Volume 3 Issue 9, September 2010

The foundation of the marine food web is faltering, according to a century-long data set.

Short-lived greenhouse gases and black-carbon aerosols have contributed to past climate warming. Curbing their emissions and quantifying the forcing by all short-lived components could both mitigate climate change in the short term and help to refine projections of global warming.

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.

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.

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.

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.

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.

Slow slip, a mechanism by which faults can relieve stress, was thought to be distinct from earthquakes. However, a global review of slow-slip phenomena suggests that instead there is a continuum between the two types of event.

Ocean eddies generated through instability of the mean flow are a vital component of the energy budget of the global ocean. Modelling combined with satellite altimetry data suggests that the energy from westward-propagating eddies is scattered and eventually dispersed when they reach the western boundary of an ocean basin.

In the American west, operational forecasts for spring–summer streamflow rely heavily on snow-water storage. Simulations with a suite of land-modelling systems suggest that snow-water storage generally contributes most to forecasting skill, but that the contribution of soil moisture is often significant, too.

The degradation of submerged Sphagnum mosses generates significant quantities of methane in peat bogs. A global survey of these mosses reveals the presence of an active population of methane-oxidizing bacteria.

Reconstructions of land and ocean temperatures over the past 18,000 years in the high southern latitudes have shown conflicting trends. Analyses of temperatures on Campbell Island, south of New Zealand, confirm this behaviour, and lead to the suggestion that it reflects changes in the position and intensity of the westerly winds.

Varying concentrations of atmospheric oxygen have affected the development of animals and the role of wildfire in ecosystems. Reconstructions of past oxygen concentrations from fossil charcoal constrain atmospheric oxygenation over the past 400 million years.

At subduction zones, andesite lavas erupt in greater abundance than the individual magmas that mix to produce them. Textural and geochemical analyses of andesites from Mount Hood, Oregon, reveal that injection and mixing of iron- and magnesium-rich magma in the magma chamber can initiate the volcanic eruption.

The age of the Solar System is defined by the formation of the first solid grains in the solar nebula. Pb–Pb age dating of these solids, which were later trapped in a meteorite, indicates that the Solar System is 0.34–1.91 million years older than previously thought.

Present-day changes in the thickness of ice sheets and glacial isostatic adjustment both affect space geodetic measurements. A combination of gravity measurements and geodetic data of surface movement with a data-assimilating model of ocean bottom pressure allows the simultaneous estimation of present-day water transport and glacial isostatic adjustment.

The photosynthetic production of oxygen in the ocean is thought to have begun at least 2.7 billion years ago. The geochemistry of marine sediments deposited 2.6 billion years ago suggests that ocean margins were oxygenated at least 100 million years before the first significant increase in atmospheric oxygen concentrations.

The Trezona Formation of South Australia pre-dates the 635-million-year-old Marinoan glaciation. Fossils found at this location are up to several millimetres in size, and share morphological characteristics with sponge-grade animals.

Nardy Kip, Julia F. van Winden, Huub J. M. Op den Camp and an array of colleagues braved hostile acidic peat bogs around the world in a feat of truly collaborative research.