Expedition dates 5/4/15 to 5/11/1015. Ports: Gulfport, MS to Galveston, TX

Cruise report for EV Nautilus cruise NA058: MPI cruise to sample mussels and examine water chemistry from discrete seep sites, continuation of ECOGIG2 objectives Expedition dates 5/4/15 to 5/11/1015 Ports: Gulfport, MS to Galveston, TX Funding: Gulf of Mexico Research Initiative through the ECOGIG II program, Max Plank Institute for Microbiology (funding science) Logistics and outreach co-shared with Ocean Exploration Trust Primary objectives accomplished during this cruise 1) We collected mussels of two different species with co- located chemical measurements 2) We established coral monitoring sites near and far from natural seepage at GC234 3) We explored new seeps sites at GB903 4) We held the largest single- day web interaction for Nautilus Live following the airing of the 60 Minutes episode on May 10 th. E/V Nautilus Science Personnel NA058 1. Erik Cordes (ecordes@temple.edu) Temple Chief Scientist 2. Fanny Girard (fag119@psu.edu) Penn State Grad Student 3. Sam Vohsen (sav146@psu.edu) Penn State Grad Student 4. Iliana Baums (baums@psu.edu) PSU Scientist 5. Jillian Petersen (jmpeters@mpi-bremen.de) MPI Scientist 6. Silke Wetzel (swetzel@mpi-bremen.de) MPI Scientist 7. Rebecca Ansorge (ransorge@mpi-bremen.de) MPI Grad. Student 8. Niko Leisch (nleisch@mpi-bremen.de) MPI Scientist 9. Charles Vidoudez (charlesvidoudez@gmail.com) Harvard Scientist

May 4 1300 Depart Gulfport MS May 5 0800 Launch H1422 May 5 0900 Recover H1422 May 6 0400 Launch H1423 at MC853 May 6 1200 Recover H1423 May 7 1200 Launch H1424 at GC234 May 8 0000 Recover H1424 May 8 0400 Launch H1425 at GC234 May 8 0800 Recover H1425 May 8 1300 Launch H1426 at GC852 May 8 1700 Recover H1426 May 9 1300 Launch H1427 at GB903 May 9 2000 Recover H1427 May 10 1600 Arrive at anchorage May 11 1000 Arrive Galveston TX Cruise overview May 4 1300 Depart Gulfport Cruise Summary We swapped out some personnel, including a new Captain, and headed back out to sea. We are making our way to MC640 to get mussels for the Max Plank group. May 5 0800 Launch of H1422 We arrived on site on the morning of May 5 and attempted a launch in marginal conditions. As Hercules went into the water, the ship turned its heading, and the tether was pulled at 90 degrees from Argus. The cone on the back of Argus was pulled and the termination at Argus damaged. Hercules was immediately recovered. 0900 Recovery of H1422 After recovery the ROV group began the process or re-terminating. While this was happening, we moved over to MC853 to map the site and wait for the seas to calm. Once the termination was complete, we re-evaluated the conditions, but it was still too rough to dive. Enough time passed that the dive at MC640 was cancelled and we continued to evaluate the situation at 4 hour intervals. May 6 0400 Launch of 1423 at MC853

This was entirely a mussel sampling dive. We dove on the old targets from the Chemo III dives at this site and immediately found some mussel beds. The first one was a mix of B. childressi and B. brooksi. We used the mass spec at a few different locations and then decided on one of the small clumps of mussels to sample. A mass spec sample was taken afterwards as well in order to see if there was a change in chemical conditions without the mussels. We then moved on and found a few more small mussel beds to scan and sample. The mussels and seep areas were mostly located at the bottoms of long trenches, and we continued through a few of these to locate the addition beds. The brine pool that was sampled on the Chemo III cruise was never located, but some decent sized mixed mussel beds were located and characterized. 1200 recovery of 1423 After recovery, we continued to the west to try to pick up the time-lapse camera at GC600. We arrived at the site, but the conditions were too rough for a dive, including a 2 knot current at the surface. We moved over to GC852 to see if the current was less over there. When we arrived at 0800, the current was still too high to dive. There was a large eddy in the area that pinched off of the loop current a week or two ago, so it was still generating sustained 2 knot currents. We tried to move shallower to GC234 to see if the eddy didn t extend up onto the upper slope. The currents and seas were more favorable, so we dove there. May 7 1200 Launch of H1424 at GC234 On this first dive at the site, the water sampler was deployed near a coral-seep overlap site, and a series of stations were set up for coral monitoring. The first station was where the water sampler was deployed and consisted of white bacterial mats, tubeworms, and Callogorgia. The mass spec was used to see if there was any evidence of sulfide or methane near the corals. A series of corals were imaged and two were sampled at this location. On our way away from this site, we noticed an old mooring, about 3-4 m high, right next to the water sampler. Our view was so obstructed on the way in that we had failed to notice it. We dropped a target at its location in order to avoid it when we returned to pick it up. We then went to the main tubeworm site to look for mussel beds and see if there was another good seep-coral transition site. A mussel bed was located, but there were no good areas of coral and red bacterial mats right around this area. We began to transit further away to the northwest, and quickly found an outcrop with numerous Callogorgia colonies and a large, roughly oval patch of red and white bacterial mats and small mounds that likely had gas hydrate beneath them. We deployed a marker, imaged the corals, and took coral samples. We started to take a push core, when the ship lost DP and we were yanked off of the site. It took about an hour to recover and make it back to the location for a push core.

We then continued to the northwest towards the Lophelia ridge. We found another good control site and imaged there. We deployed our marker, and realized that we did not have another one because one had fallen apart earlier on the dive. We then transited over to the old markers on the Lophelia ridge and found an appropriate site to complete the imagery. We then ran out of time, and started recovery. May 8 0000 recovery from H1424 The vehicles were recovered and the camera removed for the bounce dive to get the water sampler. 0400 launch of H1425 at GC234 We launched the vehicles on the mussel bed target that we dropped on the last dive. When we got to the bottom, we landed on another mussel bed just to the southeast of the previous target. It was mostly dead mussel shells, but there were enough small B. childressi to complete a collection. We then moved a short distance and immediately found the other mussel bed. We completed a much larger collection in a few grabs, and then headed to the water sampler. The sampler was found immediately and we began the process of retrieving it. We secured it quickly and left the seafloor for a slightly early recovery. 0730 recovery from H1425 After recovery, we returned to GC852 to attempt a dive there. The currents were still over a knot, but the winds were down and the ship seemed to be holding position well. 1300 launch of H1426 at GC852 We launched the vehicles a little late and began our decent to the seafloor. We arrived at the site and were in the middle of the coral area. We began to move upslope towards the center of the site over large vertical outcrops with bamboo corals, small Paramuricea biscaya colonies, Iridogorgia, and small Paragorgia. We were preparing to set up to image some corals when the vehicles went dead. All power to the vans was out and the winch was dead. We came out and the winch on deck was dead as well. The jet pumps had been at full power and the load made the generator shut down. Apparently, all of these systems were on the same circuit. It took a few minutes to restart the generator, and then we pulled the vehicles up to about 100m off the bottom. The ship drifted off site, and eventually the DP system was recovered. It was struggling to hold station, so the decision was made to recover the vehicles and turn on the main engine. 1700 recovery from H1426 There has been a lot of discussion about exactly what happened and why the overload to the jet pumps caused a full shutdown of the generator. After the dive, the ROV group

took the opportunity to fix a small problem with the manipulator. The decision was made to transit to GB903 to get closer to Galveston and to see if the conditions would be better over there. In the morning, we were in 0.85 kts of current with winds at 20 kts, and the ship still could not hold station. We changed the launch target to the southeast to be able to work with the currents for the whole dive. The current came down a bit, and the winds died to 15-17 kts, and we were able to get in the water. May 9 1300 Launch of H1427 at GB903 We launched after lunch and were on the seafloor at about 1400. We were setting up and trying to get the BFC lights deployed, when we realized that the kraft arm was not functional. We tried a few solutions from on the surface, but nothing worked. Because there is bad weather expected, we do not have time to return to the surface (2 hrs) to repair the arm (3-4 hrs) and still have time to return to the seafloor (1 hr) before our agreed-upon 2000 recovery (2 hrs) time. We were at the opening of the canyon feature at the site. There were very steep mud flows falling down from the valley. As we climbed these, we came on an outcrop of rock with brine-stained sediments beneath and small mussel beds. These appeared to all be B. childressi. We continued climbing, roughly 320 degrees along the eastern edge of the canyon. As we came into the canyon, more brine features were seen, including a number of small brine pools with bacterial mats and mussels. When a larger pool was found, we lowered the front porch of Herc into it in order to submerge the wand of the mass spec. There were good hits for both methane and sulfide. We continued up the valley, which consisted of flat brine pool areas and steep steps of carbonates and mud flows. Some of the pools consisted of barite precipitates, and some of reddish iron-rich deposits. A few more mass spec readings were taken with high methane, and in the last case, very high sulfide readings. Towards the top of the valley, we stopped to take a 360 degree panorama for use by the Catlin Seaview Survey to create a large mosaic that is suitable for Google underwater street view. Shortly after this was complete, we left the valley to look for the nearest coral colony. There was a Paramuricea B3 colony approximately 30-40 meters away, but there were no corals noted near seepage during the dive. 2000 Recovery of H1427 The vehicles were recovered in an increasing sea state with 6-8 foot swells rolling through. We transited over to GB535 to attempt one last dive. When we got up at 0130 to talk it over, the winds were over 20 knots, currents at 0.6 to 0.8 kts, and the swells were still at 6-8 feet. We decided to cancel the dive and return to port.

H1423 Dive Plan Nautilus Cruise NA058 Gulf of Mexico Date May 5, 2015 Lead Scientist Erik Cordes Expedition Leader Mike Brennan Vital Stats Expected launch time: 1600 Expected length of dive: 16 hours On deck by: 0800 06 May Expected depth at launch: 1058 m Expected depth range: 1050 to 1100 m On bottom: Latitude: 28.12835 Longitude: -89.14100 Vehicle Configuration Forward Box: 2 partitions Front porch: BFC 6000 Starboard box: 6 partitions (2 large, 4 small), 5 push cores outside starboard box 4 markers Coral cutters mass spec niskins Watch Leaders on bottom: Cordes 6-10: Fanny & Sam 10-12: Cordes & Petersen 12-recovery: MPI Dive Site MC853 Dive Plan & Objectives Purpose of this dive is to establish new coral monitoring locations, make collections for the Max Plank mussel work and work out any kinks with the mass spec Dive on the launch target o Chase sonar towards coral 1 waypoint, look for corals o Drop a marker, fire a niskin, take a push core, image corals o Repeat as necessary Stay around here if mussels seen in coral survey Otherwise, proceed to mussel 1 waypoint o Sniff with mass spec, collect good looking mussels o repeat Head to each of the other mussel targets o Sniff with mass spec, collect good looking mussels

H1424 Dive Plan Nautilus Cruise NA057 Gulf of Mexico Date May 7, 2015 Lead Scientist Erik Cordes Dive Site GC 234 Expedition Leader Mike Brennan Vital Stats Expected launch time: 1200 Expected length of dive: 8 hours On deck by: 2000 07 May Expected depth at launch: 537 m Expected depth range: 500 to 550 m On bottom: Latitude: 27.74628 Longitude: -91.2222 Vehicle Configuration Forward Box: 2 partitions Front porch: BFC 6000 camera, water sampler Starboard box: 6 partitions (2 large, 4 small), Coral cutters mass spec niskins Watch Leaders Launch: Erik, Iliana, Jill 12-8: Iliana, Fanny & Sam Dive Plan & Objectives Launch in the middle of tubeworms Deploy water sampler on western edge survey field looking for mats and mussels Find western edge, start coral transect o Previous Callogorgia: 27.7474, - 91.2238, 512m o Image, sample, image, push core o Continue to the west and repeat away from seepage Return to main tubeworm area and repeat near- far Repeat again Go get stained coral (M47, 27.7468, - 91.2227, 530m) Come home

H1425 Dive Plan Nautilus Cruise NA057 Gulf of Mexico Date May 8, 2015 Lead Scientist Erik Cordes Dive Site GC 234 Expedition Leader Mike Brennan Vital Stats Expected launch time: 0400 Expected length of dive: 4 hours On deck by: 0800 08 May Expected depth at launch: 537 m Expected depth range: 500 to 550 m Launch target: mussel bed Vehicle Configuration Forward Box: 2 partitions Front porch: empty Starboard box: 6 partitions (2 large, 4 small), Coral cutters mass spec niskins Watch Leaders Erik, Jill Dive Plan & Objectives Launch on the mussel target Collect Bathymodiolus childressi into biobox Proceed to second mussel target Make second collection Go to water sampler target Get sampler and come home

H1426 Dive Plan Nautilus Cruise NA057 Gulf of Mexico Date May 8, 2015 Lead Scientist Erik Cordes Dive Site GC852 Expedition Leader Mike Brennan Vital Stats Expected launch time: 1200 Expected length of dive: 24 hours On deck by: 1200 09 May Expected depth at launch: 1395m Expected depth range: 1390 to 1420 m On bottom: Latitude: 27.11018 Longitude: -91.16607 Vehicle Configuration Forward Box: 2 partitions Front porch: BFC 6000 camera Starboard box: 6 partitions Coral cutters mass spec niskins Watch Leaders Launch: Erik 10-12: Fanny & Sam 12-4: Jill & Charles 4-6: Fanny & Sam Dive Plan & Objectives Launch in stony coral area, image Paramuricea o Work your way north along ridge Proceed to M1, look for good mussel collection sites o Sniff around base of mussels (5-7 min) o Collect mussels in large biobox chamber o Re- sniff collection area Continue north, chasing sonar towards other mussel targets o Repeat collections When collections complete, go into tow mode towards C2 Image Paramuricea until time to come home

H1427 Dive Plan Nautilus Cruise NA057 Gulf of Mexico Date May 9, 2015 Lead Scientist Erik Cordes Dive Site GB 903 Expedition Leader Mike Brennan Vital Stats Expected launch time: 0800 Expected length of dive: 28 hours On deck by: 1200 10 May Expected depth at launch: 1074m Expected depth range: 1000 to 1100 m On bottom: Latitude: 27.0840 Longitude: -92.8207 Vehicle Configuration Forward Box: 2 partitions Front porch: BFC 6000 camera Starboard box: 4 partitions Coral cutters mass spec niskins Dive Plan & Objectives Launch at the western edge of the site Head 110 degrees over the hash marks If you encounter corals, stop to image If you find mussels, stop to collect Repeat on the way to the brine river Drop down to bottom of the river Work your way up, making mussel collections Look up slope for corals. If you find both, get Erik! At the top of the valley, re- assess

NAUTILUS DIVE REPORT Cruise ID: NA058- COLD SEEPS Vehicles: Hercules/Argus Lowering ID: H1422 Site: MC 640 Launch Time UTC: 5 MAY 2015 14:13:19 Recovery Time UTC: 5 MAY 2015 14:23:55 On Bottom Time UTC: 5 MAY 2015 14:15:11 Off Bottom Time UTC: 5 MAY 2015 14:15:22 Location: In water: 28.3552 N, 88.7922 W On Bottom: N/A On Deck: 28.3551 N, 88.7923 W Off Bottom: N/A Vehicle Depth: On Bottom: N/A Off Bottom: N/A Samples: N/A Targets: Mud Volcano, Foggy Brine, Pock mark waypoints Dive Summary: Objectives: We will make collections for the Max Plank mussel work and work out any kinks with the mass spec while exploring noteworthy topographic features at MC640. Observations: 14:13 Hercules in water. 14:15 Hercules caught up in Nautilus thruster wash and pulled 90 degrees to Argus (still on deck). Resulting tension pulled the BSR cone out of Argus. Start recovery of Hercules. 14:23 Hercules on deck.

NAUTILUS DIVE REPORT Cruise ID: NA058 COLD SEEPS Lowering ID: H1423 Vehicles: Hercules/Argus Site: MC853 Launch Time UTC: 6 MAY 2015 09:22:35 Recovery Time UTC: 6 MAY 2015 17:45:42 On Bottom Time UTC: 6 MAY 2015 10:26:51 Off Bottom Time UTC: 6 MAY 2015 16:12:19 Location: In water: 28.1230 N, 89.1395 W On Bottom: 28.1231 N, 89.1398 W On Deck: 28.1211 N, 89.1306 W Off Bottom: 28.1247 N, 89.1413 W Vehicle Depth: On Bottom: 1067m Off Bottom: 1067m Samples: NA057-001 to NA057-010 Targets: Waypoints Mussel1, Mussel2, Mussel3, and coral1 Dive Summary: Objectives: This dive on MC 853 was conducted to establish new coral monitoring locations, make collections for the Max Plank mussel work and work out any kinks with the mass spec operations. We also searched the area around each waypoint for mussels or corals per the dive plan. Observations: NOTE: Argus camera was not recorded and no screen grabs were taken during this dive due to camera swap after the Herc HD glass dome chip during H1420. 09:22-10:26 Vehicles in water; Descending to 340m. On bottom. 10:48 Bottom is muddy with both red and white bacterial mat. Approaching a large slope with the potential for mussel activity. 10:54 Some isolated mussels spotted, some relief in the seafloor may indicate gas hydrates. 11:05 Much larger bacterial mats with crusty white and brown colonies, anoxic sediment 11:22 11:38 Large mussel bed observed with about 100 live mussels on an orange and white bacterial mat. Spp. include both B. cbrooksi and B. childressi. No sulfide detected in the mass spec. repositioning for another reading and collection. 11:57 12:21 SAMPLE: NA58-001: Bathymodiolus spp. seep mussels of many size classes. Small sulfide signal detected on mass spec. Other associates include gastropod spp. and squat lobsters. 12:25 12:39 Following a thin brine pool upstream. Long thin brine pool has mussels suspended over it. Moving closer for a mass spec reading and sampling.

12:59 SAMPLE: NA58-001: Bathymodiolus spp. suspended above brine pool. Two small clusters. Sampling was paired with before/after mass spec readings. 13:12 Continuing northward march for sightings of additional mussel beds along a deep canyon. 13:41 Mussel patch sighted on opposite wall of the canyon. Getting into position to take another mass spec reading. 14:06 SAMPLE: NA58-001: Bathymodiolus spp. in white bacterial mat. Some white bacterial growth on shells. Mass spec detected methane but sulfide was inconclusive. 14:46 Scanning area for more mussels. Some small patches found but in insufficient numbers for a collection. Other associates include urchins, squat lobsters, clam shells. 14:56 15:23 Using mass spec to sniff for sulfides at various mussel patches. No significant readings detected but some patches had indicative levels. 15:44-16:01 SAMPLE: NA58-001: Bathymodiolus spp. of various sizes collected in the vicinity of a clam shell bed. Some clams collected. Sample was not cohesive so individuals had to be collected separately. 16:21 16:24 SAMPLES: NA058-005 NA058-010: Niskin water samples collected during recovery, 950-916m depth. Water used for sample processing later. 17:01 A/C units in the control van are failing. No solution detected. 17:45-16:12 Starting recovery; Off bottom; Vehicles on deck.

NAUTILUS DIVE REPORT Cruise ID: NA058 COLD SEEPS Lowering ID: H1424 Vehicles: Hercules/Argus Site: GC234 Launch Time UTC: 07 MAY 2015 18:47:08 Recovery Time UTC: 08 MAY 2015 05:02:04 On Bottom Time UTC: 07 MAY 2015 19:30:54 Off Bottom Time UTC: 08 MAY 2015 04:08:19 Location: In water: 27.7460 N, 91.2218 W On Bottom: 27.7464 N, 91.2219 W On Deck: 27.7496 N, 91.2220 W Off Bottom: 27.7470 N, 91.2243 W Vehicle Depth: On Bottom: 530 m Off Bottom: 499 m Samples: NA057-011 to NA057-17 Targets: LS2, BB, 3, M Dive Summary: Objectives: This dive on GC234 was conducted to deploy the Max Planck water sampler, establish new coral monitoring locations, make coral collections for the Fisher and Cordes labs, and sediment cores for USGS. We also searched the area around the mound of tube worms for mussels or corals per the dive plan. Observations: NOTE: Argus camera was not recorded and no screen grabs were taken during this dive due to camera swap after the Herc HD glass dome chip during H1420. 18:47-19:30 Vehicles in water; On bottom. 19:37 20:30 Move to deploy water sampler next to Callogorgia colony; deployed may have started prior to deployment because it was set to auto- start after 2 hrs 20:31 20:36 Deploy marker LS2 20:36 21:02 Image callogorgia corals with BFC6000: LS2-1, LS2-2, LS2-3 21:05 21:15 SAMPLE: NA058-011- ROVG, callogorgia LS2-2; sniff with mass spec; re- image 21:22 21:31 Image callogorgia corals with BFC6000: LS2-4, LS2-5, LS2-6 21:36 21:52 SAMPLE: NA058-012- ROVG, callogorgia LS2-6; sniff with mass spec; re- image 22:03 22:06 SAMPLE: NA058-013- ROVPC, push core at LS2 near water sampler 22:07 Discover mooring previously unidentified by Erik next to LS2 marker 22:14 22:34 Start exploring the area for next target; begin moving east over tubeworms,

callogorgia, red bacterial mats, diverse fish, clathrates 22:34 22:36 Reach marker C near bed of tubeworms, continue to marker A 22:38 22:43 Continue towards eastern edge over mussel beds, sponges, seastars, fish, tubeworms 22:43 23:08 Follow eastern edge of tubeworm field to the north then continue around the field to the west; pass over tubeworms, bacterial mats, trash, fish 23:12 23:55 Leave tubeworm bed, head north along ridge for coral collection and imaging 23:55 00:11 Image callogorgia corals with BFC6000, will be named later 00:13 00:17 SAMPLE: NA058-014- ROVG, callogorgia; re- image 00:20 Deploy marker BB 00:24 00:36 SAMPLE: NA058-015- ROVG, callogorgia; re- image 00:44 00:54 Take mass spec measurements of sampled corals 00:56 01:46 Lose DP, pulled off site; struggle reacquiring marker BB, but drop marker CS4 at callogorgia site during return transit 01:48 02:04 SAMPLE: NA016- ROVPC, push core at marker BB after several failed attempts 02:07 02:24 Image callogorgia corals with BFC6000, BB- 1, BB- 2, BB- 3, BB- 4, BB- 5, BB- 6, BB- 7, BB- 8, BB- 9, BB- 10, BB- 11, BB- 12, BB- 13, BB- 14, BB- 15 02:26 02:49 Take over- view image of BB site; move on to next target over lophelia rubble 02:56 Deploy marker 3 03:02 03:20 Image callogorgia corals with BFC6000, 3-1, 3-2, 3-3, 3-4, 3-5, 03:20 03:31 SAMPLE: NA058-017- ROVG, callogorgia 3-5; re- image 03:34 03:49 Move to site M - previously deployed markers M, M4, M7 are all located here 03:52 04:00 Image callogorgia corals with BFC6000, M- 1, M- 2, M- 3, M- 4 04:08 05:02 Starting recovery; Off bottom; Vehicles on deck.

NAUTILUS DIVE REPORT Cruise ID: NA058 COLD SEEPS Lowering ID: H1425 Vehicles: Hercules/Argus Site: GC234 Launch Time UTC: 8 MAY 2015 09:09:37 Recovery Time UTC: 8 MAY 2015 12:49:52 On Bottom Time UTC: 8 MAY 2015 09:37:42 Off Bottom Time UTC: 8 MAY 2015 11:30:59 Location: In water: 27.7458 N, 91.2215 W On Bottom: 27.7458 N, 91.2217 W Vehicle Depth: On Bottom: 532m On Deck: 27.7368 N, 91.076 W Off Bottom: 27.7466 N, 91.2229 W Off Bottom: 525m Samples: NA058-018 to NA058-019 Targets: Mussel Bed Dive Summary: Objectives: This dive was conducted to launch on a mussel bed target, collect samples of Bathymodiolus sp. from two different beds and retrieve the water sampler deployed on a previous dive. Observations: 09:09 09:37 Argus/Hercules launched; in water; on bottom and moving to find a target and begin mussel sampling. 09:40 09:50 Landed on mussel bed target, taking readings with the in situ mass spectrometer to determine best location for sampling. 09:51 10:45 SAMPLE: NA058-018- ROVG; Bathymodiolus sp. mussels near a bed of tube worms. 10:45 10:50 Moving to a second mussel bed. 10:50 10:59 SAMPLE: NA058-019- ROVG; Bathymodiolus sp. mussels from a lively seep sitting on top of a bed of tube worms. 11:08 11:11 Firing non- sample Niskin bottles for extra water. 11:17 11:26 Moving to retrieve water sampler; sampler successfully stowed. 11:30 12:50 Starting recovery; Off bottom; On deck.

NAUTILUS DIVE REPORT Cruise ID: NA058 COLD SEEPS Lowering ID: H1426 Vehicles: Hercules/Argus Site: GC852 Launch Time UTC: 08 MAY 2015 17:51:42 Recovery Time UTC: 08 MAY 2015 22:05:32 On Bottom Time UTC: 08 MAY 2015 19:14:25 Off Bottom Time UTC: 08 MAY 2015 19:59:30 Location: In water: 27.1095 N, 91.1664 W On Bottom: 27.1099 N, 91.1664 W On Deck: 27.1188 N, 91.1637 W Off Bottom: 27.1130 N, 91.1645 W Vehicle Depth: On Bottom: 1392.6m Off Bottom: 1242.4m Samples: N/A Targets: N/A Dive Summary: Objectives: Diving to image and collect corals at a non- seep site, but end the dive shortly after acquiring bottom due to massive shipwide power failure. Observations: 17:51 19:15 Argus/Hercules launched; in water; descending to 1400m. On bottom. 19:21 19:29 Setting up for tour of the site. Travel over very diverse coral species on large carbonate boulders 19:30 19:57 Lost all power to vehicles and winch. Computer monitors stay on, but the rest of the ship goes completely dark. Ship- wide power failure. Restart 60 Hz closet, pull up vehicles, re- gain communications and power. Various accounts of the ultimate cause. Go into safety and recovery mode. 19:59-22:05 Starting recovery; off bottom; several pauses along ascent to re- evaluate the situation; on deck.

NAUTILUS DIVE REPORT Cruise ID: NA058 COLD SEEPS Vehicles: Hercules/Argus Lowering ID: H1427 Site: GB 903 Launch Time UTC: 09 MAY 2015 17:12:48 Recovery Time UTC: 10 MAY 2015 01:30:27 On Bottom Time UTC: 09 MAY 2015 18:37:20 Off Bottom Time UTC: 09 MAY 2015 23:44:19 Location: In water: 27.0796 N, 92.814 W On Bottom: 27.0804 N, 92.8150 W On Deck: 27.0681 N, 92.8100 W Off Bottom: 27.0852 N, 92.8169 W Vehicle Depth: On Bottom: 1085.6m Off Bottom: 1069.4m Samples: N/A Targets: Brine river and mussel beds along S- N canyon transect. Dive Summary: Objectives: Image corals, collect mussels, and use the mass spec on brine pool fluids up the canyon transect. Repeat as often as necessary. Observations: 17:12 18:37 Argus/Hercules launched; in water; descending to ~1100m. Needed to take out difficult tether wrap on the way down. On bottom. 18:42 18:48 Tracking upslope along a canyon with bacterial mat and traces of brine. Some patches of mussels 18:57 Lost comms with Kraft arm. Unable to regain connection. No samples will be collected this dive. 19:11 19:27 Bed of live clams and mussels continuing upslope. Using BFC- 6000 to get close- ups of mussels. Continuing up very steep slope. 19:32 Some corals including large CORO Paramuricea sp. and CORO Paragorgia sp. 19:55 Cycled power to Kraft arm for one last shot. Still no comms. 20:05 20:36 HIGHLIGHT: Amazing brine pool footage with Herc hoving above the surface of the pool. Barium precipitate crystals are visible on the pool shores and at the bottom of the pool. Using mass spec wand to collect chemical readings from inside a shallow brine pool. Very high, off the charts sulfide detected. 20:42 20:44 Very large red squid observed in Herc HD. Squid was approx. 60-70cm without laser measurements.

21:11 21:21 CORO Paragorgia sp. and CORA cf. Parantipathes sp. 21:35 Large healthy- looking mussel bed with both B. brooksi and B. childressi 21:40 Largest brine pool on the dive so far. Very large Barite precipitate in elevated pool. We will be setting up here to do Google StreetView image transects with BFC- 6000. 22:10-22:30 Starting street- view transect 1. End circle 1. 22:34-22:54 Starting street- view transect 2. End circle 2. 22:54-23:09 Starting street- view transect 3. End circle 3. 23:36 Continuing upslope and entering a short valley with substantial clam and mussel rubble. Removing wraps from tether again. 23:40 Reached the top of a large promontory with several colonies of CORO Paramuricea sp. One colony 1/3 covered with zoanthids. 23:44 01:30 Starting recovery; off bottom; Cycled Hercules power once on ascent; on deck.