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Tuesday, September 30, 2008

Better to play safe with nature

With this election there are many questions related to how the presidential candidates feel about global warming and its future effects on the United States. When John McCain is asked about global warming, he usually responds with something like, "I will clean up the planet; I will make global warming a priority." Barack Obama likes the phrase "I will clean up the planet." And Tina Fey as Sarah Palin says it's just God hugging us closer. So if this is such an important stance for presidents to be confident about, why do people say global warming's not true? Even if it isn't true, it's not bad if people are more environmentally friendly.

I'm not completely sure how I feel about the issue of global warming. I can see cases in which it appears to be a legitimate problem and then other cases where it doesn't make any sense. But I know it doesn't matter which way we want to look at it. People should ignore the issue of what it's called and focus on the benefits of Earth-friendly actions.

People seem to be torn on this issue for many different reasons. Some blame any type of extremely hot weather on global warming but then scoff at the thought of it being real when it's lower than 110 degrees outside. The issue is taken too far by pushing every commercial product into a "green" form and the matchbox sized Smart Cars that people drive. It's also pushed a little much by Hollywood and celebrities battling to be the most green.

When this issue was brought up in class last week, my friend and senior political science major Ben Wall said, "Earth has been here for billions of years, and it has gone through many changes. Global warming is just another change, just another one of Earth's cycles. I'm not saying don't be careless or don't go green; it's good to be resourceful. I'm just saying that global warming is just something for people to talk about."

I agree with his last statement about global warming being a trend or a conversation starter because I've seen its effect on the presidential campaign and Hollywood. Maybe it would help if we thought of global warming as sort of a Santa Claus for adults. Some parents tell their children about Santa for years, and the children just abide by the rules of conduct of this so-called Santa.

Like I've mentioned in previous articles, Starkville could help supply more options to help people be more conscious of their environmental actions, but at least there are a few options for people.

I can easily see the issue of global warming on a TV show such as "I Love The '00s" in about 15 years, completely harassing ourselves for believing in an idea as crazy as this.

I can see it becoming a more serious factor for how we live.

And I do feel there are more important issues for presidential candidates to be concerned about, such as the economy or their running mates, but global warming can't be completely ignored for fear that people will quit believing in the effects that it can have on the world.

It's much smarter to be on the safe side when issues like this are potential death threats from the environment. I personally don't know the point of not believing in it. It shouldn't necessarily be used as an excuse for everything bad that happens in the world but as a backbone of being more resourceful. And now that the weather is getting cooler and it's more comfortable to walk to class instead of driving a car, this can be a jumpstart for people's attempts to battle global warming, whether it really exists or not.

Monday, September 29, 2008

How the jellyfish got its sting

From a bacterium, surprisingly.

jellyfishThe venom of the box jellyfish can paralyse the central nervous system of its victims.NHPA/A.N.T. PHOTO LIBRARY

Jellyfish may owe thanks to a humble bacterium for their ability to sting prey. Scientists have found that one of the genes necessary for them to sting is similar to a gene in bacteria, suggesting the ancestors of jellyfish picked up the gene from microbes. The research is published this week in Current Biology1.

"The result was a great surprise," says developmental biologist Nicolas Rabet of the Pierre and Marie Curie University in Paris, France, who led the team. "[This kind of] horizontal gene transfer is often neglected, and could sometimes be more important than we thought." Unlike vertical gene transfer from parent to offspring, the horizontal variety happens between organisms, or even between different species. Common in microbes, it has only been described a few times in animals. Japanese beetles have picked up sequences from a parasitic bacterium2 and microscopic aquatic creatures called bdelloid rotifers have collected genes from bacteria, fungi and plants3.

The gene in question codes for a subunit of poly-gamma-glutamate (PGA) synthase - PGA itself is a major component of stinging cells4. The gene appears in all known genomes of creatures from the phylum cnidaria, which includes jellyfish, anemones and corals.

By collecting positive ions, PGA allows the cells to regulate their osmotic pressure; a sudden change in that pressure launches a poisonous barb. In bacteria, the same compound can form a protective capsule. It also gives the fermented Japanese food natto its stringy texture and pungent aroma.5

Using phylogenetic analysis, Rabet and his colleagues found that the cnidarian gene fits well into the bacterial family tree. They also showed that the gene turns on in at least one jellyfish, Clytia hemisphaerica. The same gene pops up in certain sponges, worms and fungi, suggesting it jumped between species more than once, the scientists say. It is not yet clear how the transfer might have occurred, or why this particular gene would be so well-travelled.

Vertical or horizontal?

"I think the author's interpretation is probably correct," says Michael Syvanen, who studies comparative genomics at the University of California, Davis. However, he is not convinced that other possibilites can be ruled out.

"There are other explanations for the incongruencies they see in the tree," agrees Casey Dunn, an evolutionary biologist who studies phylogenetic problems at Brown University in Providence, Rhode Island.

For instance, the gene could be vertically transferred from a distant progenitor, before being lost from some organisms. Or, it may be possible that more than one animal independently evolved the gene; such sequence conversion is not unheard of, Dunn says. "At the end of the day, it will probably take far more data to paint a conclusive picture of what's happening."

Rabet responds that since the PGA synthase gene is approximately 1000 bases long, it is statistically unlikely to be the product of multiple distinct genes converging on the same sequence

And if the gene was lost from all but the cnidarians and a few other animals, it must have disappeared from all related organisms. "It's possible, but we need to imagine a lot of lost genes," he says.

Scientists are finding that horizontal gene transfer, once thought to be the domain of single-celled critters, is not uncommon in the animal world, says Syvanen. "Horizontal gene transfer with the animals is going to turn out to be more widespread than anybody believes now. When that realization comes down, it will definitely change the way people think about evolution."

Thursday, September 25, 2008

Science News

Old Growth Forest Must

No Longer BeIgnored

In Carbon Balances

ScienceDaily (Sep. 25, 2008) — An international study involving a team from LSCE (CNRS-CEA-UVSQ) has revealed that ancient forests, which accumulate large quantities of carbon over the centuries, should be taken into account in global carbon balance assessments. However, such old growth forests were not included in the Kyoto protocol.

In the carbon cycle, forests help to slow down the build-up of atmospheric carbon dioxide by absorbing this gas, thereby mitigating climate change. Specifically, forests use CO2 to synthesise the organic molecules that are stored in trees, and thereafter in organic soil matter and dead leaves, which decompose slowly.

The ability of forests to fix carbon dioxide depends on the balance between the amounts removed from the atmosphere through photosynthesis and those released as a result of plant respiration.

In the late 1960's, an American scientist named Eugene Odum put forward the hypothesis that the carbon dioxide fixing and release rates in old growth forests, (i.e. woodland more than 150 years old) reached an equilibrium, rendering them neutral from a carbon balance perspective. Although little empirical evidence was produced in support of this hypothesis, it was nonetheless accepted by the vast majority of ecologists and "non-ecologists" alike. As a result, old growth forests were disregarded in the Kyoto protocol.

An international research team that includeds scientists from CEA's Laboratory of Climate and Environmental Science (LSCE - Laboratoire des Sciences du Climat et de l'Environnement) has compiled a new database using measurements made by the "CarboEurope" and "AmeriFlux" observatory networks, with the aim of accurately assessing Odum's hypothesis. "Old growth forests may actually still be accumulating carbon, in defiance of Odum's equilibrium hypothesis, explains Philippe Ciais, Deputy Director of LSCE, and co-author of the study. More than 30% of the planet's total forested area is unmanaged primary forest, half of which is located in temperate regions in the northern hemisphere. The database established for this study reveals that these ancient forests fix between 0.8 and 1.8 billion tonnes of carbon each year, and that 15% of the total forest area that has until now been totally ignored in carbon balances is in fact responsible for at least 10% of all carbon sinking activity."

The study finds that ancient forests accumulate large quantities of carbon over the centuries, which might be released in case of accidental disturbance (e.g. fire, insects, disease, storms, extreme droughts, etc.). In conclusion, carbon balance assessments should take these old growth forests into account.

Journal reference:

  1. Luyssaert et al. Old-growth forests as global carbon sinks. Nature, 2008; 455 (7210): 213 DOI: 10.1038/nature07276
Adapted from materials provided by CNRS.

CNRS (2008, September 25). Old Growth Forest Must No Longer Be Ignored In Carbon Balances. ScienceDaily. Retrieved September 25, 2008, from­ /releases/2008/09/080922175137.htm

Ancient forests, which accumulate large quantities of carbon over the centuries, should be taken into account in global carbon balance assessments. However, such old growth forests were not included in the Kyoto protocol. (Credit: iStockphoto)

Wednesday, September 24, 2008

Magnetar flashes astronomers

First optical signals spied from dead star.
magnetarMagnetars are the cores of massive stars that blew up in supernova explosions.NASA/JPL-Caltech

Astronomers believe they have spotted an aurora around of one of the densest objects in the Universe.

In the first observation of its kind, researchers say that they have seen optical light from a magnetar, an extremely dense, dying neutron star with a very powerful magnetic field. Astronomers watched for days as the magnetar flared, brightening at one point by over 200 times in just four seconds. The flash was far too bright to come from any normal stellar processes, and the leading explanation is that the light was emitted from ions accelerated by its magnetic field.

"It's a little bit similar to what you'd see in the Northern Lights," says Alexander Stefanescu, an astronomer Max-Planck Institute for Extraterrestrial Physics in Garching, Germany, and an author on one of two papers about the flares in this week's Nature1,2.

“[A magnetar] could rip your flesh off you from 1,000 kilometers.”

Alexander Stefanescu
Max-Planck Institute for Extraterrestrial Physics in Garching, Germany

The mysterious object was first spotted as a gamma-ray burst by the orbiting Swift spacecraft on 10 June 2007. Within minutes, optical telescopes around the world swivelled to observe the source of the activity. Much to their surprise, they saw a series of bright optical flashes. The first occurred just minutes after the initial burst, but the source continued to flare for a few nights.

The observations showed that whatever the object was, it was in our own Milky Way and no more than 10,000 to 16,000 light years away, less than a quarter of the distance across the Galaxy. Moreover, the energy contained in the flares was far too great to have come from a normal star, Stefanescu says.

In a spin

The suspected source of the flashes is an exotic variety of neutron star — neutron-rich remnants of stars that have exploded in a supernova. Theorists believe that neutron stars contain a smattering of charged particles that create its magnetic field, although how they do so is still not entirely understood.

But in rare cases, some neutron stars can develop an even stronger field. These magnetars can spin at rates of many revolutions per second, giving them a magnetic field up to 1,000 times that of a regular neutron star. "This field is actually so strong that it could erase a credit card from the distance of the moon," Stefanescu says. "It could rip your flesh off you from 1,000 kilometres."

Only 15 magnetars have ever been seen, according to Stefanescu. Most are invisible at optical wavelengths, but can occasionally be seen as bursts of high-energy gamma-rays and x-rays, possibly triggered by massive starquakes in the magnetar's crust. But such surface shifts would be too powerful to create the lower-energy optical flashes.

Stefanescu says that the most likely sources of the flashes are ions and electrons being accelerated through the turbulent magnetic fields above the magnetar's surface. As the charged particles spiral along the magnetar's powerful field lines, they emit radiation in a way that's somewhat analogous to the way the same particles create Earth's own celestial light shows, the aurora borealis and aurora australis. But he admits that "the exact details of how it works are not really well understood".

It's an intriguing find, says Chryssa Kouveliotou, an astronomer at the NASA Marshall Space Flight Center in Huntsville, Alabama. Kouveliotou finds the burst so odd that she remains "on the fence" over whether the source really is a magnetar. "I'd like to see at least one more example before I put my money down," she says.

Saturday, September 20, 2008