Highlights: 00:19:34 Yellow sea fan 00:30:50 Solenosmilia coral on carbonate shelf 00:34:58 Fish 00:40:49 Neolithodes grimaldi, fishing line caught in coral 02:30:00 Black plastic 02:34:00 Solenosmilia coral with feather stars & sponges

A dramatic canyon wall rising from 1521 m to 1250 m and consisting of spectacular geological and biological features is present here. The substrate of the canyon floor is soft sediment and is inhabited by cup corals, cerianthids, xenophyophores, ophiuroids and echinoids. Fish species such as grenadier, eels and sharks including lantern sharks, are common here. On the slope soft sediment gives way to stone/pebble fields before reaching a series of ledges and rock overhangs. Brisingids, ophiuroids and cup corals attach to the top and sides of 10-20 m long horizontal ridges. The ridges, 1 to 2 m in height, are noteworthy and may in fact be old seabed. There is litter and plastic in the sediment and trawl marks are evident in areas of apparent decreased faunal diversity. Solenosmilia variabilis is frequent throughout but develops into a large reef formation at the canyon summit; much of this is dead but continues to support a rich reef fauna. Common species include corals such as bamboo coral, Acanella arbuscula, Bathypathes sp., Anthomastus sp., cup corals and a variety of sea pens. Sponges, including glass sponges, are particularly prevalent among this Solenosmilia reef.

START VIDEO A [00:00:00]/19:14 [1]: The dive starts on epifaunally diverse soft muddy sediment with xenophyophores (Syringammina fragilissima) and cup corals. [00:16:00] [2]: The soft sediment biotope continues but carbonate shelves are periodically encountered hosting mixed corals. [00:59:00] [3]: the muddy substrate starts to display frequent Acanella arbuscula together with the xenophyophores (fewer cup corals, although they are still present), the hard substrate transitions from carbonate rock features to sparse/patchy pebbles and cobbles and is dominated by barnacles although many other epifauna are also present. A couple of times the pebble/cobble patches are dense enough to be considered geogenic reef. [01:38:22] One Orange Roughy encountered. [02:06:00] [4]: the mud and xenophyophores continue, with patchy A. arbuscula, and areas of Solenosmilia variabilis coral gravel with sparse fauna, mainly a small orange anemone (OTU605). [02:10:00] [5]: The first area of living Solenosmilia variabilis biogenic reef is encountered, with diverse epifauna, on a rolling landscape. Although by [02:11:00] [6]: it is clear that is has been trawl damaged with areas of sparse epifauna and clear trawl marks (see especially IMG_7146.jpg). [02:12:00] [7]: living reef returns [02:14:00] [8]: then trawl damage [02:15:00] [9]: then living reef again, although traversing the edge of the damaged reef. END VIDEO A 21:32.

START VIDEO B [02:17:00]/21:33. Between coral reef patches [02:18:00] [10]: A. arbuscula and S. fragilissima return on muddy sediment. [02:20:00] [11]: coral reef returns and a sponge and push core are sampled. [02:36:00] [12]: mud/coral gravel, Xenophyophores, A. arbuscula [02:37:00] [13]: another coral reef patch. [02:38:00] [14]: trawl damage. [02:40:00] [15]: mud and coarse coral rubble patches, and at [02:42:10] a rarely encountered large “sofa shark” (Pseudotriakidae microdon) [02:44:00] [16]: trawl damaged coral reef [02:45:00] [17]: transition to edge of area with mixed coral gravel/mud with cerianthid anemones and occasional pebbles with barnacles before END VIDEO B [02:47:00]/22:03.