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| Lacan, F.; Radic, A.; Jeandel, C.; Poitrasson, F.; Sarthou, Geraldine; Pradoux, C.; Freydier, R.. |
| This work demonstrates for the first time the feasibility of the measurement of the isotopic composition of dissolved iron in seawater for a typical open ocean Fe concentration range (0.1-1 nM). It also presents the first data of this kind. Iron is preconcentrated using a Nitriloacetic Acid Superflow resin and purified using an AG1x4 anion exchange resin. The isotopic ratios are measured with a MC-ICPMS Neptune, coupled with a desolvator (Aridus II), using a Fe-57-Fe-58 double spike mass bias correction. Measurement precision (0.13%, 2SD) allows resolving small iron isotopic composition variations within the water column, in the Atlantic sector of the Southern Ocean (from delta Fe-57 = -0.19 to +0.32 parts per thousand). Isotopically light iron found in... |
| Tipo: Text |
Palavras-chave: MC ICP MS; Chelating resin; Southern ocean; Fractionation; Seawater; Earth; Separation; Accuracy; Pacific; FE(III). |
| Ano: 2008 |
URL: https://archimer.ifremer.fr/doc/00202/31374/29781.pdf |
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| Steffen, Will; Stockholm Resilience Centre, Stockholm University; Australian National University, Australia; will.steffen@anu.edu.au; Noone, Kevin; Stockholm Resilience Centre, Stockholm University; Department of Applied Environmental Science, Stockholm University; kevin.noone@stockholmresilience.su.se; Chapin, F. Stuart III; Institute of Arctic Biology, University of Alaska Fairbanks; fschapiniii@alaska.edu; Lambin, Eric; Department of Geography, University of Louvain; lambin@geog.ucl.ac.be; Lenton, Timothy M; School of Environmental Sciences, University of East Anglia; t.lenton@uea.ac.uk; Scheffer, Marten; Aquatic Ecology and Water Quality Management Group, Wageningen University; Marten.Scheffer@wur.nl; Folke, Carl; Stockholm Resilience Centre, Stockholm University; The Beijer Institute of Ecological Economics, Royal Swedish Academy of Sciences; carl.folke@beijer.kva.se; Schellnhuber, Hans Joachim; Potsdam Institute for Climate Impact Research; Environmental Change Institute and Tyndall Centre, Oxford University ; schellnhuber@pik-potsdam.de; de Wit, Cynthia A; Department of Applied Environmental Science, Stockholm University; cynthia.de.wit@itm.su.se; Hughes, Terry; ARC Centre of Excellence for Coral Reef Studies, James Cook University; terry.hughes@jcu.edu.au; van der Leeuw, Sander; School of Human Evolution and Social Change, Arizona State University; vanderle@asu.edu; Rodhe, Henning; Department of Meteorology, Stockholm University; rodhe@misu.su.se; Snyder, Peter K; Department of Soil, Water, and Climate, University of Minnesota; pksnyder@umn.edu; Costanza, Robert; Stockholm Resilience Centre, Stockholm University; Gund Institute for Ecological Economics, University of Vermont; rcostanz@uvm.edu; Svedin, Uno; Stockholm Resilience Centre, Stockholm University; uno.svedin@formas.se; Falkenmark, Malin; Stockholm Resilience Centre, Stockholm University; Stockholm International Water Institute; malin.falkenmark@siwi.org; Karlberg, Louise; Stockholm Resilience Centre, Stockholm University; Stockholm Environment Institute; louise.karlberg@stockholmresilience.su.se; Corell, Robert W; The H. John Heinz III Center for Science, Economics and the Environment ; Corell@heinzctr.org; Fabry, Victoria J; Department of Biological Sciences, California State University San Marcos; fabry@csusm.edu; Hansen, James; NASA Goddard Institute for Space Studies; James.E.Hansen@nasa.gov; Walker, Brian; Stockholm Resilience Centre, Stockholm University; CSIRO Sustainable Ecosystems; Brian.Walker@csiro.au; Liverman, Diana; Environmental Change Institute, School of Geography and the Environment; Institute of the Environment, University of Arizona ; diana.liverman@eci.ox.ac.uk; Richardson, Katherine; Earth System Science Centre, University of Copenhagen; kari@science.ku.dk; Crutzen, Paul; Max Planck Institute for Chemistry; air@mpch-mainz.mpg.de; Foley, Jonathan; Institute on the Environment, University of Minnesota; jfoley@umn.edu. |
| Anthropogenic pressures on the Earth System have reached a scale where abrupt global environmental change can no longer be excluded. We propose a new approach to global sustainability in which we define planetary boundaries within which we expect that humanity can operate safely. Transgressing one or more planetary boundaries may be deleterious or even catastrophic due to the risk of crossing thresholds that will trigger non-linear, abrupt environmental change within continental- to planetary-scale systems. We have identified nine planetary boundaries and, drawing upon current scientific understanding, we propose quantifications for seven of them. These seven are climate change (CO2 concentration in the atmosphere <350 ppm and/or a maximum change... |
| Tipo: Peer-Reviewed Reports |
Palavras-chave: Atmospheric aerosol loading; Biogeochemical nitrogen cycle; Biological diversity; Chemical pollution; Climate change; Earth; Global freshwater use; Land system change; Ocean acidification; Phosphorus cycle; Planetary boundaries; Stratospheric ozone; Sustainability. |
| Ano: 2009 |
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| Leye, P. O.; Tarits, Pascal. |
| At and near the Earth surface, electromagnetic (EM) fields radiated from VLF transmitters are commonly used in geological exploration to determine the shallow Earth conductivity structure. Onboard satellites such as DEMETER, the electric and magnetic sensors detect the VLF signal in altitude. While we know for surface measurement that the VLF EM field recorded at some distance from the transmitter is a function of the ground conductivity, we do not know how this relationship changes when the field is measured at satellite altitude. Here we study the electromagnetic field radiated by a vertical electric dipole located on the Earth surface in the VLF range and measured at satellite altitude in a free space. We investigate the EM field as function of distance... |
| Tipo: Text |
Palavras-chave: VLF; Satellite; Earth. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00639/75141/75492.pdf |
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