. Earth Science News .
WATER WORLD
Rise and fall of the Great Barrier Reef
by Staff Writers
Sydney, Australia (SPX) May 29, 2018

Associate Professor Webster said previous studies have established a past sea surface temperature rise of a couple of degrees over a timescale of 10,000 years. However, current forecasts of sea surface temperature change are around 0.7 degrees in a century.

A landmark international study of the Great Barrier Reef has shown that in the past 30,000 years the world's largest reef system has suffered five death events, largely driven by changes in sea level and associated environmental change.

Over millennia, the reef has adapted to sudden changes in environment by migrating across the sea floor as the oceans rose and fell.

The study published in Nature Geoscience, led by University of Sydney's Associate Professor Jody Webster, is the first of its kind to reconstruct the evolution of the reef over the past 30 millennia in response to major, abrupt environmental change.

The 10-year, multinational effort has shown the reef is more resilient to major environmental changes such as sea-level rise and sea-temperature change than previously thought but also showed a high sensitivity to increased sediment input and poor water quality.

Associate Professor Webster from the University's School of Geosciences and Geocoastal Research Group said it remains an open question as to whether its resilience will be enough for it to survive the current worldwide decline of coral reefs.

"Our study shows the reef has been able to bounce back from past death events during the last glaciation and deglaciation," he said. "However, we found it is also highly sensitive to increased sediment input, which is of concern given current land-use practices."

The study used data from geomorphic, sedimentological, biological and dating information from fossil reef cores at 16 sites at Cairns and Mackay.

The study covers the period from before the "Last Glacial Maximum" about 20,000 years ago when sea levels were 118 metres below current levels.

History of death events
As sea levels dropped in the millennia before that time, there were two widespread death events (at about 30,000 years and 22,000 years ago) caused by exposure of the reef to air, known as subaerial exposure. During this period, the reef moved seaward to try to keep pace with the falling sea levels.

During the deglaciation period after the Last Glacial Maximum, there were a further two reef-death events at about 17,000 and 13,000 years ago caused by rapid sea level rise. These were accompanied by the reef moving landward, trying to keep pace with rising seas.

Analysis of the core samples and data on sediment flux show these reef-death events from sea-level rise were likely associated with high increases in sediment.

The final reef-death event about 10,000 years ago, from before the emergence of the modern reef about 9000 years ago, was not associated with any known abrupt sea-level rise or "meltwater pulse" during the deglaciation. Rather it appears to be associated with a massive sediment increase and reduced water quality alongside a general rise in sea level.

The authors propose that the reef has been able to re-establish itself over time due to continuity of reef habitats with corals and coralline-algae and the reef's ability to migrate laterally at between 0.2 and 1.5 metres a year.

Future survival
However, Associate Professor Webster said it was unlikely that this rate would be enough to survive current rates of sea surface temperature rises, sharp declines in coral coverage, year-on-year coral bleaching or decreases in water quality and increased sediment flux since European settlement.

"I have grave concerns about the ability of the reef in its current form to survive the pace of change caused by the many current stresses and those projected into the near future," he said.

Associate Professor Webster said previous studies have established a past sea surface temperature rise of a couple of degrees over a timescale of 10,000 years. However, current forecasts of sea surface temperature change are around 0.7 degrees in a century.

"Our study shows that as well as responding to sea-level changes, the reef has been particularly sensitive to sediment fluxes in the past and that means, in the current period, we need to understand how practices from primary industry are affecting sediment input and water quality on the reef," he said.

Research paper


Related Links
University of Sydney
Water News - Science, Technology and Politics


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only


WATER WORLD
World's biggest fisheries supported by seagrass meadows
Swansea UK (SPX) May 24, 2018
The study entitled 'Seagrass meadows support global fisheries production' published in Conservation Letters, provides evidence that a fifth of the world's biggest fisheries, such as Atlantic Cod and Walleye Pollock are reliant on healthy seagrass meadows. The study also demonstrates the prevalence of seagrass associated fishing globally. The study, carried out in partnership with Dr Leanne Cullen-Unsworth at Cardiff University and Dr Lina Mtwana Nordlund at Stockholm University, demonstrates for t ... read more

Comment using your Disqus, Facebook, Google or Twitter login.



Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

WATER WORLD
Arkema's Texas plant unprepared for Harvey floods, inquiry finds

Navy captain accused in deadly Tunisia migrant boat sinking

'Our families would be killed': Rohingya brace for monsoon

An electronic rescue dog

WATER WORLD
Astonishing effect enables better palladium catalysts

Glass-forming ability: fundamental understanding leading to smart design

Waterloo chemists create faster and more efficient way to process information

Supercomputing the emergence of material behavior

WATER WORLD
Study reveals how high-latitude corals cope with the cold

Excess nutrients, coupled with climate change, damage the most highly resilient corals

Loss of marine habitats is threatening the global fishing industry

Japanese student discovers new crustacean species in deep sea hydrothermal vent

WATER WORLD
Canada, Denmark seek to settle Arctic island dispute

A promising target in the quest for a 1-million-year-old Antarctic ice core

Remote camera network tracks Antarctic species at low cost

Arctic coastal powers back 'peaceful' dialogue over disputes

WATER WORLD
A hidden world of communication, chemical warfare, beneath the soil

Research suggests sweet potatoes didn't originate in the Americas as previously thought

Long-term study shows crop rotation decreases greenhouse gas emissions

Scientists' new way to identify microscopic worm attacking coffee crops

WATER WORLD
17 missing as cyclone pummels Yemen's Socotra island

Cyclone Mekunu intensifies as it advances on Oman

Gemini Observatory Cloud Camera Captures Volcano's Dramatic Glow

Lightning in the eyewall of a hurricane beamed antimatter toward the ground

WATER WORLD
China, Russia rise in C. Africa as Western influence shrinks

China, Burkina Faso establish ties following Taiwan snub

France to pump 65 million euros into African startups

12 civilians killed in Mali market attack

WATER WORLD
Prehistoric people also likely disrupted by environmental change

'Uniquely human' muscles have been discovered in apes

Chimpanzee calls differ according to context

Trait tied to autism may explain emergence of realistic art









The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.