In brief– Research news and discovery

THIS is getting serious. Climate

change could cause forests in

Europe to spew out more and

more nitrous oxide, aka laughing

gas, a potent contributor to

global warming.

As a greenhouse gas, N2O is

296 times as powerful as carbon

dioxide and accounts for 6 per

cent of the greenhouse effect. To

better understand the N2O output

from forests, Klaus Butterbach-

activity adds more nitrogen to the

biosphere, the production of N2O

by the bacteria looks set to grow.

The team also found that

deciduous forests made more N2O

than coniferous ones – a concern,

as Europe is promoting deciduous

forests to increase biodiversity.

Worryingly, denitrifying

bacteria worked best in warm and

moist soil. “If it is going to be

warmer and wetter, as predicted

for many parts of Europe, then

N2O emissions will go up,” says

Zechmeister-Boltenstern.

Bahl of the Karlsruhe Research

Centre in Germany and team

members Per Ambus and

Sophie Zechmeister-Boltenstern

studied N2O emissions from

11 European forests

(Biogeosciences, vol 3, p 135).

They found that nitrifying soil

bacteria thrive on high nitrogen

levels, producing mainly nitrates,

which are turned into N2O by

denitrifying bacteria. As human

No laughing matter for forests

ANCIENT Greek hairdressers

could teach us a thing or two

about nanotechnology.

When hair is dyed using a lead-

based dye popular 2000 years

ago, crystals of lead sulphide just

5 nanometres across form within

the microstructure of the hair

fibres, according to a team led by

Phillipe Walter at the French

Museums’ Research and

Restoration Centre in Paris.

A hair-like scaffold could be

used to grow “quantum dots” –

tiny crystals which confine a

handful of electrons in a way that

makes it possible to exploit their

quantum properties, such as spin,

for use in emerging quantum

computing systems. Existing

methods for producing quantum

dots create defects. The work will

be reported in Nano Letters.

Greeks invented

quantum hair dye

FERN

ANDO

MOL

ERES

/PAN

OS

16 | NewScientist | 16 September 2006 www.newscientist.com

WE HAVE tried killing bacteria,

but stopping them talking to

each other might be key to

halting infections.

Bacteria usually only attack

their host when they sense that

there are enough of them, a

process called “quorum sensing”.

Disrupting this signalling can

stop bacteria making toxins to

increase their virulence (New Scientist, 4 January 2003, p 30).

But it takes time to build the

right compounds. Now Helen

Blackwell at the University of

Wisconsin, Madison, and her

team have used microwaves to

speed up the process 100-fold.

So far they have identified two

compounds that could tame

Pseudomonas aeruginosa, which

causes lung infection in people

with cystic fibrosis. Blackwell told

the American Chemical Society in

San Francisco that these

molecules are designed to buy

time for conventional antibiotics

to work rather than replace them.

Not good to talk

A BILLION people depend on the Indian monsoon, yet

predicting its success or failure has till now been a somewhat

hit-or-miss affair. This could change with the discovery that

conditions in the eastern Pacific hold the key.

It’s well known that the monsoon is affected by the

warming of the Pacific Ocean associated with El Niño events.

Failed monsoons have always been accompanied by an

El Niño, but monsoons do not fail in every El Niño year.

To better understand this link, K. Krishna Kumar of the

Indian Institute of Tropical Meteorology in Pune and

colleagues looked at figures for rainfall in India and sea

surface temperatures from the equatorial Pacific since 1871.

They found that in the years when an El Niño strongly

warmed the central Pacific, drought conditions ensued in

India, whereas the monsoons were normal when the

warming was concentrated in the eastern Pacific (Science,

DOI: 10.1126/science.1131152)

The reason, says team member Martin Hoerling of

the US National Oceanic and Atmospheric Administration

in Boulder, Colorado, is that as the central Pacific warms,

the atmosphere above it heats up and rises. This induces a

large, dry air mass to sink over India, depriving it of

nourishing rains.

Global warming and rising ocean temperatures may

reinvigorate the monsoons, which have been declining over

the past three decades. “The trend could be mitigated as the

eastern Pacific warms,” Hoerling says.

This year the rains came,

but what about next year?

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