WoRaDD (World Radiolarian Distributional Database): A worldwide compilation of all available Recent radiolarian distributional and taxonomic data

BOLTOVSKOY DEMETRIO; KLING, STANLEY; TAKAHASHI, KOZO; BJORKLUND, KJELL

Wellington, New Zealand

Congreso; XI Interrad: Radiolarians in Stratigraphy and Paleoceanography. 11th meeting of the International Association of Radiolarian Paleontologists; 2006

Interrad

WoRaDD (WORLD RADIOLARIAN DISTRIBUTIONAL DATABASE): A WORLDWIDE COMPILATION OF ALL AVAILABLE RECENT RADIOLARIAN DISTRIBUTIONAL AND TAXONOMIC DATA D. Boltovskoy1, K. Bjørklund2, S. A. Kling3 & K. Takahashi4 1Dto. EGE, FCEN, Universdad de Buenos Aires, Buenos Aires, Argentina. 2Natural History Museum, University of Oslo, Dept. of Geology, P.O. Box 1172 Blindern, Oslo, Norway. 3416 Shore View Lane,  Leucadia, California 92024, USA. 4Dept. Earth & Planetary Sciences, Graduate School of Sciences, Kyushu UniversityHakozaki 6-10-1, Higashi-ku, Fukuoka 812-8581, JAPAN WoRaDD is compiling all existing (published and unpublished) information on radiolarian (Polycystina) distribution from plankton and sediment trap samples, and from surface sediment materials. The information will be critically “cleaned” and analyzed with the aid of objective numerical and GIS techniques in order to derive global distributional patterns of both species and cell numbers. As of October 2005, the state of completion of the different phases of the project is as follows: (1) identification and location of the sources of information: 90% complete; (2) data acquisition and entry: 70% complete; (3) critical evaluation of the data and “cleaning” of the database: 10% complete; (4) analysis of patterns: 0% complete. At present the database hosts a total of 3851 samples; 1118 plankton (net or pump) samples, 492 sediment trap samples, and 2240 surface sediment samples. The total number of datapoints available so far is 186,638 individual species records, as presence/absence, or relative or absolute abundance. Overall coverage trends indicate that plankton materials cover adequately the equatorial belt and the North Atlantic; very few datapoints from Southern Hemisphere waters are available. Most plankton samples (72%) are from surface or subsurface (<100 m) waters. A similar pattern is also shown by sediment trap sites; most of these series cover at least one year of time-series samples. Surface sediment materials, on the other hand, depict a much more comprehensive[?] geographic distribution, with both the northern and the southern hemispheres well-covered by datapoints; poorly represented areas are restricted to the middle latitudes of the southern Pacific and the northern half of the Indian Ocean. For plankton and sediment trap materials most of the data (around 80%) are given in absolute densities (cells per m3, or cells per m2 per day), but sedimentary materials are commonly expressed in relative abundance values (% of each species with respect to the overall radiolarian assemblage); absolute abundances (shells per g dry sediment) are restricted to less than 10% of the data. We anticipate addressing the following questions: How many extant radiolarian species are there? How well do radiolarian distribution patterns match water-mass patterns? How do radiolarian patterns compare with those derived from functional attributes of the ecosystems (such as mixed layer depth, insolation and photic depth, seasonality, etc.)? What are the species diversity vs. latitude relationships in radiolarian asemblages? Are these trends alike in plankton and sediments or are they different? Are there regional variations in pattern or trend? How cosmopolitan are radiolarian species? How do these ranges compare with those of other protists and multicellular plankton? How do these comparisons stand in the light of recent claims that morphologically simpler organisms have wider distribution ranges? Among the questions more specific to radiolarian biological, ecological, and paleoecological studies we anticipate touching on the following: What is the imprint of chlorophyll fields on radiolarian distribution? How congruent are distributional patterns in the plankton and in the sediments? Are there regional or latitudinal trends in the differences? Cold-water species are thought to preserve better in sediments because their shells are more solution-resistant; do the patterns support this notion? Biogenic opal seems to preserve better in the eupelagic province than in the hemipelagic one. Is this a result of surface production, pore-water diagenesis resulting in selective species dissolution, or some other variable or variables?