News & Views in 2011

Animals originated in a world with marine oxygen levels only a fraction of those found in today's oceans. Observations of microbial habitats in present-day lagoons suggest that early animals could have found refuge in oxygen-producing mats.

Observations from the Cassini–Huygens mission have produced potentially contradictory constraints on the origin of Titan's atmosphere. Experiments and a simple model demonstrate that a new mechanism for late formation is plausible.

Why broad fields of volcanism are found in the interior of tectonic plates is hard to explain. Spatial correlations between sheared mantle flow and volcanism suggest that differential motion between surface plates and the mantle generates upwelling and melt.

Mitigating greenhouse gas emissions from agriculture is important and achievable. However, cutting emissions to meet the UK's legal targets for 2050 will bring technical and political challenges, and may affect food production.

Estimates of sea level during the mid-Pliocene warm period three million years ago vary by 35 m. Model simulations of glacial isostatic adjustment reconcile these values and indicate little to no melting of the East Antarctic ice sheet during this time.

Mountain-forming systems on Earth occur at present either at the edge of continental plates or in their centre. Isotopic signatures from orogenic rocks worldwide indicate that these two distinct systems have existed for at least 550 million years.

Empirical data on mangrove carbon pools and fluxes are scarce. A field survey in the Indo-Pacific region suggests that the sediments below these remarkable trees hold exceptionally high quantities of carbon.

Motion along faults can occur in sudden earthquakes or through steady, aseismic creep. Rock samples retrieved by drilling deep into a creeping section of the San Andreas Fault show that clay minerals in fault rock promote creep behaviour.

How the chemical composition of sea water changes on its journey through the world's oceans is poorly understood. Systematic measurements of dissolved trace metals across the Pacific Ocean suggest that these metals may help track sources and mixing of water masses.

Chondritic meteorites are remnants of the ancient Solar System. Analysis of the dust rims often found on their constituent particles shows that the rims were swept up while the particles wafted about and collided in a weakly turbulent protoplanetary nebula.

Extreme climate events can cause widespread damage and have been projected to become more frequent as the world warms. Yet as discussed at an interdisciplinary workshop, it is often not clear which extremes matter the most, and how and why they are changing.

The contribution of the East Antarctic ice sheet to the 120 m of sea-level rise since the Last Glacial Maximum is unclear. New terrestrial and marine data suggest the thinning of East Antarctic ice was responsible for only a metre of this rise.

Massive amounts of natural gas catastrophically released into the Gulf of Mexico last year are missing. Two investigations suggest that a bloom of tiny specialized bacteria is responsible for this heavy-duty scrubbing job.

The neurotoxin methylmercury accumulates in marine biota and their predators. An analysis of seabird egg shells suggests that sea-ice cover reduces the breakdown of this highly toxic compound in sea water.

An observed hemispheric structure in the Earth's inner core has been hard to reconcile with evidence that it rotates faster than the mantle. Detection of a shift of the hemisphere boundary that occurred over geological timescales removes the contradiction.

Mineral dust and biological particles of terrestrial origin initiate ice formation in the atmosphere. Laboratory experiments suggest that ocean diatoms are another potential source of ice nuclei in clouds.