D472 Transect 36 Xenophyophores common on soft/mixed (gravel) sediments, large healthy Solenosmilia variabilis reef. Features of Interest: canyon, escarpments Water Depth: 1644-1488 m
Highlights: Sea pen - Umbellula White demosponge Fish Fish Giant sea spider - Colossendeis sp. Chimaera - Hydrolagus cf. affinis Octopus Soft coral - Anthomastus Solenosmilia with sponges & sea fans Solenosmilia coral garden Solenosmilia & brisingids Solenosmilia with sponges & sea fans Sea fan & sponges Chimaera - Hydrolagus cf. affinis Chimaerid
The canyon contains a variety of substrates and a moraine feature; the fauna reflects this variability. A greater apparent biomass compared to neighbouring canyon systems (5 & 6) is evident. On the canyon floor the sediment is soft leading onto coarse sediment at the canyon base and on the incline. Patches of carbonate outcrops are evident on the slope and canyon crest. A series of sharp ridges interspersed with soft sediment describe the terrain.
In soft sediment holothurians and xenophyophores are the most conspicuous fauna, with cerianthids occurring occasionally. The starfish Zoroaster fulgens is present, as are hermit crabs carrying one or two anemones are very common. On stones, pebbles or small rocks barnacles prevailed, even on otherwise soft sediment. At 1600 m small clumps of Solenosmilia variabilis occur and grow in abundance towards the upper slope of the ridges eventually forming a distinct reef. Sponge fields consisting of a variety of sponges are evident as are black, gorgonian and bamboo corals, crinoids and brisingids. Specimens of the octocoral Paramuricea sp. with squat lobsters Chirostylus sp. are noted. Fish abundance is generally low here; grenadiers occur throughout the site, with oreos confined to areas of reef. Species of interest include a leafscale gulper shark, l orange roughy and a ray. There are also areas of large burrows which appear to be associated with galatheids.
START VIDEO A [00:00:00]/[10:58:00] [1] Soft sediment with holothurians (Amperima sp.). [00:03:00] [2] xenophyophores start to dominate along with holothurians. [00:06:00] [3] Again just holothurians on muddy substrate. [00:14:00] [4] Ophiomusa lymaniis now the most frequent fauna on the soft sediment, sparse pebbles and cobbles are dominated by barnacles. [00:14:00] [5] the soft sediment continues without the pebbles. [00:16:00] stop for pushcore sampling until [00:22:00] [6] continue until pebbles and cobbles become more dominant on the mud, with barnacles again being the most abundant organism along with O. lymani [00:24:00] [7] mud with xenophyophores and holothurians [00:26:00] [8] barnacles/sparse pebbles and cobbles return as a mosaic [00:29:00] [9] xenophyophores on mud continue for a while mosaicking again at [00:30:00] [10] with barnacles and pebbles/cobbles, back to [00:32:00] [11] xenophyophores on mud [00:36:00] [12] mosaic with barnacles and pebbles [00:45:00] [13] an area of denser pebbles allow the barnacles to dominate, but still xenophyophores occur here. [00:48:00]-[00:54:00] stop to test the sediment and sample. [00:54:00] mud and pebbles fluctuate in dominance but the assemblage continues. [00:57:00]-[00:58:00] stop to view pycnogonid. [01:06:00] [14] cobbles/boulders/pebbles barnacles still dominante, but some corals and sponges are present. [01:07:00] [15] dense pebbles with xenophyophores [01:07:00] [16] cobbles dominate densely with pebbles, xenophyophores are still present along with dominant barnacles, and some corals and sponges. The had substrate becomes less dense until [01:08:58] [17] mud with sparse pebbles hosting cup corals and barnacles, occasional carbonate patches and boulders. [01:10:00] [18] O. lymani on the dominant mud/sand while carbonate/boulders host mixed corals [01:11:00] [19] back to the mud/xenophyophores with pebbles/barnacles [01:12:00] [20] mud/ O. lymani and pebbles/barnacles with some corals and sponges also present 01:014-[01:14:00] stop for imagery. Continue and pebbles become dense. [01:23:00] [21] reached the base of an exposed carbonate crust slope with mud veneer and pebbles/cobbles/boulders of varying density. Stichopathes sp. (OTU560) dominates the carbonate, while barnacles adhere to loose hard substrate. 01:032-01:033 stop to view octopus and corals. Mud veneer grows thicker. [01:41:00] [22] Reach the edge of the first patch of healthy-looking Solenosmilia variabilis reef . [01:47:00] [23] short patch of mud/pebbles with barnacles and sparse xenophyophores. [01:48:00] [24] large S. variabilis reef patch, several stops for imagery. [01:58:00] [25] mud/sand with xenophyophores and sparse gravel changing into S. variabilis coral rubble until END VIDEO A [02:01:00]/[12:59:00].
START VIDEO B [00:00:00]/13:00pm. Continue until [02:02:00] [26] S. variabilis reef on an upslope reaching the crest of a hill at [00:03:00]. [00:04:00]-[00:17:00] stopped for imagery and sampling. [02:18:00] [27] mud/sand xenophyophores, downslope visible off to left. [00:20:00] [28] sparse pebbles/cobbles/boulders on mud/sand with xenophyophores in varying densities and barnacles on the hard substrate. [02:32:00] [29] S. variabilis reef, great footage. [00:33:00] reach sharp downslope/escarpment, bottom not visible as ROV proceeds over edge. [00:35:00] run to face edge with reef at top and near vertical mud veneered carbonate (?) dropoff. Stope for imagery. [00:38:00] turn back t to descend escarpment, glimpses of very steep mud slope and patches of coral rubble. [00:39:00] reach better angled downslope where bottom now visible again as ROV laterals downslope over S. variabilis reef. [00:42:00] slope flattens out, coral reef continues. [00:43:00] ROV starts moving forwards along and gently upslope over continued coral reef. [00:56:00] [30] end of reef to reach again mud/sand with sparse pebbles and xenophyophores/barnacles. [01:02:00] [31] O. lymani and barnacles on mud/pebbles/cobbles some mixed corals and sponges also present but not dominant. [01:03:00] return to xenophyophores/mud barnacles/pebbles until END VIDEO B [01:18:00]/14:19.
Progression | Start | Duration | Code | Name |
---|---|---|---|---|
1 | [00:00:00] | 00:03:43 | M.AtUA.Mu.HolCom | Holothurian dominated community on Atlantic upper abyssal mud |
25 | [00:00:00] | 02:01:01 | M.AtLB.Mu.XenCom.SyrFra | Syringammina fragilissima field on Atlantic lower bathyal mud |
26 | [00:01:42] | 00:15:58 | M.AtLB.Bi.CorRee.SolVar | Atlantic lower bathyal live Solenosmilia variabilis reef (biogenic structure) |
2 | [00:03:44] | 00:03:05 | M.AtLB.Mu.XenCom.SyrFra | Syringammina fragilissima field on Atlantic lower bathyal mud |
3 | [00:06:50] | 00:07:23 | M.AtUA.Mu.HolCom | Holothurian dominated community on Atlantic upper abyssal mud |
4 | [00:14:15] | 00:00:32 | M.AtLB.Mx.SurOph.OphCer | Ophiomusa lymani and cerianthid anemone assemblage on Atlantic lower bathyal mixed sediment |
5 | [00:14:48] | 00:07:46 | M.AtLB.Mx.SurOph.OphCer | Ophiomusa lymani and cerianthid anemone assemblage on Atlantic lower bathyal mixed sediment |
27 | [00:17:41] | 00:02:30 | M.AtLB.Mu.XenCom.SyrFra | Syringammina fragilissima field on Atlantic lower bathyal mud |
28 | [00:20:12] | 00:10:58 | M.AtLB.Mu.XenCom.SyrFra | Syringammina fragilissima field on Atlantic lower bathyal mud |
6 | [00:22:35] | 00:01:33 | M.AtLB.Mx.SurOph.OphCer | Ophiomusa lymani and cerianthid anemone assemblage on Atlantic lower bathyal mixed sediment |
7 | [00:24:09] | 00:02:46 | M.AtLB.Mu.XenCom.SyrFra | Syringammina fragilissima field on Atlantic lower bathyal mud |
8 | [00:26:57] | 00:02:43 | M.AtLB.Mu.XenCom.SyrFra | Syringammina fragilissima field on Atlantic lower bathyal mud |
9 | [00:29:41] | 00:00:52 | M.AtLB.Mu.XenCom.SyrFra | Syringammina fragilissima field on Atlantic lower bathyal mud |
10 | [00:30:34] | 00:01:46 | M.AtLB.Mu.XenCom.SyrFra | Syringammina fragilissima field on Atlantic lower bathyal mud |
29 | [00:31:11] | 00:25:31 | M.AtLB.Bi.CorRee.SolVar | Atlantic lower bathyal live Solenosmilia variabilis reef (biogenic structure) |
11 | [00:32:21] | 00:04:11 | M.AtLB.Mu.XenCom.SyrFra | Syringammina fragilissima field on Atlantic lower bathyal mud |
12 | [00:36:33] | 00:08:57 | M.AtLB.Mu.XenCom.SyrFra | Syringammina fragilissima field on Atlantic lower bathyal mud |
13 | [00:45:32] | 00:20:30 | M.AtMB.Ro.BarCom | Barnacle dominated community on Atlantic mid bathyal rock and other hard substrata |
30 | [00:56:43] | 00:05:43 | M.AtLB.Mu.XenCom.SyrFra | Syringammina fragilissima field on Atlantic lower bathyal mud |
31 | [01:02:27] | 00:00:28 | M.AtLB.Mx.SurOph.OphCer | Ophiomusa lymani and cerianthid anemone assemblage on Atlantic lower bathyal mixed sediment |
32 | [01:02:56] | 00:15:12 | M.AtLB.Mu.XenCom.SyrFra | Syringammina fragilissima field on Atlantic lower bathyal mud |
14 | [01:06:03] | 00:00:57 | M.AtMB.Ro.BarCom | Barnacle dominated community on Atlantic mid bathyal rock and other hard substrata |
15 | [01:07:01] | 00:00:47 | M.AtLB.Mu.XenCom.SyrFra | Syringammina fragilissima field on Atlantic lower bathyal mud |
16 | [01:07:49] | 00:01:09 | M.AtMB.Ro.BarCom | Barnacle dominated community on Atlantic mid bathyal rock and other hard substrata |
17 | [01:08:59] | 00:01:23 | M.AtLB.Sa.SolScl | Solitary scleractinian field on Atlantic lower bathyal sand |
18 | [01:10:23] | 00:00:45 | M.AtLB.Mx.SurOph.OphCer | Ophiomusa lymani and cerianthid anemone assemblage on Atlantic lower bathyal mixed sediment |
19 | [01:11:09] | 00:01:18 | M.AtLB.Mu.XenCom.SyrFra | Syringammina fragilissima field on Atlantic lower bathyal mud |
20 | [01:12:28] | 00:10:42 | M.AtLB.Mx.SurOph.OphCer | Ophiomusa lymani and cerianthid anemone assemblage on Atlantic lower bathyal mixed sediment |
21 | [01:23:11] | 00:18:34 | M.AtLB.Ro.MixCor | Mixed cold water coral community on Atlantic lower bathyal coarse sediment |
22 | [01:41:46] | 00:05:30 | M.AtLB.Bi.CorRee.SolVar | Atlantic lower bathyal live Solenosmilia variabilis reef (biogenic structure) |
23 | [01:47:17] | 00:01:21 | M.AtMB.Ro.BarCom | Barnacle dominated community on Atlantic mid bathyal rock and other hard substrata |
24 | [01:48:39] | 00:09:38 | M.AtLB.Bi.CorRee.SolVar | Atlantic lower bathyal live Solenosmilia variabilis reef (biogenic structure) |
Unknown mud fluff : 1123 : R
Foraminifera
Syringammina fragilissima : 261 : F
Porifera
cf. Polymastia boletiformis : 1030 : O
Geodia cf. atlantica (Porifera massive lobose sp. 6) : 83 : O
Porifera encrusting sp. 1 (white) : 1 : R
Porifera lamellate sp. 10 : 1010 : O
Porifera massive globose sp. 15 (Solenosmilia rubble) : 1051 : R
Porifera massive globose sp. 6 : 137 : R
Porifera massive lobose sp. 21 (Hertwigia sp. ?) : 611 : R
Blue Porifera encrusting : 800 : R
Cnidaria
Cerianthidae sp. 1 : 2 : R
Actiniaria sp. 1 : 4 : R
Actinoscyphiidae sp. 1 (pink) : 1047 : O
Actinostolidae sp. 1 : 132 : O
Adamsia sp. : 1066 : R
Liponema sp. : 1055 : R
Antipatharia sp. 4 cf. Stauropathes : 592 : R
Stichopathes sp. : 560 : F
Bathypathes sp. (brown) : 284 : O
Parantipathes sp. : 1042 : O
Stauropathes arctica : 547 : R
Caryophyllia sp. 2 : 6 : R
Solenosmilia variabilis : 700 : F
Flabellum sp. : 1056 : R
Anthomastus grandiflorus : 278 : R
Pseudoanthomastus sp. : 1080 : R
Anthothela grandiflora : 311 : R
Chrysogorgidae sp. 1 : 1008 : R
cf. Clavulariidae sp. : 289 : R
Acanella arbuscula : 585 : O
Keratoisis sp. 2 : 578 : R
Lepidisis sp. : 557 : R
Isididae sp. (fine branching) : 1064 : R
Paramuricea sp. : 1050 : O
Gorgonacea sp. (pink, Solenosmilia assoc.) (Jasonisis) : 1070 : R
Gorgonacea sp. 7 (pink) cf. Isidella : 307 : R
cf. Halipteris sp. : 1060 : O
Pennatulacea (indet.) : 1114 : R
Pennatula aculeata : 1046 : O
Umbellula sp. : 581 : O
Annelida
Aphroditidae sp. 1 : 146 : R
Arthropoda
Chirostylidae sp. 2 (indet.) : 1054 :
Paguridae sp. : 205 : R
Caridea (indet.) : 1077 : R
Colossendeis sp. 1 : 1059 : R
Cirripedia sp. 1 : 82 : F
Mollusca
Octopoda (indet.) : 659 : R
Margarites sp. 1 : 277 : R
Bryozoa
Reteporella sp. : 204 : R
Echinodermata
Bathycrinidae sp. 1 : 1041 : R
Pentametrocrinus atlanticus : 436 : R
Koehlermetra porrecta : 315 : F
Crinoidea sp. : 1072 : R
Asteronyx loveni : 471 : R
Ophiomusa lymani : 551 : F
Ophiuroidea (indet.) : 1076 : R
Brisingidae sp. : 274 : F
Zoroaster fulgens : 988 : F
Pseudarchaster sp. 1 : 433 : R
Porania sp. : 263 : R
Solaster endeca : 573 : R
Echinidae sp. (white) : 559 : R
Phormosoma placenta : 555 : O
Elpidiidae (indet.) : 1122 : R
cf. Amperima sp. : 628 : F
Chordata
Ascidiacea sp. 2 : 20 : F
Rajiformes sp. 1 (Neoraja caerulea?) : 652 : R
Squaliformes sp. : 569 : O
Hydrolagus cf. affinis : 1039 : O
Synaphobranchus kaupii : 440 : O
Hoplostethus atlantica : 651 : O
Coryphaenoides guentheri : 577 : O
Coryphaenoides rupestris : 566 : O
Mora moro : 349 : R
Polyacanthonotus rissoanus : 552 : R
Notacanthidae sp. 1 : 1009 : O
Cataetyx laticeps : 1111 : R
cf. Rouleina attrita : 1074 : O
Zoarcidae sp. 1 : 259 : R
Neocyttus helgae : 563 : R
Number of species = 80
© Marine Institute, MERC Consultants, Bernard Picton 2022