Deep ocean current linked to global climate change
LONDON, Aug 2 (Reuters) - A deep ocean current originating south
of New Zealand near Antarctica is influencing marine life nearly
halfway around the world and could be a key to understanding
climate change, an American scientist said on Wednesday.
Much of the research into global warming involves atmospheric
conditions but geologist Paul Loubere said what is going on under
the waves is just as important as what is happening above them.
The professor of geology and environmental geosciences at
Northern Illinois University in DeKalb said the equatorial
current 300-400 feet (90-120 metres) below the surface is like a
secret river that delivers nutrients to tropical marine life,
such as plankton, in the eastern Pacific Ocean.
The microscopic plants absorb the greenhouse gas carbon dioxide
and help to regulate its release into the atmosphere.
"Up until now it has mostly been assumed that ocean conditions in
the eastern equatorial Pacific were largely controlled by
atmospheric conditions, such as trade winds blowing across the
tropics," he said.
"My research presents the first evidence that there's something
else to seriously consider here. And it demonstrates how the
climates of different regions of the earth -- in this case the
South Pole and the Pacific equator -- are intrinsically linked,"
Loubere added in a statement.
SECRETS BURIED IN DEEP SEA SEDIMENT
He unearthed the secrets of the equatorial current by taking
hundreds of sediment samples from the ocean floor from four sites
near the Galapagos Islands to reconstruct a picture of marine
life during the past 130,000 years.
The results of his three years of painstaking efforts are
published in the latest edition of the science journal Nature.
Loubere found differences in the samples that seemed to be
determined by their closeness to the equatorial current.
"I've provided physical evidence for the theoretical idea that
the equatorial current could have a chemical and biological
effect on the tropics," Loubere said in a telephone interview. If
only tropical and atmospheric processes were influencing events
he would have seen the same biological record everywhere. The
only way to explain the differences in the sediment samples was
the equatorial current.
"What I've shown is that in terms of the probable control of the
release of carbon dioxide the oceanic patterns of circulation,
including the equatorial current are important," he added.
The equatorial current begins south of New Zealand and flows to
the tropics then along the equator from the West Pacific to the
East Pacific where it reaches the surface.
News by Reuters
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