Marine Institute
SeaRover Dive Video

D479 Transect 48 Dense xenophyophores, heavily mud veneered ledges and slopes, and dense sea pens (Pennatula aculeata). Features of Interest: predicted Lophelia reef Water Depth: 1063-949 m

Highlights: Ling Shark Sea pen Bolocera anemones? Sea pens & brittlestars

The feature here is a steep vertical incline of soft sediment beginning at 972 m. The initial dense beds of xenophyophores give way to sporadic individuals. The faunal assemblage is characterised by sea pens, with Pennatula sp. occurring in very dense patches on occasion and are densest at ~ 980 m. Other species of sea pen are also observed within these beds. Fish species included the northern cut-throat, grenadiers, chimerids, ling and sharks. Trawl marks and fishing debris (lines/rope) are evident throughout the site.

START VIDEO [00:00:00]/ 22:23 [1] The dive starts on dense xenophyophore aggregations (Syringammina fragilissima) on a mud bottom, with many associated epifaunal species. ROV moves left a couple of times before heading forwards. [00:12:00] -[00:14:00] Brief stop (perhaps for ship movement). [00:14:00] ROV moves diagonally right. [00:20:00] ROV moving slowly forwards. [00:23:00] ROV moving diagonally right. [00:24:00] The seabed slopes down to the right with the ROV moving along and up slope. [00:25:00] -[00:34:00] sparse pebbles and cobbles are encountered, often hosting barnacles, but these are too rare to be defined as a mosaicked biotope. [00:29:00] ROV encounters a leafscale gulper shark (Centrophorus squamatus). [00:35:00] The first of several mound features, assumed to be indicative of rock features with a heavy mud veneer. [00:47:00]-[00:54:00] sampling Halipteris sp . sea pen. [00:56:00]- END rare cobbles are encountered. [00:57:00] the landscape slopes down to the left in front of the ROV. [01:01:00] landscape slopes to right. [01:04:00] more mounds indicating rock features beneath the sediment. [01:06:00] [2] juvenile Pennatula aculeata seapens become the dominant fauna, often dense though this wavers. The similar sizing suggests that a mass colonisation event may have occurred with one cohort of larval seapens settling. [01:07:35] the edge of a buried carbonate ledge is visible (sufficiently buried to resemble a rope lying on the seafloor). [01:12:00] more mound features [01:13:00] [3] the fauna becomes sparse/ with no clear dominant species, the mud substrate continues. [01:14:00] the landscape slopes down to the right quite steeply and the ROV traverses along slope. [01:19:00]-[01:20:00] another buried carbonate ledge stop to image. [01:22:00] ridge feature with heavy mud draping, small patch of denser pebbles and cobbles on the ledge with a few actinostolid anemones then [01:23:00] transition back to traversing along the mud slope with sparse pebbles/cobbles. [01:29:00] [4] The juvenile seapen aggregation begins again, with rare other (mainly fully grown) sea pen species interspersed but vastly dominated by juvenile Pennatula aculeata. [00:33:00] stop briefly for imagery. [00:36:00] Here seapens continue, but there are also many xenophyophores until [00:27:00] where the seapens are dense. [01:44:00] a single large boulder is encountered, it is sparsely colonised. The seapen aggregation continues until the END VIDEO [02:00:00] / 00:23.

Progression Start Duration Code Name
1[00:00:00]01:06:49M.AtMB.Mu.XenCom.SyrFraSyringammina fragilissima field on Atlantic mid bathyal mud
2[01:06:50]00:06:48M.AtMB.Mu.SpnMegSea pens and burrowing megafauna on Atlantic mid bathyal mud
2[01:08:42]00:01:42M.AtMB.Mu.SpnMegSea pens and burrowing megafauna on Atlantic mid bathyal mud
3[01:13:39]00:15:58M.AtMB.MuAtlantic mid bathyal mud
4[01:29:38]00:30:34M.AtMB.Mu.SpnMegSea pens and burrowing megafauna on Atlantic mid bathyal mud
4[01:36:08]00:01:18M.AtMB.Mu.SpnMegSea pens and burrowing megafauna on Atlantic mid bathyal mud

Unknown mud fluff : 1123 : O
Foraminifera
Syringammina fragilissima : 261 : C
Porifera
cf. Polymastia penicillus : 1137 : R
Porifera encrusting sp. 1 (white) : 1 : R
Blue Porifera encrusting : 800 : R
Cnidaria
Cerianthidae sp. 1 : 2 : O
Pachycerianthus multiplicatus : 458 : R
Actiniaria sp. 18 : 582 : R
Actiniaria sp. 20 : 605 : R
cf. Halcampoididae sp. : 984 : R
Sagartidae sp. (wide oral disc) : 1118 : F
Actinostolidae sp. 1 : 132 : O
Phelliactis sp. 1 : 255 : O
Epizoanthus sp. 1 (Paguridae associated) : 317 : R
Acanella arbuscula : 585 : O
Paramuricea sp. : 1050 : O
Pennatulacea (indet.) : 1114 : R
Halipteris cf. finmarchica : 622 : O
Pennatula aculeata : 1046 : C
Distichoptilum gracile : 1108 : R

Umbellula sp. : 581 : O
Corymorphidae sp. : 120 : R
Pliobothrus sp. : 207 : O
Annelida
Serpulidae sp. 1 : 106 : R
Arthropoda
Munida tenuimana : 339 : O
Paguridae sp. : 205 : R
Caridea (indet.) : 1077 : R
Colossendeis sp. 1 : 1059 : O
Siphonophora sp. (indet.) : 1135 : O
Cirripedia sp. 1 : 82 : O
Eucarida sp. (red deep) : 1138 : R
Mollusca
Sepiolidae sp. : 1095 : R
Echinodermata
Crinoidea sp. : 1072 : O
Asteronyx loveni : 471 : R
Gorgonocephalus sp. 1 : 214 : R
Stichastrella rosea : 198 : R
Zoroaster fulgens : 988 : O
Pseudarchaster sp. 1 : 433 : O
Velatida sp. 1 : 199 : R

Phormosoma placenta : 555 : O
Echinoidea sp. 1 : 279 : O
Benthogone sp. : 432 : O
Chordata
Centrophorus squamosus : 1048 : R
Hydrolagus cf. mirabilis : 1024 : O
Chimaera opalescens : 653 : R
Synaphobranchus kaupii : 440 : F
Molva molva : 654 : R
Nezumia aequalis : 1003 : O
Coelorinchus caelorhincus : 303 : R
Coryphaenoides rupestris : 566 : O
Trachyrincus sp. : 446 : O
Lepidion eques : 249 : R
Mora moro : 349 : O
Phycis blennoides : 1020 : R
Lophius piscatorius : 273 : R
cf. Rouleina attrita : 1074 : O
Aphanopus carbo : 1097 : R
Trichiurus lepturus : 1016 : R
Actinopterygii sp. 3 : 930 : R

Number of species = 59

© Marine Institute, MERC Consultants, Bernard Picton 2022