Volume 1 Issue 2, February 2008

Volume 1 Issue 2

A significant fraction of the anthropogenic nitrogen input into the coastal oceans from fertilizers is transferred back to land by commercial fisheries. This fraction has decreased over the past few decades, because fertiliser loads have increased at a faster rate than harvests from fisheries. The photo was taken on the beach at St Louis in Senegal where women were drying and smoking fish. (Image credit: Kieran Kelleher/Marine Photobank.)

Cover design by Karen Moore

Editorial

  • Editorial |

    US geoscience departments are still heavily weighted towards men, especially in the most senior ranks. All scientists, male or female, should work towards a more equal distribution.

Correspondence

Feature

  • Feature |

    Geoscientists explain women's under-representation in our field along three dominant themes: the structure of academia, historically low numbers of women, and women's views and choices. Which factor they perceive as most important depends overwhelmingly on their gender.

    • Mary Anne Holmes
    • , Suzanne O'Connell
    • , Connie Frey
    •  & Lois Ongley

Research Highlights

News and Views

  • News & Views |

    The influence of global warming on temperature trends at higher altitudes has been hotly debated. Stratospheric ozone depletion is another piece in the remaining tropical climate puzzle.

    • Drew Shindell
  • News & Views |

    Rising carbon levels contributed to profound climate change 55 million years ago. Where did that extra carbon come from? One proposal — a cometary impact — is rebuffed by two analyses of magnetic particles in clay sediment cores from New Jersey.

    • Gerald R. Dickens
  • News & Views |

    Local changes in the velocity of ambient seismic noise just before volcanic eruptions could indicate increased magma pressure within volcanoes. Continuous monitoring of such changes may therefore prove to be a potent tool for forecasting eruptions.

    • Karim G. Sabra
  • News & Views |

    Impact craters often have asymmetric shapes, which have been used to infer the direction and angle of impact. But pre-existing structural or topographic heterogeneities also play an important role in crater asymmetry.

    • Peter Schultz
  • News & Views |

    Ice-sheet stability is affected by a complex interplay between meltwater and the geological characteristics of the bedrock under the ice. The identification of a recently active subglacial volcano in Antarctica adds uncertainty to this system.

    • Stefan W. Vogel
  • News & Views |

    In the auroral region, solitary plasma waves form in a low-density plasma when energetic electron beams hit and energize ambient ions to escape velocity. Electromagnetic waves from lightning trigger similar plasma behaviour in the equatorial ionosphere.

    • Michael Kelley

Progress Article

  • Progress Article |

    Rivers may be efficient environments for metabolizing terrestrial organic carbon that was previously thought to be recalcitrant, owing to pockets that provide geophysical opportunities by retaining material for longer, and to the adaptation of microbial communities, which has enabled them to exploit the energy that escapes upstream ecosystems.

    • Tom J. Battin
    • , Louis A. Kaplan
    • , Stuart Findlay
    • , Charles S. Hopkinson
    • , Eugenia Marti
    • , Aaron I. Packman
    • , J. Denis Newbold
    •  & Francesc Sabater

Letters

  • Letter |

    Observed estimates of ice losses in Antarctica combined with regional modelling of ice accumulation in the interior suggest that East Antarctica is close to a balanced mass budget, but large losses of ice occur in the narrow outlet channels of West Antarctic glaciers and at the northern tip of the Antarctic peninsula.

    • Eric Rignot
    • , Jonathan L. Bamber
    • , Michiel R. van den Broeke
    • , Curt Davis
    • , Yonghong Li
    • , Willem Jan van de Berg
    •  & Erik van Meijgaard
  • Letter |

    Nanoscale evidence suggests that the Tumbiana Formation stromatolites in Australia were influenced by microbial activity. In the stromatolites, clusters of organic globules are closely associated with 2,724-million-year-old aragonite crystals.

    • Kevin Lepot
    • , Karim Benzerara
    • , Gordon E. Brown Jr
    •  & Pascal Philippot
  • Letter |

    A strong radar reflection in the West Antarctic ice sheet is related to the eruption of the newly identified Hudson Mountains Subglacial Volcano dated to 207 BC. This eruption probably caused short term changes in regional glacial and meltwater flow.

    • Hugh F. J. Corr
    •  & David G. Vaughan
  • Letter |

    It may be possible to predict eruptions of the Piton de la Fournaise volcano by continuously monitoring changes at depth using very small fluctuations in the ambient seismic noise. The changes are probably related to inflation caused by movement of magma at depth.

    • Florent Brenguier
    • , Nikolai M. Shapiro
    • , Michel Campillo
    • , Valérie Ferrazzini
    • , Zacharie Duputel
    • , Olivier Coutant
    •  & Alexandre Nercessian
  • Letter |

    The final geometry of an impact crater can be significantly influenced by the geological and geomorphological structure of the impact site; therefore, it may not on its own provide accurate information regarding the direction and angle of impact.

    • Sean P. S. Gulick
    • , Penny J. Barton
    • , Gail L. Christeson
    • , Joanna V. Morgan
    • , Matthew McDonald
    • , Keren Mendoza-Cervantes
    • , Zulmacristina F. Pearson
    • , Anusha Surendra
    • , Jaime Urrutia-Fucugauchi
    • , Peggy M. Vermeesch
    •  & Mike R. Warner
  • Letter |

    Viscous relaxation, rather than afterslip, most likely dominated ground deformation after two large earthquakes in Iceland. This suggests that afterslip may play a relatively less important role in immature fault zones as compared with more mature ones such as the San Andreas fault.

    • Sigurjón Jónsson

Backstory

  • Backstory |

    Beneath the dust and hummock grass of the remote Pilbara region of Western Australia, Pascal Philippot and Martin Van Kranendonk searched for signs of ancient life in some of the oldest rocks recovered on Earth.

  • Backstory |

    Sean Gulick and colleagues circumnavigated a flotilla of floating skin divers' platforms to obtain seismic profiles of an impact crater.