Juan de Fuca Ridge Cruise
July 20 - August 1, 2000
Over 650 km (~400 miles) off the Washington-Oregon Coast
July 22: Day #3
Log Entry: We took more wax core samples off the stern of the boat early in the morning, and continued through the wee hours until around 6 am. We arrived at our dive location for today, and Tiburon was in the water by 7:00 am. At 8:30 am the ROV reached bottom, at a depth of 2979 meters. The dive lasted over 10 hours, including ascent time back to the surface. When we are diving at such depths, it takes over an hour (sometimes up to two hours) to travel from the surface to the bottom or vice versa. Having so much time to wait for the vehicle to reach bottom or to surface gives us some time to get things organized for the dive here on the ship, or for the sample recovery after the ROV returns. A majority of the work gets done before the ROV touches the water.
Here is our predive checklist:
- Someone must give the captain on the bridge our dive coordinates and the dive track in case there were any last minute changes
- Tiburon wax corers must be loaded with wax, and coring barrels cleaned and reinstalled if used on the previous dive (can take up to 1.5 hours for each of 4 barrels)
- Recheck drop site latitude and longitude
- Record the # and position of wax corers on the ROV (crucial for post-dive sample identification)
- Record location and barrel # of drill coring tubes
- Label video tapes (we typically use 10 hour-long tapes each dive)
- Check navigation program to be used for tracking ROV location
- Cue first video tape
The most crucial part of the predive is making sure everybody understands the places where the samples are to be stored. If there is any confusion, and there sometimes is because we have more than one person taking notes during the 10 hour dive, samples can be very difficult to identify, since most rocks look very similar.
Once the vehicle is ascending to the surface after the dive has ended, we again have over an hour to get the wet lab ready for the samples that are on their way to the surface. We first label Ziploc bags and index cards with the sample numbers. The photo area is setup for taking pictures of each sample. "Frame grabs" are still images that the computer can take during the dive. We take frame grabs of each sample when it is in the arm of the ROV, close to the camera. The time and video tape position are recorded. After the dive, we take the frame grabs from a UNIX operating system and FTP (transfer) them to the server. Then a windows machine in the dry lab runs a program to pull the images off the server. They are then adjusted in Photoshop, if necessary, printed out on a color printer, and labeled with the sample number. This step is very useful in identifying the samples, especially when we have a large basket with many similar looking rock samples.
By the time we are done with all this, the ROV is back in the ship, and the samples are removed and identified. Today, the identification process took nearly an hour, with 12 samples taken. Everybody helped out in comparing the rocks to the frame grabs and the images on the computer in order to identify a couple of similar looking rocks. This is done very carefully, in order to ensure that no two samples are mislabeled.
During today’s dive, along with the rocks we collected, we obtained 2 wax cores, and one rock core from the rock coring sled. We were all extremely happy to see the sled and vehicle communicating without any problems at all! We did not lose hydraulic power at any point during the dive. Yesterday, in order to remedy the communication issue that we experienced, we contacted engineers back and MBARI and received an email with some corrections to the ROV's computer code. With good cooperative efforts, we overcame what seemed a very serious problem! We cored today into a rock outcrop for approximately 2 hours, and were rewarded with a 2 inch long core of very hard basalt rock, the hardest rock for coring.
While samples were being identified, cleaned, and photographed, the rock coring tube was being disassembled, the sample removed, and the tube cleaned, greased, and reassembled. The wax cores were being removed, melted to separate the glass from the wax, labeled, and examined under the microscope. We have one biologist aboard who was removing, identifying, and preserving the biological samples that were recovered. This is all taking place in the wet lab it becomes a really busy, exciting place.
This was all completed by about 9 pm, and wax coring off the stern of the ship began. This will again take place all night long, until we reach our ROV dive site tomorrow morning.
We had an exciting visit today by two ocean sunfish, or Mola mola. If you have ever visited the Monterey Bay Aquarium, you may have seen a Mola mola in the Open Ocean tank. These are large fish, weighing up to 500 kilograms. They have distinctive dorsal and ventral (top and bottom) fins that move in unison as they swim. The Mola mola showed up today while the ROV was diving. We were rewarded with a very unusual symbiotic interaction between two very different marine species, the Mola mola and an albatross. We have had a group of albatross sitting in the water near the boat for a couple of days now. The Mola mola came to the surface and started "chasing" the Albatross. They were asking the birds for a favor: to remove the parasites from their skin! The birds responded by approaching the large fish, which were now lying on their sides, and started pecking at their skin. It appeared as if the birds were eating the fish, but they were actually removing the parasites from the fish’s skin. This type of interaction is called "mutualism" because both parties involved benefit: the fish benefit by having their skin cleaned, and the birds benefit by getting an easy meal!
Another busy, exciting day at sea has ended!
Oatmeal with raisins and brown sugar
Eggs to order
Omelet's – ham, mushroom, bell pepper, cheese, onion
Coleslaw – fruit salad
Sopa de Lima (Lime soup)
Flyer burrito bar
Spanish rice – refried beans
Fresh salsa and tortilla chips
Sopa de Lima
Honey glazed ham and sweet potatoes
5 cheese tortellini
Jell-O with fruit (and optional whipped cream topping!)