Nature Geoscience contents: December 2013 Volume 6 Number 12 pp987-1065

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We'll be posting updates about the launch on Twitter and Facebook TABLE OF CONTENTS December 2013 Volume 6, Issue 12 Editorials In the press Research Highlights News and Views Review Letters Articles Subscribe   Facebook   RSS   Recommend to library   Twitter   Advertisement Nature Geoscience Insight: Marine cycles in flux In this Nature Geoscience Insight we highlight some of the most intriguing advances in the microbial biogeochemistry of the oceans, a field that is very much in flux.  Free online for a limited time  Produced with support from:       Editorials Top Save our sea-level observations   p987 doi:10.1038/ngeo2035 The UK's Permanent Service for Mean Sea Level has operated for 80 years. Such long-term records are invaluable and their diversity must be maintained. The upside of impacts   p987 doi:10.1038/ngeo2036 The Chelyabinsk fireball highlighted the threat of asteroids and comets. But actually, for life on Earth, impacts may have once played the role of hero. See also: Letter by Howard et al. | Article by Martins et al. In the press Top To the Moon with LADEE   p988 Emily Lakdawalla doi:10.1038/ngeo2024 Research Highlights Top Planetary science: Weighing Phobos | Oceanography: Ice loss and ocean life | Palaeoceanography: Southern upwelling | Tectonics: Sunken islands News and Views Top Volcanology: Mobile magma under Antarctic ice   pp990 - 991 John C. Behrendt doi:10.1038/ngeo2011 Volcanoes have been active under the West Antarctic Ice Sheet for millions of years, and there is evidence for recent activity. Now swarms of tiny earthquakes detected in 2010 and 2011 hint at current magma movement in the crust beneath the ice. See also: Letter by Lough et al. Planetary science: Evolved magma on Mars   pp991 - 992 Briony Horgan doi:10.1038/ngeo2010 The surface of Mars is dominated by basalt that has undergone little magmatic evolution. However, minerals now identified in some ancient terrains suggest that extensive magma processing and intrusive volcanism were not uncommon on the red planet. See also: Letter by Wray et al. | Letter by Carter & Poulet Climate science: Breaks in trends   pp992 - 993 Felix Pretis and Myles Allen doi:10.1038/ngeo2015 Global temperature rise since industrialization has not been uniform. A statistical analysis suggests that past changes in the rate of warming can be directly attributed to human influences, from economic downturns to the regulations of the Montreal Protocol. See also: Article by Estrada et al. Palaeoclimate: Deglacial decoupling   pp994 - 995 Jeffrey P. Severinghaus doi:10.1038/ngeo2023 Antarctic temperatures and atmospheric carbon dioxide levels generally co-varied at the end of glacial periods. Detailed analysis of an Antarctic ice core suggests a decoupling during the deglaciation 130,000 years ago, possibly linked to a strengthening of ocean circulation. See also: Article by Landais et al. Atmospheric chemistry: Radical regeneration from isoprene   pp995 - 996 Jason D. Surratt doi:10.1038/ngeo2022 Significant quantities of the ozone and aerosol precursor isoprene are released into the atmosphere in densely forested regions of the world. Experimental observations suggest that the oxidation of isoprene in these pristine environments adds to the self-cleansing capacity of the atmosphere. See also: Letter by Fuchs et al. Planetary science: Occam's origin of the Moon   pp996 - 998 Linda T. Elkins-Tanton doi:10.1038/ngeo2026 Following almost three decades of some certainty over how the Moon was formed, new geochemical measurements have thrown the planetary science community back into doubt. We are either modelling the wrong process, or modelling the process wrong. Geoscience JOBS of the week Assistant, Associate, or Full Professor - Solid Earth Geophysics and Atmospheric Sciences King Abdullah University of Science and Technology (KAUST) Environmental Engineer / Geologist - San Francisco Bay Area Webuild Services LLC / Webuild Staffing Postdoctoral Fellowships Carnegie Institution of Washington Graduate Student and Postdoctoral opportunities to study the marine nitrogen cycle Dalhousie University More Science jobs from Review Top Projected response of the Indian Ocean Dipole to greenhouse warming   pp999 - 1007 Wenju Cai, Xiao-Tong Zheng, Evan Weller, Mat Collins, Tim Cowan et al. doi:10.1038/ngeo2009 The Indian Ocean Dipole is a key mode of interannual climate variability influencing much of Asia and Australia. A Review suggests that in response to greenhouse warming, mean conditions of the Indian Ocean will shift toward a positive dipole state, but with no overall shift in the frequency of positive and negative events as defined relative to the mean climate state. Letters Top Ancient plutonic processes on Mars inferred from the detection of possible anorthositic terrains   pp1008 - 1012 J. Carter and F. Poulet doi:10.1038/ngeo1995 The formation of the silicate mineral anorthosite is thought to require magmatic processes that are not expected on Mars because of its predominately mafic terrains. Localized spectral detections by the Mars Reconnaissance Orbiter are consistent with anorthosite, suggestive of ancient intrusive igneous processes similar to those active on Earth. See also: News and Views by Horgan Prolonged magmatic activity on Mars inferred from the detection of felsic rocks   pp1013 - 1017 James J. Wray, Sarah T. Hansen, Josef Dufek, Gregg A. Swayze, Scott L. Murchie et al. doi:10.1038/ngeo1994 Felsic rocks have not been identified on Mars, a planet that lacks plate tectonics to drive the magmatic processes that lead to evolved silica-rich melts. Spectral observations by the Mars Reconnaissance Orbiter indicate that felsic lithologies occur at multiple localities on Mars and suggest prolonged magmatic activity on ancient Mars. See also: News and Views by Horgan Biomass preservation in impact melt ejecta   pp1018 - 1022 Kieren Torres Howard, Melanie J. Bailey, Deborah Berhanu, Phil A. Bland, Gordon Cressey et al. doi:10.1038/ngeo1996 The pressures and temperatures experienced by material flung from craters following impact events are expected to preclude survival of organics. The preservation of biomarkers in impact glass from the Darwin crater in Tasmania suggests that organic matter can survive in the distal products of meteorite impact. See also: Editorial Experimental evidence for efficient hydroxyl radical regeneration in isoprene oxidation   pp1023 - 1026 H. Fuchs, A. Hofzumahaus, F. Rohrer, B. Bohn, T. Brauers et al. doi:10.1038/ngeo1964 Field measurements have revealed much higher concentrations of hydroxyl radicals than expected in regions with high loads of the biogenic volatile organic compound isoprene. Results from isoprene oxidation experiments suggest that the additional recycling of radicals in the presence of isoprene contributes to hydroxyl radical enhancement in these regions. See also: News and Views by Surratt The role of fire in Miocene to Pliocene C4 grassland and ecosystem evolution   pp1027 - 1030 Sebastian Hoetzel, Lydie Dupont, Enno Schefuß, Florian Rommerskirchen and Gerold Wefer doi:10.1038/ngeo1984 Modern grasslands are dominated by grasses that use the C4 photosynthetic pathway, and were established about 8 million years ago. A sediment record suggests that in southwestern Africa, the expansion of grasslands was associated with increasing aridity and fire activity, both of which favour grasses that use the C4 pathway. Seismic detection of an active subglacial magmatic complex in Marie Byrd Land, Antarctica   pp1031 - 1035 Amanda C. Lough, Douglas A. Wiens, C. Grace Barcheck, Sridhar Anandakrishnan, Richard C. Aster et al. doi:10.1038/ngeo1992 Several volcanoes exist in Marie Byrd Land, a highland range in West Antarctica, but none were thought to be currently active. Analysis of seismic data from the region shows that magma could be moving beneath the West Antarctic Ice Sheet, with potential implications for ice flow. See also: News and Views by Behrendt Viscous roots of active seismogenic faults revealed by geologic slip rate variations   pp1036 - 1040 P. A. Cowie, C. H. Scholz, G. P. Roberts, J. P. Faure Walker and P. Steer doi:10.1038/ngeo1991 The flow of ductile rocks in the deep crust and uppermost mantle is thought to add stress to faults in the shallow crust, potentially bringing the faults closer to rupture. Measurements of fault offsets in the Italian Apennines show that earthquake recurrence is largely controlled by viscous flow of deeper rocks in localized zones. Ponded melt at the boundary between the lithosphere and asthenosphere   pp1041 - 1044 Tatsuya Sakamaki, Akio Suzuki, Eiji Ohtani, Hidenori Terasaki, Satoru Urakawa et al. doi:10.1038/ngeo1982 The boundary between Earth's rigid lithosphere and ductile asthenosphere is marked by a seismic discontinuity. Laboratory experiments on basaltic magmas show that melts should pond at pressures that correspond to the lithosphere-asthenosphere boundary. Thus, magma ponding could explain the observed seismic discontinuity. Articles Top Shock synthesis of amino acids from impacting cometary and icy planet surface analogues   pp1045 - 1049 Zita Martins, Mark C. Price, Nir Goldman, Mark A. Sephton and Mark J. Burchell doi:10.1038/ngeo1930 Comets harbour the organic precursors of amino acids. High-velocity impact experiments into icy targets suggest that impacts involving icy planetary bodies could be a viable pathway to synthesize the complex organic compounds needed for life. See also: Editorial Statistically derived contributions of diverse human influences to twentieth-century temperature changes   pp1050 - 1055 Francisco Estrada, Pierre Perron and Benjamín Martínez-López doi:10.1038/ngeo1999 The causal connection between human activities and the evolution of climate warming over the past century is not fully understood. A state-of-the-art statistical analysis of time series of temperature and radiative forcing reveals that reductions in ozone-depleting substances and methane have contributed to the slow-down in warming since the late 1990s. See also: News and Views by Pretis & Allen Probability of US heat waves affected by a subseasonal planetary wave pattern   pp1056 - 1061 Haiyan Teng, Grant Branstator, Hailan Wang, Gerald A. Meehl and Warren M. Washington doi:10.1038/ngeo1988 The predictability of heat waves in the mid-latitudes has been limited to the 10-day range of weather forecasts. An integration of a climate model that spans 12,000 years reveals a pattern in atmospheric planetary waves that tends to precede heat waves in the US, extending potential predictability to 20 days. Two-phase change in CO2, Antarctic temperature and global climate during Termination II   pp1062 - 1065 A. Landais, G. Dreyfus, E. Capron, J. Jouzel, V. Masson-Delmotte et al. doi:10.1038/ngeo1985 Glacial Termination II was marked by a rise in atmospheric CO2 concentrations and global temperature. An analysis of air bubbles from an Antarctic ice core suggests that during the first phase of deglaciation, Antarctic temperature and atmospheric CO2 concentrations increased together, whereas CO2 lagged behind temperature rise during the second phase. See also: News and Views by Severinghaus Top Advertisement Subscribe to Nature this Holiday season for only $50, £50 or €50 Enjoy 51 issues in print, online and multimedia content, and access via the nature.com app for iPhone, iPod touch and the new issue-based NatureJournals iPad app with enhanced features.  Subscribe today!    Natureevents is a fully searchable, multi-disciplinary database designed to maximise exposure for events organisers. The contents of the Natureevents Directory are now live. The digital version is available here. Find the latest scientific conferences, courses, meetings and symposia on natureevents.com. For event advertising opportunities across the Nature Publishing Group portfolio please contact natureevents@nature.com More Nature Events

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