Characterization of atmospheric iron over and its fluxes to the Southern Ocean through shipboard measurements

Start Date: 5/15/2010

Award Number: 944589

NSF Funding Organization: ANT

Principal Investigator: Gao, Yuan

Co-PI:

Award Amount: $300,000

Program(s): ANTARCTIC OCEAN & ATMOSPH SCI

Abstract: Abstract High nutrient low chlorophyll regions of the Southern Ocean are conventionally explained by lack of bioavailable iron (Fe). Various localized sources of Fe in the Southern Ocean/Antarctic continental margins have been proposed and studied. In areas removed from obviously localized terrestrial dust sources, air-sea deposition of aerosol Fe, the particle size distribution of atmospheric Fe and the variability of aerosol composition, including other atmospheric constituents that may affect the bioavailability of Fe and micronutrients, is not well observed. This project seeks to conduct shipboard atmospheric sampling and analysis from a Chinese ice breaker (R/V Xue Long) passing through the Southern Ocean on route from Shanghai to Zhongshan Station, Antarctica Bulk aerosol and size segregated aerosol samples will be measured for their chemical, physical and morphological properties, Fe content by capillary waveguide spectrophotometry, elemental composition by mass spectrometry (ICPMS), along with corresponding water soluble fractions. Precipitation samples, when encountered, will also be analyzed to derive wet deposition fluxes. Satellite remote sensing of aerosol dust products and chemical transport modeling approaches will also be used in data interpretation.

Low - Dimensional Transition Metal Oxides with Correlated Electronic Properties: Synthesis and Characterization

Start Date: 5/15/2010

Award Number: 966829

NSF Funding Organization: DMR

Principal Investigator: Greenblatt, Martha

Co-PI:

Award Amount: $166,000

Program(s): SOLID STATE & MATERIALS CHEMIS

Abstract: TECHNICAL SUMMARY The focus of the experimental program, supported by the Solid State and Materials Chemistry program is to synthesize new materials with strongly correlated electronic properties that are on the verge of electronic and structural instabilities, and to fine-tune the competing electronic interactions through the unstable region in a controlled way. Experience shows that materials with novel behavior are likely to be discovered when competing electronic interactions exist. In low-dimensional (LD) materials the interplay of competing electronic interactions is enhanced. The object of this project is the synthesis and characterization of new reduced/oxidized-transition metal compounds with quasi-LD properties. A number of systems will be investigated which share the common feature of interplay between localized and itinerant degrees of freedom, a highly variable conduction electron bandwidth, which may be tuned by changing e.g., the crystal structure, chemical composition, external strain and degree of disorder. The variability of bandwidth leads to a variety of important phenomena, including metal-insulator transitions (or sharp crossovers) driven by variation of temperature, pressure, magnetic field, electric field, illumination, lattice distortion and other variables. We expect that in the vicinity of these transitions the transport, electronic/magnetic properties will also change dramatically and will be tunable. The experimental studies will be augmented by theoretical investigation of the electronic structure by density functional theoretical calculations. These studies are expected to yield novel materials, provide fundamental insights into correlated electronic and magnetic behavior and ultimately allow the enhancement and control of electron-phonon and/or electron-electron interactions and the concurrent magnetic couplings that lead to interesting and useful macroscopic properties. NON-TECHNICAL SUMMARY The research will provide advanced materials for potential applications in microelectronics and magneto-electronics, including computers, sensors and communications. These are critical areas for maintaining US technological leadership worldwide. Moreover, the education and training of undergraduate and graduate students and postdoctoral fellows in solid state chemistry/materials science is essential to meet the technological challenges of the twenty first century. The research proposed is highly interdisciplinary. Collaborative work of the PI with other chemists, physicists and ceramicists is well established nationally and internationally. Single crystals and other material products of the work are provided to the scientific community for detailed further investigations.

Stable Isotopic Evidence of the pCO2 Response to the Central Atlantic Magmatic Province

Start Date: 5/1/2010

Award Number: 958867

NSF Funding Organization: EAR

Principal Investigator: Wright, James

Co-PI: Dennis Kent

Award Amount: $52,799

Program(s): SEDIMENTARY GEO & PALEOBIOLOGY

Abstract: Stable isotopic evidence of the pCO2 and temperature response to the Central Atlantic Magmatic Province James Wright and Dennis Kent, Rutgers University EAR-0958867 ABSTRACT Our planet is habitable because the carbon cycle maintains a balance between the supply and the consumption of atmospheric pCO2. Plate tectonics influence the long-term (>105 yr.) cycling of carbon, controlling both the rate of volcanic CO2 outgassing and the removal of CO2 through the exhumation of weatherable rocks. Earth has undergone several periods of large-scale volcanic eruptions termed Large Igneous Provinces (LIPs). Three of the largest and most recent LIPs are the Deccan Traps at 65 Myr, Central Atlantic Magmatic Province (CAMP) at ~200 Myr, and Siberian Traps at ~250 Myr. Various researchers have postulated that volcanic outgassing associated with the emplacement of each LIP led to large-scale environmental/climatic changes, which are closely linked to mass extinctions and subsequent evolutionary recovery. However, a major tenet of these hypotheses, that large-scale outgassing is associated with LIPs, has yet to be demonstrated. Here, PIs will reconstruct atmospheric CO2 levels using stable isotope measurements from sediments deposited before, during, and after the emplacement of the CAMP. They make use of a ?paleo-barometry? method that is based on stable carbon isotope values in both the inorganic and organic phases of paleosols (e.g., Cerling et al. 1999). Variations in the carbon isotope values respond directly to the levels of CO2 in the atmosphere. In the Newark and Hartford Basins, numerous paleosol horizons are found interbedded with igneous rocks of the CAMP; such superposition combined with cycle stratigraphy allows very little age uncertainty. These paleosol isotope reconstructions will test the hypothesis that atmospheric pCO2 increases with LIP emplacements. An under appreciated consequence of LIP emplacement is that well after the initial injection of CO2, long-term weathering of the CAMP rocks may lower atmospheric CO2 below pre-event levels. PIs sampling strategy will collect data to test whether chemical weathering of CAMP volcanic rocks resulted in a long-term decrease in pCO2.