Please select your home edition
Edition
Helm Events 728x90

Great Barrier Reef sheds light on climate change catastrophes

by Sydney University on 13 Mar 2011
Great Barrier Reef -satellite image . .
Limestone terraces - the relics of the Great Barrier Reef of the past - could give hints on a 'tipping point' that could trigger catastrophic climate change in the greenhouse in future, according to new research from the University of Sydney.

An international team of scientists jointly led by Dr Jody Webster, of the University of Sydney, and Dr Yusuke Yokoyama, of the University of Tokyo, is analysing sediment cores drilled by the research ship, the Greatship Maya, across the Great Barrier Reef last year.

The scientists are using the reef as a record of sea level fluctuations and climate change from the peak of the last Ice Age, about 21,000 years ago, to the first two millennia of the current warm Holocene epoch, which started about 12,000 years ago.

Coral reefs are markers of sea level. Coral gets its energy from photosynthetic algae in a symbiotic relationship with it. When the sea level gets too high, less sunlight is captured by the algae, and the reef dies. Dead reefs form systems of terraces, ridges and pinnacles, the dates of which reveal sea level changes.

Scientists want to pin down the timing and impact of abrupt sea level rise when ice sheets melted in the past, in order to make predictions about the greenhouse future. The behaviour of the ice sheets is among the big unknowns of climate science. If the West Antarctic ice sheet melted, the impact would be catastrophic, leading to a five to six metre sea level rise and changes to seawater salinity that could send ocean circulation awry.

The team took cores of extinct coral reef and sediment from 34 holes drilled during an expedition to the Great Barrier Reef mounted by the Integrated Ocean Drilling Program, a multi-million-dollar international research effort to explore the ocean floor.

The cores were obtained along transects from the outer reaches of the continental shelf beyond the base of the Great Barrier Reef, which started to assume its modern configuration up to 8000 years ago.

The Australian team members, also including scientists at the Australian National University and the University of Wollongong, are dating the relict reefs using the radiocarbon and uranium-thorium techniques on the calcium carbonate coral exoskeletons. Geochemists are using the fossil corals in the cores to work out past oceanographic conditions such as sea surface temperature and ocean salinity at key turning points in the reef's history.

Dr Webster said the scientists were focusing on three periods of 'meltwater pulses', one of which is thought to have happened about 14,000 to 15,000 years ago, when the sea level rose up to 20 metres within a few hundred years.

'We're trying to get a better handle on the dynamics of ice sheet behaviour and global sea level changes,' he said.

'The information will be used by sea level and ice sheet modellers to better understand how the ice sheets have collapsed in the past and hopefully improve future predictions.'

Meanwhile, Dr Webster told the meeting of the American Geophysical Union in San Francisco in December that the team had pinpointed the remnants of the coral reef that was growing at the height of the last Ice Age.

'There has been a lot of debate over where the Great Barrier Reef goes during times of lower sea level during ice ages,' he said.

The Australian Research Council, universities and government agencies fund the Australian research effort within the Integrated Ocean Drilling Program. Australia and New Zealand form the Australian and New Zealand IODP Consortium (ANZIC) within the IODP. The Australian IODP Office is based at the ANU.

More at http://www.iodp.org.au/
Bakewell-White Yacht DesignZhik Dinghy 660x82Barz Optics - Kids range

Related Articles

The Bridge – The Queen Mary – Essence of historical transatlantic race
The Bridge has invited the Queen Mary 2 to take part in an ocean challenge in a race against a fleet of giant trimarans On 2nd December, the press conference for the official launch of The Bridge was held in the prestigious setting of the Salle Turenne at the Hôtel des Invalides. The Bridge, a unique, festive, maritime, cultural and popular event, will take place from June 15th until the beginning of July 2017, in Nantes, Saint-Nazaire and New York.
Posted on 3 Dec
Mark Light appointed Race Director of Clipper Round the World Race
Mark replaces former Race Director Justin Taylor who decided to stand down after almost a decade with the company. With four years’ experience assisting the race planning, he is now looking forward to stepping up to the lead role, one of the most challenging that exists in global sailing.
Posted on 28 Nov
Predictwind release improved racing and cruising routing function
PredictWind has released a major upgrade to its Routing function, taking a much more graphic and interactive approach PredictWind has released a major upgrade to its Routing function, taking a much more graphic and interactive approach to what has been a black art of weather routing, used to chose the fastest route for racers or most comfortable route for cruisers.
Posted on 28 Nov
Only room for one at the top
The results of RMIT's (Royal Melbourne Institute of Technology) independent testing are in. The results of RMIT's (Royal Melbourne Institute of Technology) independent testing are in. Zhik® is the market leader in waterproof durability with a new standard that replicates the real world sailing environment and conditions. It is an astounding four times more so than the previous leader.
Posted on 28 Nov
Fourth Blog from on board Perie Banou II
Oh no - not the coffee cup Oh no - not the coffee cup - Jon keeps us all entertained as he approaches Reunion Island. The B&G chartplotter tells me since leaving the pleasant mid Western Australian town of Carnarvon (by world standards, an isolated town), that I have sailed some 2559 NM and have 751nm to go to Le Port Reunion Island. French. Reunion is a Suburb (department) of Paris. Population 844,000.
Posted on 23 Nov
Marine Resources job updates
The latest jobs in the marine industry Marine Resources specialises in filling job vacancies within the Leisure Marine Industry. We have a variety of recruitment services to suit all types of marine employer.
Posted on 18 Nov
Third Blog from onboard Perie Banou II
Wind over the last week has been quiet and mild - Trade Winds from South East and South South East. It is 0830am here. 1030 in Western Australia. Windy. Rather Windy. Wind over the last week has been quiet and mild - Trade Winds from South East and South South East. Barometer 1018 to 1020 whatever they are. Last night I tapped the barometer and it sorta went oops. 1015hPa. Blimey.
Posted on 18 Nov
Zhik Avlare wins 2016 METS DAME Award
Do you know a child or perhaps a dog or a cat that absolutely hates having a bath? Do you know a child or perhaps a dog or a cat that absolutely hates having a bath? Well here are a range of Men’s and Women’s tops that are so hydrophobic the only adjective that describes them is hate.
Posted on 17 Nov
Second Blog from onboard Perie Banou II
This is day 13 since leaving the mid Western Australian town of Carnarvon. Remote region. Beautiful town. This is day 13 since leaving the mid Western Australian town of Carnarvon. Remote region. Beautiful town. Kept cooler by the strong south winds, which make the trees bend and grow to the north. Carnarvon is nice, especially the months of September, October, November, and December. The wind is strong. Often near gale strength, with squalls and blue skies.
Posted on 15 Nov
Southern Spars at METS Trade Show, Amsterdam
Southern Spars is attending the METS Trade Show in Amsterdam, the Netherlands again this year. Southern Spars is attending the METS Trade Show in Amsterdam, the Netherlands again this year. On the stand this year we will have founder and director of sales, Mark Hauser, senior designer Steve Wilson, sales managers Dean Harper and Paul MacDonald, general manager Peter Batcheler and other sales and technical staff.
Posted on 14 Nov