Please select your home edition
Edition
Zhik Yachting Range

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/
North Technology - Southern SparsNaiad/Oracle SupplierWildwind 2016 660x82

Related Articles

America's Cup - Southern Spars to build AC50 for Emirates Team NZ
Southern Spars has been appointed to build Emirates Team New Zealand’s AC50 wingsailed foiling catamaran One of the world's leading composite engineering companies, Southern Spars has been appointed to build Emirates Team New Zealand’s AC50 wingsailed foiling catamaran for the 35th America’s Cup campaign. The move marks a shift away from Cookson Boats who have been Team New Zealand's boatbuilder since 2000. No reasons have been given for the decision to change the builder.
Posted on 24 Jul
Upffront.com - Tuff Luff and Harken Headfoils
Upffront.com is a comprehensive online purchasing platform for performance sailing hardware and rigging systems Upffront.com is a comprehensive online purchasing platform for performance sailing hardware and rigging systems; orders are processed 24 hours a day, 365 days a year and we deliver to customers located anywhere in the world.
Posted on 8 Jul
Barz floating sunglasses - Ideal for sailing in rough conditions
Our SAN JUAN floating model fitted with 1.1mm Acetate Lenses have a density of 0.95 GM/ML Barz floating sunglasses float in rough conditions. Most sunglasses that say they float, only float in the bathtub as once they break surface tension (or if there is any movement on top of the water)... down they go...
Posted on 7 Jul
Free $US3,000 Carbon Vang with SouthernFurl boom orders in July
Southern Spars is giving a free carbon vang - valued at US$3,000 - with SouthernFurl in-boom furlers ordered in July Southern Spars is giving away a free carbon vang - valued at US$3,000 - with all of their SouthernFurl in-boom furlers ordered in July. Carbon gas vangs make a great addition to the furling boom package, though if you’d prefer to keep your existing one, Southern Spars will offer you a 5% discount on the price of your boom instead.
Posted on 29 Jun
11th Hour Racing to present at annual Green Sports Alliance Summit
11th Hour Racing is headed to Houston, Texas, to present at the annual Green Sports Alliance Summit 11th Hour Racing is headed to Houston, Texas, to present at the annual Green Sports Alliance Summit, June 28-30, the world’s largest gathering for the sports community around sustainability, including both professional and collegiate sports teams, leagues and venues.
Posted on 25 Jun
PredictWind - Stunning new forecast maps
When developing the Offshore App, we had to rethink maps for offshore sailors. When developing the Offshore App, we had to rethink maps for offshore sailors. The mapping technology was rebuilt to be faster, have smaller downloads and be able to smoothly animate PredictWind’s advanced forecasts. Following the success of the Offshore App, we’re releasing this unique display technology across all other platforms, including the forecast website, Android and iOS Apps
Posted on 24 Jun
Extreme Sailing Series™ partners with Cisco Systems
The global technology company will provide exclusive networking solutions that will transform wireless connectivity The first venue at which members of the public, race officials and sailors will benefit from the Cisco WiFi solutions will be Cardiff – the third Act of the 2016 season – where the action gets underway on the water on 23 June. As an Official Series Supplier, Cisco will provide similar facilities at the remaining Acts of 2016.
Posted on 22 Jun
Volvo Ocean Race makes key changes to its leadership team
The re-shuffle which follows Mark Turner’s appointment as CEO, is aimed at driving innovation of sailing’s offshore race Lawrence is currently Race Director of the Extreme Sailing Series, and arrives with bags of sailing and commercial expertise, having previously managed events in all of the territories that will be visited during the 2017-18 edition.
Posted on 21 Jun
WHO statement on Zika virus
The third meeting of the EC convened by the Director-General under IHR 2005 regarding microcephaly and Zika virus The third meeting of the Emergency Committee (EC) convened by the Director-General under the International Health Regulations (2005) (IHR 2005) regarding microcephaly, other neurological disorders and Zika virus was held by teleconference on 14 June 2016, from 13:00 to 17:15 Central European Time.
Posted on 16 Jun
Interview with Tristan Hutt at the Zhik Avlare launch party
We spoke to Tristan Hutt of Zhik at the Avlare launch party which was held at Ocean Leisure in London on 2nd June. We spoke to Tristan Hutt of Zhik at the Avlare launch party which was held at Ocean Leisure in London on Thursday 2nd June.
Posted on 14 Jun