Seamount

The HPIES instrument is being lowered over the side of the R/V Thompson for installation at the base of Axial Seamount. The HPIES (Horizontal Electrometer Pressure Inverted Echosounder) measures the horizontal electrical field, the bottom pressure, and the acoustic travel time from the seafloor to the sea surface to characterize the properties of the water column.

One of the most exciting parts of any ocean voyage is the prospect of seeing something new and different, possibly something that no one (or only a few people) has seen before. And one of the goals of the Ocean Observatories Initiative is to give us a more constant, long-term window on the ocean, which will allow us to make new and important observations and potential discoveries. While conducting ROPOS dives to install and connect extension cables at the Axial Base site (at the eastern base of Axial Seamount), one of the students onboard (Alex Mitchell-Morton) took a frame grab from the video feed when he saw a strange fish. That frame grab may be a Paralepidid (aka Barracudina), but it could also be a Bathylychnops exilis, a species of bizarre barreleye fish that has four eyes and has never before been seen alive in the wild. Unexpected, unrelated to the main goal of the dive, but a scientific discovery nonetheless! We are awaiting word from some fisheries experts on shore before a definitive identification can be made.

Back to the actual goals of the dive, we spent yesterday and most of the morning installing the connection cables at the site, and then began conducting deck operations to install the HPIES instrument and the deep profiler vertical mooring. The HPIES was launched directly off the ship's crane at the surface, and free fell to the seafloor, 2600 meters below. It was attached to a series of weights to keep it upright during its descent - we'll find out during tomorrow's ROPOS dive whether it made it down safely. ROPOS will carry the instrument over to the cable connection laid this morning and plug it in.

The profiler climbs up and down on a mooring cable, taking measurements of thin layers that will give us new insights into the structure of the water column at this site, and how it changes over time. Many different parts of the mooring had to be linked together, and a long time was spent prepping the instruments, going over the deployment plan, and conducting safety briefings. The profiler is being deployed anchor first, and lowered down to the seafloor near the cable connection. It will be connected to the low-voltage node tomorrow as well.

And maybe we'll see some cool biology during the dives too!