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Mission and Crew

 

October 25, 2001

 

Dive Report 3719
Pilot: Pat Hickey
Port Observer: Peggy O’Day
Stbd Observer: Becky Gast

Primary objectives: Deploy Autonomous Larval Sampler (ALS) and crab trap. Collect “hot” Alvinella. Chimney collections with Sipper and temperature readings. Basalt collection.

Dive Start: 14:00
Video Start: 15:30
On Bottom: 15:33 at a depth of 2479m
Dive End: ~19:40

  1. At ~15:40 GMT the ALS was located and moved to basalt near Riftia patch at Q vent (4462/78837 heading 300). The hoses were released to hang down from the sampler; the one with only one tube hangs a bit longer and goes down a bit of a slope (see video).
  2. Deployed crab trap in rust-colored Riftia bed near the ALS (4468/78842;16:05). Returned to pick this trap up at the end of the dive (19:29) and 5 crabs were recovered.
  3. Went to M vent (16:11) to look for area where chimney was knocked off on first day of diving – interested in seeing if there was a new chimney growing and determine whether we could use the snatcher on it (4448/78950; 16:23 for start on video). No new chimney was growing, so a different one was selected for a grab with the manipulator. The one selected was a vigorous black smoker. Temperature 353°C before catch, Sipper samples taken (#8 may have been bad, #9 was sipped at 16:39), temperature was 362°C after chimney collection. Sipper temp probe wasn’t working, so we used High temp probe. Collected chimney went into large biobox and broke into several pieces – nice pyrite. Note: the Sipper may have been damaged at this site when it accidentally sucked the extremely hot water.
  4. Moved around to the other side of the same chimney spire at M vent (2589?/78975; heading 117) to select smaller chimney for snatcher attempt. Tried to get temperature but chimney started to break off. At 16:45 we triggered the snatcher, but didn’t recover a chimney because the apparatus didn’t close completely. The temperature at this chimney was about 100°C, but the measurement may not have been accurate.
  5. Moved to Robin’s Nest/Roost near M vent to collect Alvinellids (4437/78946; 199 heading; 16:57). Began taking temperatures and Sipper samples: Sipper #10 was in 55-60° C clump – it misfired so #11 was used (17:07); Sipper #12 was in 80-90°C clump (17:11); Sipper #1 was in ~40°C clump (17:15); Sipper #2 was at 90° C (17:18), followed by #3 and #4 in the same place (temperature was actually taken after the #4 sipper sample). Alvinellids were collected for the cold small biobox first (17:50), then for the ambient/warm front chamber of the large biobox (17:54). It was very difficult to determine how many worms were in the boxes because of floating biological debris. We noticed that the worms were crawling into crevices on the recently scraped rock, so we took temperature readings that ranged from 70 – 200° C depending upon location of the probe (deeper into the crevice became hotter). The #5 Sipper sample was taken (18:07) next to a worm in one of these crevices (very cute). Note: Digital stills were taken for all of these samples, in the order written, except #3. There are three images associated with each sample – one wide angle, two zoom. Take notice of the pattern in order to determine which images go with each Sipper sample. 3 Chip video was taken at 17:36 of Alvinellids in tubes and after collection. Digital stills were taken of Robin’s Nest site as well.

    6. Note: video was changed at 17:34.

  6. Collection of second chimney at M vent (18:11; 4444/78953, heading 135). Temperature of 310°C (18:14), chimney grabbed at 18:16 and placed in back of large biobox with other chimney. Sipper samples #6 and #7 taken at 18:30 and 18:32.
  7. Went in search of glassy basalt (~18:45) 4450/78868, heading 50. Collected several pieces into Rock box, pulled pin, then went back and collected another large piece that was placed into the milk crate (18:51). Had to readjust ballast due to heavy rocks and the consumption of lunch.
  8. Went collecting crabs for slurp gun, and at 19:18 had to stop and investigate battery imbalance problem.
  9. Notified top lab that we would be up in about 20 minutes and went back to Q vent to retrieve the crab trap (19:29). After collecting the trap, the manipulator arm was placed on top of the cold biobox, we dropped the weights and began to surface.