Day 40 HEAD SHRINKERS

The search for black smokers in the Malaguana-Gadao spreading center continued through the night. During the search the Jason Team members in the control van, Bob, Tom C. and Tito, navigated a systematic and precise “mowing-the-lawn” survey of the area around the vents we discovered yesterday. The 3-hour survey encompassed an area of almost 15,000 square meters. The scientists took detailed notes and many pictures and have an excellent record of the site. We still believe there are black smokers in the Malaguana-Gadao Spreading Center but we didn’t find them. We went back to the hydrothermal vent site and spent a fun 4 hours taking pictures, testing the waters and taking as many samples as Jason could possibly bring to the surface. This is fun beyond description and without a doubt, one of the highlights of my life.

The sprint to collect samples when Jason reached the surface was more like a stampede. Out in front were Patty and Andrea. Patty rushed to collect her shrunken head and Andrea for the snotsicles. Andrea is a biologist and she gets a lot of teasing from a ship full of geologists. While she is oohing and awing over the microbial mats, the geologists are icking and yucking and calling it snotsicles. Actually, Andrea is a molecular microbiologist—she studies microorganisms at the molecular level—you can't get much smaller than that. She came on this trip to get microbes from the mud volcanoes where she collected the mud and took scrapings from the rocks and chimneys. Her samples of microbial mats and the animals of the hydrothermal vent communities were a bonus she didn’t expect.

I asked Andrea about the differences between archaea and bacteria. She explained that archaea are chemoautotrophs—they produce their own food using chemicals as a source of energy. In the extreme environment of the mud volcanoes Andrea is looking at archaea in the top 10 inches of mud and sediment. In the top few inches, the microbes are 10% archaea, 90% bacteria and microscopic eukaryotes. At 5 inches deep the proportion changes to 100% archaea.

Archaea are typically found in extreme environments where most bacteria cannot survive. The archaea of hydrothermal vents and hot springs such as those found at Yellowstone National Park have been well studied. The discovery of archaea in the mud volcano environments of the Mariana forearc came as a complete surprise. No one thought microbes could survive in an environment with extremely high alkalinity and a pH as high as 12.5. These archaea were just discovered in 2001 and their presence was confirmed in 2002.

The archaea of the serpentine mud have not yet been identified because they are so different from any other archaea studied. Archaea are identified and classified through studies of their DNA. Only very small samples of DNA can be obtained. These small samples are copied (called gene amplification) by PCR (polymerase chain reaction) to get a large enough sample to study. The gene amplification methods used on other archaea are not working with these mud microbes. This is the focus of Andrea’s work.

Patty’s shrunken head. Patty brought a wig stand on this expedition just for you! A wig stand is a head-shaped piece of Styrofoam used to hold wigs or hats. Styrofoam is mostly air. Patty put the wig stand, decorated by Dax, on Jason’s collecting tray and it traveled to a depth of almost 2 miles. As Jason went down, the pressure on the Styrofoam increased, air escaped and the foam compressed. Check out the pictures: before and after—no trick photography, honest.

Science Summary - Day 40, May 1st

Science Objectives, Day 40:

The fortieth day of the cruise, May 1, we will finish the Jason2/Medea on the spreading center of the Mariana backarc basin, survey during a transit to Patgon-Masala Seamount, an arc volcano with a large central caldera (as deep as the seamount is high), and launch Jason2/Medea in the evening to dive in the caldera and sample the caldera walls of the edifice. We anticipate hydrothermal activity and hope that the comparison of the fluids from this edifice with those from the spreading center will further help us to understand the cycling of slab constituents.