Fig 1.
Dive locations (numbered) for the 2013 NEUS.
Canyons Expedition. All canyons and seamounts surveyed during the expedition are labeled. Mytilus Seamount bathymetry is at 50 m resolution.
Table 1.
Total number of morphospecies observed across six broad-scale habitat features for three taxonomic groups.
Depth range and total distance travelled per area are included. Dive numbers are included.
Table 2.
Marginal test results followed by results from the BEST model using the AIC criterion. P-values in bold are significant (Bonferroni Adjustment, α = 0.01).
Fig 2.
Examples of geology and geomorphology.
(A) Vertical exposure of chalk in Atlantis Canyon showing biological and physical erosion morphologies (pits, burrows, horizontal striations). (B) Heavily eroded and partially colonized wall within Atlantis Canyon containing large caves. (C) Downslope abrasion marks along the wall of Alvin Canyon most likely from cascading sediment/water flows. (D) Transition from a well-developed erosional channel/chute to a linear abrasion mark on the wall of Alvin Canyon. (E) Spalling failure of a thin surficial layer of a layered mudstone exposure in Block Canyon. (F) "Recent" rockfall and spalling failure exposing a clean wall section within Oceanographer Canyon. (G) Debris apron at the base of a wall in Block Canyon. (H) ROV D2 inspecting a large displaced block of layered mudstone, Heezen Canyon.
Fig 3.
Benthic communities and habitats.
(A) Corals and sponges colonizing a vertical wall in Hydrographer Canyon (1376 m) with the octopus Muusoctopus johnsoniana. (B) Paragorgia arborea colonizing the wall of Heezen Canyon (709 m). (C) Lophelia pertusa and additional sessile species growing on the underside of a ledge in Hydrographer Canyon (867 m). (D) An isolated dropstone in the Lydonia-Powell inter-canyon (501 m) with anemones (Hormathiidae) and Phycis chesteri. (E) A heavily colonized outcrop in the Nygren-Heezen inter-canyon area (793 m). (F) Desmophyllum dianthus and P.? johnsoni attached to authigenic carbonate at Veatch Seeps (1421 m). (G) Bathymodiolus sp. living on the wall of Nygren Canyon (1560 m). (H) Zoanthids and ophiuroid brittle stars covering a mostly dead primnoid octocoral on Mytilus Seamount (3057 m).
Fig 4.
Notable observations and range extensions.
(A) Methane gas hydrate observed at NE Seep 2 (1055 m). (B) Telopathes magna in Block Canyon (1345 m). (C) Metallogorgia melanotrichos in Atlantis Canyon (1755 m). (D) Gaidropsarus argentatus under a ledge in Block Canyon (1008 m). (E) Lepidion guentheri in Oceanographer Canyon (995 m). (F) Guttigadus latifrons in Heezen Canyon (1645 m). (G) Uroptychus sp. inhabiting Parantipathes sp. in Oceanographer Canyon (1079 m). (H) Munidopsis spp. inhabiting a hexactinellid sponge in Atlantis Canyon (1744 m).
Fig 5.
Cumulative number of putative species (solid line) by taxon observed across all dives conducted.
95% confidence intervals are indicated (dotted lines).
Fig 6.
(A) corals. (B) fishes. (C) crustaceans. Best-fit linear trend lines are included.
Fig 7.
Non-metric multi-dimensional scaling plots based on Sorensen's Index of Similarity.
(A) corals. (B) fishes. (C) crustaceans. Significantly (SIMPROF, p<0.05) dissimilar assemblage clusters are noted. Dive numbers are noted. Circle size denotes median depth of dive. Pink = Open Slope/Landslide Scar, Orange = Inter-canyon Slope, Gray = Cold Seep, Blue = Slope Canyon, Dark Blue = Shelf-breaching Canyon, Red = Seamount.
Fig 8.
Abundance estimates of dominant species in the region.
(A) Paragorgia spp. (B) Primnoa? resedaeformis. (C) Synaphobranchus spp. (D) Neocyttus helgae. (E) Chaceon quinquedens. Circle size corresponds to number observed 10 m-2 as shown in key inset at lower left of each graph. Black symbols denote dives in which no species were observed. OS/L = Open Slope/Landslide Scar, IS = Inter-canyon Slope, CS = Cold Seep, SC = Slope Canyon, SBC = Shelf-breaching Canyon, SMT = Seamount.
Fig 9.
(A) A ghost fishing trap with red crabs (Chaceon quinquedens) and banded shrimp (USGS4, 575 m). (B) A ghost fishing trap in Nygren-Heezen inter-canyon area (697 m). (C) Fishing line with C. quinquedens at USGS1 (782 m). (D) Fishing line wrapped around a partially dead Paramuricea sp. in Oceanographer Canyon (1222 m). (E) Remnants of a balloon wrapped around a dead coral skeleton in Hydrographer Canyon (1376 m). (F) Ribbon wrapped around a dead coral skeleton in Oceanographer Canyon (1220 m).
Fig 10.
Abundance estimates of marine litter observed during each dive.