Articles in 2014

Many insights of Russian scientists are unknown or long-forgotten outside of Russia. Making the Russian literature accessible to the international scientific community could stimulate new lines of research.

The composition of mid-ocean ridge basalts varies with the properties of the mantle that feeds the ridges. Thermodynamic calculations of melt evolution suggest that most of the mantle melting occurs by an overlooked mechanism, focused melting.

The amount of carbon stored in peats exceeds that stored in vegetation. A synthesis of the literature suggests that smouldering fires in peatlands could become more common as the climate warms, and release old carbon to the air.

In the first decades of the twentieth century, the Earth warmed rapidly. A coral-based climate proxy record of westerly winds over the equatorial Pacific suggests that wind strength and warming rate were linked, as they are today.

Soil contains aged organic carbon that can be hundreds or thousands of years old. Human disturbance in small and large watersheds is mobilizing some of this fossil carbon from soils to aquatic systems.

Most dissolved organic carbon in rivers originates from young carbon in soils and vegetation. A global radiocarbon data set suggests that human disturbance is also introducing aged carbon to rivers and to active carbon cycling.

Global temperatures rose quickly between 1910 and 1940. A reconstruction based on corals suggests that the Pacific trade winds were weak during this period of rapid warming, but strengthened as warming slowed in the following decades.

Carbon dioxide can stimulate photosynthesis in trees and increase their growth rates. A study of tree rings from three seasonal tropical forests shows no evidence of faster growth during 150 years of increasing atmospheric CO₂ concentrations.

A period of rapid warming about 55.5 million years ago was triggered by a massive release of carbon. The carbon isotope composition of soil nodules provides evidence for a smaller, but still important, carbon release prior to the main event.

The release of massive amounts of carbon led to abrupt warming 55.5 million years ago. An analysis of soil carbonates shows two distinct carbon injections at the event onset, each releasing over 0.9 petagrams of carbon per year over hundreds to thousands of years.

Increasing CO₂ concentrations are expected to increase plant growth and water efficiency. Tree-ring data covering 150 years from tropical forests show that water-use efficiency has increased with CO₂ concentrations but tree growth has not.

Some of the glacial CO₂ drawdown has been attributed to CO₂ storage in the deep Pacific and Southern oceans. Reconstruction of apparent oxygen utilization suggests that respired CO₂ storage was also enhanced in the deep northeast Atlantic.

Atmospheric phosphorus contributes to terrestrial biogeochemical cycles. Estimates of phosphorus emissions from combustion suggest that anthropogenic emissions represent more than 50% of atmospheric sources of phosphorus.

The fate of water that enters the mantle within subducting slabs is unclear. Laboratory experiments indicate that subducted crust can transport large amounts of water into the deep Earth, and the lower mantle may become more hydrated over time.

High Arctic soils can act as sources or sinks of methane. Scaled-up field measurements suggest that northeast Greenland’s ice-free soils currently act as a net sink for methane, and may take up more methane with rising temperatures.

Linear sand dunes on equatorial Titan are shaped by winds. The morphologies of smaller dunes that have been reoriented with respect to the linear dune crests suggest that winds shift with long-term orbitally driven climate cycles on Titan.

Plumes are thought to transport water-rich material from the deep mantle to Earth’s surface. High-pressure experiments identify a hydrous mineral phase that is stable under lower-mantle conditions and could provide a source for this water.