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Ecosystem CO2 uptake: Prolonged after-effects of an extremely warm year. Earth's terrestrial ecosystems strongly modulate levels of CO2 in the atmosphere through seasonal changes in net plant productivity (CO2 absorbance) and soil microbial respiration (CO2 release). It has been known for decades that these processes respond to seasonal shifts in climate, especially temperature, resulting in the zig-zag form of the global CO2 curve, but the data necessary to quantify impacts of a single climate variable at interannual timescales have been lacking. A four-year study using intact tallgrass prairie ecosystems in controlled environment chambers (like the one on the cover, showing plant communities a few weeks after summer mowing) now provides some of the missing data. The results show that one anomalously warm year reduces net ecosystem CO2 exchange for that year and the year after. Carbon sequestration in ecosystems exposed to high temperatures for a year is a third of that in controls. These findings suggest that more frequent anomalously warm years, a possible consequence of rising anthropogenic CO2 levels, could lead to a sustained decrease in CO2 uptake by terrestrial ecosystems. Cover photo: J. Arnone [Letter p. 383; www.nature.com/podcast]
For a different perspective on the 2008 indicators from the US National Science Foundation, take a look at Nature's cartograms. Words and maps by Declan Butler.
In the third of our election-themed podcasts available online, Nature looks at where US innovation policy might go under a new president. Excerpts from our panel discussion:
Białowieża is one of the best-preserved woodlands in Europe. But is it a good reference point for what Europe looked like 5,000 years ago? Emma Marris goes deep into the forest to find out.
This summer a group of high-profile researchers met in Altenberg, Austria, to try and plot the future course of evolutionary theory. John Whitfield was there.
A tale of the endangered Atlantic bluefin tuna reveals how overfishing and unreported catches threaten to wipe out this majestic predator. But it stops short of offering original solutions, explains Geoff Arnold.
The California meeting set standards allowing geneticists to push research to its limits without endangering public health. Organizer Paul Berg asks if another such meeting could resolve today's controversies.
The poet Archilochus wrote “The fox has many tricks, and the hedgehog one great one”. Yet a signalling-pathway namesake of hedgehog may have two great tricks that could be exploited for cancer therapy.
Active galaxies are thought to be the supermassive cousins of binary systems in our Galaxy that contain black holes. Observations of an unusual active galaxy provide compelling evidence that these systems are indeed related.
A network of Hox factors specifies the identity of motor neurons in the spinal cord. Studies of an essential Fox-class accessory factor illuminate the developmental and evolutionary subtlety of the process.
Free-electron lasers could produce X-rays intense enough to make atomic-resolution movies. Initial designs are kilometres long, but a prototype working in the ultraviolet points a way to shorter machines.
Metamaterials are the key to perfect lenses, 'invisibility' cloaks and slow and stored broadband light. A three-dimensional optical metamaterial with a negative refractive index has now been created.
The unique structure of an enzyme that synthesizes lipid mediators in plants defines its function and serves as a characteristic footprint in genomes of plants and some animals.
Small-molecule catalysts are vital for countless chemical reactions. The development of these catalysts, which include transition-metal complexes and small organic molecules, is being stimulated by Insights into the mechanisms of existing small-molecule catalysts, by advances in computational chemistry, and by inspiration drawn from enzymes and from the challenges of making natural products.