Articles in 2014

Low levels of iron limit primary productivity across much of the Southern Ocean. Measurements of dissolved iron levels combined with hydrographic data suggest that much of the iron in the surface waters of the Southern Ocean is supplied by deep mixing during winter.

Fluctuations in North Atlantic climate and hydrography over the past 1,000 years are seemingly linked to changes in solar irradiance. Reconstructions of marine conditions compared with an analysis of climate model output indicate that low solar irradiance is associated with the development of a high-pressure system in the eastern basin that affects the dynamics of the subpolar gyre.

Ozone-depleting substances emitted through human activities cause large-scale damage to the stratospheric ozone layer, and influence global climate. An analysis of unpolluted air sampled from Tasmania and firn snow reveals the emergence of four new ozone-depleting substances in the atmosphere since the 1960s.

Following the Chicxulub impact, many foraminifera in near-surface waters perished, but bottom-dwelling species survived. Impact experiments suggest that sulphate in Chicxulubs target rocks was released as predominantly sulphur trioxide, which would have been converted to sulphuric acid in the atmosphere and swept down swiftly by larger particles, acidifying the ocean surface.

The oxygenation of the Earth's deep oceans is often thought to have triggered the evolution of simple animals. A review article proposes that instead, the evolution of animal life set off a series of biogeochemical feedbacks that promoted the oxygenation of the deep sea.

Regions of intense continental deformation, termed continental slivers, have been identified in Chile, Bolivia and Ecuador. Analyses of GPS data now identify another large sliver in Peru, the Inca Sliver, that is moving away from a neighbouring sliver in Ecuador—implying that moving continental slivers control the deformation of almost the entire Andean mountain range.

Decadal climate variability has long received limited attention. With the slow-down in surface warming since the late 1990s, the decadal scale has rightly become a focus of attention: for assessing climate change and its impacts, it is of critical importance.

The recent slow-down in the rate of warming, averaged over the surface of the entire planet, has incited much discussion. As climate scientists are tracking down the causes, we must not forget that average surface temperatures are only one indicator of climate change.

Climate models projected stronger warming over the past 15 years than has been seen in observations. Conspiring factors of errors in volcanic and solar inputs, representations of aerosols, and El Niño evolution, may explain most of the discrepancy.

During the Last Glacial Maximum, tropical glacier snowlines were lower than expected, based on estimates of tropical sea surface temperatures. Sea surface temperature reconstructions suggest the Indo-Pacific warm pool was cooler than previously thought; these temperatures and convective mixing processes can explain snowline altitude in this region.

Humic substances make up a significant fraction of the natural organic matter in terrestrial and aquatic environments. Laboratory experiments suggest that humic substances serve as fully regenerable electron acceptors in recurrently anoxic environments such as peatlands.

Breaking waves on the ocean surface generate air bubbles that yield sea spray aerosols when released to the atmosphere. Measurements of sea spray aerosols in the North Atlantic Ocean and the coastal waters of California suggest that the surface water organic carbon reservoir is responsible for the organic carbon enrichment of freshly emitted sea spray aerosol.

The age of the oldest Jack Hills zircons — Earth's oldest minerals — is contentious. Atomic-scale mapping of the distribution of radiogenic isotopes within a Jack Hills zircon confirms that the oldest known continental crust formed just after the Earth–Moon system.

The end-Permian extinction decimated marine life on an unprecedented scale. However, an analysis of the lifestyles of the surviving genera shows that very little functional diversity was lost at the sea floor.

Global mean surface and tropospheric temperatures have shown slower warming since 1998 than found in climate model simulations. A detailed analysis of observations and climate model simulations suggests that the observed influence of volcanic eruptions on tropospheric temperature has been significant, and that the discrepancy between climate simulations and observations is reduced by up to 15% when twenty-first century volcanic eruptions are accounted for in the models.