Plumbing key to flowering plants’ evolutionary success

The evolution of an efficient water transport system may be how flowering plants came to dominate terrestrial plant life 60-70 million years ago.

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New doubt cast on dinosaur-killing asteroid theory

The asteroid blamed for a mass extinction event 65 million years ago could actually predate the demise of dinosaurs by 300,000 years.

By analysing sediments near the asteroid's site of impact, called the Chicxulub crater, researchers have found that the impact did not cause the extinction of any species.

In the Mexican town of El Penon, Princeton University geologist Gerta Keller and her research team found evidence of 52 species in sediments that were deposited both before, and after, the impact.

"We found that not a single species went extinct as a result of the Chicxulub impact," she said.

Keller's report contradicts the popular theory that the Chicxulub impact heralded the extinction of 65 percent of all species, including plants, dinosaurs, and other animals.

She expects her findings to be unsurprising, as no other great mass extinctions are associated with an impact, and no other large craters are known to have caused a significant extinction event.

Keller suggests that the massive volcanic eruptions at the Deccan Traps in India may be responsible for the extinction.

Huge amounts of dust and gases from the eruptions could have blocked out sunlight and brought about a significant greenhouse effect, she said.

More information is available from the National Science Foundation's press release.

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Ancient nickel famine may have birthed complex life

Almost 3 million years ago, a subtle geochemical change in volcanic lava may have set the stage for complex life to evolve.


According to geologist Mark Barley, nickel levels in lava and in the sea water began to drop approximately 2.7 million years ago, decreasing by more than half within the subsequent 200,000 years.

Decreased nickel levels were detrimental to the methane-producing microbes that inhabited Earth at the time, paving the way for the proliferation of oxygen-producing bacteria that eventually oxygenated the atmosphere.

"Methane-producing microbes, [which are called] methanogens, require the element nickel for their life and for the formation of methane," explained Barley, who is a professor in the University of Western Australia's School of Earth and Environment.

“The nickel crash after its early boom 2.7 billion years ago helped make our planet habitable by complex life,” he said.

Barley and his colleagues say their findings could explain the puzzling 'Great Oxidation Event' that led to a dramatic rise of oxygen in Earth's atmosphere approximately 2.4 billion years ago.

The researchers' report was published today in the international weekly journal, Nature.

More information is available from the Carnegie Institution's press release.

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Curbing deforestation could stop climate change - if it exists

By Liz Tay
The effect of human activities on climate change is real, according to a new study on tropical deforestation in areas like the Amazon and Indonesia.

Conducted by an international team of researchers from the U.S., U.K., Brazil, France and Australia, the study claims to have confirmed that avoiding deforestation can play a key role in reducing future greenhouse gas concentrations.

Nearly 20 percent of carbon emissions is said to be contributed by deforestation in the tropics. This equates to about 1.5 billion tonnes of carbon each year, adding up to an estimated 130 billion tonnes of carbon by the year 2100.

"[The 2100 projection] is greater than the amount of carbon that would be released by 13 years of global fossil fuel combustion," said CSIRO atmospheric scientist Pep Canadall, who is also a researcher on the Global Carbon Project and on the deforestation study.

"Maintaining forests as carbon sinks will make a significant contribution to stabilising atmospheric greenhouse gas concentrations," he said. "The new body of information … also demonstrates the need to avoid higher levels of global warming, which could slow the ability of forests to accumulate carbon."

"Climate changes all the time, so if the goal is to keep it constant, or 'sustainable', it is a hopeless task"
- Bjarne Andresen

According to thermodynamics expert Bjarne Andresen, however, the very concept of global warming could be a farce. A professor of physics at the esteemed Niels Bohr Institute in Denmark, Andresen's recent report in the international Journal of Non-Equilibrium Thermodynamics claims that the notion of an overall global temperature is both a thermodynamical and mathematical impossibility.

Explaining 'temperature' as a comparative quantity that can only have meaning at a point or for a homogeneous system, Andresen argued that Earth consists of a huge number of components. Adding temperatures together to form a global average would have the same, meaningless effect as calculating the average phone number in a telephone directory, he said.

"The whole idea of global anything is a figment of the imagination," he said. "Effects happen locally and will be different at different spots on Earth; some places will heat up, others cool down."

"Climate changes all the time, so if the goal is to keep it constant, [or] 'sustainable', it is a hopeless task," he said, although stressing that the futility of a constant climate is his personal opinion, and not part of his scientific work.

While he is also of the opinion that humans are ethically obliged not to pollute the environment with poisonous substances like PCB and mercury, Andresen questioned the purpose of using wood, which has sometimes been touted as renewable energy source, instead of coal.

"What is the big difference between the so-called renewable energy source wood as opposed to coal?" he said. "Coal used to be wood as well, so we are actually just burning old wood. In both cases the carbon originally came from the atmosphere and we are returning it there."

Andresen urged climatologists to rethink their methods of analysing climate, as 'equally correct' methods of averaging could each yield wildly different conclusions about the state of the environment.

Emphasising that strong physical arguments are needed to decide on which averaging method to use in describing the climate, Andresen argued that currently approaches to 'global warming' could be employing more of a political, fear-mongering tactic than a scientific approach to the issue.

Atmospheric physicist Michael Box, of the University of New South Wales, defended the averaging methods currently favoured by many climatologists, saying that while 'average temperature' may be a term used loosely by policy makers, 'real' climate scientists use a vast range of inputs as best they can.

"I'm sure all atmospheric physicists know that you can't average temperatures in a strictly formal sense," he said. "However, it is a piece of data that we have going back for a century, so we have something we can compare to."

"We all know that it is temperature gradients which drive the atmosphere - i.e. meteorology," he said. "Nevertheless, an increase in global average temperature is a clear sign that something is going on!"

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Shock, awe, and science journalism

Airing the views of climate change sceptics in the media only serves to keep controversy boiling, scientists have told the World Conference of Science Journalists in Melbourne, Australia.

Kevin Hennessy, Australian scientist and lead author of the Intergovernmental Panel on Climate Change (IPCC) Working Group II report, said this week that media attention on "the view of a handful of climate change sceptics" amplifies their opinions and "implies that there is little agreement about the basic facts of global warming".

Speaking in a session about climate change reporting, he said editors and journalists have a duty to ensure that facts are presented in context. Balanced reporting, he said, "perpetuates the public's perception that scientists are in disarray, which is misleading in the case of climate change".

Geoff Love, vice chair of the IPCC Working Group II, said that the IPCC assessment reports ― from 1990, 1995, 2001 and February 2007 ― are strong evidence of "the coming together of the scientific community" and that emphasis on the sceptic view does not help public understanding of climate change.

Media coverage has not always reflected the consensus of the majority of the scientific community, said Ian Lowe, president of the Australian Conservation Foundation. "That only makes the public and political discussion more difficult," he said.

More information is available from the original article at SciDev.net.

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Happy feet hit treadmills to track climate change

By Liz Tay
They may not be able to tap dance, but king penguins in the Antarctic could in fact have a role in monitoring the effects of climate change, new research suggests.

Scientists have long studied our changing environment in terms of unusual animal behaviour, such as altering patterns of fish and bird migration. Now, a research team from the University of Birmingham is finding out if the energy requirements of king penguins could be used as an alternative bio-indicator to monitor the health of the environment.

King penguins predominantly feed on a variety of fish called myctophid fish, explained bioscientist Lewis Halsey, who led the research on Possession Island in the South Indian Ocean. As the Southern Oceans warm, these fish tend to migrate further South, and away from the Islands inhabited by king penguins, he said, which makes hunting more difficult for the penguins.

“As the king penguins have to work harder to forage for the fish, their energy expenditure in doing so will increase,” Halsey said. “[This tells] us that the myctophid fish are changing location and becoming more sparse in areas of the Southern Oceans where king penguins forage.”

King Penguin - Lewis HalseyKing penguins are good candidates as bio-indicators for several reasons, the researchers say. Firstly, while at sea foraging, they cover hundreds of kilometres and are able to dive to depths of several hundred metres, so they explore a relatively large portion of the expansive Southern Oceans. Secondly, the diets of several populations of king penguins are well known. Thirdly, while foraging for food is done at sea the penguins also come ashore to breed and moult, making them accessible to researchers.

To ascertain the penguins’ energy requirements, researchers have implanted miniature heart rate data loggers into the birds. The penguins’ heart rates are then collaborated against energy expenditure under laboratory conditions, by getting the penguins to walk on a treadmill at different speeds. This data provides a correlation between heart rate and rate of energy expenditure, so any heart rate data subsequently obtained when the king penguins go to sea to forage can be used to estimate energy expenditure.

“We have deployed these loggers on birds for several years so we can look to see if the energy expended by king penguins from year to year is changing, which may give us information on the availability of myctophid fish in the Southern Oceans each year,” Halsey said.

More data is needed from the heart rate loggers during the next few years before any long term trends can be established. If the energy expended by king penguins at sea increases over time, it is likely that myctophid fish are getting harder to come by, which could be due to the warming of the Southern Oceans, Helsey said.

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Genetically modified crops, ten years on

Is the expansion of genetically modified (GM) crops still seen as risky, or will it in fact help with the doubling of the food supply required as Earth’s population hits nine billion within the next 40 years?

Ten years after the first GM crops were planted, evidence is mounting that the technology can increase crop yields with apparently little environmental impact, particularly in developing countries. In India, for example, GM cotton has increased yields by around 150 per cent, trebled small farmers’ profits, and reduced pesticide volumes by 80 per cent. In Australia, GM cotton has also significantly decreased pesticide use while raising farmers’ yields.

Anti-GM groups, however, argue that in many developing countries, GM crops are now grown mainly for export by big farmers, not for local consumption, and that there are big effects of this monoculture cropping.

Most Australian states, including Victoria and New South Wales, have imposed moratoria on GM crops until 2008. But according to a 2005 ABARE report, ongoing moratoria could result in Australia losing billions of dollars in foregone profits over the next decade, particularly as global warming impacts crop environments.

University of Melbourne agronomist Rob Norton claims that the vigorous seedling growth of hybrid GM canolas helps them compete against weeds and shortens the interval to harvest, reducing exposure to heat at the end of the growing season, and meaning less irrigation is required. This trait would allow canola plantings to be expanded into drier areas, potentially boosting annual Australian production of canola by 295,000 tonnes annually.

More information is available from CSIRO's press release

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Climate change: a political hot potato

Climate change certainly is the hot topic of recent times, with enviro-friendly doomsayers, businesses and politicians making headlines across the globe.

Australian politicians this month took up a challenge set by studies in the UK and Australia, aiming to reduce greenhouse emissions by 60 percent before the year 2050. With the 2007 federal elections on the horizon, plans for meeting the greenhouse target seem to be on every party’s agenda, with solutions ranging from more effective coal-fired electricity to carbon pricing, nuclear power, better public transport, and investment in more research and development.

Meanwhile, in the U.S., the Bush administration has been charged with interfering with climate science to downplay the significance of global warming. Political appointees are being accused of editing scientific reports to emphasise scientific uncertainty and even trying to silence scientists in some cases.

Elsewhere, a debate rages on about whether global warming even exists. A recent paper by physicist Bjarne Andresen of the Niels Bohr Institute in Denmark asserts that the concept of a ‘global temperature’ is a statistical impossibility, thereby claiming that the entire debate surrounding global warming is more a political than scientific gesture.

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