Antarctic Starfish (Echinodermata: asteroidea) from the ANDEEP3 expedition

Study Extent

Four study regions were selected, but the main focus was on the Powell Basin and the Weddell Basin of the Weddell Sea, and their slopes. Two comparative samples were taken further north in the adjacent Agulhas and southern Cape Basins, which are separated from each other by the Agulhas Ridge.

Sampling

A 3-m wide Agassiz trawl (AGT) was deployed at two locations in the South Atlantic and 14 locations in the Southern Ocean during the PFS Polarstern expedition ANT XXII/3 WECCON 2005— ANDEEP III in January–April 2005. The sample depths ranged from 1047 to 4931 m, sampling continental slopes of the eastern Weddell Sea (off Kapp Norvegia) and western Weddell Sea and the South Orkney Islands, and deep Cape, Agulhas, Weddell and Powell Basins. At the stations 074-7, 078-11 and 081-9, the cod end mesh size was 10mm, while at all other stations, an inlet of 500 mm mesh size was inserted. The 500 mm mesh size was used because of smaller adult size of deep- sea macrobenthos compared to shelf macrobenthos. The deployment protocol was standardised to 10 min trawling at 1 knot with 1.5x cable length to water depth to facilitate comparability between the different sites. At station 059-10, the AGT was trawled for 20 min. The haul distances were calculated from the time the Agassiz trawl travelled on the ground. The tension meter of the winch clearly indicated when the AGT left the seabed. Haul length varied from 731 to 3841m. Sample volumes were estimated and the general sediment composition was noted. Mega- and larger macrofauna were separated by eye on deck. The taxa of each trawl sample were identified to morphospecies level.

Quality Control

The initial geo-referencing was done by means of the RV Polarstern onboard GPS systems. Geospatial data was directly imported from those systems to avoid potential errors in transcribing. Samples identification was supervised and checked by Michel Jangoux, Marine Biology Lab, Université Libre de Bruxelles. The taxonomic names were matched against two authoritative, expert-driven species registers: the Register of Antarctic Marine Species (RAMS) and the World Register of Marine Species (WoRMS). The automatic matching tools available on both these web sites were utilized.

Method steps

1. see quality control above.

This dataset focuses on Starfish (Echinodermata: Asteroidea). It includes data on 6 orders (Forcipulatida, Notomyotida, Paxillosida, Spinulosida, Valvatida, Velatida) and 11 families (Asteriidae, Astropectinidae Benthopectinidae, Echinasteridae, Freyellidae, Goniasteridae, Labidiasteridae, Notasteriinae, Porcellanasteridae, Pterasteridae, Solasteridae). The most represented families are the Astropectinidae (Paxillosida), followed by Porcellanasteridae (Paxillosida) and Pterasteridae (Velatida).

1. Dytaster felix
   rank: species
2. Freyella attenuata
   rank: species
3. Psalidaster mordax
   rank: species
4. Lophaster gaini
   rank: species
5. Bathybiaster loripes
   rank: species
6. Psilaster charcoti
   rank: species
7. Pteraster hirsutus
   rank: species
8. Freyastera tuberculata
   rank: species
9. Hymenaster pellucidus
   rank: species
10. Hymenaster praecoquis
    rank: species
11. Freyella
    rank: genus
12. Benthopecten pedicifer
    rank: species
13. Hyphalaster inermis
    rank: species
14. Eremicaster pacificus
    rank: species
15. Lophaster stellans
    rank: species
16. Eremicaster crassus
    rank: species
17. Rhopiella hirsuta
    rank: species
18. Notioceramus anomalus
    rank: species
19. Hymenaster crucifer
    rank: species
20. Styracaster chuni
    rank: species
21. Cheiraster planeta
    rank: species
22. Pteraster spinosissimus
    rank: species
23. Hyphalaster scotiae
    rank: species
24. Notasterias pedicellaris
    rank: species
25. Diplasterias brucei
    rank: species
26. Lysasterias adeliae
    rank: species
27. Asteriidae
    rank: family
28. Astropectinidae
    rank: family
29. Benthopectinidae
    rank: family
30. Echinasteridae
    rank: family
31. Freyellidae
    rank: family
32. Goniasteridae
    rank: family
33. Labidiasteridae
    rank: family
34. Notasteriinae
    rank: family
35. Porcellanasteridae
    rank: family
36. Pterasteridae
    rank: family
37. Solasteridae
    rank: family
38. Forcipulatida
    rank: order
39. Notomyotida
    rank: order
40. Paxillosida
    rank: order
41. Spinulosida
    rank: order
42. Valvatida
    rank: order
43. Velatida
    rank: order
44. Bathibiaster
    rank: genus
45. Cheiraster
    rank: genus
46. Diplasterias
    rank: genus
47. Dytaster
    rank: genus
48. Eremicaster
    rank: genus
49. Freyastera
    rank: genus
50. Freyella
    rank: genus
51. Hymenaster
    rank: genus
52. Hyphalaster
    rank: genus
53. Lophaster
    rank: genus
54. Lysasterias
    rank: genus
55. Marsipaster
    rank: genus
56. Notasterias
    rank: genus
57. Notioceramus
    rank: genus
58. Parachaster
    rank: genus
59. Psalidaster
    rank: genus
60. Psilaster
    rank: genus
61. Rhopiella
    rank: genus
62. Ripaster
    rank: genus
63. Styracaster
    rank: genus

ANDEEP 3 cruise track, from Cape Town (SA) to Punta Arenas (CH). Four study regions were selected, but the main focus was on the Powell Basin and the Weddell Basin of the Weddell Sea, and their slopes. Two comparative samples were taken further north in the adjacent Agulhas and southern Cape Basins, which are separated from each other by the Agulhas Ridge. Four study regions were selected, but the main focus was on the Powell Basin and the Weddell Basin of the Weddell Sea, and their slopes. The major South Atlantic deep-sea basins started forming during Jurassic and Cretaceous times in connection with the Gondwana break-up and seafloor spreading (Brandt et al., 2004a, 2007; Lawver and Gahagan, 2003). The Weddell Basin is separated from the northerly basins by the South- west India Ridge (LaBrecque, 1986). The Powell Basin on the western side of the Weddell Sea was formed in the Tertiary by geological processes opening the Drake Passage and tectonic movements in the Scotia Sea (Lawver and Gahagan, 2003; Mitchell et al., 2000). The oceanography of the deep South Atlantic seafloor is defined by its prominent water mass, the Antarctic Bottom Water (Tomczak and Godfrey, 2001). The Antarctic Bottom Water expands north- wards into the Atlantic basins east and west of the Mid-Atlantic Ridge, like the Agulhas Basin, but can only enter the basins north of the Walvis Ridge (e.g., Cape Basin) via the northerly Romanche Fracture Zone. The Weddell Sea Bottom Water (WSBW), defined by a temperature of 0.7 1C and a salinity of 34.64 ppt (Orsi et al., 1993), is the main water mass above the Weddell Sea benthos (Fahrbach et al., 2001). The WSBW flows from the western Weddell Sea into the Scotia Sea and South Sandwich Forearc, and its circulation is driven by the Weddell Sea gyre. The sediments in the bathyal and abyssal Weddell and Powell Basins are dominated by silt and clay.