DIVE 3521
18 JANUARY 2000

Pilot: Pat Hickey
Pilot in Training: Phil Forte
Observer: George Luther

08:07 — Alvin enters the water surrounded by a large pod of pilot whales off R/V Atlantis’ starboard side.

08:11 — Alvin dives.

09:11 — 1500 m, powered on electrochemistry and tested wand temperature probe.

09:29 — 2629X, 1352Y. Neutral trim and simulated a hard ground for Pilot in Training.

09:43 — Forward Niskin fired for ambient water. 2607X, 1379Y. 2007 m, hdg 147.

10:02 — Spotted microbial mat at XY 2724 : 1289 2013 m.

10:10 — Hi-Temperature Probe: 9.6° C, max. at 12.6° C. Began DLK electrode scans on wand.

10:22 — Sipper #1 sample taken, but pump was not turned on. Turned on pump and began flow-cell electrode checks and scans.

10:28 — Sipper #2 fired in oxygenated water.

10:41 — Four cores taken in mat. First was Core #4 (Alvin). Then Core #1 (UD at 10:46). Core #3 (UD at 10:52) 3-chip camera recorded a good core. Last core was Core # 2 (Alvin at 10:58) and mat was intact via 3-chip video. Temp was 12.9° C max.

11:02 — Began sonar search.

11:15 — Departed for Rebecca’s Roost. Hdg 241. Saw many crabs on the way.

11:26 — Riftia clump observed at 2632X, 1224Y.

11:39 — 2615X, 1234Y toppled over a beehive structure — good for major and/or gas-tight sampling in the future. 296.4° C at orifice; 298.5° C at mouth of orifice; 270° C at orifice again, 170° C about 8 cm above orifice.

12:01 — Departed for twin-tower structures detected by sonar.

12:03 — 2607X, 1178Y. Riftia with polychaetes ~ 17° C. 1997 m.

12:23 — Electrochemical scans taken at Riftia.

12:33 — Sipper sample # 3 taken.

12:45 — Niskin # 2 taken in diffuse flow above Riftia.

12:52 — Wand in Riftia for electrochemical analyses.

12:58 — ~ 10 Riftia collected. Began search for new sulfide structures.

13:24 — Reached XY 2604 : 1172 1989m. Noted flange below Riftia. Max Temp 244 oC. Upper and right part ranged from 10 to 110 oC. Began Electrochemical and noted significant sulfide levels (tens of micro-molar) that changed with time.

13:39 — Sipper #4 sample taken.

13:55 — Sipper #5 sample taken. Sulfide structure appears to be 15 m tall.

14:21 — Sulfide sample taken and put in forward box. Began new search with sonar.

14:27 — 2618X, 1185Y. Another mat with shimmering water of 80° – 90° C max.

14:32 — Started to go farther west.

14:59 — 2378X, 847 Y. Found tall structure noted from the tall site of 1988.

15:05 — Shimmering water from microbial mat 79° C max. Temperature of bottom of mat with Hi-Temperature Probe was 103° C.

15:09 — Core # 5 taken (Alvin) in orange mat. 2378X, 847Y. Core was taken near a sulfide structure which had Riftia a meter away.

15:14 — Sipper #6 sample taken.

15:17 — Moving on and saw purple worms at 2369X, 843Y. Another sulfide structure observed at 2357X, 840Y.

15:20 — Another sulfide structure observed at 2357X, 840Y. Looks top-heavy.

15:27 — Triple Tower found via sonar. 2368X, 827Y.

15:30 — Saw crabs on the peak, octopus nestled in a cold area on the structure. Clams possible??

15:32 — 2394X, 799Y. Another sulfide structure.

15:33 — Dropped weights.

16:46 — On surface.

17:05 — Alvin on deck.