Volume 7 Issue 6, June 2014

As well as being a milestone in technology, the Chang'e lunar exploration programme establishes China as a contributor to space science. With much still to learn about the Moon, fieldwork beyond Earth's orbit must be an international effort.

Microbes quickly consumed much of the methane released in the 2010 Gulf of Mexico oil spill. Time-series measurements now suggest that, after a steep rise, methane oxidation rates crashed while hydrocarbon discharge was still continuing at the wellhead.

Ethanol has been heralded as a cleaner fuel for cars than gasoline. An analysis of air quality data suggests that a switch from ethanol to gasoline use in São Paulo in response to changing prices led unexpectedly to lower local levels of ozone pollution.

Abrupt climate changes during the last glacial period affected most of the Northern Hemisphere. Greenland ice core data suggest that for the penultimate abrupt warming event, climate change was nearly synchronous at high and low latitudes.

Rapid deposition of wind-borne silt after the end of the last glacial period buried a large reservoir of organic carbon in the deep soil. Geochemical analyses suggest that this sequestered soil carbon could be released to the atmosphere if exposed to decomposition.

The discovery of water in lunar samples in 2008 challenged the notion that the Moon's interior had lost all its volatiles. Since then, analyses of the water concentrations and isotopic compositions in lunar samples taken together suggest that the Moon is heterogeneously wet, which may lend clues to its origin.

An active core dynamo may have operated on the early Moon. Extraction of palaeomagnetic pole positions on the Moon from magnetic anomalies measured by the Lunar Prospector and Kaguya orbiters suggests that the ancient lunar dynamo experienced reversals and an ancient reorientation of the Moon rotated the geographic locations of the poles.

River water circulates through river bed and bank sediments. Model simulations suggest that practically all of the river water that reaches the mouth of the Mississippi River network has circulated laterally through its banks.

The bed topography beneath the Greenland ice sheet controls the flow of ice and its discharge into the ocean. A combination of sparse radar soundings of ice thickness and high-resolution ice motion data suggest that many submarine ice-covered valleys extend significantly deeper below sea level and farther inland than thought.

The blowout of the Macondo oil well in the Gulf of Mexico in April 2010 injected up to 500,000 tonnes of natural gas, mainly methane, into the deep sea. Spatially extensive measurements of methane dynamics in the months following the spill reveal a rapid rise and fall in the microbial consumption of methane.

The Brady soil body was buried by loess deposits as a result of early Holocene climate change. Geochemical analyses suggest that large amounts of organic carbon were trapped in this soil as a result of fire activity and slow decomposition resulting from rapid burial.

Bioavailable iron is released from anoxic sediments, such as those that underlie the Peruvian upwelling zone. Analyses of iron levels in sediments from this region suggest that iron release occurs in a relatively narrow range of redox conditions, and that the amount of iron released to the upwelling waters has varied over the past 140,000 years.

During volcanic eruptions, solidifying magma ascends through the volcanic conduit, often accompanied by repetitive, drum-beat seismicity. Laboratory experiments on magma samples from Soufrière Hills Volcano, Montserrat, and Mount St Helens Volcano, USA, show that viscous melt formed at the surface between the rising magma and conduit walls can temporarily halt magma ascent, accentuating the cyclical seismicity.

The observed depletion of the stratospheric ozone layer from the 1980s onwards is attributed to halogens released through human activities. Model simulations show that stratospheric ozone loss has declined by over 10% since stratospheric halogen loading peaked in the late 1990s, indicating that the recovery of the ozone layer is well under way.

Ethanol-based vehicles are thought to generate less pollution than gasoline-based vehicles. An analysis of pollutant concentrations in the subtropical megacity of São Paulo, Brazil, reveals that levels of ozone pollution fell, but levels of nitric oxide and carbon monoxide rose, during periods of prevailing gasoline use relative to ethanol use.

During the last glacial termination, climate changes associated with the Bølling–Allerød warming were seen throughout much of the Northern Hemisphere. A combination of ice-core records and box modelling shows that this climate change was nearly synchronous across high and temperate latitudes.

The explosive style of volcanic eruptions has been linked to gas separation from magmas in the shallow crust. Geochemical analysis of magmas erupted over the past 600 years at Kīlauea Volcano, Hawai‘i, now reveal a link between eruption style and the geochemistry of magmas formed at greater depths, implying that some magmas are predisposed towards explosivity.

The Changbaishan volcanic complex in China cannot be easily explained as the consequence of a mantle plume. Seismic images from the region identify buoyant mantle material that may have been entrained and dragged downwards by the subducting Pacific Plate, but is now escaping upwards through a gap in the plate and producing the intraplate volcanism.

The ability to predict surface winter climate in the Euro–Atlantic sector on seasonal timescales has been limited. Maximum covariance analysis now reveals that Arctic sea-ice variability represents a good predictor of the winter Euro–Atlantic climate, with as much as three months’ lead time.

The long-held notion of a bone-dry Moon was challenged in 2008, with the detection of water in some of the Apollo samples. Since then, lunar scientists have sought to understand how much water is in the Moon, where it is, and where it comes from. In this web focus, we present an overview article, research papers and opinion pieces that evaluate the evidence for water in the lunar interior and on the lunar surface and discuss its origin — whether it was added by cometary impacts, implanted by the solar wind, or indigenous to a Moon that may not, in fact, have formed dry.