Archive of September 20th, 2007

Teacher at Sea log for September 20, 2007

Today Jason 2 is down at the bottom working collecting rocks. The scientists are rotating through their watches in the Jason Van. The ship's deck crew is taking advantage of the calm seas and they are painting some of the doorways. They also took the opportunity to practice their Cardio Pulmonary Resuscitation (CPR) and the use of the ships Automated Electric Defibrillator (AED). They taught everyone on the crew what to do in a medical emergency and where all the first aid equipment is on board.
I went through some of the images of the virtual van to try to share with you the variety of rocks we are seeing below the surface and of course any creatures we have come across. The creatures are rare; some sea anemones, a sea star, shrimp, sea cucumber or a nudibranch, some coral stalks, and one fish.
How does the scientist decide where to work on the ocean floor? First we do a survey with the sonar and make a back scatter map that shows the areas of high reflectivity, which may mean they are hard rock. These areas are dark on the map. They plan to take the Jason 2 up and over the various formations to determine if they are flows, vents, or landslides. The plan is done on a map with the longitude and latitude of the places to turn called way points. Soon we will post the way points of a survey so those watching can have some way point practice. Yesterday there was an interesting place. The map we made from our scan looked like there would be a shallow basin. It turned out to be one deep small hole and the signal from the Sonar must have hit the hole right smack in the middle. Then the map making tool averaged this data with the data all around and smoothed it out into a basin. When Jason 2 went through to look, it was very different than what we expected to see.

Science Update by Ashton Flinders

Jason 2 was submerged at 12 a.m. (HST) Thursday morning, reaching ocean bottom at 2:30 a.m., officially marking Dive 298. The Jason 2 persists to have some mechanical malfunction with its left arm rendering our preferred claw unusable. Another problem also exists between the syncing mechanism of the digital still camera and the external strobe (our flash) causing pictures to be underexposed. Later, we will have to go back and brighten these photos because they are important for archiving our data.

During the dive, we repeatedly observed large lobate sediment avalanches, which were easily traceable to their origin, and were marked by chutes and head walls. The toes of these slides tended to be half-meter size blocks, as opposed to fine sediment. Large sediment tables we also visible, often marred by fracturing. Many of these sediment blocks have appeared to slide, resulting in talus avalanches.

As of now the consensus is that majority of visible blocks, as well as samples taken thus far on Dive 298, are predominantly sedimentary. The goal of our work is to recover volcanic rocks, however the dive will end tomorrow night, and there is no need avoid picking up sediment if those are the only samples. All of the samples contain some information, and we can expect to extract that information if we examine them and keep and open mind.

Presented by the School of Ocean and Earth Science and Technology at the University of Hawaii, with financial support from the National Science Foundation.