Asteroids, ophiuroids and holothurians from the South-Eastern Weddell Sea (Southern Ocean)

Dieter Piepenburg

doi:10.15468/3pf2mg

Asteroids, ophiuroids and holothurians from the South-Eastern Weddell Sea (Southern Ocean)

Citation

Piepenburg D, Gutt J, Voß J (2014) Asteroids, ophiuroids and holothurians from the South-Eastern Weddell Sea (Southern Ocean). AntaBIF dataset https://doi.org/10.15468/3pf2mg accessed via GBIF.org on 2024-12-13.

Description

The South-Eastern Weddell Sea in the Atlantic Sector of the Southern Ocean is a typical high-latitude Antarctic region. It is located in the circumpolar permanent pack-ice zone (Hempel 1985a), characterized by summary polynyas (areas of open water surrounded by sea ice). Due to its remoteness and persistent sea-ice cover, it was not accessible for extensive scientific surveys before the availability and support of modern research platforms that are capable to operate independently in sea-ice covered waters. First multidisciplinary marine research was carried out in this area in the 1980s during the first Antarctic cruises of the German icebreaking research and supply vessel "Polarstern”. Embedded in a broad ecological research programme, addressing a range of evolutionary, systematic, zoogeographical and ecological issues, first comprehensive faunistic inventories of the asteroid (starfish), ophiuroid (brittle star) and holothurian (sea cucumber) bottom fauna were conducted, based on field sampling efforts during “Polarstern” cruises ANT-I/2 (PS01), ANT-II/04 (PS04), and ANT-III/3 (PS06) (for cruise reports see Hempel 1983, Drescher et al. 1983, Kohnen 1984, and Hempel 1985b, respectively). The major objective of this collection work was to provide material for subsequent zoogeographical and ecological studies on the asterozoan (asteroid and ophiuroids together; Voß 1988, Piepenburg et al. 1997) and holothurian fauna (Gutt 1988, Gutt 1991), as well as for analyses of entire macrozoobenthos communities (Gutt 2000; for a compilation: Gutt et al. 2013). Here, we publish the complete original dataset of asteroid, ophiuroid and holothurian abundances (and absences) that formed the basis of the scientific findings published in the research papers mentioned above, to allow for the general accessibility to such data associated with starfishes, brittle stars and sea cucumbers from the South-Eastern Weddell Sea. Asteroid, ophiuroid, and holothurian specimens were sampled at a total of 59 sites distributed across the South-Eastern Weddell Sea at water depths between 160 and 1,180 m (for more detailed information see section on “Geographic coverage” below). In general, this region characterized by a relatively homogenous physical environment, especially in terms of water masses, poorly sorted sediments, persistent sea-ice cover and hardly predictable occurrence of coastal polynyas. As such, it is representative for the entire high-latitude Antarctic habitat. Some drivers of faunistic heterogeneity, in addition to biological interactions and unknown unpredictable factors, are briefly summarized in the section on “Project Data - Study area description” below. The field samples were mainly taken by means of an Agassiz trawl, but also with a commercial bottom trawl and, in one case, a smaller dredge. During the cruises, GPS positions were available approximately each six hours. Between the GPS fixes, the ship's positions were death reckoned. Swept areas were estimated for each haul as described in Voß (1988) and Gutt (1988). Water depths were measured by a DWD echo sounder. For more detailed information see section on “Sampling methods - Sampling description” below. Specimens were collected from either total catches or, in some cases subsamples, counted and preserved on board. Using the swept-area estimates, individual counts were standardized to abundance values (ind m^-2). After the cruises, the preserved specimens were identified to species in the lab. Some holothurian species, which were assumed to be new to science, were formally described (Gutt 1990a, b). Some of these new descriptions were later revised. The specimens were not integrated into a museum's collection, and original data were never published at that time when electronic data bases did not yet exist. The quality of the data and metadata published here was enhanced prior to publication following the best practices suggested in the literature during the digitalization and geo-referencing processes. Moreover, the current accurate spelling of scientific names - except for the ophiuroid Theodoria conveniens ("nomen dubium") - was reviewed based on the World Register of Marine Species (www.marinespecies.org/). For more information see “Sampling methods - Quality control” below. The dataset comprises a total of 4,509 records of absences and abundances of 35 asteroid species (with a total of 2,089 specimens) and 38 opiuroid species (with a total of 18,484 specimens) from 34 stations, as well as of 66 holothurian species (with a total of 20,918 specimens) from 59 stations. Asteroid, ophiuroid and holothurian species were present at all sites investigated in the study area but composition and abundance of the asterozoan and holothurian assemblages varied considerably. In the case of asterozoan patterns (Voß 1988, Piepenburg et al. 1997), water depth and latitude seemed to be the most important drivers of assemblage distribution and composition. At shallow shelf sites rare asteroid and ophiuroid predators, such as, e.g., Acodontaster conspicuus and Odontaster validus, respectively, as well as epibiotic ophiuroids, e.g., Astrotoma agassizii, occurred in addition to the common and widely distributed opportunistic feeders. In the case of holothurians (Gutt 1988, Gutt 1991), one assemblage co-occurred with the rich macrozoobenthic community dominated by dense epifauna consisting of, e.g., sponges and gorgonians, which are often used as substratum by epibiotic filter feeders. Others live mainly as vagrant deposit feeders on the predominantly non-colonised substratum, such as typical deep-sea species, e.g. Elpidia glacialis and Protelpidia murrayi (Gutt and Piepenburg 1991). In addition, a mixed holothurian assemblage was identified. Virtually nothing was known about echinoderms in the south-eastern Weddell Sea before the field sampling work, in the course of which the data published here have been gained. Also from other Antarctic regions only sporadic information on the three echinoderm classes, especially holothurians, was available at that time, mainly found published in the taxonomic literature. However, the application of a whole-assemblage approach was novel, and comparable surveys are even nowadays rare. The unique dataset encompasses some of the first observations of asteroids, ophiuroids and holothurians in this area and represents a significant contribution of primary data about Antarctic benthos assemblages. Moreover, it provides unique baseline data for future faunistic, ecological and conservation studies to evaluate the effects of climate change and possible future fishing activities in this area. At present and in the future these faunistic data can gain further importance in the context of a number of further applications: (1) More comprehensive circumpolar analyses and comparative studies with other large taxa become possible if these data are merged with similar datasets from other regions, see e.g., http://ipt.biodiversity.aq/resource.do?r=asteroidea_zoogeography and http://ipt.biodiversity.aq/resource.do?r=biopearl_asteroida. Data on these three echinoderm classes can also be compared within the same region with other taxa or environmental parameters, as compiled, e.g., by De Broyer et al. (in press). (2) At the time of sampling in the 1980s, the study area was almost pristine and hardly affected by any anthropogenic activities. In the meantime, exploratory fishing started on the deeper shelf, and the knowledge on the fauna before the onset of these activities can serve as a valuable baseline for an assessment of the impact of further fishing. (3) The same holds true for the study of the effects of climate change. The area is so far climatologically relatively stable but an increase of bottom-water temperatures is expected during the 21st century (Hellmer et al. 2012). (4) The data can also be used for nature conservation initiatives (Teschke et al. 2013). They are especially suited for such applied ecological comparative studies, since all specimens - with few well-defined exceptions - were sorted from the catches, meaning that not only the presence of the species were registered but also very valuable absence data and the even more informative abundances. In general, the latter data are known to be more sensitive indicators of environmental change than binary presence-absence data.

Purpose

The publication of the complete dataset of asteroid, ophiuroid and holothurian abundances (and absences) in the South-Eastern Weddell Sea, which formed the basis of the scientific findings already published in a number of original research papers, shall allow for the general accessibility to such data associated with starfishes, brittle stars and sea cucumbers from this high-Antarctic region. The unique dataset encompasses some of the first observations of asteroids, ophiuroids and holothurians in the study area and represents a significant contribution of primary data about Antarctic benthos assemblages. Moreover, it provides unique baseline data for future faunistic, ecological and conservation studies to evaluate the effects of climate change and possible future fishing activities in this area.

Sampling Description

Study Extent

See "Study Area Description"

Sampling

Three sampling gears were used: An Agassiz trawl that was deployed most frequently consisted of a metal sled, with an opening of 3 m width and 1 m height, to which a net, which was 5 m long and had a mesh size of 20 mm in the front part and 10 mm in the cod end, was attached. In front of the opening a tickler chain was fixed to the rig of the sled. The average trawling speed was 0.5 to 0.7 knots (nm/h), and the haul duration was approx. 20-30 min, resulting in swept areas of approx. 1,700 to 3,000 m2. This strategy was a compromise to gain comparable semi-quantitative information about both relatively poor Antarctic communities, based on catches that were, nevertheless, large enough to be representative, and rich communities without clocking the net. The bottom trawl used was a 140 feet commercial otter trawl with a 22.5 m wide and approximately 3 m high opening. The mesh size of the net was 10 cm in the front part and 15 mm in the cod end. The bottom trawl was towed over ground at an average speed of 3 knots (nm/h), mostly for 0.5 hours, as it is standard for research fishing of demersal fish. The dredge used has an opening of 100 x 30 cm and a mesh size of 10 mm. The swept areas were calculated according to Voß (1988) for the asterozoan study and according to Gutt (1988) for the holothurian study. Due to technical constraints, only one position and time was provided for the catches and only in some cases information on the depths at the start and end of the hauls was available. Metadata (position and time) are available at www.pangaea.de for the expeditions PS01 and PS06. For cruise PS04, metadata were published by Voß (1988), with the exception of stn 490 (Gutt 1988). Metadata are based on the station tables published in the cruise reports (Hempel 1983, Drescher 1983, Kohnen 1984).

Quality Control

Identifications were based on the taxonomic references cited by Voß (1988) and Gutt (1988). All species names in the dataset are in accordance with the World Register of Marine Species (www.marinespecies.org/), with the sole exception of the ophiuroid Theodoria conveniens ("nomen dubium"). Consequently, some species names have changed in comparison to the ones used in past publications, as these are synonyms that are not valid anymore.

Method steps

See "Sampling Description"

Additional info

marine, harvested by iOBIS

Taxonomic Coverages

All asteroids, ophiuroids, and holothurians caught by the gear mentioned in the section on “Sampling Methods" were considered in this study, with the exception of the very rare species Amphiura deficiens Koehler, 1992 and A. atlantica Ljungman, 1867. The taxonomic and morphological range even covers two holothurian species, which are assumed or known to be able to swim occasionally, Rhipidothuria racovitzai and Peniagone vignioni. Due to the mesh size used, not only adult but also juvenile specimens of all three classes are included in the collections. However, their abundance values are likely more biased than those of the adults. The trawls predominantly caught epifaunal species in a semi-quantitative way, the Agassiz trawl obviously with a higher catchability of macro-epibenthic invertebrates than the bottom trawl. Therefore, the swept-area approach is most useful for within-gear comparisons and only with less precision between-gear. The presence of typical infaunal species in the catches, such as the holothurian Molpadia and the asteroid Hymenaster, suggests that endobenthic species were also sampled to a considerable degree. Overall, organisms from a broad variety of ecological guilds among all three classes, such as deposit, sediment and filter feeders, infaunal, epifaunal and epibiotic (symbiotic) species, predators spezialized on various prey items, and scavengers, are present in the samples.

Asteroidea
common name: Starfish rank: class
Ophiuroidea
common name: Brittle stars rank: class
Holothuroidea
common name: Sea cucumbers rank: class

Geographic Coverages

The study area extends northward to 70°27'S, a latitude which is typical for the northern shelf off East Antarctica, with the exception of the large embayments of the Weddell and Ross Seas, and for the more southerly situated West Antarctic shelf regions, with the exception of the Antarctic Peninsula area. The southernmost station in the study area was located at 77°44'S. With regard to its longitudinal extent, the study area ranged from 008°01'W in the eastern Weddell Sea to 061°08'W at the basis of the Antarctic Peninsula at 061°08'W. With regard to water depth, the samples were taken along a gradient ranging from 160 m at the shelf to a maximum of 1,180 m at the upper slope, encompassing stations at relatively shallow banks as well as those in overdeepened basins, such as the Filchner Trough.

Bibliographic Citations

De Broyer C, Koubbi P, Danis B, David B, Grant S, Griffiths H, Gutt J, Held C, Huettmann F, Post A, Ropert-Coudert Y (in prep) The CAML / SCAR-MarBIN Biogeography Atlas of the Southern Ocean. -
Drescher HE, Hubold G, Piatkowski U, Plötz J, Voss J (1983) Das biologische Programm der ANARKTIS-I-Expedition mit FS "Polarstern". Berichte zur Polarforschung 12: 1-34. -
Fahrbach E, Rohardt G, Krause G (1992) The Antarctic coastal current in the southeastern Weddell Sea. Polar Biology 12: 171-182. -
Grosfeld KM, Schröder M, Fahrbach E, Gerdes R, Mackensen A (2001) How iceberg calving and grounding chqnge the circulation and hydrography in the Filchner Ice Shelf-Ocean System. Journal of Geophysical Research 6 (C5): 9039-9055. -
Gutt J (1988) Zur Verbreitung und Ökologie der Seegurken (Holothuroidea, Echinodermata) im Weddellmeer (Antarktis). Berichte zur Polarforschung 41: 1-87. -
Gutt J (1990) New Antarctic holothurians (Echinodermata)-I. Five new species with four new genera of the order Dendrochirotida. Zoologica Scripta 19: 101-117. -
Gutt J (1990) New Antarctic holothurians (Echinodermata)-II. Four species of the orders Aspidochirotida, Elasipodida and Apodida. Zoologica Scripta 19: 119-127. -
Gutt J (1991) On the distribution and ecology of holothurians on the Weddell Sea shelf (Antarctica). Polar Biology 11: 145-155. -
Gutt J, Piepenburg D (1991) Dense aggregations of three deep-sea holothurians in the southern Weddell Sea, Antarctica. Marine Ecology Progress Series 68: 277-285. -
Gutt J (2000) Some "driving forces" structuring communities of the sublittoral Antarctic macrobenthos. Antarctic Science 12: 297-313. -
Gutt J, Barnes DK, Lockhart SJ, van de Putte A (2013) Antarctic macrobenthic communities: A compilation of circumpolar information. Nature Conservation 4: 1-13. -
Gutt J, Starmans A (2001) Quantification of iceberg impact and benthic recolonisation patterns in the Weddell Sea (Antarctica). Polar Biology 24: 615-619. -
Hellmer HH, Kauker F, Timmermann R, Determann J, Rae J (2012) Twenty-first-century warming of a large Antarctic ice-shelf cavity by a redirected coastal current. Nature 485: 225-228. -
Hempel G (1983) Die Expedition ANTARKTIS-I mit FS "Polarstern" 1982/83. Berichte zur Polarforschung 14: 1-141. -
Hempel G (1985a) On the biology of polar seas, particularly the Southern Ocean. In: J.S. Gray JS, Christiansen ME (Eds) Marine biology of polar regions and effects of stress on marine organisms. Proceedings of the 18th European Marine Biology Symposium, University of Oslo, Norway, 14-20 August 1983. Wiley, Chichester, 3-33. -
Hempel G (1985b) Die Expedition ANTARKTIS III mit FS "Polarstern" 1984/85. Berichte zur Polarforschung 25: 1-222. -
Kohnen H (1984) Die Expedition ANTARKTIS-II mit FS "Polarstern" 1983/84 Bericht vom Fahrtabschnitt 4 Punta Arenas - Kapstadt (ANT-II/4). Berichte zur Polarforschung 19: 1-185. -
Piepenburg D, Voß J, Gutt J (1997) Assemblages of sea stars (Echinodermata: Asteroidea) and brittle stars (Echinodermata: Ophiuroidea) in the Weddell Sea (Antarctica) and off Northeast Greenland (Arctic): A comparison of diversity and abundance. Polar Biology 17: 305-322. -
Schröder M, Fahrbach E (1999) On the structure and the transport of the eastern Weddell Gyre. Deep-Sea Research II 46(1-2): 501-527. -
Teschke K, Bornemann H, Bombosch A, Burkhardt E, Brtnik P, Dorschel B, Feindt-Herr H, Gerdes D, Gutt J, Hain S, Herata H, Jerosch K, Knust R, Kock K-H, Pehlke H, Schlüter M, Schwarzbach W, Siegel V, Strass V, van Opzeeland I, von Nordheim H, Brey T (2013) Progress report on the scientific data compilation and analyses in support of the development of a CCAMLR MPA in the Weddell Sea (Antarctica). SC-CAMLR-XXXII, (BG/07), pp. 1-29. -
Voß J (1988) Zoogeographie und Gemeinschaftsanalyse des Makrtozoobenthos des Weddellmeeres (Antarktis). Berichte zur Polarforschung 45: 1-145. -
Arndt JE, Schenke H-W, Jakobson M, Nitsche FO, Buys G, Goleby B, Rebesco M, Bohoyoy F, Hong J, Black J, Greku R, Udintsev G, Barrios F, Reynoso-Peralta W, Taisei M, Wigley R (2013) The International Bathymetric Chart of the Southern ocean (IBCSO) Version 1.0 - A new bathymetric compilation covering circum-Antarctic waters. Geophysical Research Letters 40: 1-7, doi:10.1002/grl.50413, 2013. - doi:10.1002/grl.50413, 2013

Contacts

Dieter Piepenburg
originator
Institute for Ecosystem Research of Kiel University
Düsternbrooker Weg 20
Kiel
24105
DE
Telephone: +49 431 600 1264
email: dpiepenburg@ecology.uni-kiel.de
homepage: http://www.ecosystems.uni-kiel.de/e_abt_polar.shtml

Dieter Piepenburg
metadata author
Institute for Ecosystem Research of Kiel University
Düsternbrooker Weg 20
Kiel
24105
DE
Telephone: +49 431 600 1264
email: dpiepenburg@ecology.uni-kiel.de
homepage: http://www.ecosystems.uni-kiel.de/e_abt_polar.shtml

Julian Gutt
content provider
Alfred Wegener Institute Hemholtz Centre for Polar and Marine Research
Columbusstraße
Bremerhaven
27515
DE
email: julian.gutt@awi.de

Joachim Voß
content provider
Landesamt für Landwirtschaft, Umwelt und ländliche Räume
Hamburger Chaussee 25
Flintbek
24220
Schleswig-Holstein
DE
email: joachim.voss@llur.landsh.de

Dieter Piepenburg
administrative point of contact
Institute for Ecosystem Research of Kiel University
Düsternbrooker Weg 20
Kiel
24105
DE
Telephone: +49 431 600 1264
email: dpiepenburg@ecology.uni-kiel.de
homepage: http://www.ecosystems.uni-kiel.de/e_abt_polar.shtml