Keck Expedition 2004
August 20, 2004 Day 6

Cruise log as of 1500 August 20,2004

by Katie Roberts

The weather has been extremely calm so far on this leg, and the moon has been an elegant crescent each night, setting as an orange sliver around 10:30pm. Needless to say, everyone on board enjoyed the nice weather.

On Thursday August 19, 2004, we did two back-to-back dives. During the first dive we positioned the RAS/PPS water sampling package experiment, being run by Andrew Opatkiewictz and Kevin Roe. It is a water sampler designed to look at spatial and temporal variation in microbial and fluid chemistry at diffuse vent sites. We also collected larger volumes of water to study the microbes that live in the water above areas of weak flow. Also during these dives, we saw two impressive tubeworm towers, where huge balls of worms were shimmering in the diffuse flowing warm water. It was incredible.

tubeworms.jpg (169179 bytes)On August 20, 2004, the dive started out awesome. We went to Smoke Mirrors, a huge hydrothermal vent chimney complex in the Main Endeavour field. It’s called smoke an mirrors because of all the smokey-looking particles in the water, and because of the mirror-like pools of hot water that collect underneath the flanges (which are pieces of chimney that stick out of the tower) Next, we went to Dudley. Both sites have beautiful, big structures, shapes that couldn’t exist on land, and all standing out vividly against the dark, blue water. Some pieces of chimney were broken and collected for scientific observations. Breaking them off sent a cloud of shimmering specks swirling up through the water. We also collected 3 water samples from hot smokers (that’s what they call the underwater geysers when they are really focused and really hot), and then set off to explore, climbing up and over and around shelves and up chimneys. The chimney material is very porous in appearance, and is primarily a matte black, with large areas of a shimmery green, which is a copper, iron sulfide, and some white crystallized areas which are calcium sulfate, or anhydride.

Unfortunately, the ROV lost power around noon. When it was brought back up, three thrusters were out of commission. However, within 3 hours the ROV was back in the water, and on the way to collect 20 liters of diffuse flow water for Chris Preston. After that we made our way back to the RAS/PPS water sampler and released it. It was an exciting recovery. The RAS/PPS water sampler made it back to the surface and was picked up by crewmembers in the small inflatable boat, during a misty grey Pacific northwest evening.

Maybe tomorrow the flamingo will make it down to the seafloor. I’ll explain later.

easter_island.jpg (161620 bytes) Easter Island, a reef built from hydrothermal venting.  Tubeworms and other animals flourish here. 

smoker2.jpg (126978 bytes) Black smoker on the Faulty Towers complex

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