Nature Geoscience contents: October 2012 Volume 5 Number 10 pp675-754

TABLE OF CONTENTS October 2012 Volume 5, Issue 10 Editorial Correspondence Commentary In the press Books and Arts Research Highlights News and Views Correction Progress Article Letters Articles Subscribe   Facebook   RSS   Recommend to library   Twitter   Advertisement Nature Geoscience web focus - Rivers Rivers connect the highest mountains with the ocean's depth, carving up the land as they flow. En route, they transport and transform large quantities of terrestrial material, and exchange elements with the atmosphere, land and sea. In this web focus we present opinion pieces and research articles that examine the topographic, biogeochemical and cultural significance of rivers. Access the web focus    Editorial Top Rivers in transition   p675 doi:10.1038/ngeo1606 Rivers run through nearly every landscape on Earth. Ascertaining the influence of this flux on carbon dynamics is necessary for a full understanding of the climate system. Correspondence Top Problematic plate reconstruction   pp676 - 677 Brian E. Tucholke & Jean-Claude Sibuet doi:10.1038/ngeo1596 See also: Correspondence by Bronner et al. Reply to 'Problematic plate reconstruction'   p677 Adrien Bronner, Daniel Sauter, Gianreto Manatschal, Gwén Peron-Pinvidic & Marc Munschy doi:10.1038/ngeo1597 See also: Correspondence by Tucholke & Sibuet Commentary Top An expanded role for river networks   pp678 - 679 Jonathan P. Benstead & David S. Leigh doi:10.1038/ngeo1593 Estimates of stream and river area have relied on observations at coarse resolution. Consideration of the smallest and most dynamic streams could reveal a greater role for river networks in global biogeochemical cycling than previously thought. In the press Top The state of the seas   p680 Mark Schrope doi:10.1038/ngeo1592 Books and Arts Top Tributaries through time   p681 Anna Armstrong reviews Rivers: A Very Short Introduction by Nick Middleton doi:10.1038/ngeo1598 Research Highlights Top Tsunami: Onshore shake-up | Planetary science: Mars bedevilled | Palaeoclimate: Circulation shrinkage | Biogeochemistry: Arctic nitrogen fix News and Views Top Planetary science: Uninhabitable martian clays?   pp683 - 684 Brian Hynek doi:10.1038/ngeo1560 Clay minerals on Mars have been interpreted as an indication for a warm, wet early climate. A new hypothesis proposes that the minerals instead formed during brief periods of magmatic degassing, diminishing the prospects for signs of life in these settings. See also: Article by Meunier et al. Biogeochemistry: Riverine carbon unravelled   p684 Anna Armstrong doi:10.1038/ngeo1599 Air quality: Emissions versus climate change   pp685 - 686 Christian Hogrefe doi:10.1038/ngeo1591 Climate change is likely to offset some of the improvements in air quality expected from reductions in pollutant emissions. A comprehensive analysis of future air quality over North America suggests that, on balance, the air will still be cleaner in coming decades. Volcanology: A volcano's sharp intake of breath   pp686 - 687 Andrew Hooper doi:10.1038/ngeo1584 Shallow magma bodies that feed regularly erupting volcanoes are usually considered enduring features that grow steadily between eruptions. Measurements of deformation at Santorini, however, reveal sudden rapid magma accumulation after half a century of rest. See also: Article by Parks et al. Geomorphology: Tectonically twisted rivers   pp688 - 689 Eric Kirby doi:10.1038/ngeo1594 Tracking diffuse, shearing deformation of continents is difficult. Numerical modelling of drainage evolution in the Southern Alps, New Zealand, suggests that rivers can act as dynamic markers of tectonic deformation over geological timescales. Climate change: Tropical extremes   pp689 - 690 Geert Lenderink doi:10.1038/ngeo1587 Climate model projections of future precipitation extremes in the tropics are highly uncertain. Observations of year-to-year variations in extremes of present-day climate help to narrow down these projections to a rise in extreme rainfall by 6-14% per °C of warming. See also: Letter by O'Gorman Geoscience JOBS of the week Professor in geology of sedimentary basins Department of Geography and Geology, Faculty of Science, University of Copenhagen Assistant Professor at the University of Pennsylvania University of Pennsylvania Professor for Physical Oceanography (W3) University of Rostock More Science jobs from Geoscience EVENT Appreciating Physical Landscapes: Geotourism 1670-1970 22.-23.10.12 London, UK More science events from Correction Top Hydrology: Supply and demand   p690 doi:10.1038/ngeo1607 Progress Article Top An update on Earth's energy balance in light of the latest global observations   pp691 - 696 Graeme L. Stephens, Juilin Li, Martin Wild, Carol Anne Clayson, Norman Loeb, Seiji Kato, Tristan L'Ecuyer, Paul W. Stackhouse, Jr, Matthew Lebsock & Timothy Andrews doi:10.1038/ngeo1580 Climate change is governed by changes to the global energy balance. A synthesis of the latest observations suggests that more longwave radiation is received at the Earth's surface than previously thought, and that more precipitation is generated. Letters Top Sensitivity of tropical precipitation extremes to climate change   pp697 - 700 Paul A. O'Gorman doi:10.1038/ngeo1568 Precipitation extremes increase in intensity over many regions of the globe in simulations of a warming climate, but not always consistently. Observational constraints, together with a close relationship between model responses to interannual variability and climate change, suggest a high sensitivity of tropical extreme precipitation to warming. See also: News and Views by Lenderink Modelled suppression of boundary-layer clouds by plants in a CO2-rich atmosphere   pp701 - 704 Jordi Vilà-Guerau de Arellano, Chiel C. van Heerwaarden & Jos Lelieveld doi:10.1038/ngeo1554 Boundary-layer clouds modify the near-surface climate and interact with the water and carbon cycles. Biophysical modelling suggests that rising atmospheric CO2 levels and the associated closing of plant stomata may suppress boundary-layer cloud formation in the mid-latitudes, and demonstrates how biological and physical aspects of the climate system are intertwined. Elevation-dependent influence of snow accumulation on forest greening   pp705 - 709 Ernesto Trujillo, Noah P. Molotch, Michael L. Goulden, Anne E. Kelly & Roger C. Bales doi:10.1038/ngeo1571 Increased temperatures and declines in water availability have influenced the productivity of mountain forests over the past half century. An analysis of 25 years of observational and satellite data suggests that mid-elevation forest greenness is strongly regulated by snow accumulation. Biogeochemically diverse organic matter in Alpine glaciers and its downstream fate   pp710 - 714 Gabriel A. Singer, Christina Fasching, Linda Wilhelm, Jutta Niggemann, Peter Steier, Thorsten Dittmar & Tom J. Battin doi:10.1038/ngeo1581 Glaciers store and transform organic carbon, which, on release, could support downstream microbial life. An analysis of 26 glaciers in the European Alps suggests that a significant fraction of glacier organic matter is available for microbial consumption. Dependence of riverine nitrous oxide emissions on dissolved oxygen levels   pp715 - 718 Madeline S. Rosamond, Simon J. Thuss & Sherry L. Schiff doi:10.1038/ngeo1556 Nitrous oxide is a potent greenhouse gas that destroys stratospheric ozone. Measurements of nitrous oxide emissions from a Canadian river suggest that future increases in nitrate export to rivers will not necessarily lead to higher nitrous oxide emissions, but more widespread hypoxia most likely will. Significant contribution to climate warming from the permafrost carbon feedback   pp719 - 721 Andrew H. MacDougall, Christopher A. Avis & Andrew J. Weaver doi:10.1038/ngeo1573 Permafrost soils contain almost twice as much carbon as the current atmospheric carbon pool. Climate model simulations suggest that the feedback generated by future permafrost carbon release could lead to a further warming of 0.13-1.69 °C by 2300. Contributions to late Archaean sulphur cycling by life on land   pp722 - 725 Eva E. Stüeken, David C. Catling & Roger Buick doi:10.1038/ngeo1585 Life on land dates back at least 2.7 billion years, but the effects of this early terrestrial biosphere on biogeochemical cycling are poorly constrained. Marine sulphur data and geochemical modelling suggest that microbial pyrite weathering has transferred a substantial amount of sulphur to the oceans for at least 2.5 billion years. Mantle flow deflected by interactions between subducted slabs and cratonic keels   pp726 - 730 Meghan S. Miller & Thorsten W. Becker doi:10.1038/ngeo1553 Subducting slabs can influence mantle flow, but the importance of neighbouring continental cratons is little understood. Geodynamical modelling, constrained by seismic data that identify regions of mantle flow beneath the Caribbean-South American Plate margin, shows that the deep-rooted South American craton acts to deflect and enhance mantle flow into a narrow channel. Episodic tremor and slow slip potentially linked to permeability contrasts at the Moho   pp731 - 734 Ikuo Katayama, Tatsuya Terada, Keishi Okazaki & Wataru Tanikawa doi:10.1038/ngeo1559 Slow earthquakes in subduction zones have been linked to high pore-fluid pressures. Laboratory measurements reveal a high permeability contrast between crust and mantle rocks, implying that water released from the subducting slab could accumulate at the crust-mantle boundary of the overlying plate, raising pore-fluid pressures and generating slow earthquakes. Hotspot trails in the South Atlantic controlled by plume and plate tectonic processes   pp735 - 738 John M. O'Connor, Wilfried Jokat, Anton P. le Roex, Cornelia Class, Jan R. Wijbrans, Stefanie Keβling, Klaudia F. Kuiper & Oliver Nebel doi:10.1038/ngeo1583 Seamount chains in the southeast Atlantic Ocean are thought to have formed above plumes sourced from the deep mantle. Dating of lavas erupted along the trails show that the formation and distribution of the seamount chains is also controlled by the motion and structure of the African Plate. Articles Top Magmatic precipitation as a possible origin of Noachian clays on Mars   pp739 - 743 Alain Meunier, Sabine Petit, Bethany L. Ehlmann, Patrick Dudoignon, Frances Westall, Antoine Mas, Abderrazak El Albani & Eric Ferrage doi:10.1038/ngeo1572 Hydrous clay minerals detected on the ancient martian crust have been proposed to have formed by aqueous weathering on a warm, wet early Mars. However, analyses of terrestrial clay minerals and comparisons to Mars suggest that the Noachian clays could have alternatively formed by precipitation from magmatic fluids. See also: News and Views by Hynek River drainage patterns in the New Zealand Alps primarily controlled by plate tectonic strain   pp744 - 748 Sébastien Castelltort, Liran Goren, Sean D. Willett, Jean-Daniel Champagnac, Frédéric Herman & Jean Braun doi:10.1038/ngeo1582 The persistence of dendritic drainage patterns implies that rivers reorganize after a tectonic perturbation, preserving no long-term record of that tectonic event. Numerical simulations of the evolution of drainage patterns in the Southern Alps, New Zealand, however, reveal rivers that resist reorganization and thus preserve a record of plate tectonic strain over 10 million years. Evolution of Santorini Volcano dominated by episodic and rapid fluxes of melt from depth   pp749 - 754 Michelle M. Parks, Juliet Biggs, Philip England, Tamsin A. Mather, Paraskevi Nomikou, Kirill Palamartchouk, Xanthos Papanikolaou, Demitris Paradissis, Barry Parsons, David M. Pyle, Costas Raptakis & Vangelis Zacharis doi:10.1038/ngeo1562 Santorini Volcano in Greece was thought to be continually charged by small injections of magma. Measurements of surface deformation show that magma equivalent to 10-50% of that emitted in previous small eruptions has been injected beneath Santorini since January 2011, implying that the volcano is instead charged by rapid, episodic fluxes of melt. See also: News and Views by Hooper Top Advertisement Online-only personal subscriptions now available to Nature Geoscience and Nature Physics For only 49 USD/29 GBP/29 EUR Subscribe now!   Natureevents is a fully searchable, multi-disciplinary database designed to maximise exposure for events organisers. 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