In New York lab, centuries-old corals hold clues to climate shifts
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[December 07, 2019]
By Maria Caspani
PALISADES, N.Y. (Reuters) - Some 20 miles
north of New York City, a team of scientists is searching for clues
about how the environment is changing by studying organisms not usually
found in the woods around here: corals.
In the labs of the Lamont-Doherty Earth Observatory, a research unit of
Columbia University overlooking the Hudson River, the scientists led by
Professor Braddock Linsley pore over feet-long coral cores they
extracted from far-away reefs.
For Linsley and his colleagues, corals are a precious repository of
clues https://tmsnrt.rs/360ebeX about the past that may help predict
future climate trends. They can also reveal how much and how fast
environmental conditions have changed during a certain period of time.
Cores are the hard, stony part of a coral underneath the top of the
colony - its skeleton. Much like trees, corals produce growth rings that
record climatic conditions like seawater temperatures and rainfall as
In a lab room packed with boxes of coral samples, Linsley and a small
team of colleagues cut the cores into slabs and then X-ray the slabs to
reveal the annual growth bands.
Using dentist drills, they pulverize small pieces and run geochemical
analyses of the coral dust to reconstruct changes in the temperature,
salinity and acidity of the water around the coral on a monthly basis
going back hundreds of years.
"It is years of lab work and a lot of frustration but once you get to
that point, the final product is just so exciting because you've got
this long dataset," Linsley said.
Coral reefs develop over thousands of years and are vital to the
survival and prosperity of countless marine species. They also curtail
flood damage from storms and support human activities like fisheries.
As humans burn more fossil fuel - the biggest contributor to global
warming - oceans absorb growing amounts of carbon dioxide (CO2).
Some of Linsley's recent research on corals from the South Pacific
island of Tonga suggests that increased seawater acidification caused by
excess CO2 could lead to a decline in coral growth rates, endangering
the wellbeing of entire reefs.
[to top of second column]
A school of fish swim above a staghorn coral colony as it grows on
the Great Barrier Reef off the coast of Cairns, Australia October
25, 2019. REUTERS/Lucas Jackson
LOVE AT FIRST CHANCE
Linsley, a tall and soft-spoken 60-year-old, grew up on the
Connecticut coast, making dams in the sand and observing erosion on
the beaches near the town of Guilford. He loved water and began his
career studying ocean sediments and fossils.
His work on corals began after a chance encounter with a colleague
who was visiting his girlfriend at the University of New Mexico -
where Linsley was studying to get his PhD in the late 1980s - led to
"I was fascinated by the fact that the corals had these annual bands
in them and you could potentially extract annual resolve records
back several hundred years," he said at his office in the leafy
campus, papers and books scattered on his desk and photos of diving
expeditions on the wall.
Corals also brought him closer to the water and he had to learn how
to dive, a perk of the job for Linsley.
By studying the environmental records derived from corals, the
scientist is hoping to be able to shine a light on issues like the
rate of surface ocean warming, ocean acidification and the impact on
coral reef ecosystems worldwide.
But one thing is already evident, he said. Environmental changes are
happening much more rapidly than in the last several thousand years
and they are "clearly linked" to human activity.
Linsley's childhood home in Connecticut – which he said now
regularly battles encroaching waters - stood as a stark reminder.
"My children are 11 and 13. I think about in 50 years from now when
I'm not here, what's it going to be like," he said.
(Reporting by Maria Caspani; Editing by Rosalba O'Brien)
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