The meteorite and tektite collections of Yale University

The last catalogue of the meteorite collections at Yale University was made by Kurt Servos (1956) and included the Peabody Museum Collection and the Bosch Collection which was provisionally deposited at Yale University in 1949…

Magnesium, strontium, and barium concentrations and calcite-aragonite ratios of some recent molluscan shells

Approximately 100 recent molluscan shells have been analyzed spectrographically for Mg, Sr and Ba; their calcite-aragonite ratios were determined by X-ray diffraction. The methods are described in detail. The most important parameter controlling the concentration of these trace elements in calcium carbonate shells appears to be generic association rather than water temperature or calcite-aragonite ratio of the shell. As a group, snails are higher in Mg and lower in Sr and Ba than clams...

Climatic Implications of Barbados Coral Growth

Results from a coral growth band analysis utilizing samples of M. annularis from the Recent Barbados reef and from three fossil raised reefs (Barbados I, II, and III dated at 82,000, 105,000, and 125,000 yrs. B.P.) indicate that in the Barbados II collection both average band width and variability were lower than in the other samples. We suggest the climate during formation of the 105,000 yrs. B.P. reef was significantly different than that of the present

Transport and residence times of tropospheric aerosols inferred from a global three-dimensional simulation of 210_Pb

A global three‐dimensional model is used to investigate the transport and tropospheric residence time of Pb, an aerosol tracer produced in the atmosphere by radioactive decay of Rn emitted from soils. The model uses meteorological input with 4°×5° horizontal resolution and 4‐hour temporal resolution from the Goddard Institute for Space Studies general circulation model (GCM). It computes aerosol scavenging by convective precipitation as part of the wet convective mass transport operator in order to capture the coupling between vertical transport and rainout. Scavenging in convective precipitation accounts for 74% of the global Pb sink in the model; scavenging in large‐scale precipitation accounts for 12%, and scavenging in dry deposition accounts for 14%. The model captures 63% of the variance of yearly mean Pb concentrations measured at 85 sites around the world with negligible mean bias, lending support to the computation of aerosol scavenging. There are, however, a number of regional and seasonal discrepancies that reflect in part anomalies in GCM precipitation. Computed residence times with respect to deposition for Pb aerosol in the tropospheric column are about 5 days at southern midlatitudes and 10–15 days in the tropics; values at northern midlatitudes vary from about 5 days in winter to 10 days in summer. The residence time of Pb produced in the lowest 0.5 km of atmosphere is on average four times shorter than that of Pb produced in the upper atmosphere. Both model and observations indicate a weaker decrease of Pb concentrations between the continental mixed layer and the free troposphere than is observed for total aerosol concentrations; an explanation is that Rn is transported to high altitudes in wet convective updrafts, while aerosols and soluble precursors of aerosols are scavenged by precipitation in the updrafts. Thus Pb is not simply a tracer of aerosols produced in the continental boundary layer, but also of aerosols derived from insoluble precursors emitted from the surface of continents. One may draw an analogy between Pb and nitrate, whose precursor NO is sparingly soluble, and explain in this manner the strong correlation observed between nitrate and Pb concentrations over the oceans.Engineering and Applied Science

Science Perspectives on the CCSP Strategic Plan

Scientists offer comments on the Climate Change Science Program Strategic Pla

Dietary carbon sources of mussels and tubeworms from Galápagos hydrothermal vents determined from tissue 14C activity

The large quantities of reduced carbon that are required to support the filter-feeding mytilid mussels (Mytilus sp.), vesi-comyid clams (Calyptogena sp.) and various other animals in the Galápagos hydrothermal vent systems are thought to be derived from either the in situ synthesis of particulate organic matter by chemoautotrophic, sulphide-oxidizing bacteria1,2 or by the advection of sedimentary organic carbon into the vent environment from surrounding areas3,4. In contrast, the dense populations of vestimentiferan tubeworms (Riftia pachyptila), which lack mouth organs and digestive tracts, apparently utilize organic carbon synthesized by symbiotic chemoautotrophs5. We present evidence here, based on 14C activities and 13C/12C ratios, that the principal source of dietary carbon for mussels and tubeworms is derived from the dissolved inorganic carbon (DIOC) in the vent effluent waters. © 1981 Nature Publishing Group

Oceans

149 p. : il.; 22 cm