. Earth Science News .

Oceans in distress foreshadow mass extinction
by Staff Writers
Paris (AFP) June 20, 2011

Runoff from nitrogen-rich fertiliser, killer microbes, and hormone-disrupting chemicals, for example, have all contributed to the mass die-off of corals, crucial not just for marine ecosystems but a lifeline for hundreds of millions of people too.

Pollution and global warming are pushing the world's oceans to the brink of a mass extinction of marine life unseen for tens of millions of years, a consortium of scientists warned Monday.

Dying coral reefs, biodiversity ravaged by invasive species, expanding open-water "dead zones," toxic algae blooms, the massive depletion of big fish stocks -- all are accelerating, they said in a report compiled during an April meeting in Oxford of 27 of the world's top ocean experts.

Sponsored by the International Programme on the State of the Ocean (IPSO), the review of recent science found that ocean health has declined further and faster than dire forecasts only a few years ago.

These symptoms, moreover, could be the harbinger of wider disruptions in the interlocking web of biological and chemical interactions that scientists now call the Earth system.

All five mass extinctions of life on the planet, reaching back more than 500 million years, were preceded by many of the same conditions now afflicted the ocean environment, they said.

"The results are shocking," said Alex Rogers, an Oxford professor who heads IPSO and co-authored the report. "We are looking at consequences for humankind that will impact in our lifetime."

Three main drivers are sickening the global marine environment, and all are a direct consequence of humans activity: global warming, acidification and a dwindling level oxygen, a condition known as hypoxia.

Up to now, these and other impacts have been studied mainly in isolation. Only recently have scientists began to understand how these forces interact.

"We have underestimated the overall risks, and that the whole of marine degradation is greater than the sum of its parts," Rogers said. "That degradation is now happening at a faster rate than predicted."

Indeed, the pace of change is tracking or has surpassed the worst-case scenarios laid out by the UN Intergovernmental Panel on Climate Change (IPCC) in its landmark 2007 report, according to the new assessment.

The chain reaction leading to increased acidification of the oceans begins with a massive influx of carbon into Earth's climate system.

Oceans act as a massive sponge, soaking up more than a quarter of the CO2 humans pump into the atmosphere.

But when the sponge becomes too saturated, it can disrupt the delicately balanced ecosystems on which marine life -- and ultimately all life on Earth -- depends.

"The rate at which carbon is being absorbed is already far greater now than during the last globally significant extinction of marine species 55 million years ago," when some 50 percent of deep-sea life was wiped out, the report said.

That event, called the Paleocene-Eocene Thermal Maximum, or PETM, may be an ancient dress rehearsal for future climate change that could be even more abrupt and more damaging, some scientists fear.

Pollution has also taken a heavy toll, rendering the oceans less resilient to climate change.

Runoff from nitrogen-rich fertiliser, killer microbes, and hormone-disrupting chemicals, for example, have all contributed to the mass die-off of corals, crucial not just for marine ecosystems but a lifeline for hundreds of millions of people too.

The harvesting up to 90 percent of some species of big fish and sharks, meanwhile, has hugely disrupted food chains throughout the ocean, leading to explosive and imbalanced growth of algae, jellyfish and other "opportunistic" flora and fauna.

"We now face losing marine species and entire marine ecosystems, such as coral reefs, within a single generation," said Daniel Laffoley, head of the International Union for Conservation of Nature's (IUCN) World Commission on Protected Areas, and co-author of the report.

"And we are also probably the last generation that has enough time to deal with the problems," he told AFP by phone.

Related Links
Water News - Science, Technology and Politics

Get Our Free Newsletters Via Email
Buy Advertising Editorial Enquiries

. Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

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

Mississippi river flooding predicted to cause biggest dead zone ever recorded
Washington DC (SPX) Jun 17, 2011
The Gulf of Mexico's hypoxic zone is predicted to be the largest ever recorded due to extreme flooding of the Mississippi River this spring, according to an annual forecast by a team of NOAA-supported scientists from the Louisiana Universities Marine Consortium, Louisiana State University and the University of Michigan. The forecast is based on Mississippi River nutrient inputs compiled annually ... read more

Weather catastrophes in China soar: reinsurer

Moody's cuts Japan's TEPCO to junk status

No 'business as usual' as IAEA meets on nuclear safety

TEPCO to open second Fukushima reactor building

Self-assembling Electronic Nano-components

Nokia heralds 'new season' as market share slumps

Asian tech fair spotlights tablets, smartphones

Rare earth prices surge as China tightens grip

Fastest sea level rise in two millennia linked to increasing temperatures

Ocean's harmful low-oxygen zones growing, are sensitive to small changes in climate

Three Gorges tarnishes new hydropower?

Salt marsh sediments help gauge climate-change-induced sea level rise

NASA to embark on last leg of Arctic sea study

Life Between Snowball Earths

Arctic snow harbors deadly assassin

Glaciations may have larger influence on biodiversity than current climate

New curation tool a boon for genetic biologists

Native Bees are Selective about Where They Live and Feed

Where have all the flowers gone?

Salivating over wheat plants may net Hessian flies big meal or death

Flight chaos in Australia as ash cloud returns

Mexico's Pacific coast hit by hurricane

China braces for tropical storm amid floods

Japan considers 'gigantic' tsunami

Somalia Islamists vow loyalty to Zawahiri

Sudan army 'to fight by all means' in border state

Abyei clashes 'resume' on Sudan's embattled border

UN condemns North Sudan offensive

Can humans sense the Earth's magnetism

Walker's World: Here come the 'age wars'

Family genetic research reveals the speed of human mutation

Bones give peek at key evolutionary period

Memory Foam Mattress Review
Newsletters :: SpaceDaily Express :: SpaceWar Express :: TerraDaily Express :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News

The content herein, unless otherwise known to be public domain, are Copyright 1995-2011 - Space Media Network. AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA Portal 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. 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. Privacy Statement