Marine Institute
SeaRover Dive Video

D488 Transect 20 Very diverse. Extensive coral garden mostly on cobbles/boulders, but also pinnacle/cliff features with Solenosmilia reef/rubble aprons at the base. Sediment also diverse (xenophyophores, cup corals, Acanella). Features of interest: canyon, escarpment Water Depth: 1351-971 m

Highlights: Aphroditid worm moving and shaking bristles Solenosmilia reef Solenosmilia reef with hexactinellid sponges & antipatharian corals Hexactinellid sponges Hexactinellid sponges & bamboo coral Brisingid starfish Large yellow sea fan Hexactinellid sponge - Asconema Sea fan Stylasterid coral & anemones Canon ball Hexactinellid sponge with zoanthid anemones Sea fan Hexactinellid sponge - Pheronema

Soft substrate of the canyon floor is dominated by xenophyophores, sea pens, echinoids, Acanella sp., eels and grenadiers. On the slope dropstones are colonised by sponges, Hyalonema sp., and anemones, transitioning into an area of coral rubble and stones where small glass sponges and soft coral are more common. At the base of a distinct 30 m high carbonate pinnacle Solenosmilia variabilis is recorded while at its pinnacle sponges and soft corals occur.

Moving along a steep rock cliff the bivalve Acesta excavata, sponges and clumps of S. variabilis occur. In an area of boulders with bamboo corals, the black coral Leiopathes sp. along with very large specimens of sponges are present. There is a wide diversity of species here including ophiuroids, hormathiid anemones, the soft coral Anthomastus sp., hydroids, Pycnogonids, Galatheidae sp. and echinoids, including Cidaris cidaris. These boulder areas alternate with areas of soft sediment to the top of the canyon, the latter containing xenophyophores and sponges.

START VIDEO A [00:00:00]/03:59 [1]: The dive starts in a soft bottom coral garden of cup corals on rippled sand. Acanella arbuscula and xenophyophores are also present. Rare boulders and cobbles present with mixed corals and encrusting fauna. [00:49:00] [2]: A steep slope and stack-like bedrock outcropping feature host a predominantly dead Solenosmilia variabilis reef framework with mixed corals and sponges, and living discrete S. variabilis on rock. [01:36:00] [3]: low-lying bedrock hosts mixed corals, mosaicked with a larger area of mixed mud/pebbles dominated by xenophyophores. [01:38:00] [4]: continues to mud where xenophyophores continue, along with A. arbuscula, mixed sea pens, and cup corals. Occasional rocks. [01:42:00] [5]: low-lying bedrock hosts mixed corals and erect sponges and is dominated by a lamellate sponge (OTU606) and serpulids among other fauna. [01:48:00] [6]: more mud with occasional boulders, again soft substrate corals especially A. arbuscula and cup corals, while boulders continue the lamellate sponge and mixed corals assemblage. [01:58:00] [7]: dense cobbles and pebbles, with some boulders/protruding bedrock, the same hard bottom assemblage continues. END VIDEO A 05:58.

START VIDEO B [01:59:00]/05:59 [8]: back to boulders and protruding bedrock with (mature) mixed corals and erect sponges interspersed with erect corals on soft sediment. [02:12:00] [9]: a steeper slope displays mixed dead S. variabilis framework and bedrock protrusions with mixed corals and sponges (especially Aphrocallistes sp) continuing around a large bedrock protrusion. [02:20:00] [10]: traverse along some cliffs, serpulids again dominating, but continued mixed corals/sponges. [02:32:00] [11]: Continuing over the top of the cliffs, soft sediment slope hosts A. arbuscula and xenophyophores while occasional boulders/protruding bedrock hosting mature mixed corals and sponges. [02:45:00] [12]: xenophyophores are now dominant, occasional hard substrate as before. [02:49:00] [13]: a Psolus squamatus dominated sparse encrusting assemblage occupies a slope of cobbles/boulders/pebbles. [02:51:00] [14]: bedrock cliffs, again dominated by serpulids and mixed mature corals and sponges. The top of the cliffs transitions into a similar assemblage on cobbles/boulders with greater dominance of P. squamatus, but the mixed corals and sponges continue. [03:30:00] [15]: patchy hard substrate continues with smaller corals and sponges, while sparse A. arbuscula dominates intermediate areas of mud. [03:46:00] [16]: an extended area of xenophyophores on mud. [03:48:30] [17]: bedrock protrusions continuing into a cobble/boulder field host again mature mixed corals and sponges, especially lamellate sponges. END VIDEO B 07:59.

START VIDEO C [03:59:00]/08:00. [17 ctd]. [04:01:00] [18]: another extended area of xenophyophores and soft sediment with sparse rock substrate. [04:05:00] [19]: dense cobbles boulders, then cobbles/boulders on flat mud, again host mixed corals and sponges and encrusting community with A. arbuscula sparsely interspersed . [04:27:00] [20]: rippled sand begins as the slope inclines, occasional urchins and fish species dominate. [04:30:25] [21]: dense cobbles/boulders on sand slope/carbonate crust slope/ mixed/coarse sediment plateau continue the mixed coral and sponge assemblage. END VIDEO C [04:48:00]/08:48.

Progression Start Duration Code Name
1[00:00:00]00:49:12M.AtLB.Mu.SolSclSolitary scleractinian field on Atlantic lower bathyal mud
17[00:00:00]02:00:33M.AtLB.Ro.MixCorMixed cold water coral community on Atlantic lower bathyal coarse sediment
8[00:00:00]00:13:49M.AtLB.Ro.MixCorMixed cold water coral community on Atlantic lower bathyal coarse sediment
18[00:02:02]00:04:17M.AtLB.Mu.XenCom.SyrFraSyringammina fragilissima field on Atlantic lower bathyal mud
19[00:06:20]00:22:17M.AtLB.Ro.MixCorMixed cold water coral community on Atlantic lower bathyal coarse sediment
9[00:13:50]00:07:48M.AtLB.Bi.CorRee.SolFraMixed coral assemblage on Atlantic lower bathyal Solenosmilia reef framework (biogenic structure)
10[00:21:39]00:12:17M.AtLB.Ro.MixCorMixed cold water coral community on Atlantic lower bathyal coarse sediment
20[00:28:38]00:02:08M.AtLB.Sa.UrcComUrchin dominated community on Atlantic lower bathyal sand
21[00:30:47]00:17:52M.AtLB.Ro.MixCorMixed cold water coral community on Atlantic lower bathyal coarse sediment
21[00:32:31]00:02:32M.AtLB.Ro.MixCorMixed cold water coral community on Atlantic lower bathyal coarse sediment
11[00:33:57]00:12:21M.AtLB.Mu.EreCor.AcaArbAcanella arbuscula assemblage on Atlantic lower bathyal mud
12[00:46:19]00:03:46M.AtLB.Mu.XenCom.SyrFraSyringammina fragilissima field on Atlantic lower bathyal mud
2[00:49:13]00:47:16M.AtLB.Bi.CorRee.SolFraMixed coral assemblage on Atlantic lower bathyal Solenosmilia reef framework (biogenic structure)
13[00:50:06]00:02:45M.AtMB.Ro.SpaEnc.PsoAnoPsolus squamatus, Anomiidae, serpulid polychaetes and Munida on Atlantic mid bathyal rock and other hard substrata
14[00:52:52]00:38:34M.AtLB.Ro.MixCorMixed cold water coral community on Atlantic lower bathyal coarse sediment
15[01:31:27]00:16:19M.AtLB.Mu.EreCor.AcaArbAcanella arbuscula assemblage on Atlantic lower bathyal mud
3[01:36:30]00:01:39M.AtLB.Mx.XenCom.SyrFraSyringammina fragilissima field on Atlantic lower bathyal mixed sediment
4[01:38:10]00:04:20M.AtLB.Mu.EreCorErect coral field on Atlantic lower bathyal mud
5[01:42:31]00:05:40M.AtLB.Ro.MixCorMixed cold water coral community on Atlantic lower bathyal coarse sediment
16[01:47:47]00:01:36M.AtLB.Mu.XenCom.SyrFraSyringammina fragilissima field on Atlantic lower bathyal mud
6[01:48:12]00:09:52M.AtLB.Mu.EreCor.AcaArbAcanella arbuscula assemblage on Atlantic lower bathyal mud
7[01:58:05]00:01:05M.AtLB.Ro.MixCorMixed cold water coral community on Atlantic lower bathyal coarse sediment

Unknown Annelida or Foraminifera : 1073 : O
Foraminifera
Syringammina fragilissima : 261 : C
Porifera
Hyalonema sp. 1 : 917 : O
cf. Pheronema sp. (Rock possibly Aphorme horrida) : 1084 : O
Asconema sp. : 1038 : O
Aphrocallistes beatrix : 264 : F
cf. Phakellia ventilabrum : 202 : O
Mycale lingua : 171 : O
Porifera branching glassy : 1091 : O
Porifera cup 2 : 535 : O
Porifera encrusting (blue) : 532 : O
Porifera encrusting (orange) : 9 : R
Porifera encrusting sp. 10 (yellow) : 30 : R
Porifera lamellate sp. 10 : 1010 : F
Porifera lamellate sp. 10 (Yellow Solenosmilia assoc.) : 623 : F
Porifera lamellate sp. 13 : 1053 : F
Porifera lamellate sp. 9 : 606 : F
Porifera massive globose sp. 15 (Solenosmilia rubble) : 1051 : R
Porifera massive globose sp. 6 : 137 : R
Porifera massive globose sp. 9 : 380 : F
Blue Porifera encrusting : 800 : R
Cnidaria
Cerianthidae sp. 1 : 2 : R
Actiniaria sp. 1 : 4 : R
Actiniaria sp. 18 : 582 : O
Actiniaria sp. 20 : 605 : R
Actinernus michaelsarsi : 554 : O
Bolocera tuediae : 12 : O
Actinoscyphiidae sp. 1 (pink) : 1047 : O
Actinostolidae sp. 1 : 132 : O
Adamsia sp. : 1066 : R
Phelliactis sp. 1 : 255 : O
Liponema sp. : 1055 : R
Antipatharia sp. 4 cf. Stauropathes : 592 : O
Stichopathes sp. : 560 : O
Phanopathes sp. 2 : 1081 : O
Chrysopathes sp. Trissopathes sp. : 540 : R
Leiopathes sp. : 305 : O
Dendrobathypathes ( prev. Stauropathes sp. 1) : 1015 : O
Caryophyllidae sp. (tentative) : 1057 : O
Caryophyllidae/Fabellidae (indet.) : 1058 : O
Caryophyllidae/Fabellidae (indet.) : 1058 : O
Caryophyllia sp. 5 (bullseye) : 584 : O
Desmophyllum cf. dianthus : 335 : R
Solenosmilia variabilis : 700 : F
Enallopsammia sp. (?) : 1093 : R
Flabellum sp. : 1056 : R

Zoanthidae sp. 2 : 586 : O
Acanthogorgia sp. : 331 : O
Anthomastus grandiflorus : 278 : O
Pseudoanthomastus sp. : 1080 : O
Anthothela grandiflora : 311 : R
Chrysogorgidae sp. 1 : 1008 : F
Acanella arbuscula : 585 : F
Eknomisis sp. : 649 : O
Isididae sp. (fine branching) : 1064 : O
Paragorgia (twiggy) (poss. Swiftia) : 1065 : O
Paramuricea sp. : 1050 : F
Callogorgia verticillata : 280 : R
cf. Thouarella sp. : 1086 : O
Gorgonacea sp. 7 (pink) cf. Isidella : 307 : O
cf. Halipteris sp. : 1060 : F
Pennatula aculeata : 1046 : O
Umbellula sp. : 581 : R
Branchiocerianthus norvegicus : 1069 : R
Stylaster sp. 1 : 361 : F
Rhodaliidae sp. 2 : 1079 : R
Annelida
Bonellia viridis : 267 : R
Aphroditidae sp. 1 : 146 : R
Serpulidae sp. 1 : 106 : F
Arthropoda
Chirostylidae sp. 2 (indet.) : 1054 : R
Majidae sp. 1 : 11 : R
Munida tenuimana : 339 : O
Paguridae sp. : 205 : R
Caridea (indet.) : 1077 : R
Mysida (indet) : 1026 : R
Colossendeis sp. 1 : 1059 : O
Cirripedia sp. 1 : 82 : O
Mollusca
Acesta excavata : 1062 : O
Colus sp. : 113 : R
Opisthoteuthis extensa : 918 : R
Sepiolidae sp. : 1095 : R
Margarites sp. 1 : 277 : R
Brachiopoda
Brachiopoda sp. 1 : 34 : R
Echinodermata
Bathycrinidae sp. 1 : 1041 : R
Pentametrocrinus atlanticus : 436 : O
Crinoidea sp. : 1072 : R
Crinoidea sp. 1 : 131 : F
Crinoidea sp. 1 : 131 : R
Asteronyx loveni : 471 : R
Gorgonocephalus sp. 1 : 214 : O

Ophiuroidea (indet.) : 1076 : R
Ophiuroidea sp. 11 (red disc) : 1036 : R
Ophiuroidea sp. 7 - yellow : 340 : R
Novodinia sp. : 1087 : O
Brisingidae sp. : 274 : O
Stichastrella rosea : 198 : R
Zoroaster fulgens : 988 : O
Pseudarchaster sp. 1 : 433 : R
Henricia sanguinolenta : 208 : R
Ceramaster/Peltaster/Plinthaster sp. 1 : 234 : R
Lophaster furcifer : 1089 : R
Velatida sp. 1 : 199 : R
Echinus sp. : 445 : O
Cidaris cidaris : 211 : O
cf. Histocidaris purpurata (deep) : 1092 : R
Phormosoma placenta : 555 : R
Araeosoma fenestratum : 188 : O
Echinothuroidea sp. : 1094 : O
Psolus squamatus : 252 : F
cf. Amperima sp. : 628 : R
Chordata
Ascidiacea sp. 2 : 20 : O
Galeus melastomus : 1005 : O
Apristurus profundorum : 1082 : R
Rajiformes sp. 1 (Neoraja caerulea?) : 652 : O
Centrophorus squamosus : 1048 : R
Squaliformes sp. : 569 : O
Hydrolagus cf. mirabilis : 1024 : R
Chimaera opalescens : 653 : R
Synaphobranchus kaupii : 440 : F
Ipnopidae sp. : 1078 : R
Hoplostethus atlantica : 651 : R
Brosme brosme : 258 : O
Molva molva : 654 : O
Coryphaenoides guentheri : 577 : F
Coryphaenoides rupestris : 566 : O
Lepidion eques : 249 : F
Mora moro : 349 : R
Phycis blennoides : 1020 : O
Polyacanthonotus rissoanus : 552 : R
Notacanthidae sp. 1 : 1009 : O
Aphanopus carbo : 1097 : O
Zoarcidae sp. 2 : 291 : O
Cottunculus microps : 128 : R
Neocyttus helgae : 563 : O
Actinopterygii sp. 3 : 930 : R
Actinopterygii sp. 4 : 1006 : R

Number of species = 136

© Marine Institute, MERC Consultants, Bernard Picton 2022