Marine Institute
SeaRover Dive Video

D650 Transect 39 Mosaic sediments alternate between muddy slope with ophiuroid aggregations and vertical mud veneered carbonate walls hosting mixed soft and stony corals (Acanella arbuscula and Lophelia pertusa) P1. Water Depth: 1184m. Feature: Slope with escarpment

Highlights: Octopus & soft coral - Drifa sp. Dumbo octopus - Grimpoteuthis Red sea fan Sea cucumber - Psolus Sea pens Lophelia & bamboo coral Lophelia & crinoids Octopus

Of note: Escarpments with coral (Lepidisis and Madrepora)

Unusual geology here in the form of large rounded pillars. The substrate is largely an overlay of fine sediment on carbonate rock. Larger outcrops, both carbonate and igneous, are also present. About midway through the dive a series of escarpments occur, first as small ridges then as very large vertical escarpments. Along the escarpments the biodiversity is rich and include the corals Lepidisis and Madrepora, crinoids and anemones. Orange roughy and octopuses are observed.

START VIDEO [00:00:00]/00:46. Mosaic sediments alternate between muddy slope with ophiuroid aggregations and vertical mud veneered carbonate walls hosting mixed soft and stony corals (respectively Acanella arbuscula and Lophelia pertusa). [1] Dive starts on steep rippled mud slope with frequent ophiuroids buried in the sediment, possibly Ophiomusa lymani. [00:07:00] [2] here biotope changes into frequent boulders and muddy sediments with various anemones living on rock and soft sediment. [00:13:00] [3] here boulders are not as frequent and mud becomes the predominant biotope hosting ophiuroids and anemones. [00:14:00] Orange Roughy observed. [00:15:00] Escarpment on slope with sparse and scarce epifauna including ophiuroids and anemones. [00:17:00] [4] Here substrata is mainly mud veneered carbonate with ophiuroids and anemones. [00:28:00] [5] Now carbonate and coral rubble are the dominant biotopes, with sparse L. pertusa and Paramuricea sp. . [6] [00:30:00] Mixed seafloor inclination and substrata made of boulders and hills with vertical walls and flat surfaces hosting scarce epifauna. [00:42:00] A few filaments of fishing line at the bottom of vertical wall. [00:43:00] Orange Roughy encountered. [00:43:00] Bio-filaments present on carbonate wall. [00:51:00] ROV stops for imagery of Swiftia. [00:53:00] [7] Carbonate bedrock and boulders on steep slope with sparse epifauna, including ceriantharia and anemones. [00:56:00] [8] Ophiuroids bed on sediment . [01:00:00] [9] Vertical walls and scattered large cobbles/boulders with scarce epifauna. [01:08:00] [10] The seafloor is muddy with a plethora of burrows inhabited by ophiuroids. [01:15:00] [11] The ROV circumnavigates around a man-made structure which looks like a funnel (ship) similar to the smokestack or chimney on a ship. A few epifaunal species are found attached to this object, including sea cucumbers, ophiuroids, gastropods, crinoids, colonies of scleractinians, and asteroids. [01:18:00] [12] now muddy upslope with cerianthids and some visible polychaetes. [01:21:00] [13] vertical mud veneered wall hosts cup corals, A. arbuscula, Koehlermetra porrecta and Jasonisis sp. . [01:26:00] The ROV does a 180 turn and hovers again on the vertical wall section where the octocorals were present. ROV stops for core sampling. [01:39:00] [14] Here mud veneered bedrock interspersed with soft sediment predominates, with scarce epifauna. END VIDEO [01:50:00]/02:37.

Progression Start Duration Code Name
1[00:00:05]00:07:50M.AtMB.Mu.BurOphBurrowing ophiuroid community on Atlantic mid bathyal mud
2[00:07:56]00:05:47M.AtMB.RoAtlantic mid bathyal rock and other hard substrata
3[00:13:44]00:03:17M.AtMB.Mu.BurOphBurrowing ophiuroid community on Atlantic mid bathyal mud
4[00:17:02]00:11:12M.AtMB.RoAtlantic mid bathyal rock and other hard substrata
5[00:28:15]00:02:49M.AtMB.RoAtlantic mid bathyal rock and other hard substrata
6[00:31:05]00:19:16M.AtMB.RoAtlantic mid bathyal rock and other hard substrata
7[00:50:22]00:05:04M.AtMB.RoAtlantic mid bathyal rock and other hard substrata
8[00:55:27]00:04:45M.AtMB.Mu.BurOphBurrowing ophiuroid community on Atlantic mid bathyal mud
9[01:00:13]00:04:08M.AtMB.RoAtlantic mid bathyal rock and other hard substrata
10[01:04:22]00:10:01M.AtMB.Mu.BurOphBurrowing ophiuroid community on Atlantic mid bathyal mud
11[01:14:24]00:03:27M.AtMB.Ro.MixCorMixed cold water coral community on Atlantic mid bathyal rock and other hard substrata
12[01:17:52]00:04:11M.AtMB.MuAtlantic mid bathyal mud
13[01:22:04]00:16:55M.AtMB.Ro.MixCorMixed cold water coral community on Atlantic mid bathyal rock and other hard substrata
14[01:39:00]00:11:50M.AtMB.RoAtlantic mid bathyal rock and other hard substrata

Cnidaria
Cerianthidae sp. 1 : 2 : F
Pachycerianthus multiplicatus : 458 : R
Actiniaria sp. 20 : 605 : O
Sagartidae sp. (wide oral disc) : 1118 : R
Actinostolidae sp. 1 : 132 : O
Phelliactis sp. 1 : 255 : F
Stichopathes cf. gravieri : 283 : R
Stauropathes arctica : 547 : R
Caryophyllia sp. 2 : 6 : O
Lophelia pertusa : 250 : F
Acanthogorgia cf. armata : 608 : R
Pseudoanthomastus sp. : 1080 : R
Acanella arbuscula : 585 : F
Eknomisis sp. : 649 : R
Keratoisis sp. (fine branching) : 1157 : R
Gersemia sp. 3 : 1022 : R
Paramuricea sp. : 1050 : R

Swiftia sp. : 661 : F
Primnoidae sp. (unbranching) : 1193 : R
Gorgonacea sp. (pink, Solenosmilia assoc.) (Jasonisis) : 1070 : O
Pennatula aculeata : 1046 : R
Arthropoda
Munida tenuimana : 339 : R
Caridea (indet.) : 1077 : R
Mollusca
Graneledone sp. 1 : 937 : R
Opisthoteuthis extensa : 918 : R
Teuthida sp. 1 : 1017 : R
Margarites sp. 1 : 277 : R
Echinodermata
Democrinus sp. : 1103 : R
Koehlermetra porrecta : 315 : O
Ophiomusa lymani : 551 : A
Zoroaster fulgens : 988 : R
Echinus sp. : 445 : R

cf. Psolus sp. : 1049 : R
Chordata
Synaphobranchus kaupii : 440 : R
Hoplostethus atlantica : 651 : R
Nezumia aequalis : 1003 : R
Macrouridae sp. (cf. Coelorhynchus) : 1172 : R
Lepidion eques : 249 : O
Mora moro : 349 : R
Polyacanthonotus rissoanus : 552 : R
Trachyscorpia cristulata : 1216 : R
Neocyttus helgae : 563 : R

Number of species = 42

© Marine Institute, MERC Consultants, Bernard Picton 2022