Summary

The purpose of this dive was to survey the sulfide mound at 12°50’N that was visited during the preceding leg, characterize the alvinellid habitat with echem and temperatures, and then sample worms in RNA Later and in the biobox. The e-chem sensor had an 8 hard ground as soon as we hit the water. We checked it on bottom and during ascent — the hard ground remained.

This dive was extremely interesting given the sulfide blocks, structures, seemingly complete iron-oxide staining and the distribution of biological communities relative to the black smokers that have grown like columns on the top of this mound. The mound is 60 m+ tall and ~200 m wide with several tall sulfide columns (active and inactive with alvinellid tube scars). Metazoan communities are situated at the base of these columns (large Riftia, brachyurans, abundance zoarcids, and sparse limpets). Sampled two black smoker sulfide columns for RNA Later (also collected a grab sample of alvinellids), encountered Marker 14 chimney where Pat had sampled last month (site #3), a beehive chimney at site #4 (large elongate beehive chimney — uncolonized), and collected Riftia and Tevnia from site #5 (surrounding smaller chimney). All of these sites were within ~25 m of P60.

GMT Time — Activity

14:10 Free of ship.

14:24 500 m — DLK has a hard ground and will be secured for the dive.

14:40 250 m at 100° to marker PP60 put us 200 w of the mound where we want to land and drive up.

14:54 230 m west of landing target.

15:19:36 Set video time code, framegrabber and digital cam on.

15:35 2619 m — On bottom. Sitting on pillows and red silted sediment, brittle stars, sponges, sea pens, broken-up pillows. 270 m, 100°, x 8024, y 4198 — Atlantis surveyed us in – running Doppler.

16:04:24 2564 m — At Riftia patch at PP60. Surveying the area. Came up 60 m to top of sulfide mound.

16:09 2581— Flying out to come upslope to find where Pat sampled large Alvinellids last time (ending up being site 3 on this dive).

16:13 351 on south side of site #1 spire.

16:19 2572 m — Position 1 (at SITE 1) (digital pictures).

16:29 2572 m — P60, Sipper off at an angle in tube. Went in and then back out.

16:30 087 4.5 m altitude; pumping Sipper, up to 32°C (bottom temp is 1.9), fired Sipper #1.

16:38 Position 2, pumping Sipper #2, 24–54°C, fired Sipper at 40°C.

16:49 Position 3, pumping Sipper #3, 50–94°C, fired Sipper at 70°C.

16:50:10 Position 4, pumping Sipper #4, 60–67°C, fired Sipper at 60°C.

16:51:05 Position 5, pumping Sipper #5, 45–48°C, fired Sipper at 43°C (16:53:25).

17:02 Collection of A. pompejana over the surface where the Sipper samples were taken. Place in RNA chamber #3 using hydraulic slurp (grab 1).

17:05 Collection of A. pompejana over the surface where the Sipper samples were taken. Place in RNA chamber #3 (2 or 3 worms containing crabs).

17:09 Collection of A. pompejana over the surface where the Sipper samples were taken. Place in RNA chamber #3 (3 or 4 worms containing crabs).

17:13 Collection of A. pompejana over the surface where the Sipper samples were taken. Place in RNA chamber #3 (grab 4).

17:21 RNA Later observed through release valve.

17:25 Located alvinellid pillar ~10 meters from the first one near PP60. At SITE 2; 051 2574 m, 9.4 m altitude – 7 m tall.

17:28:05 2574 m, Video starboard pan-and-tilt of large Alvinellid with smaller Alvinellid stump down to starboard.

17:35 Position 6, Sipper wand inside worm tube. (digital pictures)

17:38:25 Start pumping. 19–45°C. Stopped pumping 17:41:00. Fired #6 at 17:42:03 at 22°C. Pat seems to have punctured through the top of the tube. Temps are a little lower (17°C). Retook temperature in tube 17°C.

17:45:04 Position 7, Sipper wand inside worm tube. Start pumping till 17:46:15. 44-51°C. Fired Sipper at 50°C at 17:46:16. This is 2 cm left of position #6. Took digital images of Site #2.

17:54:04 Position 8, down and left one-half meter from #7. This is a double tube. We will do the right tube first.

17:49:30 Pump on. 14–38°C. Stable at 38°C. Start pumping till 17:46:15. Fired at 37.4°C at 17:51:05. Sipper wand inside worm tube.

17:52:47 Position 9, left side of double tube. 37–47°C. Pump on at 17:52:47 to 17:53:47. Fired at 40°C at 17:54:00

17:57:20 Position 10 2/3rd of a meter from #9. Pump on 17:57:20, 25–38°C.

17:58:20 Did not fire on command, retried.

17:55:55 Fired #10 at 38°C.

18:04:15 Position 11, down and right about 1 meter from #10. Started pumping. Stopped at 18:05:07. Temp. very stable at 53°C. Fired at 52°C at 18:05:12.

18:09:00 Position 12, down and right one-half meter from #11.

18:09:00 Pump on 7–44°C. Stable at 39°C. Pump off at 18:11:11. Fired #11 at 18:10:47 at 40°C.

18:12: 50 Called up for a good fix at this site. X8256, y4224.

18:27:18 Alvinella collection for Chamber #1. Three grabs, suction samples into Chamber 1 — at least 4 big worms.

18:37:40 RNA Later suction collection into chamber #2.

18:46 Several Alvinella grabs going into forward biobox.

18:51:57 Sampled Alvinellids into Chamber #2 (still at site 2) — 4 to 5 big worms.

18:54:36 Another A. pompejana grab off of the sulfide surface into the forward biobox.

18:58 Sampled two more worms with slurp into RNA Later chamber #2.

19:02:30 Confirmed RNA Later flushing through top of chamber. Then departed Site 2 still looking for place where Pat sampled last cruise. Traversed about 20 meters.

Site #3

19:18:30 Found beehive chimney with Riftia at the base. This is the Marker 14 Alvinellid Chimney where Pat sampled. A beehive had grown 3/4 m since Pat was last here (last leg). (digital picture 19:17:28).

19:21:20 Hi T temp probe survey around the beehive. 312°C inside. ~Top of one of the tubes yet on beehive margin – 271°C; beehive surface 55°C; just scratching the surface of the Alvinellids ­ 68°C at base of beehive.

19:27:05 Mouth of tube – 30°C.

19:27:36 Mouth of another tube – 27°C. Left this area and continued to transit to the north.

Site #4

19:31 On to another chimney with large beehive spires.

19:35 035 2582 at beehive chimney — tape change.

19:36:45 Beehive sample in Cary biobox. This beehive is at the foot of several elongate, uncolonized chimney structures.

Site #5

19:40 256 2573 at Riftia and Tevnia chimney (short). Digital pictures of the tubeworm community to starboard. Lots of zoarcid fish here.

20:02 Sampled Riftia and Tevnia and placed in middle biobox.

20:04 Weights away.