Marine Institute
SeaRover Dive Video

D546 Transect RB23 Mud/cobble/boulders with many epifauna including holothurians, ophiuroids, scleractinians and sponges. Not Priority. Features: Rise, Depth. Water depth: -2320 m. TL: 2.1 km SOL: 15° 3.138' W 55° 24.068' N

Highlights: Stalked crinoids & brittlestar - Ophiomusa

Poor visibility with extreme levels of marine snow. Soft sediment with occasional rocks and an area of large rocks. The benthic community is composed of urchins, ophiuroids and stalked crinoids. Glass sponges and interesting Pheronema-type sponges are also common.

START VIDEO A AT [00:00:00]/13:43 Muddy sediment. Vision is obscured by suspended sediment until [00:46:14]. [1] Muddy sediment with occasional boulders/cobbles with sparse epifauna, including Holothuroidea and Ophiuroidea. [00:51:00] ROV leaves the bottom and swims high from the bottom. Vision is poor. [00:53:00] Vision back to normal, although still suspended sediment. [00:56:00] ROV leaves the bottom again and hovers high. Vision obscured again. [00:58:00] Vision is back to normal. [00:59:00] ROV stops for imagery and sampling of anemone (unknown). [01:00:00] Mud cloud obscures vision. [01:28:00] Fishing net hosts Ophiuroidea sp. 7 (red) OTU340. [01:31:00] [2] Boulders/cobbles/mud with sparse Phakellia ventilabrum and stalked crinoids. Boulders host crinoids stalked and anemones. [15:22:00] [3] mud flat/gentle uphill dominated by ophiuroids. [01:43:00] [4] Boulders and mud sediment. Sparse anemones and scleractinians dominate on hard rock; Ophiomusa lymani dominates on mud. [01:43:00] [5] Carbonate mounds/escarpment hosting many epifauna species, reaching gentle upslope of pebble/cobble field. [01:44:00] [6] ROV goes up a steep hill with mud, cobbles/pebble fields and occasional bouders. [01:57:00] ROV stops for imagery and sampling of unknown sponges until END VIDEO A AT [02:25:00]/16:08.

START VIDEO B AT 16:10. [02:25:00] [7] Muddy sediment with cobbles/boulders field on gentle uphill. Crinoids and Ophiomusa lymani are dominant species. [02:30:00]-[02:46:00] ROV stops for imagery and sampling of sponges (possibly cf. Pheronema sp. OTU1084). [02:54:00] ROV goes backwards and goes 45 left and forward. Camera moves up and down erratically and then mud cloud. Vision is obscured. [02:55:00] Vision clear again and ROV moves slowly forward. [03:04:00] ROV stops for imagery of sponges. [03:06:00] ROV moves again. [03:07:00] ROV stops and moves again. Blue water for a few seconds. Then ROV descends to the bottom. [03:08:00] Vision clear again. [8] Boulders/cobbles and pebbles fields hosting Bathycrinidae sp.1. [03:10:00] ROV stops again. [03:13:00] ROV circumnavigates a group of boulders. Then moves forward. [03:15:00] [9] mud and occasional pebbles again. Epifauna sparse. Mainly stalked crinoids, a few soft corals and ophiuroids. ROV climbs a steep hill. Muddy/pebble sediment with occasional/frequent cobbles/boulders. [03:16:00] ROV moves fast, distant from the bottom. Vision blurred. [03:17:00] Vision back to normal. [03:18:00] [10] Bedrock/boulders/mud hosting sparsely Phakellia ventilabrum, Brisingidae OTU274 and crinoids. [03:20:00] [11] Muddy sediment again with sparse cobbles. [03:24:00] Vision blurred for few seconds. [03:25:00][03:59:00] Vision obscured due to mud cloud. [03:55:00]-[03:57:00] ROV sampled 1 pushcore. [04:08:00] ROV stops for imagery of mud cloud/biological debris (?). [04:11:00] Vision still blurred. [04:13:00] Vision clear again. [04:16:00] ROV stops for imagery of sea urchin (poss OTU559 or OTU1129). END VIDEO B AT [04:26:00].

START VIDEO C AT 18:15. Muddy sediment/sparse cobbles hosting sea urchin (dominant) and ophiuroids. [04:30:00]-[04:37:00] ROV stops for imagery. [04:40:00] Vision obscured for 30 sec. [04:43:00] Vision obscured. [04:55:00] Vision back to normal. ROV climbs a moderate steep hill. [04:56:00] Vision obscured. [04:58:00] Vision clear again. END VIDEO C AT [05:00:25]/18:49.

Progression Start Duration Code Name
6[00:00:00]01:35:30M.AtUA.RoAtlantic upper abyssal rock and other hard substrata
7[00:00:00]02:01:02M.AtUA.Mu.UrcComUrchin dominated community on Atlantic upper abyssal mud
1[00:00:05]01:26:24M.AtUA.MuAtlantic upper abyssal mud
8[00:29:55]00:05:07M.AtUA.MuAtlantic upper abyssal mud
2[01:26:30]00:12:10M.AtUA.RoAtlantic upper abyssal rock and other hard substrata
4[01:42:10]00:04:28M.AtUA.RoAtlantic upper abyssal rock and other hard substrata
5[01:46:39]00:37:41M.AtUA.MuAtlantic upper abyssal mud

Foraminifera
Syringammina fragilissima : 261 : R
Porifera
cf. Pheronema sp. (Rock possibly Aphorme horrida) : 1084 : R
cf. Phakellia ventilabrum : 202 : R
Porifera encrusting sp. 1 (white) : 1 : R
Porifera globose (muddy) : 1128 : R
Porifera globose lobose : 1178 : R
Porifera lamellate sp. 13 : 1053 : R
Porifera lamellate sp. 7 : 422 : R
Porifera massive lobose sp. 32 : 1090 : R
Cnidaria
Actiniaria sp. 20 : 605 : R
Actinernus michaelsarsi : 554 : R
Actinauge richardi : 499 : R
Phelliactis sp. 1 : 255 : R
Caryophyllia sp. 5 (bullseye) : 584 : R
Anthomastus grandiflorus : 278 : R
Anthoptilum grandiflorum : 594 : R

Arthropoda
Caridea (indet.) : 1077 : R
Bathynectes sp. : 235 : R
Eucarida sp. (red deep) : 1138 : R
Mollusca
Colus sp. : 113 : R
Graneledone verrucosa : 973 : R
Echinodermata
Bathycrinidae sp. : 1141 : R
Anachalypsicrinus nefertiti : 1031 : R
Crinoidea sp. 1 : 131 : R
Ophiomusa lymani : 551 : R
Ophiuroidea sp. 7 - yellow : 340 : R
Brisingidae sp. : 274 : R
Brisingidae sp. : 274 : R
Zoroaster fulgens : 988 : R
Porania sp. : 263 : R
Solaster endeca : 573 : R
cf. Hymenaster (yellow) : 1174 : R

Velatida sp. 1 : 199 : R
cf. Echinus (deep pink spine) : 1129 : R
Echinidae sp. (white) : 559 : R
Peniagone sp. : 1167 : R
Mesothuria intestinalis : 536 : R
Chordata
Synaphobranchus kaupii : 440 : R
Coryphaenoides armatus : 1105 : R
Coryphaenoides guentheri : 577 : R
Trachyrincus sp. : 446 : R
Mora moro : 349 : R
Phycis blennoides : 1020 : R
Polyacanthonotus rissoanus : 552 : R
Actinopterygii sp. 3 : 930 : R

Number of species = 45

© Marine Institute, MERC Consultants, Bernard Picton 2022