News & Views in 2010

Most of the oceanic crust has a simple layered structure. The discovery that slow-spreading ridges exhibit a comparatively complex crustal structure and some of the largest extensional faults on Earth is leading to the recognition of a new mode of seafloor spreading.

Direct evidence for the role of volatiles in magmatic ore formation has been elusive. Magma degassing at Merapi volcano in Indonesia is found to be directly linked to the selective leaching of metals from sulphide melts that ultimately form ore deposits.

Pine Island Glacier on West Antarctica's Amundsen Sea coast has experienced accelerating retreat over the past few decades. Oceanographic observations under the associated ice shelf show how changes in water flow and ice-cavity geometry have contributed to ice melting.

The Triassic/Jurassic boundary was marked by widespread environmental changes, including greenhouse warming. Palaeoecological reconstructions from East Greenland reveal a dramatic rise in fire activity, driven by vegetation shifts and climate change.

Low atmospheric carbon dioxide concentrations during glacial periods must have been accompanied by changes in surface-ocean carbonate chemistry. But it is unclear whether concurrent changes in the deep sea contributed to the glacial carbon dioxide decline.

The ocean's nitrogen budget has escaped quantification. A modelling study shows how a small shift in the nitrate-to-phosphate uptake ratio of phytoplankton has a large effect on calculated nitrogen fixation rates.

Greenland's ice sheet does not look like an alpine glacier. However, it behaves like one in the way its meltwater lubricates basal motion, suggesting that projections of sea-level change will require unified knowledge of basal processes in glaciers and ice sheets.

The duration of Earth's creation remains unknown. Elegant modelling of the Earth's core formation reaffirms that the bulk of accretion occurred within a few tens of millions of years, but another 100 million years or so were needed to finish the job.

The rate at which new marine animals evolve has varied through time, but the factors that ultimately drive these fluctuations are unclear. A statistical analysis shows that global changes in abiotic factors play an important role.

The organic matter stored in frozen Arctic soils could release significant quantities of carbon dioxide and methane on thawing. Now, laboratory experiments show that re-wetting of previously thawed permafrost could increase nitrous oxide production by 20-fold.

Increasing temperatures stimulate the decomposition of soil organic matter in the short term. But a shift in microbial carbon allocation could mitigate this response over longer periods of time.

The amount of pore space in most unweathered granite is too small to support a plant-based ecosystem. But porosity grows as intact rock interacts with surface waters beneath the soil.

The formation and flow of deep water around Antarctica contributes to the global ocean circulation. New measurements report the strongest flow speeds recorded so far in a current below 3,000 m depth, and help to document a pathway for Antarctic Bottom Water.

Many species of nannoplankton with carbonate shells vanished during the mass extinction 65 million years ago. An analysis of extinction rates from the world's oceans reveals a geographic bias in the demise and recovery of nannoplankton species.

The fragmentation of continents at convergent plate boundaries is thought to be influenced by the subducting lithosphere. Numerical modelling suggests that instead, the forces exerted by the underlying mantle can drive the formation of continental microplates.

Oceanic crust forms through the addition of volcanic rock to mid-ocean ridges. Widely dispersed, young lavas observed at an ultraslow-spreading ridge provide impetus for the redevelopment of models of oceanic magmatism.