Volume 1 Issue 4, April 2008

Volume 1 Issue 4

Blue jets, gigantic jets, cloud-to-cloud discharges and cloud-to-ground lightning are all electrical discharges from thunderclouds. An analysis of numerical simulations and observations of these phenomena places them all in a unifying framework. The image shows a cloud-enshrouded 'bolt-from-the-blue' lightning discharge in a storm near Langmuir Laboratory in central New Mexico, that produced an incipient upward jet above the top of the storm before turning downward to ground.

Image credit: Harald Edens.

Cover design by Karen Moore

Editorial

  • Editorial |

    The analysis of mantle-derived rocks on increasingly smaller scales and advances in geodynamic modelling are providing new insights into the nature of mantle heterogeneity and magmatic processes.

Correspondence

Commentaries

  • Commentary |

    Scientists know much more about their field than is ever published in peer-reviewed journals. Blogs can be a good medium with which to disseminate this tacit knowledge.

    • Gavin Schmidt
  • Commentary |

    Explaining science to journalists and the public on blogs is fast and efficient. But is it all just too good to be true? Can science survive Web 2.0?

    • Myles Allen

Research Highlights

News and Views

  • News & Views |

    Violent uplift of western Crete in AD 365 generated a Mediterranean-wide tsunami that tossed boats onto house-tops in Alexandria, Egypt. Although a similar earthquake may not recur for 5,000 years, contiguous fault segments could rupture sooner.

    • Roger Bilham
  • News & Views |

    All organisms require elements to live, grow and reproduce, but some of these are hard to find or take up. Nitrogen-fixing bacteria solve the problem by secreting compounds that allow them to acquire the metals they need.

    • Benjamin D. Duval
    •  & Bruce A. Hungate
  • News & Views |

    Extraction of the continental crust has left the Earth's mantle depleted in certain elements. Some rocks from the Arctic Ocean floor suggest that the extent of depletion and heterogeneity in the Earth's mantle may be greater than we thought.

    • Andreas Stracke
  • News & Views |

    Electrical discharges from thunderstorms include bolts-from-the-blue, blue jets and gigantic jets along with the more common intracloud and cloud-to-ground lightning. All these phenomena can be understood in a single framework.

    • Earle R. Williams
  • News & Views |

    Because of difficulties in creating a radiocarbon calibration that covers the end of the last glaciation, defining the timing and duration of the Younger Dryas cold event has been a challenge. Linking related cosmogenic isotopes in tree rings and ice cores may provide new insights into abrupt climate changes.

    • Paula J. Reimer
    •  & Konrad A. Hughen

Review

  • Review Article |

    Black carbon in soot is an efficient absorbing agent of solar irradiation that is preferentially emitted in the tropics and can form atmospheric brown clouds in mixture with other aerosols. These factors combine to make black carbon emissions the second most important contribution to anthropogenic climate warming, after carbon dioxide emissions.

    • V. Ramanathan
    •  & G. Carmichael

Letters

  • Letter |

    Blue jets, gigantic jets, cloud-to-cloud discharges and cloud-to-ground lightning are all electrical discharges from thunderclouds. An analysis of numerical simulations and observations of these phenomena places them all in a unifying framework.

    • Paul R. Krehbiel
    • , Jeremy A. Riousset
    • , Victor P. Pasko
    • , Ronald J. Thomas
    • , William Rison
    • , Mark A. Stanley
    •  & Harald E. Edens
  • Letter |

    At nanometre scales, organic matter forms in soil are spatially, rather than chemically, complex, according to X-ray spectromicroscopy studies of thin sections of entire and intact free microaggregates. Organic matter forms detected at this spatial scale have no similarity to organic carbon forms of total soil.

    • Johannes Lehmann
    • , Dawit Solomon
    • , James Kinyangi
    • , Lena Dathe
    • , Sue Wirick
    •  & Chris Jacobsen
  • Letter |

    Biological availability of molybdenum and vanadium is facilitated by siderophores that are produced by cultures of the bacterium Azotobacter vinelandii during the fixation of atmospheric nitrogen. This suggests that the production of strong binding compounds may be a widespread strategy for metal acquisition by bacteria and implies that the availability of molybdenum and vanadium may be critical for the nitrogen cycle of terrestrial ecosystems.

    • J. P. Bellenger
    • , T. Wichard
    • , A. B. Kustka
    •  & A. M. L. Kraepiel
  • Letter |

    Destruction of the Earth’s ozone shield due to the release of hydrogen sulphide and methane has been suggested as a cause of mass extinctions during periods of ocean anoxia over the past two billion years. This mechanism does not explain the end-Permian mass extinction, according to simulations with a two-dimensional atmospheric chemistry-transport model, which show that the ozone shield remains intact even with massive releases of hydrogen sulphide and methane.

    • Michael B. Harfoot
    • , John A. Pyle
    •  & David J. Beerling
  • Letter |

    The largest earthquakes often cause rupture for hundreds of kilometres along a single subducting plate, and often begin or end at structural boundaries on the overriding plate. But the Solomons earthquake on 1 April 2007 ruptured across a triple junction, where the Australian and Woodlark plates subduct beneath the overriding Pacific plate.

    • Frederick W. Taylor
    • , Richard W. Briggs
    • , Cliff Frohlich
    • , Abel Brown
    • , Matt Hornbach
    • , Alison K. Papabatu
    • , Aron J. Meltzner
    •  & Douglas Billy

Articles

  • Article |

    Attaching a ‘floating’ tree-ring chronology to ice core records that cover the abrupt Younger Dryas cold interval during the last glacial termination provides a better estimate of the onset and duration of the radiocarbon anomaly. The chronology suggests that marine records may be biased by changes in the concentration of radiocarbon in the ocean, which may affect the accuracy of a popular radiocarbon calibration program during this interval.

    • R. Muscheler
    • , B. Kromer
    • , S. Björck
    • , A. Svensson
    • , M. Friedrich
    • , K. F. Kaiser
    •  & J. Southon
  • Article |

    In the year AD 365, an earthquake and tsunami destroyed much of the eastern Mediterranean coastal regions. The distribution of uplift at the time suggests that the earthquake occurred on a fault within the overriding plate at the subduction zone beneath Crete, and not on the subduction interface itself.

    • B. Shaw
    • , N. N. Ambraseys
    • , P. C. England
    • , M. A. Floyd
    • , G. J. Gorman
    • , T. F. G. Higham
    • , J. A. Jackson
    • , J.-M. Nocquet
    • , C. C. Pain
    •  & M. D. Piggott

Backstory

  • Backstory |

    Beth Shaw and colleagues found the corals they were sampling being used as wall decorations, and braved nudist beaches in full field gear to understand the AD 365 earthquake.

  • Backstory |

    A group of botanists, geographers and physicists foraged through gravel pits, tunnel plots and lignite mines for very rare logs from the Late Glacial.

  • Backstory |

    After a magnitude 8.1 earthquake caused a deadly tsunami in the Solomon Islands, Fred Taylor and colleagues rushed to the epicentral area to learn about rupture across a subducting triple junction.