January 13, 2009
Tiny Bugs Are The Most Fearsome Predators In Antarctica
Scientists say the Antarctic Peninsula's most fearsome land predator is a reddish bug called the Rhagidia mite.
Although the continent is best known for penguins, seals and whales, the tiny mite is considered it's top predator.Now researchers are stepping up their study of these miniscule creatures in Antarctica for possible early warnings about how climate change may disrupt life around the planet in coming decades.
Pete Convey, a biologist at the British Antarctic Survey, said Antarctica is strikingly different to other continents in terms of what you find on land.
"There are no land mammals, there are no grazing animals like gazelles, no land birds," he added.
One of the first rocks he picked up had a tiny, reddish mite racing around the surface.
"It's the lion of the ecosystem," he said of the 0.04 inch across mite. The mites have eight legs and are related to spiders.
Convey also pointed out that the biggest land animal on the entire continent, which covers more land than the United States, is a flightless midge about 0.2 inch long.
All of these tiny creatures have found ways to live year-round on land and shut down their bodies to survive the oppressive deep winter freeze. The simplicity of the ecosystem means the impact of new threats such as climate change can be more easily assessed.
Convey said there are only two (land) predators within 500 miles of the area. "It makes it a lot easier to understand the way the ecosystem functions."
"Everywhere people go they take roads, they take pollution, they take farming, they move species around," said David Vaughan, a glaciologist at BAS.
He added that it's very hard to see how climate change affects a natural ecological system, except somewhere like the Rothera area, ringed by mountains and with icebergs crowding the bay."
"The Antarctic Peninsula, because the climate is warming so rapidly, is the one place on the world's surface where you can come to see the effects on the ecology in a pure form," he said.
Scientists say the peninsula, sticking up toward the southern tip of South America, is the part of the southern hemisphere that has warmed fastest in the past 50 years, apparently because of an increase in temperature stoked by human use of fossil fuels.
The Antarctic peninsula's temperatures have risen by 5.4 Fahrenheit in the past half century, almost the difference in mean annual temperatures between France's southern city of Nice and Paris.
Convey and others believe that the Antarctic ecosystem may already be changing"”with both benefits and possible disruptions. "Global warming is going to make life easier for tiny creatures on the peninsula, almost certainly."
Plants would be able to grow more easily in warmer temperatures, making parts of the peninsula greener, therefore benefiting the animals that feed on them. But rising temperatures might also dry out the climate, threatening life.
It is likely that higher temperatures could make the Antarctic Peninsula more open to invasive species -- such as seeds, insects or spores brought in from outside sources.
Convey said more than 50,000 people, including tourists, scientists and other visitors come to Antarctica every year.
"That carries a far greater risk of bringing an alien biological organism into the Antarctic than natural colonization," he said.
A large number of those invasive species will die because of the cold "” the winters are still too cold for rats or mice.
In Antarctica, midget creatures have evolved where ever ground is exposed and there is fresh water in the summer. Temperatures around Rothera reach a maximum of about 44.60F in summer.
Rhagidia hunt for springtails, a primitive type of insect that live off vegetation. Sparse patches of green, black or orange lichen dot some rocks. Antarctica also boasts two flowering plants, some tiny worms and countless microbes.
Convey said many of Antarctica's animals have blood proteins that act as a natural anti-freeze and he can collect them in the winter.
"They are absolutely stationary ... they are perfectly well capable of surviving months and months and months of 14.0 to minus 4.00 Fahrenheit," he said.
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