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Sub-Antarctic changing quicker than expected -

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Sub-Antarctic changing quicker than expected

The World Today - Monday, 27 April , 2009 12:47:00

Reporter: Felicity Ogilvie

PETER CAVE: Scientists are warning that global warming is affecting the survival of the tiny
creatures that are the basis of life if the sub-Antarctic.

An international forum in Hobart has been told the Southern Ocean is becoming so acidic that
microscopic plankton are losing their ability to make shells.

The tiny creatures are the basis of the food web there.

The scientists blame manmade climate change, saying more carbon dioxide is being absorbed by the
ocean, turning it into acid.

Felicity Ogilvie reports from Hobart.

FELICITY OGILVIE: The sub-Antarctic is the area of the Southern Ocean that's just north of
Antarctica.

Doctor Will Howard says the water down there's getting more acidic than it's ever been

He's a research scientist at the Antarctic Climate and Ecosystems Centre in Hobart.

Doctor Howard says when the ocean absorbs carbon dioxide from the atmosphere it produces a weak
form of carbonic acid.

WILL HOWARD: This impact is happening faster than I and a lot of other scientists anticipated. The
impact has already begun to be felt where previously many models would have suggested that we would
only begin to see it in, maybe the next century.

But both the models and the data are coming together to tell us that we will see these impacts
within the coming decades. And indeed our data are saying we're seeing it now.

FELICITY OGILVIE: And what exactly are you seeing now?

WILL HOWARD: Well, we're seeing a decrease in the shell-making ability of some of the key organisms
in the Southern Ocean ecosystems.

FELICITY OGILVIE: The animals that are losing their ability to make shells are microscopic zoo
plankton. Their only one cell creatures, but they are the basis for an ecosystem that goes all the
way up to whales.

But scientists can't say what ocean acidification will mean for animals higher up in the food
chain.

WILL HOWARD: That's an area of active research that we still don't really understand what it means
for, let's say, some of the higher organisms that we're used to seeing and interacting with, like
whales, seals, birds.

But we do know that significant impacts at this level in the food web almost always reverberate up
the food webs to, in many ways, in unpredictable ways.

FELICITY OGILVIE: The International Forum on the Sub-Antarctic has also been hearing from
scientists who've been studying what effects climate change has on the region's islands.

South African oceanographer, Isabelle Ansorge has been studying the Prince Edward Islands. They're
directly south of Africa on the edge of the Antarctic.

ISABELLE ANSORGE: Well, we've basically been looking at trends over the island to see that there's
been a big drop in precipitation. Sea surface temperatures have gone up by about 1.4 degrees
Celsius. We're seeing an increase in the wind systems from the north.

So we're seeing less rain, warmer winds, and certainly a rise in temperatures over the last 50
years.

FELICITY OGILVIE: And why is it significant to look at the sub-Antarctic in terms of how that area
is warming?

ISABELLE ANSORGE: Why it's interesting is that the sub-Antarctic islands are home to hundreds of
thousands of birds, seals.

So changes that you see in your ocean environment are picked up very easily at the islands, by
changes in breeding patterns, increases in pup mortalities, seal pup mortality, changes in foraging
behaviour.

So, it's very easy to sort of watch the animals, and try and relate that to changes in the ocean
environments.

FELICITY OGILVIE: She says by studying the sub-Antarctic islands, predictions can also be made
about what will happen in the rest of the world if the oceans continue to change.

PETER CAVE: Felicity Ogilvie reporting.