Linking global drivers of agricultural trade to on-the-ground impacts on biodiversity.

Consumption of globally traded agricultural commodities like soy and palm oil is one of the primary causes of deforestation and biodiversity loss in some of the world's most species-rich ecosystems. However, the complexity of global supply chains has confounded efforts to reduce impacts. Companies and governments with sustainability commitments struggle to understand their own sourcing patterns, while the activities of more unscrupulous actors are conveniently masked by the opacity of global trade. We combine state-of-the-art material flow, economic trade, and biodiversity impact models to produce an innovative approach for understanding the impacts of trade on biodiversity loss and the roles of remote markets and actors. We do this for the production of soy in the Brazilian Cerrado, home to more than 5% of the world´s species. Distinct sourcing patterns of consumer countries and trading companies result in substantially different impacts on endemic species. Connections between individual buyers and specific hot spots explain the disproportionate impacts of some actors on endemic species and individual threatened species, such as the particular impact of European Union consumers on the recent habitat losses for the iconic giant anteater (Myrmecophaga tridactyla). In making these linkages explicit, our approach enables commodity buyers and investors to target their efforts much more closely to improve the sustainability of their supply chains in their sourcing regions while also transforming our ability to monitor the impact of such commitments over time.UK Global Food Security programme (Project 304 BB/N02060X/1

Paleomagnetism. Solar nebula magnetic fields recorded in the Semarkona meteorite.

Magnetic fields are proposed to have played a critical role in some of the most enigmatic processes of planetary formation by mediating the rapid accretion of disk material onto the central star and the formation of the first solids. However, there have been no experimental constraints on the intensity of these fields. Here we show that dusty olivine-bearing chondrules from the Semarkona meteorite were magnetized in a nebular field of 54 ± 21 microteslas. This intensity supports chondrule formation by nebular shocks or planetesimal collisions rather than by electric currents, the x-wind, or other mechanisms near the Sun. This implies that background magnetic fields in the terrestrial planet-forming region were likely 5 to 54 microteslas, which is sufficient to account for measured rates of mass and angular momentum transport in protoplanetary disks.This is the accepted manuscript. The final version is available from Science at http://www.sciencemag.org/content/346/6213/1089.abstract

Controlled-atmosphere thermal demagnetization and paleointensity analyses of extraterrestrial rocks

We describe a system for conducting thermal demagnetization of extraterrestrial rocks in a controlled atmosphere appropriate for a wide range of oxygen fugacities within the stability domain of iron. Thermal demagnetization and Thellier-Thellier paleointensity experiments on lunar basalt synthetic analogs show that the controlled atmosphere prevents oxidation of magnetic carriers. When combined with multidomain paleointensity techniques, this opens the possibility of highly accurate thermal demagnetization and paleointensity measurements on rocks from the Moon and asteroids.United States. National Aeronautics and Space Administration (Grant NNX12AH80G)

Contribution à la caractérisation physique et isotopique des micrométéorites

The Transantarctic Mountains micrometeorite collection comprises micrometeorites that accumulated for hundreds of thousands of years, among which particles larger than 400 μm in exceptional numbers, which allowed us to demonstrate that their size distribution remains the same on the 100–1600 μm size range, and to make a magnetic and isotopic characterization of these objects : the magnetite they contain in abundance is formed during atmospheric entry, it acquires a thermoremanent magnetization – by quenching in the Earth's magnetic field – that can be sufficient to induce anomalies in the palaeomagnetic record of sediments they deposit in ; the oxygen isotope ratios indicate that part of the micrometeorites are ordinary chondrite-related or originate from as yet unknown parent bodies, and not only from carbonaceous chondrites as stated by the current paradigm.La collection de micrométéorites des Monts Transantarctiques comporte des micrométéorites accumulées pendant plusieurs centaines de milliers d'années, dont un nombre exceptionnel de particules de diamètre >400 μm, qui nous ont permis de démontrer que leur distribution en taille reste la même sur la gamme 100–1600 μm, ainsi que d'en effectuer une caractérisation magnétique et isotopique : la magnétite qu'elles contiennent en abondance est formée lors de l'entrée atmosphérique, elle enregistre une aimantation thermorémanente – lors du refroidissement dans le champ terrestre – qui peut être suffisante pour causer des anomalies dans l'enregistrement paléomagnétique des sédiments dans lesquels les micrométéorites se déposent ; les rapports isotopiques de l'oxygène indiquent, contrairement au dogme actuel, qu'une partie des micrométéorites est apparentée aux chondrites ordinaires ou à des corps parents encore inconnus, et non aux seules chondrites carbonées

Contribution à la caractérisation physique et isotopique des micrométéorites

La collection de micrométéorites des Monts Transantarctiques comporte des micrométéorites accumulées pendant plusieurs centaines de milliers d années, dont un nombre exceptionnel de particules de diamètre >400 m, qui nous ont permis de démontrer que leur distribution en taille reste la même sur la gamme 100 1600 m, ainsi que d en effectuer une caractérisation magnétique et isotopique : la magnétite qu elles contiennent en abondance est formée lors de l entrée atmosphérique, elle enregistre une aimantation thermorémanente lors du refroidissement dans le champ terrestre qui peut être suffisante pour causer des anomalies dans l enregistrement paléomagnétique des sédiments dans lesquels les micrométéorites se déposent ; les rapports isotopiques de l oxygène indiquent, contrairement au dogme actuel, qu une partie des micrométéorites est apparentée aux chondrites ordinaires ou à des corps parents encore inconnus, et non aux seules chondrites carbonées.AIX-MARSEILLE3-BU Sc.St Jérô (130552102) / SudocSudocFranceF

Balancing detail and scale in assessing transparency to improve the governance of agricultural commodity supply chains

To date, assessments of the sustainability of agricultural commodity supply chains have largely relied on some combination of macro-scale footprint accounts, detailed life-cycle analyses and fine-scale traceability systems. Yet these approaches are limited in their ability to support the sustainability governance of agricultural supply chains, whether because they are intended for coarser-grained analyses, do not identify individual actors, or are too costly to be implemented in a consistent manner for an entire region of production. Here we illustrate some of the advantages of a complementary middle-ground approach that balances detail and scale of supply chain transparency information by combining consistent country-wide data on commodity production at the sub-national (e.g. municipal) level with per shipment customs data to describe trade flows of a given commodity covering all companies and production regions within that country. This approach can support supply chain governance in two key ways. First, enhanced spatial resolution of the production regions that connect to individual supply chains allows for a more accurate consideration of geographic variability in measures of risk and performance that are associated with different production practices. Second, identification of key actors that operate within a specific supply chain, including producers, traders, shippers and consumers can help discriminate coalitions of actors that have shared stake in a particular region, and that together are capable of delivering more cost-effective and coordinated interventions. We illustrate the potential of this approach with examples from Brazil, Indonesia and Colombia. We discuss how transparency information can deepen understanding of the environmental and social impacts of commodity production systems, how benefits are distributed among actors, and some of the trade-offs involved in efforts to improve supply chain sustainability. We then discuss the challenges and opportunities of our approach to strengthen supply chain governance and leverage more effective and fair accountability systems

Identification of the parent bodies of micrometeorites with high-precision oxygen isotope ratios

Oxygen isotopic compositions allow identification of potential parent bodies of extraterrestrial materials. We measured oxygen isotope ratios of 33 large (diameter N500 μm) silicate melted micrometeorites (cosmic spherules) from Antarctica, using IR-laser fluorination coupled with mass spectrometry. It is the first time that this high-precision method is used on individual micrometeorites. The selected micrometeorites are representative of the influx of extraterrestrial materials to the Earth. Our results show that most micrometeorites are related to carbonaceous chondrites, which is consistent with previous studies. However, 20–50% of them seem to be related to CO/CV carbonaceous chondrites, whereas CM/CR carbonaceous chondrites were thought to be the main source for micrometeorites. Furthermore, ~30% of measured samples have oxygen isotope ratios lying above the terrestrial fractionation line, which relates them to ordinary chondrites or other, as yet, unsampled parent bodies

Statistical properties of the Transantarctic Mountains (TAM) micrometeorite collection

International audienc

Applications of a 10 um spot size laboratory micro-XRF to environmental sciences

X-ray spectromicroscopy coupling micro-XRF and X-ray microscopy has been developed on synchrotron source more then ten years ago. At the laboratory scale such techniques were more confidential. Due to recent developments in terms of X-ray source and especially in terms of focalization (capillaries, Zone plates...) laboratory micro-XRF equipment have been commercialized in the last 4 or 5 years (Horiba-Jobin Yvon, EDAX, Shimadzu, COX...). Such laboratory instrument are not only limited to material science but they are known to be very efficient in geosciences and environmental science. In these last domains, the main issue is to assess the transfer of pollutant and/or to localise spatially some element(s) of interest. Elements are often present at low concentration and can not be detected by SEM-EDX. Otherwise,the studied samples are generally disordered, heterogeneous, and/or fragile but X-ray spectromicroscopy is a non destructive method and allows In the present work we will present and discuss the advantages and limitations of micro-XRF/microscope (XGT-5000, Horiba-Jobin-Yvon ) equipped with of a 10 µm spot size on different environmental applications.The X-ray beam is generated with a Rh X-ray tube at an acceleration voltage of 15 to 50 keV with a current adjustable up to 1 mA.The X-ray beam is focused with an X- ray guide tube, whose inner diameter is 10 µm, producing a finely focused and high-intensity X-ray beam. The latter is calibrated by measuring the absorption of a tungsten wire of 5 µm thickness, scanned through the beam. X-ray emission from the irradiated sample is detected with an Energy-Dispersive X-ray (EDX) spectrometer equipped with a liquid-nitrogen-cooled high-purity Si detector. The resolution of the detector is 145 eV at the Mn K(alpha) emission line. Furthermore, a scintillator enables transmission measurements. Many scientific topics benefit from the application of our micro-XRF. For example, the impact of waste reuse can be assessed by determining the transfer mechanism of metal pollutants. Recent results concerning by-products from steel industry indicate that vanadium is released from the initial matrix. Lab-installed m cro XRF helped to identify the mineral bearing phases of V. First results concerning the composition of marine sediments are very promising. For example, the ultra-high resolution analysis of a partly laminated sediment core from the Arabian Sea reveals element variabilities at the seasonal scale (100 µm scale).This helps to determine the extend and exact timing of individual phase transitions with respect to past climatic and oceanic changes. Micro-XRF can also be very helpful to identify and classify extra terrestrial material by analyzing e.g. Fe/Ni and Fe/Si ratio.This technique has been successfully applied to meteorites and m crometeorites. Indeed such materials are rare,fragile and very small (down to a few tens of µm in size for micrometeorites). One needs a non destructive technique. Moreover the surface is generally altered and SEM-EDX failed to discriminate samples. Lab-micro-XRF appears as a very interesting routine tool