Nature Geoscience contents: April 2014 Volume 7 Number 4 pp245-320

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TABLE OF CONTENTS April 2014 Volume 7, Issue 4 Editorial Correspondence Books and Arts Research Highlights News and Views Review Letters Articles Subscribe   Facebook   RSS   Recommend to library   Twitter   Advertisement Nature Geoscience web focus: Oxygen evolution on Earth. In this Nature Geoscience web focus we present primary research, an overview article and opinion pieces that discuss the oxygenation of the Earth's atmosphere and ocean.  Selected content free online until April 29.    Editorial Top Evolutionary two-step   p245 doi:10.1038/ngeo2136 The march from an Archaean microbial world to the modern reign of more complex life was slow but not steady. Instead, the rise of the animals may have resulted from an intricate back-and-forth between evolving life and the Earth's environment. Correspondence Top How significant is West Antarctic warming?   pp246 - 247 Armin Bunde, Josef Ludescher, Christian L. E. Franzke and Ulf Buntgen doi:10.1038/ngeo2126 See also: Correspondence by Bromwich & Nicolas | Article by Bromwich et al. Reply to 'How significant is West Antarctic warming?'   p247 David H. Bromwich and Julien P. Nicolas doi:10.1038/ngeo2127 See also: Correspondence by Bunde et al. | Article by Bromwich et al. Books and Arts Top Earth's oxygen unravelled   p248 Lee R. Kump reviews Oxygen: A Four Billion Year History by Donald E. Canfield doi:10.1038/ngeo2129 Research Highlights Top Cryosphere: Bobbing for sea ice | Planetary science: Facelift for Triton | Core processes: Patchy polarity | Biogeochemistry: Yellow River erosion News and Views Top Climate science: Tropical expansion by ocean swing   pp250 - 251 Jian Lu doi:10.1038/ngeo2124 The tropical belt has become wider over the past decades, but climate models fall short of capturing the full rate of the expansion. The latest analysis of climate simulations suggests that a long-term swing of the Pacific Decadal Oscillation is the main missing cause from the coupled climate models. See also: Letter by Allen et al. Planetary science: Shrinking wrinkling Mercury   pp251 - 252 William B. McKinnon doi:10.1038/ngeo2123 As Mercury's interior cools and its massive iron core freezes, its surface feels the squeeze. A comprehensive global census of compressional deformation features indicates that Mercury has shrunk by at least 5 km in radius over the past 4 billion years. See also: Article by Byrne et al. Palaeontology: Late to the mix   p253 Alicia Newton doi:10.1038/ngeo2125 Early Earth: Cyanobacteria at work   pp253 - 254 Alan J. Kaufman doi:10.1038/ngeo2128 Oxygen-producing photosynthesis must have evolved before the pervasive oxidation of the atmosphere around 2.4 billion years ago, but how long before is unclear. Geochemical analyses of ancient sedimentary rocks now suggest that cyanobacteria generated oxygen at least 3 billion years ago. See also: Letter by Planavsky et al. Marine biology: Twilight budget in balance   p255 Anna Armstrong doi:10.1038/ngeo2131 Atmospheric science: Desert dust and monsoon rain   pp255 - 256 William Lau doi:10.1038/ngeo2115 The climate regimes of monsoon regions and deserts are connected. Satellite data and numerical experiments reveal that an increase in dust aerosol loading over the Arabian Sea and West Asia can lead to enhanced summer monsoon rainfall over central India on timescales of days to weeks. See also: Article by Vinoj et al. Geoscience JOBS of the week Sackler-Clarendon Associate Professorship of Sedimentary Geology and Sackler Fellow in Earth Sciences University of Oxford More Science jobs from Geoscience EVENT Annual International Conference on Earth and Environmental Sciences 14.07.14 Athens, Greece More science events from Review Top Co-evolution of eukaryotes and ocean oxygenation in the Neoproterozoic era   pp257 - 265 Timothy M. Lenton, Richard A. Boyle, Simon W. Poulton, Graham A. Shields-Zhou and Nicholas J. Butterfield doi:10.1038/ngeo2108 The oxygenation of the Earth's deep oceans is often thought to have triggered the evolution of simple animals. A review article proposes that instead, the evolution of animal life set off a series of biogeochemical feedbacks that promoted the oxygenation of the deep sea. Letters Top Newly detected ozone-depleting substances in the atmosphere   pp266 - 269 Johannes C. Laube, Mike J. Newland, Christopher Hogan, Carl A. M. Brenninkmeijer, Paul J. Fraser et al. doi:10.1038/ngeo2109 Ozone-depleting substances emitted through human activities cause large-scale damage to the stratospheric ozone layer, and influence global climate. An analysis of unpolluted air sampled from Tasmania and firn snow reveals the emergence of four new ozone-depleting substances in the atmosphere since the 1960s. Influence of anthropogenic aerosols and the Pacific Decadal Oscillation on tropical belt width   pp270 - 274 Robert J. Allen, Joel R. Norris and Mahesh Kovilakam doi:10.1038/ngeo2091 The tropical belt has expanded by several degrees latitude over the past 30 years, following an earlier period of contraction. Climate simulations indicate that tropical belt width is controlled by multidecadal sea surface temperature variability associated with the Pacific Decadal Oscillation and anthropogenic aerosols. See also: News and Views by Lu Solar forcing of North Atlantic surface temperature and salinity over the past millennium   pp275 - 278 Paola Moffa-Sánchez, Andreas Born, Ian R. Hall, David J. R. Thornalley and Stephen Barker doi:10.1038/ngeo2094 Fluctuations in North Atlantic climate and hydrography over the past 1,000 years are seemingly linked to changes in solar irradiance. Reconstructions of marine conditions compared with an analysis of climate model output indicate that low solar irradiance is associated with the development of a high-pressure system in the eastern basin that affects the dynamics of the subpolar gyre. Production of sulphate-rich vapour during the Chicxulub impact and implications for ocean acidification   pp279 - 282 Sohsuke Ohno, Toshihiko Kadono, Kosuke Kurosawa, Taiga Hamura, Tatsuhiro Sakaiya et al. doi:10.1038/ngeo2095 Following the Chicxulub impact, many foraminifera in near-surface waters perished, but bottom-dwelling species survived. Impact experiments suggest that sulphate in Chicxulubs target rocks was released as predominantly sulphur trioxide, which would have been converted to sulphuric acid in the atmosphere and swept down swiftly by larger particles, acidifying the ocean surface. Evidence for oxygenic photosynthesis half a billion years before the Great Oxidation Event   pp283 - 286 Noah J. Planavsky, Dan Asael, Axel Hofmann, Christopher T. Reinhard, Stefan V. Lalonde et al. doi:10.1038/ngeo2122 The evolution of oxygenic photosynthesis should have occurred some time before the oxidation of Earth's atmosphere 2.5 billion years ago. The molybdenum isotopic signature of shallow marine rocks that formed at least 2.95 billion years ago is consistent with deposition in waters that were receiving oxygen from photosynthesis at least half a billion years before the oxidation of the atmosphere. See also: News and Views by Kaufman Motion of continental slivers and creeping subduction in the northern Andes   pp287 - 291 J-M. Nocquet, J. C. Villegas-Lanza, M. Chlieh, P. A. Mothes, F. Rolandone et al. doi:10.1038/ngeo2099 Regions of intense continental deformation, termed continental slivers, have been identified in Chile, Bolivia and Ecuador. Analyses of GPS data now identify another large sliver in Peru, the Inca Sliver, that is moving away from a neighbouring sliver in Ecuador—implying that moving continental slivers control the deformation of almost the entire Andean mountain range. Locking of the Chile subduction zone controlled by fluid pressure before the 2010 earthquake   pp292 - 296 Marcos Moreno, Christian Haberland, Onno Oncken, Andreas Rietbrock, Samuel Angiboust et al. doi:10.1038/ngeo2102 Large subduction-zone earthquakes are thought to occur where the down-going and overriding tectonic plates are strongly locked. Analysis of geodetic and seismic data collected in the decade before the 2010 Chile earthquake shows that variations in pore-fluid pressure correlate with the degree of plate-interface locking, and may therefore control earthquake rupture. Off-rift volcanism in rift zones determined by crustal unloading   pp297 - 300 Francesco Maccaferri, Eleonora Rivalta, Derek Keir and Valerio Acocella doi:10.1038/ngeo2110 As continents are stretched apart, deep rift valleys form and volcanoes can erupt both inside and outside of the valley. Numerical modelling suggests that gravitational unloading, caused by thinning of the stretched crust, can deflect rising magma towards the edges of the rift valley, causing off-rift eruptions. Articles Top Mercury's global contraction much greater than earlier estimates   pp301 - 307 Paul K. Byrne, Christian Klimczak, A. M. Celâl Şengör, Sean C. Solomon, Thomas R. Watters et al. doi:10.1038/ngeo2097 Observations of compressional structures on Mercury have fallen short of accommodating the global contraction that is required owing to cooling of the planet's interior. Mapping of folds and faults across Mercury's surface using MESSENGER spacecraft images reveals deformation consistent with a planet that has contracted radially as much as seven kilometres over its history. See also: News and Views by McKinnon Short-term modulation of Indian summer monsoon rainfall by West Asian dust   pp308 - 313 V. Vinoj, Philip J. Rasch, Hailong Wang, Jin-Ho Yoon, Po-Lun Ma et al. doi:10.1038/ngeo2107 The Indian summer monsoon is influenced by numerous factors, including aerosol-induced changes to clouds, surface and atmospheric heating, and atmospheric circulation. An analysis of satellite data and global climate model simulations suggests that dust aerosol levels over the Arabian Sea, West Asia and the Arabian Peninsula are positively correlated with the intensity of the Indian summer monsoon. See also: News and Views by Lau Surface-water iron supplies in the Southern Ocean sustained by deep winter mixing   pp314 - 320 Alessandro Tagliabue, Jean-Baptiste Sallee, Andrew R. Bowie, Marina Levy, Sebastiaan Swart et al. doi:10.1038/ngeo2101 Low levels of iron limit primary productivity across much of the Southern Ocean. Measurements of dissolved iron levels combined with hydrographic data suggest that much of the iron in the surface waters of the Southern Ocean is supplied by deep mixing during winter. Top Advertisement Download the new NatureJournals app and gain access to Nature and all Nature-branded research and review journals. All news content and open access articles are free. 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