Swath sonar bathymetry during POLARSTERN cruise ANT-XX/2 (PS63) with links to multibeam raw data files

Multibeam data were measured during R/V Polarstern cruise ANT-XX/2 along track lines of 5557 NM total length during transits and partly during stationary work. Data were achieved in the Eastern Weddell Sea, the Riiser-Larsen Sea and the Lazarev Sea.

Swath sonar bathymetry during POLARSTERN cruise ANT-XIX/2 (PS61) with links to multibeam raw data files

Multibeam data were measured during R/V Polarstern cruise ANT-XIX/2 along track lines of about 6,100 NM total length along transits, survey profiles and during stationary work, mainly in the Weddell Sea. A multibeam survey was conducted in the eastern Weddell Sea at a potential earthquake area, located east of Fimbul Canyon. The tracks complemented data from former expeditions and extended the surveyed area to 60 by 80 NM. Data were achieved during the transit to the eastern Weddell Sea and by several wide spaced track lines at the continental margin east of Antarctic Peninsula. Between 66°30'S and 67°S a systematic survey of about 35 by 40 NM was carried out at a slump area. The multibeam sonar system Hydrosweep DS-2 was operated using 59 beams and 90° aperture angle. The refraction correction was achieved utilizing the system's own cross fan calibration. The quality of data might be reduced during bad weather periods or adverse sea ice conditions. The dataset contains raw data that are not processed and thus may contain errors and blunders in depth and position.

Swath sonar bathymetry during POLARSTERN cruise ANT-XXII/2 (PS67) with links to multibeam raw data files

Multibeam data were measured during R/V Polarstern cruise ANT-XXII/2 along track lines of approximately 6800 NM total length during transits and the Ice Station POLarstern (ISPOL) experiment. Data were achieved during the transit from Cape Town via Bouvet Island towards Antarctic Peninsula for three weeks, crossing Agulhas Ridge, Agulhas Basin and Mid-Atlantic Ridge, and during the transit to Cape Town via South Georgia for two weeks. During the ISPOL station, data were gained while the vessel was drifting for five weeks anchored to an ice floe in the south-western Weddell Sea, starting at 68°13'S/54°47'W. The multibeam sonar system Hydrosweep DS-2 was operated using 59 beams and 90° aperture angle. The refraction correction was achieved using CTD profiles or utilizing the system's own cross fan calibration. The quality of data might be reduced during bad weather periods or adverse sea ice conditions. The dataset contains raw data that are not processed and thus may contain errors and blunders in depth and position.

Swath sonar bathymetry during POLARSTERN cruise ANT-XV/2 (PS47) with links to multibeam raw data files

Multibeam data were measured during R/V Polarstern cruise ANT-XV/2 along track lines of approximately 10200 NM total length during transits, surveys and partly during stationary work, mainly in the Scotia Sea and the Weddell Sea. Areal multibeam surveys were performed in the vicinity of the South Shetland trench, the Bransfield Basin, the South Sandwich trench, and off the Ekstrom Ice Shelf for time periods of three to eight days. The multibeam sonar system Hydrosweep DS-2 was operated using 59 beams and 90° aperture angle, in some shallow areas 120°. The refraction correction was achieved utilizing sound velocity profiles sampled during the cruise, and by the system's own cross fan calibration. The quality of data might be reduced during bad weather periods or adverse sea ice conditions. The dataset contains raw data that are not processed and thus may contain errors and blunders in depth and position.

Swath sonar bathymetry during POLARSTERN cruise ANT-XVI/2 (PS53) with links to multibeam raw data files

Multibeam data were collected without operator supervision on R/V Polarstern cruise ANT-XVI/2 along track lines of approximately 6800 NM. Data were achieved during transits and stationary work in the Atlantic Ocean, the South and the East Weddell Sea; amongst others between Atka Bay and Halley Bay, at the northern part of Filchner Trough, and off the Ronne Ice Shelf. A transect along the Greenwich meridian was taken between 66.5°S and 48°S during the transit from Neumayer to Cape Town. The multibeam sonar system Hydrosweep DS-2 was operated using 59 beams and 90° aperture angle. The quality of data might be reduced during bad weather periods or adverse sea ice conditions. The dataset contains raw data that are not processed and thus may contain errors and blunders in depth and position.

(Table T1) Radiolaria abundance of ODP Hole 175-1082A

A primary objective of Leg 175 was to investigate the upwelling history of the Benguela Current. Upwelling along the coast is found over the shelf in several well-established cells, as well as along the shelf-slope break, and extends over the 1000-m isobath. Streaming filaments along the coast also carry upwelled water off shore (Shannon, 1985). The upwelled nutrient-rich waters are sourced from the South Atlantic central water mass, which is a mixture of subtropical and subantarctic water masses. Below the central water mass lies Antarctic intermediate water (Shannon and Hunter, 1988, doi:10.2989/025776188784480735; Stramma and Peterson, 1989, doi:10.1175/1520-0485(1989)019<1440:GTITBC>2.0.CO;2). The upwelling system supports a robust marine community (Shannon and Pillar, 1986) where radiolarians are abundant (Bishop et al., 1978, doi:10.1016/0146-6291(78)90010-3). The endemic nature of radiolarians makes them useful in reconstructing the paleocirculation patterns. The biogeographic distribution of many species is limited by water-mass distribution. In a given geographic region, species may also have discrete depth habitats. However, their depth of occurrence can change worldwide because the depths of water masses vary with latitude (Boltovskoy, 1999). Consequently, species found at shallow depths at high latitudes (cold-water fauna) are observed deeper in the water column at lower latitudes. The low-latitude submergence of cold-water species broadens their distribution, resulting in species distributions that can cover multiple geographic regions (Kling, 1976, doi:10.1016/0011-7471(76)90880-9; Casey, doi:10.1016/0031-0182(89)90017-5; 1971; Boltovskoy, 1987, doi:10.1016/0377-8398(87)90014-4). Since radiolarian distribution is closely related to water-mass distribution and controlled by climatic conditions rather than geographic regions, similar assemblages characterize the equatorial, subtropical, transition, subpolar, and polar regions of ocean basins (Petrushevskaya, 1971a; Casey, 1989, doi:10.1016/0031-0182(89)90017-5; Boltovskoy, 1999). Numerous radiolarian species found in water masses in the Angola and Benguela Current systems have also been observed in plankton net samples, sediment traps, and surface-sediment studies in the Atlantic sector of the Southern Ocean, where they exhibited particular water-mass affinities (Abelmann, 1992a, doi:10.1007/BF00243107; Abelmann 1992b, doi:10.1007/BF00243108; Abelmann and Gowing, 1997, doi:10.1016/S0377-8398(96)00021-7). This report presents data on the radiolarian fauna recovered from Site 1082 sediments in the form of a survey of species reflecting the latitudinal migration of the Angola-Benguela Front and upwelling. The data constitute a time series of relative radiolarian abundances at very high resolution (every 20 cm) of the upper 12 m of Hole 1082A.

Lists of seamounts and knolls in different formats

Seamounts and knolls are 'undersea mountains', the former rising more than 1000 m from the sea floor. These features provide important habitats for aquatic predators, demersal deep-sea fish and benthic invertebrates. However most seamounts have not been surveyed and their numbers and locations are not well known. Previous efforts to locate and quantify seamounts have used relatively coarse bathymetry grids. Here we use global bathymetric data at 30 arc-second resolution to identify seamounts and knolls. We identify 33,452 seamounts and 138,412 knolls, representing the largest global set of identified seamounts and knolls to date. We compare estimated seamount numbers, locations, and depths with validation sets of seamount data from New Zealand and Azores. This comparison indicates the method we apply finds 94% of seamounts, but may overestimate seamount numbers along ridges and in areas where faulting and seafloor spreading creates highly complex topography. The seamounts and knolls identified herein are significantly geographically biased towards areas surveyed with ship-based soundings. As only 6.5% of the ocean floor has been surveyed with soundings it is likely that new seamounts will be uncovered as surveying improves. Seamount habitats constitute approximately 4.7% of the ocean floor, whilst knolls cover 16.3%. Regional distribution of these features is examined, and we find a disproportionate number of productive knolls, with a summit depth of <1.5 km, located in the Southern Ocean. Less than 2% of seamounts are within marine protected areas and the majority of these are located within exclusive economic zones with few on the High Seas. The database of seamounts and knolls resulting from this study will be a useful resource for researchers and conservation planners.

Swath sonar bathymetry during SONNE cruise SO202 (INOPEX) with links to multibeam raw data files

Multibeam data were measured during R/V SONNE cruise SO202 (INOPEX) along track lines of 6938 NM total length in the North Pacific and Bering Sea during transits and stationary work. Starting from Hokkaido (Japan) data were achieved east of the Kuril-Kamchatka Trench and south of the Aleutian Trench. The track crosses the Bowers Ridge, the continental margin of Alaska and the Umnak Plateau in the Bering Sea. Further data were gained in the North Pacific in the area of the Patton Seamounts, Gibson Seamount, Hess Rise and Shatsky Rise. The multibeam sonar system Simrad EM 120 from Kongsberg was operated using 191 beams and an aperture angle of 90° to 140° due to particular conditions. The refraction correction was achieved utilizing 6 CTD profiles measured during the cruise and one from cruise SO201. The quality of data might be reduced during bad weather periods. The dataset contains raw data that are not processed and thus may contain errors and blunders in depth and position.

Swath sonar bathymetry during POLARSTERN cruise ARK-XXII/1c (PS70) with links to multibeam raw data files

Multibeam data were measured as part of the project HERMES during R/V Polarstern cruise ARK-XXII/1 (2007-05-29 to 2007-07-25) along transits and survey profiles and partly during stationary work. Data were achieved mainly in the coastal areas of northern Norway, at the Hakon Mosby Mud Volcano at the continental margin approx. 200 nm off the norwegian coast and the AWI-Hausgarten area approx. 150 nm west of Svalbard. A number of surveys were carried out in the coastal areas of northern Norway (Sula Reef, Roest Reef, Traena area, Floholmen area, Sotbakken area) and around the area of the Hakon Mosby Mud Volcano. The multibeam sonar system Atlas Hydrosweep DS-2 (Atlas Hydrographic, http://www.atlashydro.com) was operated using 59 beams and 90° aperture angle. The refraction correction was achieved using CTD profiles measured during this cruise or, during transits, utilizing the system's own cross fan calibration. The quality of data might be reduced during bad weather periods or adverse sea ice conditions (only in the AWI-Hausgarten area). This dataset contains raw data that are not processed and thus may contain errors and blunders in depth and position.

Swath sonar bathymetry during POLARSTERN cruise ANT-XVI/4 (PS53) with links to multibeam raw data files

Multibeam data were collected without operator supervision on R/V Polarstern cruise ANT-XVI/4 along track lines of 6385 NM total length. Data were achieved during transits and stationary work on the route from Cape Town to Bremerhaven via the Cape Verde Islands and the Canary Islands. The multibeam sonar system Hydrosweep DS-2 was operated using 59 beams and 90° aperture angle. The quality of data might be reduced during bad weather periods or adverse sea ice conditions. The dataset contains raw data that are not processed and thus may contain errors and blunders in depth and position.

Swath sonar bathymetry during POLARSTERN cruise ANT-XV/4 (PS49) with links to multibeam raw data files

Multibeam data were collected without operator supervision on R/V Polarstern cruise ANT-XV/4 along track lines of about 7000 NM total length. Data were achieved during transits and stationary work in the western Weddell Sea, at the Weddell-Scotia Confluence, and on a transect along the Prime Meridian of about 1300 NM length, between 69°S and 47°S. The multibeam sonar system Hydrosweep DS-2 was operated using 59 beams and 90° aperture angle. The quality of data might be reduced during bad weather periods or adverse sea ice conditions. The dataset contains raw data that are not processed and thus may contain errors and blunders in depth and position.