Video | Business Headlines | Internet | Science | Scientific Ethics | Technology | Search

 


Coral bands reflect Pacific Ocean 20-30 year climate swings

MEDIA RELEASE

Coral bands reflect Pacific Ocean 20-30 year climate swings

13 January 2014

University of Queensland researchers have found physical evidence in Great Barrier Reef corals of a little-known, long-term climate pattern in the Pacific Ocean.

The Pacific Decadal Oscillation –discovered and named only in the 1990s – describes phases of warm and cool sea surface temperatures that alternate between the Pacific Ocean’s east and west, usually over periods of 20 to 30 years.

Lead researcher Dr Alberto Rodriguez-Ramirez, of UQ’s School of Earth Sciences, said the team shone ultraviolet light on longitudinal sections of coral colonies to see their luminescent “growth bands”, and found a record of flood plumes from central Queensland’s Fitzroy River at times coinciding with the Pacific Decadal Oscillation pattern over the past century.

“We have demonstrated that this oscillation pattern is a key driver of river runoff impacting on the Great Barrier Reef,” Dr Rodriguez-Ramirez said.

“Our study suggests that this oscillation will influence the frequency and intensity of future extreme events such as floods – as well as ecological processes – in the region.”

Co-author Professor Jian-xin Zhao, also from UQ’s School of Earth Sciences, said it was well understood that shorter-term phenomenon such as El Niño and La Niña influenced climate in the southern Great Barrier Reef.

“But this work shows that the region also feels the effects of the slower-moving Pacific Decadal Oscillation,” Professor Zhao said.

“This is a significant advance in our understanding of climate variability.”

Co-author Professor John Pandolfi, from UQ’s School of Biological Sciences, said the study examined century-old coral colonies – “bommies” – around the Keppel Islands, 50km from the Fitzroy River mouth.

“As a result of this research, we now know that corals from this area have great potential for reconstructing even longer-term historical evolution of the Pacific Decadal Oscillation,” Professor Pandolfi said.

“Some bommies are five to six metres tall and 400 years old. They can provide us with much longer-term information than is available from satellite-based data, which goes back only 40-50 years.

“This will help refine future models for predicting this important climate phenomenon.”

Dr Rodriguez-Ramirez said that although floods were not new in the region, increased human activity in the Fitzroy catchment since the mid-20th century had increased the impact of extreme weather events on reef ecosystems.

“Our findings are timely, given that extreme weather conditions – associated with La Niña and a ‘negative’ Pacific Decadal Oscillation phase – caused severe negative impacts on human populations along the east coast of Australia in 2011 and 2013,” he said.

After work by other scientists in the 1990s, it is generally understood that a “negative” or “cool” phase occurs when the east Pacific Ocean surface cools and the west warms.

A “positive” or “warm” phase occurs when the pattern reverses.

Like the growth rings found in tree trunks that give year-by-year records of climate and environmental conditions during the tree’s life, longitudinal slices from corals provide a similarly accurate environmental record when viewed under ultraviolet light.

This study produced the first coral core evidence of the massive 2011 floods.

The research was published last week in PLOS ONE, a peer-reviewed, open-access resource produced by the Public Library of Science.

Researchers from NIOZ Royal Netherlands Institute for Sea Research and The University of Western Australia’s Oceans Institute/School of Earth and Environment also worked on the research.

Funding for the project came from the Marine and Tropical Science Research Facility, the NERP Tropical Ecosystems Hub, as well as from the Australian Research Council Discovery Projects scheme, the Endeavour International Postgraduate Research Scholarship scheme, the UQ Living Allowance Scholarship, the UQ Graduate School International Travel Award, and the PADI Foundation.


© Scoop Media

 
 
 
 
 
Business Headlines | Sci-Tech Headlines

 

Scoop Business: NZ Dollar Falls To 3-Year Low As Investors Favour Greenback

The New Zealand dollar fell to its lowest in more than three years as investors sold euro and bought US dollars, weakening other currencies against the greenback. More>>

ALSO:

Scoop Business: NZ Govt Operating Deficit Smaller Than Expected

The New Zealand’s government’s operating deficit was smaller than expected in the first five months of the financial year as a clampdown on expenditure managed to offset a shortfall in the tax-take from last month’s forecast. More>>

ALSO:

0.8 Percent Annually:
NZ Inflation Falls Below RBNZ's Target

New Zealand's annual pace of inflation slowed to below the Reserve Bank's target band in the final three months of the year, giving governor Graeme Wheeler more room to keep the benchmark interest rate lower for longer.More>>

ALSO:

NASA, NOAA: Find 2014 Warmest Year In Modern Record

Since 1880, Earth’s average surface temperature has warmed by about 1.4 degrees Fahrenheit (0.8 degrees Celsius), a trend that is largely driven by the increase in carbon dioxide and other human emissions into the planet’s atmosphere. The majority of that warming has occurred in the past three decades. More>>

ALSO:

Scoop Business: New Zealand’s Reserve Bank Named Central Bank Of The Year

The Reserve Bank of New Zealand’s efforts to stifle house price inflation by using new policy tools has seen the institution named Central Bank of the year by Central Banking Publications, a publisher specialising in global central banking practice. More>>

ALSO:

Science Media Centre: Viral Science And Another 'Big Dry'?

"Potentially, if there is no significant rainfall for the next month or so, we could be heading into one of the worst nation-wide droughts we’ve seen for some time," warns NIWA principal climate scientist Dr Andrew Tait. More>>

ALSO:

Get More From Scoop

 
 
Standards New Zealand

Standards New Zealand
 
 
 
 
 
 
 
 
Sci-Tech
Search Scoop  
 
 
Powered by Vodafone
NZ independent news