Reviews & Analysis

The Southern Hemisphere westerly winds affect the exchange of carbon dioxide between the ocean and atmosphere. Climate reconstructions from the southern mid-latitudes may reveal variability in the strength and position of the wind belt since the Last Glacial Maximum.

Passive margins were thought to be tectonically inactive. Documentation of a volcanic dyke intrusion along the eastern flank of the Red Sea rift proves this plate tectonic tenet wrong, however, with implications for hazard assessments in these regions.

The Atlantic meridional overturning circulation delivers warmth to high latitudes and carbon to depth. Historical temperature and salinity records call into question the traditional view that these waters form a single coherent conveyer system of currents.

How groundwater flow varies when long-term external conditions change is little documented. Geochemical evidence shows that sea-level rise at the end of the last glacial period led to a shift in the flow patterns of coastal groundwater beneath Florida.

Andesite magmas were once thought to be simple melts derived from a subducting oceanic slab or the mantle. Analysis of lavas at Mount Hood shows that instead andesites are a complex mixture of magmas formed in the continental crust just before eruption.

The question of how soil moisture deficits affect runoff efficiency has flummoxed river forecasters for decades. Simulations with four land surface models reveal that soil moisture can have an influence that is on a par with early season snowpack.

Peat bogs release large quantities of methane to the atmosphere. A global survey of peat mosses reveals a ubiquitous symbiotic relationship with methane-oxidizing bacteria.

Evidence from biomarkers and molecular clocks points to the existence of sponges tens of millions of years before their earliest fossil remains. Fossils from South Australia may narrow that gap.

Gravity measurements of the ice-mass loss in Greenland and Antarctica are complicated by glacial isostatic adjustment. Simultaneous estimates of both signals confirm the negative trends in ice-sheet mass balance, but not their magnitude.

Eastern Indonesia hosts one of the most complex and fascinating tectonic systems on the planet. Palaeogeographical reconstructions indicate that subduction and deformation of a single slab of oceanic crust created the complicated configuration.

Reconstructions of atmospheric chemistry and microbial life early in the Earth's history have been contentious. Observations increasingly point to the evolution of complex and variable environments earlier in time.

The formation and burial of calcium phosphate minerals removes large quantities of phosphorus from the ocean. Radiotracer experiments reveal that bacteria in marine sediments mediate the production of these mineral phases at remarkably fast rates.

The composition of the rocks brought back from the Moon by the Apollo astronauts still poses a conundrum. Spectroscopic measurements of the lunar surface may offer a resolution while providing a glimpse at the evolution of the lunar mantle.

The timing and nature of changes in the chemistry of the early oceans are intensely debated. Geochemical analyses show that a prominent transition to sulphidic marine conditions 1.8 billion years ago may have been restricted to near-shore environments.

The mechanics of slip on faults in the Earth's crust are still unclear. Field observations from New Zealand show that movement can occur where — according to conventional assumptions of fault strength — it should not be possible.

The northern plains of Mars are thought to have harboured an ocean more than 3.6 billion years ago. Delta deposits and river-valley termini ring the proposed seabed and define an equipotential palaeoshoreline.