Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Reef warns of sea level rise

10.11.2006
Margaret River in WA, famed for its wine, is about to become famous for another reason: warning coastal dwellers what they may have to cope with under global warming.


A fossil coral reef, lying several metres above today’s high tide mark at Foul Bay near Margaret River, points to the high point of the last major sea level rise.

Investigators from the ARC Centre of Excellence for Coral Reef Studies (CoECRS) consider the reef – the most southerly coral reef yet known – is a harbinger of what could happen again as global CO2 levels and temperatures rise during the 21st century.

“We’ve dated the reef to about 128-125,000 years ago, right in the middle of the last interglacial, or the last period of global warming before our most recent ice age,” says Professor Malcolm McCulloch, deputy director of CoECRS and an earth scientist at The Australian National University.

“The reef lies about 2.5 metres above the current high tide zone, which means that for it to survive and grow, sea levels would have had to be at least 3 to 4 metres higher than at present.

“There is some evidence – still controversial – that sea levels may briefly have been as much as 6 metres higher.”

The coastline of WA, being geologically stable, has a number of both living and fossil coral reefs along it, the results of the Leeuwin current bringing coral larvae down from Indonesia and northern Australia over many tens of thousands of years. Together these reefs indicate what occurred during the last big sea level rise.

“At the time when this reef grew we know that atmospheric CO2 levels were high, climate had warmed, that the northern icesheets had melted significantly and that sea levels rose - before dropping by around 130 metres again as the ice-age returned and locked up water,” Prof. McCulloch says.

“Water temperatures off Margaret River would then have been more like water temperatures off Geraldton today, allowing the corals to flourish and reefs to form. The discovery is of particular importance as it shows that sea levels rose not only because of the expansion of the oceans due to warming, which can account for ~1/2 metre of sea level rise, but also because it indicates that relatively large scale melting of landbased icesheets occurred in Greenland or the Antarctic. It is the very rapid rise in sea level from catastrophic melting of landbased icesheets where there the greatest uncertainty and concern lies. Now from the Margaret River corals we have evidence of not only unusually warm ocean temperatures, but that that this was associated with rapid melting of icesheets contributing to an additional 3 to 4 metres of sea level rise. ”

The cause of the sudden global warming leading to the end of the ice-ages is thought to be due to changes in the elliptical nature of the Earth’s orbit combining with other factors, such as variations in its tilt or wobble. During the ice ages atmospheric CO2 was around 180 parts per million, compared to 280 parts per million during interglacials. We don’t know quite why CO2 levels rose so much during the last interglacial, but it may have been partly due to a reduction in the ocean’s ability to take up atmospheric carbon, as the seas warmed.

Today CO2 levels are even higher, at 380 parts per million with the additional 100 ppm being mainly due to human activities. Prof. McCulloch says the oceans currently removed around 40 per cent of the anthropogenic CO2 from the atmosphere and it would be a matter of concern if their ability to do this decreased under global warming. If levels continue to increase, to above 500 – 600 parts per million as many scientists expect to be the case by 2050, then the climate shifts and warming effects and will become even more dramatic and surpass those of the Last Interglacial warm period”

“Sea level rises and falls have occurred throughout geological history and are all slightly different from one another. However what took place in the last period of global warming 125,000 years ago gives us an idea of what to expect under the current phase,” he said.

“We should certainly be paying attention to what the corals are telling us.”

Prof Malcolm McCulloch | EurekAlert!
Further information:
http://www.anu.edu.au

More articles from Earth Sciences:

nachricht Less radiation in inner Van Allen belt than previously believed
21.03.2017 | DOE/Los Alamos National Laboratory

nachricht Mars volcano, Earth's dinosaurs went extinct about the same time
21.03.2017 | NASA/Goddard Space Flight Center

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Pulverizing electronic waste is green, clean -- and cold

22.03.2017 | Materials Sciences

Astronomers hazard a ride in a 'drifting carousel' to understand pulsating stars

22.03.2017 | Physics and Astronomy

New gel-like coating beefs up the performance of lithium-sulfur batteries

22.03.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>