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

• Main Author: Weinheimer, Amy L
• Format: Dataset
• Language: English
• Published: PANGAEA 2001
• Subjects: 175-1082A; Acrosphaera murrayana; Actinomma cf. leptodermum; Amphirhopalum ypsilon; Anthocyrtidium ophirense; Anthocyrtidium zanguebaricum; Arachnocorys circumtexta; Arachnocorys penthacantha; Benguela Current; South Atlantic Ocean; Botryocyrtis scutum; Botryostrobus aquilonaris; Botryostrobus auritus/australis group; Carpocanarium papillosum; Carpocanistrum sp.; Clathrocyclas bicornis; Cornutella profunda; Corocalyptra columba; Counting; radiolarians; Cycladophora davisiana; Cycladophora davisiana cornutoides; Cyrtolagena laguncula; Dictyocoryne profunda; Dictyocoryne sp.; Dictyophimus crisiae; Dictyophimus gracilipes; Dictyophimus infabricatus; Didymocyrtis tetrathalamus; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Eucyrtidium acuminatum; Eucyrtidium cf. teuscheri; Helotholus histricosa; Hexacontium enthacanthum; Joides Resolution; Lamprocyclas maritalis; Lamprocyrtis hannai; Lamprocyrtis nigriniae; Lampromitra coronata; Lampromitra quadricuspis; Larcopyle buetschlii; Leg175; Lipmanella dictyoceras; Lithelius minor; Lithomelissa setosa; Lithostrobus hexagonalis; Lophospyris pentagona pentagona; Lophospyris spp.; Antarctic; Pillar; Antarc*
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.787554; https://doi.org/10.1594/PANGAEA.787554

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, ...