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USF scientist leads Antarctic expedition to study effects of climate change on animals

ST. PETERSBURG

Dozens of scientists are traveling 6,500 miles, traversing one of the world's most dangerous stretches of water, bound for one of the most remote locations on the planet.

They're looking for a killer.

The silverfish, a vital part of the food chain in Antarctica, is disappearing at an alarming rate.

"It's a mystery," says Joseph Torres, a marine biologist at the University of South Florida's College of Marine Science in St. Petersburg. Torres and colleagues, who already have begun the journey to Antarctica, have a suspect:

Global warming.

• • •

It's nearly 10 inches long but don't be fooled by its size. This is one tough fish.

It has a sort of biological antifreeze in its blood that allows it to swim in near-freezing Antarctic waters. In fact, it can live for two decades or more. The silverfish doesn't even start swimming until it is 2, and begins reproducing at age 9.

"The fish is kind of fascinating," Torres said. "It's a really important animal."

Important, among other reasons, for its role in the food chain.

Because of their moderate size, silverfish are a staple for the Adélie penguin, comprising as much 50 percent of their diet.

Or at least they did.

Research shows that around the tip of the Antarctic Peninsula the percentage has dropped from 50 percent to virtually zero. The penguins have turned to other food sources such as krill. The results have been disastrous.

Since the 1970s, roughly 70 percent of the penguin population around the peninsula has died off, says ecologist and researcher William Fraser, who has studied the penguins for more than three decades.

So, where have all the silverfish gone?

That's the substance of Torres' mission.

Silverfish researchers think the small fish hatch and grow under sea ice, which provides protection from predators.

But mid-winter air temperatures along the Antarctic Peninsula have risen 10 degrees in the past 25 years, even as other parts of Antarctica are cooling, say Torres and numerous other scientific groups, including NASA.

"This is the fastest warming region on the planet," he said.

Hence, ice is forming later and melting earlier, which may make the fish vulnerable to predators.

"The fish are preyed upon to the extent they are no longer there," Torres said.

Torres said rising temperature may be a factor. But he readily acknowledges he's no climatologist. And he has no stake in the global warming debate.

He's concerned about the fish.

• • •

The 45-foot waves will also get his attention.

This journey, Torres' 11th to Antarctica, will be funded by a $250,000 National Science Foundation grant and several other related grants.

After arriving in Punta Arenas, a major port on the southern tip of Chile, the researchers will sail to Palmer Station in Antarctica.

Aboard the 308-foot Nathaniel B. Palmer research ship, they will cross the Drake Passage, often described as the world's most treacherous stretch of ocean, sometimes producing waves of more than 40 feet.

Their research will begin at the southern portion of the Antarctic Peninsula. They will travel north, keeping one step ahead of the advancing ice.

Catching fish along the way, they will send them to other scientists who, by studying the earbone, will determine where fish spawn.

That's right, the earbone. A team of scientists have discovered they can identify the birthplace of the fish by examining the chemistry of its earbone.

The team also will visit penguin rookeries to learn more about the birds' diet. The scientists induce vomiting – "a heck of a lot better than what they used to do, which was just shoot them," Torres said – to learn what they're eating.

The group plans to return home in early May.

"Every trip there you get to see a really cool place with some really cool critters," he said.

Andy Boyle can be reached at (727) 893-8087 or aboyle@sptimes.com

Dispatches from Antarctica

This story will continue in Antarctica, with Joseph Torres writing dispatches and two of his research assistants shooting video and photos.

Mutlimedia presentation

See the awe-inspiring landscapes and wildlife of the Antarctic as you follow the team's voyage at tampabay.com/antarctica.

Antarctic food chain

The Antarctic silverfish is pink with a silver tint.

This hardy fish can live for two decades or more. It produces glycopeptides — a kind of biological antifreeze — that protect it from the area's near-freezing waters.

The silverfish is a key player in the local food chain, a staple for the Adélie penguins, below.

But the silverfish are rapidly disappearing and over the years, roughly 70 percent of the penguin population around the Antarctic Peninsula has died off, say those who study the Adélie.

So, where have all the silverfish gone? Is global warming to blame?

Finding answers to those questions is the mission of a team of scientists led by USF marine biologist Joseph Torres.

USF scientist leads Antarctic expedition to study effects of climate change on animals 03/14/10 [Last modified: Monday, March 15, 2010 11:28am]
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