Marine Institute
SeaRover Dive Video

D462 Transect 15 Sparse sea pens on rippled sediment, then mixed corals on cobbles/boulders, Acanella upper slope. Features of Interest: canyon, escarpments Water Depth: 1800-1427 m

Highlights: Sea urchin Sea pen field Brisingids & vase-shaped sponge Hexactinellid sponges on carbonate mound

The substrate at the bottom of this canyon is that of sand, this is occasionally rippled with coarser sediment in these ripples. Conspicuous fauna is sparse and includes cerianthids, sea pens, echinoids and holothurians. The occasional rock is colonised by brisingids, bamboo coral and encrusting and glass sponges. Moving up slope sea pens become more frequent in species and number. Continuing further up slope the ground becomes steeper and coarser; the sea pens are less frequent. Hard ground in the form of small rocks and stones is more apparent and is colonised by brisingids, bamboo corals, crinoids and a variety of sponges.

Carbonate substrate which on occasion is steep and forms cliffs is colonised by a wide variety of sponges and corals including Parantipathes sp., Leiopathes sp., Bathypathes sp., Lepidisis sp., as well as Stichastrella sp., stalked crinoids and brisingids. Towards the top of the feature the layer of fine sediment appears thicker; the fauna consists of a variety of sea pens, some echinoid species and a few xenophyophores.

START VIDEO [00:00:00]/11:33 [1] The dive starts alongside a small carbonate protusion, possibly at a habitat transition, the carbonate hosts several massive sponge species, but the habitat is of insufficient size to count as a separate biotope. The majority of this area is soft/mixed sediment of rippled mud with gravel in the furrows with mixed sparse sea pens (Anthoptilum sp . and Halipteris cf. finmarchia). Rare boulders are also encountered. [00:01:00] ROV laterals right, [00:02:00] moves forward. [00:06:00] there is increasing shell hash and pebbles, reducing again at [00:09:00]. 12-[00:20:00] stop for two pushcores. [00:40:00] [2] Boulders and cobbles on mud, chrysogrogiids dominate. Brisingids are also abundant. Sea pens continue in the intermediate soft sediment. [00:58:00]-[01:00:00] stop for imagery. [01:06:00] [3] denser cobbles and boulders with pebbles and mud, mixed corals are the sole biotope, with abundant chrysogorgiids, Lepidisis sp. , and yellow zoanthids colonising dead coral skeletons. The landscape transitions to cobbles and boulders of varying density on sloping carbonate. The mud veneer is thin and the corals and sponges continue to dominate. [01:19:00]-[01:20:00] stop for imagery. [01:23:00] [4] the mud veneer deepens and boulders become sparse with Acanella dominating the soft muddy substrate and mixed corals continuing on the boulders. END VIDEO [01:29:00]/13:03.

Progression Start Duration Code Name
1[00:00:00]00:21:21M.AtMB.Mu.SpnMegSea pens and burrowing megafauna on Atlantic mid bathyal mud
1[00:21:22]00:28:08M.AtMB.Mu.SpnMegSea pens and burrowing megafauna on Atlantic mid bathyal mud
2[00:49:31]00:16:34M.AtLB.Ro.MixCorMixed cold water coral community on Atlantic lower bathyal coarse sediment
3[01:06:06]00:17:42M.AtLB.Ro.MixCorMixed cold water coral community on Atlantic lower bathyal coarse sediment
4[01:23:49]00:05:57M.AtLB.Mu.EreCor.AcaArbAcanella arbuscula assemblage on Atlantic lower bathyal mud

Foraminifera
Syringammina fragilissima : 261 : R
Porifera
cf. Farreidae : 1142 : R
cf. Polymastia boletiformis : 1030 : R
Geodia cf. atlantica (Porifera massive lobose sp. 6) : 83 : O
cf. Geodia baretti (Porifera massive globose sp. 11) : 601 : O
Porifera cup 2 : 535 : O
Porifera encrusting sp. 1 (white) : 1 : R
Porifera encrusting sp. 10 (yellow) : 30 : R
Porifera lamellate sp. 9 : 606 : O
Porifera massive globose sp. 9 : 380 : R
Porifera massive lobose sp. 18 (cf. Farrea sp. ) : 576 : R
Porifera massive lobose sp. 21 (Hertwigia sp. ?) : 611 : R
Blue Porifera encrusting : 800 : R
Cnidaria
Actiniaria sp. (large red) : 1120 : R
Actiniaria sp. 20 : 605 : R
Actinernus michaelsarsi : 554 : R
Actinostolidae sp. 1 : 132 : R
Chrysopathes sp. Trissopathes sp. : 540 : O
Bathypathes sp. (brown) : 284 : O

Parantipathes sp. : 1042 : R
Stauropathes arctica : 547 : O
Caryophyllia sp. 2 : 6 : R
Flabellum sp. : 1056 : R
Zoanthidea sp. : 1149 : O
Anthomastus grandiflorus : 278 : R
Chrysogorgidae sp. 1 : 1008 : C
Acanella arbuscula : 585 : F
Keratoisis sp. 2 : 578 : R
Lepidisis sp. : 557 : F
Anthoptilum grandiflorum : 594 : C
Halipteris cf. finmarchica : 622 : F
Pennatula cf. inflata : 1083 : R
Echinodermata
Anachalypsicrinus nefertiti : 1031 : O
Ophiomusa lymani : 551 : R
Ophiuroidea (indet.) : 1076 : R
Brisingidae sp. : 274 : F
Pseudarchaster sp. 1 : 433 : O
Porania sp. : 263 : O
Solaster endeca : 573 : O
cf. Hymenaster (yellow) : 1174 : R

Echinidae sp. (pink) : 194 : R
Echinidae sp. (white) : 559 : R
Hygrosoma sp. : 1125 : O
Echinoidea sp. 5 : 572 : O
cf. Amperima sp. : 628 : R
Benthogone sp. : 432 : F
Chordata
Leucoraja sp. : 1067 : R
Synaphobranchus kaupii : 440 : F
Coryphaenoides guentheri : 577 : O
Coryphaenoides rupestris : 566 : R
Halosauridae sp. : 1113 : R
Polyacanthonotus rissoanus : 552 : R
Zoarcidae sp. 2 : 291 : R
Actinopterygii sp. 3 : 930 : R
Myxine glutinosa : 383 : R

Number of species = 55

© Marine Institute, MERC Consultants, Bernard Picton 2022