Thorium and radiocarbon measurements on sediment cores from the Northseast Atlantic

Radiocarbon and 230Thexcess data from six NE Atlantic box cores are considered. The cores form a transect from the Porcupine Abyssal Plain over the East Thulean Rise to the southern end of Feni Drift. The chronology for the cores is established from bulk sediment carbonate radiocarbon data and reveals that sections exhibiting constant accumulation rates can be identified in all the cores, with rates of 3.0-3.5 cm/kyr on the plain through the Holocene and late Holocene rates of 4.3-6.6 cm/kyr elsewhere. Five out of the six cores show accumulations of more 230Thexcess than is produced in the overlying water column, with the greatest inventories (up to 225% of production) in the cores from the rise and drift. A size fraction comparison between two cores from the plain and rise reveals that the higher overall accumulation rates and 230Thexcess inventories in the off-plain cores are due to an increased fine (<5 µm) component fraction, whereas the flux of coarser material is similar to that received on the plain. This suggests that the higher fluxes of materials observed are physically (rather than biogeochemically) driven and also that drift formation has been continuously active in the late Holocene. Sections of all the cores where regular accumulation is defined by the radiocarbon data are modeled first by a linear radiocarbon age/depth model and second by a constant rain (230Thexcess)0 model prorated for the observed core inventories. These modeling approaches yield historical mass accumulation rate estimates which are generally in reasonable agreement (±30%), but the differences observed appear to be well organized in time rather than random.

Coloquio Internacional Lenguaje, Discurso y Civilización (4 : 2006 : La Plata). Lenguaje, discurso y civilización

Tabla de contenidos: El rescate del discurso oral / Pedro Luis Barcia. Uma introduçao ao estudo e cultural da música na Grécia antiga / Fábio Vergara Cerqueira. Lenguaje, discurso y meta-teatralidad en los cantos corales de Séneca / Zelia de Almeida Cardoso. Actualidad y pervivencia del discurso político romano / Gregorio Hinojo Andrés. Lenguaje, discurso y civilización en Baquílides 11 / Ana María González de Tobia. Los ditirambos de Baquílides : Lenguaje, estructura y religiosidad / Fernando García Romero. La represión del adulterio por la Lex iulia de adulteriis coercendis / Marha Patricia Irigoyen Troconis. El imaginario empedocleo / Giuseppina Grammatico. El género lírico entre autoridad poética y prácticas enunciativas : De Goethe a Safo / Claude Calame. La isla y el exilio : Lenguaje y recuperación de la civilización en Odisea / Graciela Cristina Zecchin de Fasano. Homéridas y rehenes / Jaume Pòrtulas. Virgilio y la palabra poética / Antonio Alvar Ezquerra. Falsedad genuina y falsedad verbal en Platón / María Isabel Santa Cruz. El origen de las ideas sobre el espacio y el tiempo / Héctor Vucetich. Homero y Heródoto / Christopher Pelling. Traços teológicos comuns à tragédias de Esquilo : A Teologia de Esquilo no drama Prometheus Demótes / Jaa Torrano. Onoma, érgon y lógos en Helena de Eurípides / Juan Tobías Nápoli. Atenas y Delfos : Adivinación, ley y lenguaje en la Orestíada / Angus Bowie. Linguaggio, discorso e veritá nella Repubblica di Platone / Giovanni Casertano. El estribillo en la poesía clásica, o el poder de la repetición / David Konstan.

Metamorphic processes in sediments at DSDP Leg 65 Holes

Sites 482, 483, and 485 were drilled during Leg 65 on young oceanic crust south of the Tamayo Transform Fault. The Leg 65 drilling program was part of a multinational effort to study the East Pacific Rise (EPR) and complements sea bottom surveys conducted both in this area (Lewis, 1979; Cyamex Scientific Team and Pastouret, 1981) and farther south at 21 °N (Larson, 1971; Normark, 1976; Cyamex Scientific Team; Rise Project Group, 1980). These studies, which included deep-tow, Angus and submersible surveys, were recently complemented by sea-beam surveys conducted by the Jean Charcot on the Tamayo Fracture Zone and farther south along the EPR. They have led to a better understanding of the magmatic, tectonic, and sedimentary processes occurring on the East Pacific Rise between the Tamayo and Rivera fracture zones. The purpose of this chapter is to describe the metamorphic processes affecting Pliocene through Quaternary sediments found in contact, or inter layered, with basaltic units drilled during Leg 65 at the mouth of the Gulf of California.

Seawater carbonate chemistry, mass, size and regenerative capacity of Luidia clathrata during experiments, 2011

The present study examines sublethal effects of near-future (year 2100) ocean acidification (OA) on regenerative capacity, biochemical composition, and behavior of the sea star Luidia clathrata, a predominant predator in sub-tropical soft-bottom habitats. Two groups of sea stars, each with two arms excised, were maintained on a formulated diet in seawater bubbled with air alone (pH 8.2, approximating a pCO2 of 380 µatm) or with a controlled mixture of air/C02 (pH 7.8, approximating a pCO2 of 780 µatm). Arm length, total body wet weight, and righting responses were measured weekly. After 97 days, a period of time sufficient for 80% arm regeneration, pyloric caecal indices, and protein, carbohydrate, lipid, and ash levels were determined for body wall and pyloric caecal tissues of intact and regenerating arms of individuals held in both seawater pH treatments. The present study indicates that predicted near-term levels of ocean acidification (seawater pH 7.8) do not significantly impact whole animal growth, arm regeneration rates, biochemical composition, or righting behavior in this common soft bottom sea star.