Atlantis Diary VII
Poseidon's Excellent Adventure
The bizarre hydrothermal vent field discovered a little more than two years ago surprised scientists not only with vents that are the tallest ever seen --the one that's 18 stories dwarfs most vents at other sites by at least 100 feet -- but also because the fluids forming these vents are heated by seawater reacting with million-year-old mantle rocks, not by young volcanism. The field is unlike any seen before, according to chief scientist Deborah Kelley, a University of Washington associate professor of oceanography, and co-chief scientist Jeff Karson, a Duke University professor of earth and ocean sciences. Both have visited fields of black-smoker hydrothermal vents that scientists have been studying since the 1970s.
Now the two scientists who were the first to travel in a submersible to the field after its serendipitous discovery Dec. 4, 2000, are leading a National Science Foundation-funded expedition to map and further investigate the field. The 'Atlantis Diaries' chronicles the expedition returning with 24 scientists onboard an exploration vessel, the Atlantis, during their 32-day expedition that spans April 21 to May 22.
Monday, May 12, 2003
I had an exciting day yesterday. Every day of a research cruise is interesting, but yesterday was particularly special because I had my first dive in Alvin.
Yesterday morning, I hung out with a couple of friends and made some jokes while waiting to get in the sub. After Pat, the day's Alvin pilot, and Debbie, the other diver, got into the ball, it was my turn. I climbed up the set of stairs leading to the hatch, and was helped into the ball by Bruce, another member of the Alvin team. I descended the ladder and wedged myself into the starboard (right-side) observer's area.
|A view from inside the sub. The pilot's viewport is surrounded by monitors, switches, buttons, and lights. Credit: lostcity.washington.edu
We began the dive by exploring a topographic high point called "The Hump." This feature is to the southeast of Lost City. Pat landed Alvin directly over The Hump, and right away we saw little carbonate spires. He used a temperature probe to determine if the spires were actively venting, but they weren't very hot. Then he used the manipulator arm to grab the top of the spire and break it off, obtaining our first sample.
We drove by a BIG spire - it had to have been over 15 feet tall, and I couldn't even see the bottom of it! Then we spotted the pressure sensor that we'd deployed at the beginning of the cruise to measure tides. Pat used the manipulator arm to grab it, then shoved the sensor into the outside basket so we could bring it back onboard.
Having done our "chores" for the day, we explored the cliff edge to the east of Lost City in the hopes of finding areas of hydrothermal activity. As we began the transit, we saw lots of little carbonate "fingers" growing directly out of the wall. Because they are so light-colored, they stood out clearly against the dark rock.
Elsewhere, the carbonate fingers were replaced by veins of carbonate in the rock and by pieces of carbonate that looked like they had rolled down from higher up on the cliff. I saw many different corals, including gorgonians (fan corals). They were growing right out of the side of the cliff, and you could see them swaying in the current. I saw a bunch of big grouper (including one eating another fish! Wow!), but I also saw little purple eels, dark red shrimp, starfish, and one brittle star that decided to go for a swim just as we drove by.
We drove along the cliff face for about an hour, and only saw carbonate veins, carbonate rubble, and steep slopes of serpentinite. Because of this, Debbie decided that we should go further up the cliff, to trace where the carbonate was coming from. When we reached the top of the cliff, we found a broad, flat area that was covered in carbonate, and was the probable source for the pieces we found further down the slope. We grabbed a few samples to finish our exploration to the east.
Pat flew us back to Lost City, and we circled around Poseidon, the huge structure in the middle of the field. We were on the lookout for an active vent structure, called the Beehive, that the previous Alvin dive had knocked over. We managed to find the site of venting and took some water samples from this 90°C vent. Then we searched until we found the shattered remains of the Beehive. While we were doing this, I was looking out the window at Poseidon. The structure is so big that I couldn't see the top, the bottom, or around the corner.
After I'd gawked at Poseidon for awhile, we still had time left to explore to the west of Lost City. Along the western cliff, we saw beautiful outcrops of serpentinite, topped by breccias and carbonate. The rocks were really cool and led to discussions of how this area could have been formed.
Eventually, the sub ran out of power (a normal occurrence) and Pat began our ascent. We took the time during ascent to organize our papers, listen to a little music (Pat brings his favorite CDs into Alvin), and chitchat about nothing in particular. After we surfaced, the Alvin team and Atlantis crew brought the sub aboard. I was the first person out of the ball, and was greeted by the science crew with five buckets of ice-cold water. Even that couldn't dampen my enthusiasm for the great time I'd had diving in Alvin!
Tuesday, May 13, 2003
As we reach the last few dives of the cruise, people are beginning to get anxious. They're anxious about getting as many samples as they can before Alvin drops the ascent weights for the final time, anxious about seeing their families again, anxious about finishing up their first few rounds of analysis and their dive reports. Yet each day continues to be full of surprises, discoveries, and excitement.
|A tiny gastropod shell is one of the many exciting things discovered at Lost City by the biologists on this cruise. Credit: lostcity.washington.edu
Even though this has been a fantastic research experience, even I am anxiously awaiting the end of the cruise. I'm looking forward to seeing my one-year old daughter again. She had her first birthday while I have been away, and went from taking her first steps to learning how to walk all around the house. Unfortunately, I'm on the next cruise as well, so it will be an even longer wait until I am able to stroll in the yard with my daughter.
We've collected lots of rocks and water samples and the ABE crew has worked hard making extremely detailed maps of the seafloor terrain. We biologists are now trying to gather the last few samples needed to fully characterize the various animal communities that inhabit the Lost City.
Today, Mike Jakuba and I are taking the hydraulic slurp sampler down to sample some newly found actively venting areas. We are hoping for a good biology haul from at least five chimneys where we have good fluid chemistry samples. With both animals and water chemistry information for the same place, we can perhaps begin to understand which animals thrive in the different chemical habitats.
Our last hydraulic slurp dive was very successful. We slurped up one of the many fish seen at the site, and upon getting it to the surface found it was a beautiful lavender-bellied eel. We have also spent hours picking through the samples filled with pieces of carbonate rock that resemble shredded coconut, searching for tiny little snail shells, swarming crustaceans, worms, and even spiders- none of which are larger than half an inch or so.
Each dive brings up something that we haven't seen before, or we discover something new and interesting about things that we saw the day before. Our sieved samples often look like a mass of rock fragments, but once under the microscope we find a tangle of nematode worms, ostracods (flea-like crustaceans) the size of a pin head, or very small stomatopods (shrimp-like crustaceans) that are live in tubes made from glued together pieces of foram and snail shells. Almost all the animals living in this hydrothermal venting area are very small. If you could see an anatomy diagram of some of them, you wouldn't believe they could exist.
The project includes scientists, engineers and students from the University of Washington, Duke University, Woods Hole Oceanographic Institution, U.S. National Oceanic and Atmospheric Administration, Switzerland's Institute for Mineralogy and Petrology and Japan's National Institute of Advanced Industrial Science and Technology. Collaborators include: Jeff Karson, Duke University, Co-PI and diver during the discovery; Matt Schrenk (an astrobiology graduate student at the UW School of Oceanography); P.J. Cimino (a NASA Space grant undergraduate); and John Baross, also a faculty member in astrobiology and oceanography.
Related Web Pages
Atlantis Diaries XI: Encore
Atlantis Diaries X: Reaction Zone
Atlantis Diaries IX: Rescue
Atlantis Diaries VIII: Science Basket
Atlantis Diaries VII: Poseidon's Excellent Adventure
Atlantis Diaries VI: Portal on the Past
Atlantis Diaries V: Hump Day
Atlantis Diaries IV: Eating Iron
Atlantis Diaries III: Exploring Alien Eco-Regions
Atlantis Diaries II: First Dive
Atlantis Diaries I: Leaving Port
Life from Rocky Reaction
Lost City Expedition
Discovery of Lost City vent field-Univ. Washington
Univ. Washington School of Oceanography
Life without Volcanic Heat