(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.

Cuttlebone morphometry measurements

Changes in seawater carbonate chemistry that accompany ongoing ocean acidification have been found to affect calcification processes in many marine invertebrates. In contrast to the response of most invertebrates, calcification rates increase in the cephalopod Sepia officials during long-term exposure to elevated seawater pCO2. The present trial investigated structural changes in the cuttlebones of S. officinalis calcified during 6 weeks of exposure to 615 Pa CO2. Cuttlebone mass increased sevenfold over the course of the growth trail, reaching a mean value of 0.71 ± 0.15 g. Depending on cuttlefish size (mantle lengths 44-56 mm), cuttlebones of CO2-incubated individuals accreted 22-55% more CaCO3 compared to controls at 64 Pa CO2. However, the height of the CO2- exposed cuttlebones was reduced. A decrease in spacing of the cuttlebone lamellae, from 384 ± 26 to 195 ± 38 lm, accounted for the height reduction The greater CaCO3 content of the CO2-incubated cuttlebones can be attributed to an increase in thickness of the lamellar and pillar walls. Particularly, pillar thickness increased from 2.6 ± 0.6 to 4.9 ± 2.2 lm. Interestingly, the incorporation of non-acidsoluble organic matrix (chitin) in the cuttlebones of CO2- exposed individuals was reduced by 30% on average. The apparent robustness of calcification processes in S. officials, and other powerful ion regulators such as decapod cructaceans, during exposure to elevated pCO2 is predicated to be closely connected to the increased extracellular [HCO3 -] maintained by these organisms to compensate extracellular pH. The potential negative impact of increased calcification in the cuttlebone of S. officials is discussed with regard to its function as a lightweight and highly porous buoyancy regulation device. Further studies working with lower seawater pCO2 values are necessary to evaluate if the observed phenomenon is of ecological relevance.

Morphometry and microphotographs of devonian stromatoporoids from southern Poland

Famennian Stromatoporoidea from the Quasiendothyra communis Foraminiferal Zone and slightly younger strata from the Debnik anticline, southern Poland, form a succession of three consecutive assemblages. Assemblages 1 and 3 consist of representatives of the order Clathrodictyida, while assemblage 2 is dominated by the order Labechiida. The clathrodictyids are represented by the genus Gerronostroma, and labechiids are represented by the genus Stylostroma. Species assigned here to the genus Gerronostroma show a network of amalgamated pillars in the central part of the columns, a feature regarded by previous authors as typical of the genus Clavidictyon. Two new species, Stylostroma multiformis sp. nov. and Gerronostroma raclaviense sp. nov., are described. Stromatoporoids from southern Poland differ from the Famennian fauna of western Europe, showing affinity to eastern European and Siberian Stromatoporoidea.

(Table 1) Compositional variation with depth in a nodule of sediment sample RVG-10D

A detailed study of a nodule from the Somali Basin dated by 230Thexcess was correlated with the paleoceanographic events recorded in Site 236 (Leg 24) Deep Sea Drilling Project (DSDP) cores. Tentative indications are that the phase of nodule accretion starting with the development of pillar structure at a depth of 20 mm in the nodule around 13 Ma coincides with increased Antarctic Bottom Water (AABW) flow and an elevated calciumcarbonate compensation depth (CCD). The Late Miocene lowering of the CCD is represented by the mottled zones between 8 and 18 mm in the nodule is characterised by an abundant silicate component (>20%) of aeolian origin. The Miocene/Pliocene boundary (5 Ma) occurs at a depth of about 8 mm and is represented by the development of pillar structure and a minimum of aeolian dust (10.3%). The increased biological productivity of the Somali surface water since the Middle Miocene is demonstrated by the increasing Corg content of the nodule (from 0.11 to 0.19%) towards its surface.