Marine Institute
SeaRover Dive Video

D541 Transect RB20 Solenosmilia reefs on boulders/bedrock. Abundant juvenile sponges of Aphrocallistes sp. on boulders. Elasmobranch egg cases encountered. Non Priority. Features: Escarpment. Water depth: -1240 m. TL: 1 km SOL: 15° 17.765' W 55° 34.256' N

Highlights: Antipatharian coral Solenosmilia, sea fans & antipatharian corals Orange roughy Hexactinellid sponge - Aphrocallistes Solenosmilia, sea fans & antipatharian corals Hexactinellid sponge - Aphrocallistes

Mainly biogenic sediment. Sponges are frequent at this site including glass sponges, mainly Aphrocallistes and Pheronema. Moving up slope Leiopathes, Paragorgia and Eknomisis are evident as are orange roughy. Pebble and soft sediment substrate at the top of slope with more glass sponges, stylasterids and orange roughy.

START VIDEO [00:00:00]/23:23 The video starts on barnacle gravel substrate. [00:16:00] ROV samples 2 pushcores. [00:16:00] ROV leaves the bottom, only blue water for 1 minute. [00:17:00] [1] Continues on barnacle gravel sediment moderately flat/gentle up slope dwelled by several species of sponges. [00:19:00] Shark egg cases (no ID), possibly of Galeus melastomus OTU1005 (encountered by the end of the transect (1 juvenile)) or Rajiformes sp.1 OTU652. [00:28:00] [2] Here no more barnacle gravel. Now boulders/cobbles/mud/sparse coral gravel take place on steep up slope with many associated epifauna, including Leiopathes sp. and glass sponges. Large boulders host isolated Solenosmilia variabilis aggregations. [00:33:00] ROV stops for imagery of pink octocorallia (possibly Paragorgia sp). [00:38:00] the ROV moves slowly on the right and then forward. [00:43:00] [3] Mosaic of coral framework (mostly dead) and boulders with abundant Aphrocallistes sp. OTU264, Porifera lamellate sp.7 and Porifera encrusting sp.2 . [00:45:00] ROV climbs a steep bedrock with overhanging Solenosmilia variabilis colonies (living/dead), encrusted sponges and soft corals. [00:48:00] [4] Now the ROV reaches the summit. The site is dominated by Asconema sp. OTU1038 and Aphrocallistes sp. on coral gravel/rubble/sparse large cobbles flat/gentle up slope. Abundant Caryophyllia sp. OTU6 on gravel. [00:50:00] ROV stops for imagery of Aphrocallistes sp. (for less than a minute). [01:00:00] Now the substrate changes into large boulders/bedrock covered in coral gravel. Same epifauna as in the last biotope type. Here Orange Roughy are frequently encountered. [01:06:00] [5] Here gravel and sand/mud sediment on a gentle down slope with sparse boulders where encrusted sponges co-dominate with Aphrocallistes sp. and Porifera lamellate sp.7. [01:11:00] [6] now coral rubble and coral gravel intersperse with boulders/bedrock. Same dominant epifauna. A few Syringammina fragilissima observed sparsely on gravel/sand/mud sediment. [01:16:00] [7] Now boulders/bedrock is the primary substrate hosting abundant sponge aggregations and hydrozoa species. [01:20:00] [8] Again substrate changes into mud/gravel/sparse boulders on gentle down slope with sparse sponge aggregations. [01:35:50]-[01:41:00] ROV stops for imagery and sampling 1 pushcore. [01:41:00] [9] Now gently upslope on mud/gravel sediment with sparse cobbles/boulders hosting sponges. [01:41:00] ROV stops for imagery of Aphrocallistes sp. and encrusted sponges on boulders until END VIDEO [01:46:00].

N. B. This site is of particular interest for the abundance of small sponges, mainly Aphrocallistes sp. and (possibly) Porifera lamellate sp.9 (foliate). Moreover, throughout the transect, 26 individuals of Hoplostethus atlanticus (Orange Roughy) which is assigned to the IUCN Vulnerable species- are encountered. Additionally, Primnoa resedaeformis OTU54 is rarely encountered in the North East Atlantic. There are records from Canada and Norway but rarely from the NE Atlantic at -1100 m depth (however species is recorded in Davies et al 2017).

Progression Start Duration Code Name
1[00:00:00]00:29:31M.AtMB.CoAtlantic mid bathyal coarse sediment
2[00:29:32]00:01:27M.AtLB.Ro.MixCorMixed cold water coral community on Atlantic lower bathyal coarse sediment
3[00:31:00]00:14:18M.AtLB.Bi.CorReeAtlantic lower bathyal cold water coral reef (biogenic structure)
4[00:45:19]01:01:04M.AtUB.Ro.DeeSpoDeep sponge aggregation on Atlantic upper bathyal rock and other hard substrata

Foraminifera
Syringammina fragilissima : 261 : R
Porifera
Pheronema carpenteri : 347 : O
cf. Pheronema sp. (Rock possibly Aphorme horrida) : 1084 : R
cf. Pheronema sp. (Rock possibly Aphorme horrida) : 1084 : R
Asconema sp. : 1038 : R
Aphrocallistes beatrix : 264 : F
cf. Polymastia penicillus : 1137 : R
Porifera cup sp. 3 : 124 : R
Porifera encrusting sp. 15 (yellow) : 58 : O
Porifera encrusting sp. 2 : 7 : R
Porifera lamellate sp. 10 : 1010 : R
Porifera lamellate sp. 7 : 422 : F
Porifera lamellate sp. 9 : 606 : O
Porifera massive globose sp. 6 : 137 : R
Porifera massive lobose sp. 18 (cf. Farrea sp. ) : 576 : R
Porifera massive lobose sp. 22 (yellow cf. Hertwigia sp. ) : 616 : R
Porifera massive lobose sp. 32 : 1090 : R
Blue Porifera encrusting : 800 : R
Porifera vase (cf. Aphrocallistes) : 1162 : R
Cnidaria
Cerianthidae sp. 1 : 2 : O
Actiniaria sp. 20 : 605 : R
Leiopathes sp. : 305 : R
Stauropathes arctica : 547 : R

Caryophyllia sp. 2 : 6 : R
Caryophyllia sp. 5 (bullseye) : 584 : R
Solenosmilia variabilis : 700 : O
Zoanthidea sp. : 1149 : R
Acanthogorgia sp. : 331 : R
Anthomastus grandiflorus : 278 : R
Eknomisis sp. : 649 : R
Keratoisis sp. 2 : 578 : R
Lepidisis sp. : 557 : R
Paramuricea sp. : 1050 : R
Hydrozoa (bushy) : 50 : R
Hydrozoa (flat branched) : 56 : R
Pliobothrus sp. : 207 : R
Stylaster sp. 1 : 361 : R
Arthropoda
Chirostylidae sp. 1 (indet.) : 285 : R
Munida tenuimana : 339 : R
Caridea (indet.) : 1077 : R
Colossendeis sp. 1 : 1059 : R
Cirripedia sp. 1 : 82 : R
Mollusca
Muusoctopus johnsonianus : 1194 : R
Graneledone verrucosa : 973 : R
Echinodermata
Pentametrocrinus atlanticus : 436 : R
Crinoidea sp. : 1072 : R

cf. Henricia sp. (deep) : 1154 : R
Ceramaster/Peltaster/Plinthaster sp. 2 : 388 : R
Porania sp. : 263 : R
Solasteridae sp. (white) : 9977 : R
Echinidae sp. (pink) : 194 : R
Cidaris cidaris : 211 : R
Benthogone sp. : 432 : R
Chordata
Ascidiacea sp. 2 : 20 : R
Galeus melastomus : 1005 : R
Rajiformes sp. 1 (Neoraja caerulea?) : 652 : R
Synaphobranchus kaupii : 440 : R
Ipnopidae sp. : 1078 : R
Hoplostethus atlantica : 651 : R
Molva molva : 654 : R
Nezumia aequalis : 1003 : R
Trachyrincus sp. : 446 : R
Lepidion cf. guentheri : 1160 : R
Lepidion eques : 249 : R
Polyacanthonotus rissoanus : 552 : R
Neocyttus helgae : 563 : R
Actinopterygii sp. 3 : 930 : R

Number of species = 67

© Marine Institute, MERC Consultants, Bernard Picton 2022