Silicon isotope ratios of ODP Site 177-1089 and sediment core E33-22

Reconstruction of nutrient concentrations in the deep Southern Ocean has produced conflicting results. The cadmium/calcium (Cd/Ca) data set suggests little change in nutrient concentrations during the last glacial period, whereas the carbon isotope data set suggests that nutrient concentrations were higher. We determined the silicon isotope composition of sponge spicules from the Atlantic and Pacific sectors of the Southern Ocean and found higher silicic acid concentrations in the Pacific sector during the last glacial period. We propose that this increase results from changes in the stoichiometric uptake of silicic acid relative to nitrate and phosphate by diatoms, thus facilitating a redistribution of nutrients across the Pacific and Southern Oceans. Our results are consistent with the global Cd/Ca data set and support the silicic acid leakage hypothesis.

Neodymium isotopic record of planktonic foraminifera in sediment core MD81-LC21

A well developed sapropel (S5) was deposited in the eastern Mediterranean during the Last Interglacial (Eemian), 124-119 ka. Freshwater contributions to the basin at this time can be traced using the isotopic composition of Nd in planktonic foraminifera. This enables differentiation between radiogenic sources to the south, under the influence of the African monsoon, and unradiogenic sources to the north, relating to the mid-latitude westerlies. Here we compare new Nd data, from a core in the southeast Aegean Sea, with published data from the Ionian and Levantine Seas. Shifts towards more radiogenic Nd in the lower and middle parts of sapropel S5 are most pronounced in the Ionian Sea record, with epsioln-Nd and d18O G. ruber co-varying more closely here than in the Levantine and Aegean Seas. This is consistent with a freshwater source proximal to the Ionian Sea site, likely indicating a substantial reactivation of rivers flowing northward from the central Saharan watershed. The lack, during S5 deposition, of a noticeable shift towards more unradiogenic Nd in the Aegean record would exclude a large influx of water from the northern borders of the eastern Mediterranean during sapropel deposition. These findings support a scenario whereby the Last Interglacial eastern Mediterranean was influenced strongly by the remote effects of an intensified African monsoon, with more local precipitation in the northern borders contributing relatively little to the sea surface composition.

Budgies (parrakeets) as pets : a guide to the selection and breeding of parrakeets /

"Copyright c1955 Evelyn Miller"

How to raise and train a Chihuahua,

Mode of access: Internet.

Stories for young persons /

The deformed Boy. --Eighteen hundred thirty-eight's farewell. --Marietza. --Fanny and her dog Neptune. --Skepticism. --Ella. --Small losses. --Spring in the city. --A vision. --Saturday night. --Dogs. --Jacot; an adventure on board the St. George.

Zebrafish KLF4 is essential for anterior mesendoderm/pre-polster differentiation and hatching

Gene knockout studies of Kruppel-like factors (KLFs) in mice have shown essential roles in organogenesis. A screen for KLF family members in zebrafish identified many KLFs. One of these, zebrafish KLF4 (zKLF4) is the homologue of neptune, a Xenopus laevis KLF. zKLF4 is expressed from approximately 80% epiboly a patch of dorsal/anterior mesendodermal cells called the pre-polster and, subsequently, in the polster and hatching gland. Here we investigate the function of zKLF4 using morpholino-based antisense oligonucleotides. Knockdown of zKLF4 resulted in complete absence of hatching gland formation and subsequent hatching in zebrafish. In addition, there was early knockdown of expression of the pre-polster/anterior mesendoderm markers CatL, cap1, and BMP4. These results indicate zKLF4 is expressed within the pre-polster, an early mesendodermal site, and that it plays a critical role in the differentiation of these cells into hatching gland cells.

Physical oceanography during POLARSTERN cruise ANT-V/3

The work carried out by the physical oceanography group on POLARSTERN Leg ANT-V/3 concentrated on four major topics: A. A large scale survey of the eastern boundary between the Weddell gyre and the open ocean. On the way to the coastal polynya in early October 12 CTD stations were carried out between 54°30'S, 6°E and 70°30'S 8°W. Another set of 16 stations was obtained in early December on the way back north. During this transsect three current meter moorings were recovered at Maud Rise. The path between the current meter arrays was used to run an additional section to the NNE across the top of Maud Rise. B. A large scale survey of the Antarctic Coastal Current along the eastern shelf area. To obtain the water mass characteristics along the eastern Weddell shelf 36 CTD stations were carried out between Atka Bay and the Filchner Trench. Most of the stations were located on the shelf. Cross shelf sections were obtained both near Drescher Inlet and off Halley Bay, in the divergence area of the Coastal Current where the continental slope turns to the west and south of Vestkapp at Neptune's Point. A longshore section over 120 km was run north of Vestkapp. C. A mesoscale survey of the Antarctic Coastal Current off Drescher Inlet. The experimental work consisted of 37 CTD-stations and direct current measurements. The CTD-profiles were grouped into seven sections perpendicular to the coast line off Drescher Inlet extending once over 70 km but normally over 35 km. The profile depth ranged from 300 m on one section to the complete water column at two sections. Most sections consist of five stations providing highest resolution over the upper continental slope with offshore increasing spacing. The stations were chosen to represent the shelf (450 m), the shelf break (800 m), the upper slope (1600 m), the lower slope (2400 m) and the transition to the abyssal plain (3400 m). Rough topography and difficult ice conditions made it impossible to meet those requirements in all cases. D. A small scale survey of the hydrographic conditions under the sea ice. The motivation for these studies arose during the cruise. Consequently a suitable Instrumentation had to be developed at sea. This was done with a NB-Smart CTD which was inserted on an L-shaped lever through a hole in the ice. However, various water intrusions into the instrument resulted in the failure of this technique. In consequence a special lever system was built to position a NB Mark 3b weighing about 40 kg below the ice. Twenty four profiles were obtained reaching from the bottom of the ice down to 2 m below the ice surface with a maximum distance of 1 m from the entry hole. As the conductivity sensor was influenced by nearby ice platelets, salinity samples where drawn to check the sensor.

Chemical and isotopic composition of carbonate veins from ODP Leg 209

Carbonate veins hosted in ultramafic basement drilled at two sites in the Mid Atlantic Ridge 15°N area record two different stages of fluid-basement interaction. A first generation of carbonate veins consists of calcite and dolomite that formed syn- to postkinematically in tremolite-chlorite schists and serpentine schists that represent gently dipping large-offset faults. These veins formed at temperatures between 90 and 170 °C (oxygen isotope thermometry) and from fluids that show intense exchange of Sr and Li with the basement (87Sr/86Sr = 0.70387 to 0.70641, d7Li L-SVEC = + 3.3 to + 8.6 per mil). Carbon isotopic compositions range to high d13C PDB values (+ 8.7 per mil), indicating that methanogenesis took place at depth. The Sr-Li-C isotopic composition suggests temperatures of fluid-rock interaction that are much higher (T > 350-400 °C) than the temperatures of vein mineral precipitation inferred from oxygen isotopes. A possible explanation for this discrepancy is that fluids cooled conductively during upflow within the presumed detachment fault. Aragonite veins were formed during the last 130 kyrs at low-temperatures within the uplifted serpentinized peridotites. Chemical and isotopic data suggest that the aragonites precipitated from cold seawater, which underwent overall little exchange with the basement. Oxygen isotope compositions indicate an increase in formation temperature of the veins by 8-12 °C within the uppermost ~ 80 m of the subseafloor. This increase corresponds to a high regional geothermal gradient of 100-150 °C/km, characteristic of young lithosphere undergoing rapid uplift.

(Table S1) Trace element and isotopic compositions of anhydrites sampled in the Manus Basin, Papua New Guinea

Microchemical analyses of rare earth element (REE) concentrations and Sr and S isotope ratios of anhydrite are used to identify sub-seafloor processes governing the formation of hydrothermal fluids in the convergent margin Manus Basin, Papua New Guinea. Samples comprise drill-core vein anhydrite and seafloor massive anhydrite from the PACMANUS (Roman Ruins, Snowcap and Fenway) and SuSu Knolls (North Su) active hydrothermal fields. Chondrite-normalized REE patterns in anhydrite show remarkable heterogeneity on the scale of individual grains, different from the near uniform REEN patterns measured in anhydrite from mid-ocean ridge deposits. The REEN patterns in anhydrite are correlated with REE distributions measured in hydrothermal fluids venting at the seafloor at these vent fields and are interpreted to record episodes of hydrothermal fluid formation affected by magmatic volatile degassing. 87Sr/86Sr ratios vary dramatically within individual grains between that of contemporary seawater and that of endmember hydrothermal fluid. Anhydrite was precipitated from a highly variable mixture of the two. The intra-grain heterogeneity implies that anhydrite preserves periods of contrasting hydrothermal versus seawater dominant near-seafloor fluid circulation. Most sulfate d34S values of anhydrite cluster around that of contemporary seawater, consistent with anhydrite precipitating from hydrothermal fluid mixed with locally entrained seawater. Sulfate d34S isotope ratios in some anhydrites are, however, lighter than that of seawater, which are interpreted as recording a source of sulfate derived from magmatic SO2 degassed from underlying felsic magmas in the Manus Basin. The range of elemental and isotopic signatures observed in anhydrite records a range of sub-seafloor processes including high-temperature hydrothermal fluid circulation, varying extents of magmatic volatile degassing, seawater entrainment and fluid mixing. The chemical and isotopic heterogeneity recorded in anhydrite at the inter- and intra-grain scale captures the dynamics of hydrothermal fluid formation and sub-seafloor circulation that is highly variable both spatially and temporally on timescales over which hydrothermal deposits are formed. Microchemical analysis of hydrothermal minerals can provide information about the temporal history of submarine hydrothermal systems that are variable over time and cannot necessarily be inferred only from the study of vent fluids.

Seawater carbonate chemistry and biological processed during experiments with corals Porites sp. & Stylophora pistillata, 2010

Uptake of anthropogenic CO2 by the oceans is altering seawater chemistry with potentially serious consequences for coral reef ecosystems due to the reduction of seawater pH and aragonite saturation state (omega arag). The objectives of this long-term study were to investigate the viability of two ecologically important reef-building coral species, massive Porites sp. and Stylophora pistilata, exposed to high pCO2(or low pH) conditions and to observe possible changes in physiologically related parameters as well as skeletal isotopic composition. Fragments of Porites sp. and S. pistilata were kept for 6-14 months under controlled aquarium conditions characterized by normal and elevated pCO2 conditions, corresponding to pHTvalues of 8.09, 7.49, and 7.19, respectively. In contrast with shorter, and therefore more transient experiments, the long experimental timescale achieved in this study ensures complete equilibration and steady state with the experimental environment and guarantees that the data provide insights into viable and stably growing corals. During the experiments, all coral fragments survived and added new skeleton, even at seawater omega arag <1, implying that the coral skeleton is formed by mechanisms under strong biological control. Measurements of boron (B), carbon (C) and oxygen (O) isotopic composition of skeleton, C isotopic composition of coral tissue and symbiont zooxanthellae, along with physiological data (such as skeletal growth, tissue biomass, zooxanthellae cell density and chlorophyll concentration) allow for a direct comparison with corals living under normal conditions and sampled simultaneously. Skeletal growth and zooxanthellae density were found to decrease, whereas coral tissue biomass (measured as protein concentration) and zooxanthellae chlorophyll concentrations increased under high pCO2 (low pH) conditions. Both species showed similar trends of delta11B depletion and delta18O enrichment under reduced pH, whereas the delta13C results imply species-specific metabolic response to high pCO2 conditions. The skeletal delta11B values plot above seawater delta11B vs. pH borate fractionation curves calculated using either the theoretically derived deltaB value of 1.0194 (Kakihana et al., Bull. Chem. Soc. Jpn. 50(1977), 158) or the empirical deltaB value of 1.0272 (Klochko et al., EPSL 248 (2006), 261). However, the effective deltaB must be greater than 1.0200 in order to yield calculated coral skeletal delta11B values for pH conditions where omega arag >1. The delta11B vs. pH offset from the literature seawater delta11B vs. pH fractionation curves suggests a change in the ratio of skeletal material laid down during dark and light calcification and/or an internal pH regulation, presumably controlled by ion-transport enzymes. Finally, seawater pH significantly influences skeletal delta13C and delta18O. This must be taken into consideration when reconstructing paleo-environmental conditions from coral skeleton

Cape Lookout cold-water coral area, coral ages and environmental parameters for the last glacial cycle

Climatic and oceanographic changes, as occurring at a glacial-interglacial scale, may alter the environmental conditions needed for the development of prolific cold-water coral reefs and mounds. Studies constraining the temporal distribution of cold-water corals in the NE Atlantic suggested the cyclic changes of the Atlantic Meridional Overturning Circulation as the main driver for the development and dispersal of cold-water coral ecosystems. However, conclusions were hindered by lack of data from the NW Atlantic. Aiming to overcome this lack of data, the temporal occurrence of cold-water corals in the Cape Lookout area along the southeastern US margin was explored by U-series dating. Furthermore, the local influence of the regional water masses, namely the Gulf Stream, on cold-water coral proliferation and occurrence since the Last Glacial Maximum was examined. Results suggest that the occurrence of cold-water corals in the Cape Lookout area is restricted to interglacial periods, with corals being present during the last ~7 kyr and also during the Eemian (~125 ka). The reconstructed local environmental conditions suggest an offshore displacement of the Gulf Stream and increased influence from the Mid-Atlantic Bight shelf waters during the last glacial period. During the deglacial sea level rise, the Gulf Stream moved coastward providing present-day-like conditions to the surface waters. Nevertheless, present-day conditions at the ocean sea floor were not established before 7.5 cal ka BP once the ultimate demise of the Laurentide ice-sheet caused the final sea level rise and the displacement of the Gulf Stream to its present location. Occasional presence of the Gulf Stream over the site during the Mid- to Late Holocene coincides with enhanced bottom current strength and a slightly higher bottom water temperature, which are environmental conditions that are favorable for cold-water coral growth.

Sobre la medalla a Godoy de la Real Sociedad Económica de Amigos del País de Valencia acuñada en 1807. Documentos inéditos

Entre los documentos del archivo de la Real Sociedad Econó-mica de Amigos del País de Valencia (RSEAPV)1, se encuentra un con-junto muy interesante concerniente a la realización de una medalla por parte de esta sociedad en honor de Manuel Godoy, Príncipe de la Paz. Es en enero de 1807 cuando la RSEAPV decide nombrarlo miembro protector de esa Real Sociedad y, en agradecimiento a su aceptación y su reciente nombramiento al Grande Almirantazgo de España e Yndias, acuña la medalla sobre la cual presento este trabajo. El estudio detallado de los citados documentos nos permitirá ir más allá de las imágenes re-presentadas en el reverso de la misma, proporcionándonos su correcta interpretación dentro del contexto histórico del momento.

The Outer Solar Systems Origins Survey. I. Design and First-quarter Discoveries

We report the discovery, tracking, and detection circumstances for 85 trans-Neptunian objects (TNOs) from the first 42 deg2 of the Outer Solar System Origins Survey. This ongoing r-band solar system survey uses the 0.9 deg2 field of view MegaPrime camera on the 3.6 m Canada–France–Hawaii Telescope. Our orbital elements for these TNOs are precise to a fractional semimajor axis uncertainty <0.1%. We achieve this precision in just two oppositions, as compared to the normal three to five oppositions, via a dense observing cadence and innovative astrometric technique. These discoveries are free of ephemeris bias, a first for large trans-Neptunian surveys. We also provide the necessary information to enable models of TNO orbital distributions to be tested against our TNO sample. We confirm the existence of a cold "kernel" of objects within the main cold classical Kuiper Belt and infer the existence of an extension of the "stirred" cold classical Kuiper Belt to at least several au beyond the 2:1 mean motion resonance with Neptune. We find that the population model of Petit et al. remains a plausible representation of the Kuiper Belt. The full survey, to be completed in 2017, will provide an exquisitely characterized sample of important resonant TNO populations, ideal for testing models of giant planet migration during the early history of the solar system.