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This press release is copyright Nature. VOL.447 NO.7147 DATED 21 JUNE 2007
This press release contains:
· Summaries of newsworthy papers:
Chemistry: New method for making biofuels
Chemistry: Liquid mirror made for the Moon
Ocean science: Nitrification in the oceans — getting it right
Ecology: Managing Amazonian rainforest regrowth
Palaeoceanography: History of the Arctic Ocean
Evolution: The rise of placental mammals
· Mention of papers to be published at the same time with the same embargo
· Geographical listing of authors
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[1] Chemistry: New method for making biofuels (pp 982-985; N&V)
Simple sugars can be turned into a new, potentially useful biofuel, thanks to an approach described in this week's Nature. Although some challenges remain for commercial applications, this process may help decrease our dependence on petroleum in the near future.
James A. Dumesic and co-workers have developed a catalytic process that converts the simple sugar fructose into 2,5-dimethylfuran. Compared with ethanol, the only renewable liquid fuel currently produced in large quantities, 2,5-dimethylfuran has an energy density 40% higher and is less volatile. It's also insoluble in water, making it easier to obtain in its pure form.
Fructose can be obtained directly from biomass or derived from glucose, another simple sugar. With diminishing fossil fuel reserves and ongoing concerns about global warming, hopes are high that renewable energy sources, such as biomass, will provide a significant contribution to the world's energy needs.
CONTACT
James A. Dumesic (University of Wisconsin, Madison, WI, USA)
Tel: +1 608 262 1095; E-mail: [email protected]
Lanny D. Schmidt (University of Minnesota, Minneapolis, MN, USA) N&V author
Tel: +1 612 625 9391; E-mail: [email protected]
[2] Chemistry: Liquid mirror made for the Moon (pp 979-981; N&V)
Scientists have successfully coated an ionic liquid with silver, an achievement that may one day find use as a liquid mirror in a lunar telescope.
The surface of the liquid is smooth and the silver coating remains stable for months, Ermanno F. Borra and colleagues report in this week’s Nature. The ionic liquid underneath the silver does not evaporate in a vacuum and remains liquid down to a temperature of around 175 kelvin.
These features mean the device may be well suited for use inside a Lunar Liquid Mirror Telescope, a concept that is under consideration. An optical telescope with an aperture of 20 to 100 metres located on the Moon would be able to observe objects 100 to 1,000 times fainter than the proposed next generation of space telescopes. And a Lunar Liquid Mirror Telescope may prove easier and cheaper to build than its conventional equivalent.
CONTACT
Ermanno F. Borra (Universite Laval, Quebec, Canada)
Tel: +1 418 656 7405; E-mail: [email protected]
Robin Rogers (The Universiy of Alabama, Tuscaloosa, AL, USA) N&V author
Tel: +1 205 348 4323; E-mail: [email protected]
[3] Ocean science: Nitrification in the oceans — getting it right (pp 999-1002)
Our assumptions about the role of nitrification in the world’s oceans may be way off the mark, a Nature study suggests. The findings are likely to impact on estimates of the ocean’s carbon cycling, which are critical to get right in light of current climate warming and ocean acidification.
Nitrification, the process by which ammonia is converted to more useable forms of nitrogen, such as nitrites and nitrates, has an important impact on the world’s oceans. Phytoplankton consume nitrate as it wells up from the depths, and scientists have used phytoplankton growth as a measure of the ocean’s export flux. But accurate measurements need to incorporate other sources of biologically available nitrogen, such as nitrate production by nitrification in surface waters.
Andrew Yool and colleagues look at surface nitrification rates and use these to help quantify the global role of nitrification. They find that a large fraction of the nitrate taken up is generated through recent nitrification near the surface and, at the global scale, nitrification accounts for about half of the nitrate consumed by growing phytoplankton. This means that many previous attempts to quantify marine carbon export may be significant overestimates.
CONTACT
Andrew Yool (National Oceanography Centre, Southampton, UK)
Tel: +44 23 8059 6339; E-mail: [email protected]
[4] Ecology: Managing Amazonian rainforest regrowth (pp 995-998)
Tropical forest regrowth depends on a delicate balance between nitrogen and phosphorus, suggests a paper in this week’s Nature. The findings should help researchers predict how long it takes for tropical forests to recover after clearance, and should contribute to better management of disturbed Amazonian ecosystems.
Around 16% of the original Amazon Basin rainforest has been cleared for agriculture, but it's thought that up to half of this is now being allowed to regrow. Eric A. Davidson and colleagues now show that nitrogen and phosphorus levels influence this regrowth, with different factors proving limiting at different stages of maturation.
Early on after agricultural abandonment, nitrogen levels in the soil are low, so the plants conserve the little that they have. But as the forests mature and nitrogen levels in the soil rise, phosphorus becomes the limiting factor for plant regrowth. Trees become less conservative with nitrogen, nitrogen cycling recovers, and the ecosystem even leaks some nitrogen back to the atmosphere in the form of the greenhouse gas nitrous oxide.
CONTACT
Eric A. Davidson (Woods Hole Research Center, Falmouth, MA, USA)
Tel: +1 508 540 9900 x132; E-mail: [email protected]
[5] Palaeoceanography: History of the Arctic Ocean (pp 986-990)
The Arctic Ocean became fully oxygenated around 17.5 million years ago, analysis of the unique drill cores recovered during the Arctic Coring Expedition (ACEX) suggests. The finding has implications for our understanding of changes in global ocean circulation over time.
Deep-water formation in the northern North Atlantic Ocean and Arctic Ocean is a key driver of the global density-driven ocean circulation and hence also of global climate, but little was known about the history of ocean circulation in the Arctic Ocean owing to a lack of sediments from the Arctic's deep-sea floor. In this week's Nature, Martin Jakobsson and colleagues reveal data from the first drill cores recovered from the central Arctic Ocean.
The results suggest that the Arctic Ocean went from an oxygen-poor 'lake stage' to a fully ventilated, saline 'ocean' phase around 17.5 million years ago. The researchers attribute this change to the opening of the Fram Strait, a deep water connection linking the Arctic and North Atlantic Oceans that allows exchange of water between the two basins.
CONTACT
Martin Jakobsson (Stockholm University, Sweden)
Tel: +46 8 164 719; E-mail: [email protected]
[6] Evolution: The rise of placental mammals (pp 1003-1006; N&V)
Placental mammals probably burst onto the evolutionary scene around the time of the dinosaurs’ demise, a paper in this week’s Nature suggests.
John R. Wible and colleagues describe a new genus of placental mammal from Mongolia. By comparing its morphology with a wide range of other Cretaceous mammalian fossils, they deduce that the new find lived around seventy-five million years ago. Their results suggest that placental mammals (the group that includes humans and almost all other live-bearing mammals) had an ‘explosive’ evolutionary origin around the close of the Cretaceous period. This is at odds with a competing theory, which suggests that placental mammals have much deeper evolutionary roots.
CONTACT
John R. Wible (Carnegie Museum of Natural History, Pittsburgh, PA, USA)
Tel: +1 412 665 2613; E-mail: [email protected]
Richard Cifelli (Oklahoma Museum of Natural History, Norman, OK, USA) N&V author
Tel: +1 405 325 8978; E-mail: [email protected]
ALSO IN THIS ISSUE…
[7] Electromagnetic detection of a 410-km-deep melt layer in the southwestern United States (pp 991-994)
[8] Prostaglandin E2 regulates vertebrate haematopoietic stem cell homeostasis (pp 1007-1011)
ADVANCE ONLINE PUBLICATION
***These papers will be published electronically on Nature's website on 20 June at 1800 London time / 1300 US Eastern time (which is also when the embargo lifts) as part of our AOP (ahead of print) programme. Although we have included them on this release to avoid multiple mailings they will not appear in print on 21 June, but at a later date.***
[9] Essential autocrine regulation by IL-21 in the generation of inflammatory T cells
DOI: 10.1038/nature05969
[10] IL-21 initiates an alternative pathway to induce proinflammatory TH17 cells
DOI: 10.1038/nature05970
[11] Hebbian STDP in mushroom bodies facilitates the synchronous flow of olfactory information in locusts
DOI: 10.1038/nature05973
[12] Structural basis for substrate loading in bacterial RNA polymerase
DOI: 10.1038/nature05931
[13] Structural basis for transcription elongation by bacterial RNA polymerase
DOI: 10.1038/nature05932
[14] CD1d–lipid-antigen recognition by the semi-invariant NKT T-cell receptor
DOI: 10.1038/nature05907
GEOGRAPHICAL LISTING OF AUTHORS…
The following list of places refers to the whereabouts of authors on the papers numbered in this release. For example, London: 4 - this means that on paper number four, there will be at least one author affiliated to an institute or company in London. The listing may be for an author's main affiliation, or for a place where they are working temporarily. Please see the PDF of the paper for full details.
AUSTRALIA
Clayton: 14
Parkville: 14
BRAZIL
Belem: 4
Piracicaba: 4
CANADA:
Laval: 2
Vancouver: 2
CHILE
Concepcion: 3
FINLAND
Helsinki: 5
FRANCE
Marseille: 3
GERMANY
Bremerhaven: 5
SWEDEN
Stockholm: 5
UNITED KINGDOM
Belfast: 2
Birmingham: 14
Cambridge: 6
Plymouth: 3
Southampton: 3
UNITED STATES OF AMERICA
Alabama
Birmingham: 12, 13
Arizona
Tempe: 7
Tuscon: 2
California
Moffett Field: 2
Pasadena: 11
Kentucky
Louisville: 6
Massachusetts
Boston: 8, 10
Cambridge: 10
Falmouth: 4
Nebraska
Omaha: 13
New Hampshire
Durham: 5
New York
New York: 6
North Carolina
Triangle Park: 9
Ohio
Columbus: 12, 13
Pennsylvania
Philadelphia: 8
Pittsburgh: 6
Rhode Island
Narragansett: 5
Texas
Houston: 9
Washington
Seattle: 9
Wisconsin
Madison: 1, 12
PRESS CONTACTS…
For North America and Canada
Katie McGoldrick, Nature Washington
Tel: +1 202 737 2355; E-mail: [email protected]
For Japan, Korea, China, Singapore and Taiwan
Mika Nakano, Nature Tokyo
Tel: +81 3 3267 8751; E-mail: [email protected]
For the UK/Europe/other countries not listed above
Helen Jamison, Nature London
Tel: +44 20 7843 4658; E-mail [email protected]
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