Monday, March 16, 2015

A Dawn Elevator to Chapopote

10 March, 2015
 21o54.0' N 93o26.11' W
1859 m Depth


The elevator being launched over the side
of the METEOR just before dawn. My video
time lapse camera and other equipment
are secured to its deck. A large weight will
be released when it is time to recover the
elevator and the yellow floats will (hopefully)
bring it to the surface
The ROV has limited space to place sampling equipment and instruments. So when there is more stuff needing to go down for a dive or series of dives at a particular location, the option is to put the extra gear on the Elevator. We have arrived at the Chapopote site and will be working here for several days. My immediate research goal is to quantify the seepage rates for gas flowing out of the asphalt field. The tool for this is a video timelapse camera (VTLC) that is deployed with its own deep-sea lamp for illumination and is programmed to wake up every 5 minutes and record 15 seconds of video, then go into a rest mode until the next recording interval.

There wasn't room on the ROV to carry the VTLC to the bottom directly. So last night I started the program running and secured the VTLC to the elevator. Then we got up before dawn to lower the elevator over the side. The ship lowers the elevator down to just over the bottom, then maneuvers it to a hopefully safe location and releases it to sink the last few meters to the bottom. All this happened before breakfast.

By lunch time, the ROV was near the bottom and collecting samples. Sampling operations and exploring Chapopote occupied much of the day. Finally around 5 pm we began moving toward the site where the elevator had been placed. It took a while to find it and it was a bit of a shock when it finally came into sight. The elevator had landed on just about the only piece of open ground in the middle of a huge filed of asphalt blocks. A meter or so in any direction and the elevator would have come down on the blocks and possibly have been badly damaged.

We soon retrieved the VTLC and motored off to find a gas hydrate site where it could be positioned to monitor gas flows. Found a beautiful spot with tube worms, mussels and a big wall of exposed gas hydrate. Dropped the camera off facing a bubble stream and will come back in a couple of days to learn what it has recorded.

The video time lapse camera deployed at a gas seep in the Chapopote Asphalt field. There is a cluster of methanotrophic mussels in the foreground and chemosynthetic tubeworms all around. The trickle of bubbles the camera is watching is visible just to the left of the marker #4. We had to reposition it slightly to (hopefully) ensure a good view. We'll find out what it saw in a couple of days.


No comments:

Post a Comment