Whale Fall Cruise
August 6, 2003 - August 8, 2003
Thursday August 7, 2003
Jennifer Trask writes: Lots of clams and big fat worms. This morning our dive began at a large clam bed near the location of the whale carcass, at a depth of about 2900m. The bottom of the Monterey Canyon is sprinkled with patches of clams that live in the sediments. The clams are filled with symbiotic bacteria that help them get their nutrition from sulfides - naturally occurring toxic chemicals that leak out of the mud and smell like rotten eggs. This particular clam bed has been explored by several scientists at MBARI using the ROV Tiburon, but no one has discovered how big it really is. We set out this morning to characterize the community—to find out how far it extends and determine what kinds of clams and other organisms live there. After exploring for most of the morning, we decided that it was a very large, very healthy bed of deep-sea clams, and we proceeded on to explore the whale carcass some more.
Our goal for today's dive was to get some good photographs and collect more samples of the mysterious whale-bone worm. We found a rib bone that was carpeted with the little red plumes, and the pilot carefully picked it up with Tiburon's manipulator arm so we could get a good close look at the worms in their natural habitat. In addition to several video cameras, Tiburon is equipped with a Nikon Coolpixdigital camera. Since the organisms that live in the deep canyon are adapted to cold temperatures, high pressure and no light, many of them don't survive on board ship or in the lab. In most cases, photographs and video footage are the only evidence we have of how these creatures look when they are alive and healthy. After taking pictures, we collected the rib bone so we could examine it firsthand.
We spent some time exploring the canyon floor in search of anything new or different, anything besides the muddy sediment that covers most of the ocean bottom. Although it's slow-going (Tiburon can only travel at about one knot - about the speed of a human crawling on hands-and-knees), most discoveries of unusual communities are made through perseverance, patience and blind luck. But, our time ran out and our dive came to an end, so we headed back to the surface.
Back on board ship, we unloaded all of our samples from Tiburon and proceeded to sort, dissect, preserve, observe and categorize everything we found. We spent hours carefully pulling apart the whale rib bone to extract the worms as wholly as possible. These amazingly colorful worms have red plumes, white tubes and green root systems that extend far into the bone marrow cavity. Separating the worms from the bone was a long and delicate process, but in the end we had some beautiful specimens to take home for more detailed studies.
Our dive tomorrow will be a short one, so we'll head for a site that's a bit shallower and look for deep-sea tube worms.
- Jennifer Trask