D468 Transect 38 Sparse epifauna on mud, juvenile holothurian aggregations, small carbonate/cobble patches with corals. Features of Interest: canyon, escarpments Water Depth: 2307-1989 m
Highlights: Plastic litter Burrow complex
The substrate in this canyon is sandy sediment with some evidence of bioturbation. Ophuiroids and holothurians are ubiquitous with sea pens occurring infrequently as are small echinoids (cf. Echinus), occasionally in dense patches. The warty variety of hormathiid anemone is also present here.
Soft grey sediment is the predominant substrate on the canyon slope; fauna is not conspicuous here. At 2230 m to 2210 m small elpidiid holothurians are observed. Above 2160 m a number of different species of sea pen are evident. Large numbers of fine stalked crinoids occur from 2140 m.
Gorgonian corals and the black coral Stichopathes sp. are present at the top of the canyon. Burrow complexes were a notable feature at this site.
START VIDEO [00:00:00]/10:38 Muddy substrate dominated the dive, here colonised by white echinoids (OTU559) and mosaicked with areas of exposed horizontal carbonate colonised by Anthomastus grandiflorus. [00:05:00] [2] now exclusively muddy substrate, epifauna are sparse but dominated by sea pens (cf Anthoptilum sp.) with rare Radicipes cf. gracilis. [00:24:00] moving slowly (pull from the ship) and start heading diagonally right. [00:27:00] [3] although hard to make out due to their small size, periodic close up views reveal an aggregation of juvenile holothurians, likely from the family Elpidiidae. [00:41:00] [4] return to sparse seapens as the dominant epifauna and start moving upslope. [00:48:00]-[00:56:00] stop to take two pushcores. [01:03:00] [5] Stalked crinoids (Democrinus sp.) start to become abundant and dominate the landscape. [01:06:00] [6] continued Democrinus sp . on mud, but an area of scattered pebbles and cobbles host c hrysogorgiid sp. corals. [01:07:00] [7] back to mud, with occasional holes (possibly in the underlying carbonate rather than burrows) with Democrinus sp. END VIDEO [01:40:00]/12:18.
Progression | Start | Duration | Code | Name |
---|---|---|---|---|
1 | [00:00:00] | 00:05:58 | M.AtUA.Mu.UrcCom | Urchin dominated community on Atlantic upper abyssal mud |
2 | [00:05:59] | 00:21:56 | M.AtMB.Mu.SpnMeg | Sea pens and burrowing megafauna on Atlantic mid bathyal mud |
3 | [00:27:56] | 00:13:05 | M.AtUA.Mu.HolCom | Holothurian dominated community on Atlantic upper abyssal mud |
4 | [00:41:02] | 00:22:39 | M.AtMB.Mu.SpnMeg | Sea pens and burrowing megafauna on Atlantic mid bathyal mud |
5 | [01:03:42] | 00:02:46 | M.AtMB.Mu.CriCom | Crinoid dominated community on Atlantic mid bathyal mud |
6 | [01:06:29] | 00:01:14 | M.AtMB.Mu.CriCom | Crinoid dominated community on Atlantic mid bathyal mud |
7 | [01:07:44] | 00:32:49 | M.AtMB.Mu.CriCom | Crinoid dominated community on Atlantic mid bathyal mud |
Porifera
Porifera lamellate lobose (fleshy) : 1132 : R
Cnidaria
Cerianthidae sp. 1 : 2 : R
Actiniaria sp. 20 : 605 : R
cf. Halcampoididae sp. : 984 : R
Actinernus michaelsarsi : 554 : R
Adamsia sp. : 1066 : R
Phelliactis sp. 1 : 255 : O
Caryophyllidae/Fabellidae (indet.) : 1058 : R
Flabellum sp. : 1056 : R
Anthomastus grandiflorus : 278 : O
Radicipes cf. gracilis : 1044 : R
Chrysogorgidae sp. 1 : 1008 : F
Acanella arbuscula : 585 : F
Anthoptilum sp. : 1107 : F
Halipteris cf. finmarchica : 622 : R
Pennatula cf. inflata : 1083 : F
Branchiocerianthus norvegicus : 1069 : R
Scyphozoa (indet.) : 1134 : R
Arthropoda
Munnopsidae sp. : 1102 : R
Colossendeis sp. 1 : 1059 : O
Mollusca
Opisthoteuthis extensa : 918 : R
Echinodermata
Democrinus sp. : 1103 : O
Ophiomusa lymani : 551 : F
Brisingidae sp. : 274 : R
Pseudarchaster sp. 1 : 433 : R
Pterasteridae sp. : 1115 : O
Echinidae sp. (pink) : 194 : R
Echinidae sp. (white) : 559 : O
Phormosoma placenta : 555 : R
Elpidiidae sp. : 1116 : O
Peniagone sp. : 1167 : R
Chordata
Apristurus cf. microps : 568 : R
Rajiformes sp. 1 (Neoraja caerulea?) : 652 : R
Squaliformes sp. : 569 : R
Synaphobranchus kaupii : 440 : R
Bathysaurus ferox : 1112 : R
Coryphaenoides armatus : 1105 : O
Coryphaenoides guentheri : 577 : O
Lepidion cf. guentheri : 1160 : O
Polyacanthonotus rissoanus : 552 : O
Cataetyx laticeps : 1111 : R
cf. Rouleina attrita : 1074 : R
Zoarcidae sp. 2 : 291 : R
Actinopterygii sp. 3 : 930 : R
Number of species = 44
© Marine Institute, MERC Consultants, Bernard Picton 2022