Nature Geoscience contents: December 2014 Volume 7 Number 12 pp849-931

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TABLE OF CONTENTS December 2014 Volume 7, Issue 12 Editorial Correspondence Commentaries News and Views Letters Articles Corrigendum Subscribe   Facebook   RSS   Recommend to library   Twitter   Advertisement Attending the AGU meeting in San Francisco? Visit Nature Geoscience and Nature Climate Change at the Nature Publishing Group booth #2734 to: Browse and take free sample copies of leading journals from NPG, including Nature, Nature Geoscience and Nature Climate Change Subscribe at discounted conference rates   Editorial Top Eighty years of Redfield   p849 doi:10.1038/ngeo2319 The outstanding lifespan of the canonical Redfield ratio has shown the power of elemental stoichiometry in describing ocean life. But the biological mechanisms governing this consistency remain unknown. Correspondence Top Is sand in the Mississippi River delta a sustainable resource?   pp851 - 852 M. D. Blum & H. H. Roberts doi:10.1038/ngeo2310 See also: Correspondence by Nittrouer & Viparelli | Letter by Nittrouer & Viparelli Reply to 'Is sand in the Mississippi River delta a sustainable resource?'   p852 Jeffrey A. Nittrouer & Enrica Viparelli doi:10.1038/ngeo2311 See also: Correspondence by Blum & Roberts | Letter by Nittrouer & Viparelli Commentaries Top Redfield's evolving legacy   pp853 - 855 Nicolas Gruber & Curtis A. Deutsch doi:10.1038/ngeo2308 The ratio of nitrogen to phosphorus in organic matter is close to that in seawater, a relationship maintained through a set of biological feedbacks. The rapid delivery of nutrients from human activities may test the efficacy of these processes. The elements of marine life   pp855 - 856 Noah J. Planavsky doi:10.1038/ngeo2307 Today, the ratio of carbon to nitrogen and phosphorus in marine organic matter is relatively constant. But this ratio probably varied during the Earth's history as a consequence of changes in the phytoplankton community and ocean oxygen levels. News and Views Top Biogeochemistry: A faulty fertilizer   pp857 - 858 Whendee L. Silver doi:10.1038/ngeo2292 Elevated levels of CO2 can stimulate photosynthesis in plants and increase their uptake of atmospheric carbon. A five-year study in Minnesota grasslands shows that increased plant uptake of CO2 is restricted by the availability of vital nutrients and water. See also: Article by Reich et al. Space science: Astronauts overexposed   p858 Tamara Goldin doi:10.1038/ngeo2314 Geomorphology: Quake, rubble and roll   pp859 - 860 Nathan A. Niemi doi:10.1038/ngeo2297 Temporal variations in coarse river deposits are often attributed to climate change. Cosmogenic nuclide concentrations of river cobbles suggest that climate plays a subordinate role to earthquake-induced landslides in producing coarse sediments in arid Peru. See also: Article by McPhillips et al. Deep carbon: Subduction goes organic   pp860 - 861 Jay J. Ague doi:10.1038/ngeo2301 Aqueous subduction-zone fluids contain CO2 and methane. New calculations indicate that these fluids also host a wide array of organic carbon species, in concentrations sufficient to influence the deep carbon cycle. See also: Letter by Sverjensky et al. Ocean chemistry: Biogeochemical regimes in focus   pp862 - 863 Raymond N. Sambrotto doi:10.1038/ngeo2309 The ocean's biological pump transfers carbon to long-term storage in deep waters and sediments. Two inverse modelling studies describe the export of organic matter throughout the surface layer of the world's oceans in exceptional detail. See also: Letter by DeVries & Deutsch | Letter by Teng et al. Geoscience JOBS of the week PhD Studentship The University of Sheffield Postdoctoral Research Position in Seabed Geophysics University of Victoria More Science jobs from Letters Top Episodic warming of early Mars by punctuated volcanism   pp865 - 868 Itay Halevy & James W. Head III doi:10.1038/ngeo2293 Evidence for liquid water on the ancient Martian surface is at odds with a presumably cold climate. Aerosol modelling shows that warming by sulphur-bearing gases during episodes of volcanism could have supported liquid water for decades. Robust Arctic sea-ice influence on the frequent Eurasian cold winters in past decades   pp869 - 873 Masato Mori, Masahiro Watanabe, Hideo Shiogama, Jun Inoue & Masahide Kimoto doi:10.1038/ngeo2277 Severe winters have occurred frequently in mid-latitude Eurasia during the past decade. Simulations with a 100-member ensemble of an atmospheric model detect an influence of declining Arctic sea-ice cover. Termini of calving glaciers as self-organized critical systems   pp874 - 878 J. A. Åstrom, D. Vallot, M. Schäfer, E. Z. Welty, S. O'Neel et al. doi:10.1038/ngeo2290 Calving margins are highly sensitive to changes in climate and glacier terminus geometry. Numerical modelling suggests that calving glacier termini are self-organized critical systems that are fluctuating between states of advance and retreat. Eddy transport as a key component of the Antarctic overturning circulation   pp879 - 884 Andrew F. Thompson, Karen J. Heywood, Sunke Schmidtko & Andrew L. Stewart doi:10.1038/ngeo2289 The exchange of water across the Antarctic continental shelf break brings warm waters towards ice shelves and glacier grounding lines. Ocean glider observations reveal that eddy-induced transport contributes significantly to this exchange. Carbonate counter pump stimulated by natural iron fertilization in the Polar Frontal Zone   pp885 - 889 Ian Salter, Ralf Schiebel, Patrizia Ziveri, Aurore Movellan, Richard Lampitt et al. doi:10.1038/ngeo2285 The release of carbon dioxide during biological carbonate production counters carbon uptake by phytoplankton. The carbon chemistry of sinking particles in the Southern Ocean suggests that iron availability stimulates this carbonate counter pump. Large-scale variations in the stoichiometry of marine organic matter respiration   pp890 - 894 Tim DeVries & Curtis Deutsch doi:10.1038/ngeo2300 The elemental composition of marine organic matter varies systematically at large scales. Simulations of the ocean circulation and observations of ocean chemistry reveal close links between light and nutrient availability and stoichiometry. See also: Letter by Teng et al. | News and Views by Sambrotto Global-scale variations of the ratios of carbon to phosphorus in exported marine organic matter   pp895 - 898 Yi-Cheng Teng, François W. Primeau, J. Keith Moore, Michael W. Lomas & Adam C. Martiny doi:10.1038/ngeo2303 The ratio of carbon to phosphorus in marine phytoplankton biomass varies by ecosystem. Biogeochemical modelling suggests that organic carbon exported to depth shows similar variations in stoichiometry. See also: Letter by DeVries & Deutsch | News and Views by Sambrotto Sediment supply as a driver of river meandering and floodplain evolution in the Amazon Basin   pp899 - 903 José Antonio Constantine, Thomas Dunne, Joshua Ahmed, Carl Legleiter & Eli D. Lazarus doi:10.1038/ngeo2282 Proposed engineering projects in the Amazon Basin would disrupt sediment supplies to lowland rivers. Landsat imagery of Amazonian tributaries reveals that lower sediment loads are associated with lower meander migration and cutoff rates. Earthquake size distribution in subduction zones linked to slab buoyancy   pp904 - 908 Tomoaki Nishikawa & Satoshi Ide doi:10.1038/ngeo2279 Some of the most devastating earthquakes are generated in subduction zones. Analysis of the stress state of subduction zones worldwide suggests that large earthquakes are generated more frequently where a young, buoyant plate subducts. Important role for organic carbon in subduction-zone fluids in the deep carbon cycle   pp909 - 913 Dimitri A. Sverjensky, Vincenzo Stagno & Fang Huang doi:10.1038/ngeo2291 Earth's deep carbon cycle is poorly constrained. Theoretical calculations suggest that large amounts of carbon are returned to Earth's surface as organic and inorganic carbon ions dissolved in subduction-zone fluids. See also: News and Views by Ague A continuous 55-million-year record of transient mantle plume activity beneath Iceland   pp914 - 919 Ross Parnell-Turner, Nicky White, Tim Henstock, Bramley Murton, John Maclennan et al. doi:10.1038/ngeo2281 Ridges on the seafloor near Iceland form when hot mantle pulses through an underlying plume. Seismic data show that the frequency of ridge formation decreased about 35 million years ago implying a change in the thermal state of the plume source. Articles Top Plant growth enhancement by elevated CO2 eliminated by joint water and nitrogen limitation   pp920 - 924 Peter B. Reich, Sarah E. Hobbie & Tali D. Lee doi:10.1038/ngeo2284 Elevated CO2 is known to fertilize plant growth, resulting in greater uptake of atmospheric CO2 by plants. However, CO2 fertilization in a perennial grassland is absent when plants are jointly limited by both water and nitrogen. See also: News and Views by Silver Millennial-scale record of landslides in the Andes consistent with earthquake trigger   pp925 - 930 Devin McPhillips, Paul R. Bierman & Dylan H. Rood doi:10.1038/ngeo2278 Landslide deposits are often interpreted as the consequence of precipitation. A millennial-scale record of landslides, inferred from river cobbles in the arid Andes, is instead consistent with earthquake triggering. See also: News and Views by Niemi Corrigendum Top Corrigendum: Low simulated radiation limit for runaway greenhouse climates   p931 Colin Goldblatt, Tyler D. Robinson, Kevin J. Zahnle & David Crisp doi:10.1038/ngeo2296 See also: Article by Goldblatt et al. Top Advertisement Announcing the Nature Index: A global indicator of high-quality research The Nature Index tracks the affiliations of high-quality scientific articles. Updated monthly, the Nature Index presents research outputs by institution and country. 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