Volume 8 Issue 5, May 2015

Volume 8 Issue 5

Liquid water on equatorial Mars is inconsistent with large-scale climatic conditions. Humidity and temperature measurements by the Curiosity rover support the formation of subsurface liquid brines by hydration of perchlorates during the night. The image is a colour view of a Martian dune, taken by the Curiosity rover after crossing it during the 538th Martian day, or sol, of Curiosity's mission on Mars (Feb 9, 2014).

Letter p357

IMAGE: NASA/JPL-CALTECH/MSSS

COVER DESIGN: DAVID SHAND

Editorial

  • Editorial |

    Research on the Solar System's planets has moved beyond fly-by science. Long-term observations of planetary bodies can yield insights as the days, seasons and years pass.

Books and Arts

News and Views

  • News & Views |

    Subduction zone faults can slip slowly, generating tremor. The varying correlation between tidal stresses and tremor occurring deep in the Cascadia subduction zone suggests that the fault is inherently weak, and gets weaker as it slips.

    • Roland Bürgmann
  • News & Views |

    Mountain glaciers around the world are in decay. According to a modelling study that — unusually — includes full ice flow physics, those in Western Canada will largely be restricted to the coastal region by the year 2100.

    • Andreas Vieli
  • News & Views |

    Titan's equatorial dunes seem to move in the opposite direction to the prevailing easterly winds. Infrequent methane storms at Titan's low latitudes may briefly couple surface winds to fast westerlies above, dominating the net movement of sand.

    • Claire Newman
  • News & Views |

    Analyses of ice-core carbon isotopes show that variations in atmospheric CO2 levels during the past millennium are controlled by changes in land reservoirs. But whether climate variations or human activity were mainly responsible is uncertain.

    • Jed O. Kaplan

Perspectives

  • Perspective |

    El Niño diversity and its genesis are debated. An overview of existing work along with a fuzzy clustering analysis and simulations suggest that the asymmetry, irregularity and extremes of El Niño result from westerly wind bursts.

    • Dake Chen
    • , Tao Lian
    • , Congbin Fu
    • , Mark A. Cane
    • , Youmin Tang
    • , Raghu Murtugudde
    • , Xunshu Song
    • , Qiaoyan Wu
    •  & Lei Zhou

Letters

  • Letter |

    Mercury’s surface is darker than expected given its low iron content. The delivery of cometary carbon to Mercury in micrometeorite impacts may explain the planet’s globally low reflectance.

    • Megan Bruck Syal
    • , Peter H. Schultz
    •  & Miriam A. Riner
  • Letter |

    Liquid water on equatorial Mars is inconsistent with large-scale climatic conditions. Humidity and temperature measurements by the Curiosity rover support the formation of subsurface liquid brines by hydration of perchlorates during the night.

    • F. Javier Martín-Torres
    • , María-Paz Zorzano
    • , Patricia Valentín-Serrano
    • , Ari-Matti Harri
    • , Maria Genzer
    • , Osku Kemppinen
    • , Edgard G. Rivera-Valentin
    • , Insoo Jun
    • , James Wray
    • , Morten Bo Madsen
    • , Walter Goetz
    • , Alfred S. McEwen
    • , Craig Hardgrove
    • , Nilton Renno
    • , Vincent F. Chevrier
    • , Michael Mischna
    • , Rafael Navarro-González
    • , Jesús Martínez-Frías
    • , Pamela Conrad
    • , Tim McConnochie
    • , Charles Cockell
    • , Gilles Berger
    • , Ashwin R. Vasavada
    • , Dawn Sumner
    •  & David Vaniman
  • Letter |

    Titan’s equatorial dunes propagate eastwards, whereas Titan’s surface winds blow towards the West. Atmospheric simulations suggest that tropical methane storms generate strong eastward gusts that may dominate sand transport on Titan’s surface.

    • Benjamin Charnay
    • , Erika Barth
    • , Scot Rafkin
    • , Clément Narteau
    • , Sébastien Lebonnois
    • , Sébastien Rodriguez
    • , Sylvain Courrech du Pont
    •  & Antoine Lucas
  • Letter |

    Forests may be vulnerable to future droughts. A tree mortality threshold based on plant hydraulics suggests that increased drought may trigger widespread dieback in the southwestern United States by mid-century.

    • William R. L. Anderegg
    • , Alan Flint
    • , Cho-ying Huang
    • , Lorraine Flint
    • , Joseph A. Berry
    • , Frank W. Davis
    • , John S. Sperry
    •  & Christopher B. Field
  • Letter |

    The glaciers in western Canada are experiencing rapid mass loss. Projections of their fate with a model that couples physics-based ice dynamics with a surface mass balance model suggest that glacier volume will shrink by 70% by 2100.

    • Garry K. C. Clarke
    • , Alexander H. Jarosch
    • , Faron S. Anslow
    • , Valentina Radić
    •  & Brian Menounos
  • Letter |

    Methanotrophic bacteria can consume methane emitted from the ocean floor before it reaches the atmosphere. Variations in coastal currents can reduce methane oxidation in the ocean by limiting methanotroph residence time above methane seeps.

    • Lea Steinle
    • , Carolyn A. Graves
    • , Tina Treude
    • , Bénédicte Ferré
    • , Arne Biastoch
    • , Ingeborg Bussmann
    • , Christian Berndt
    • , Sebastian Krastel
    • , Rachael H. James
    • , Erik Behrens
    • , Claus W. Böning
    • , Jens Greinert
    • , Célia-Julia Sapart
    • , Markus Scheinert
    • , Stefan Sommer
    • , Moritz F. Lehmann
    •  & Helge Niemann
  • Letter |

    Continental breakup can occur with or without extensive magmatic activity. Numerical simulations show that magmatic and amagmatic rifts can develop in the same tectonic setting, if a rising mantle plume is deflected to one side of the continent.

    • A. Koptev
    • , E. Calais
    • , E. Burov
    • , S. Leroy
    •  & T. Gerya
  • Letter |

    The Hawaiian–Emperor volcanic chain has a distinctive bend. Geochemical analyses show that lavas erupted on the ocean floor close to the bend formed during deformation of the Pacific Plate, implying the bend was caused by changes in plate motion.

    • John M. O’Connor
    • , Kaj Hoernle
    • , R. Dietmar Müller
    • , Jason P. Morgan
    • , Nathaniel P. Butterworth
    • , Folkmar Hauff
    • , David T. Sandwell
    • , Wilfried Jokat
    • , Jan R. Wijbrans
    •  & Peter Stoffers

Articles