Oceans choking on CO2, face deadly changes: study

The world's oceans are virtually choking on rising greenhouse gases, destroying marine ecosystems and breaking down the food chain -- irreversible changes that have not occurred for several million years, a new study says.

The changes could have dire consequences for hundreds of millions of people around the globe who rely on oceans for their livelihoods.

"It's as if the Earth has been smoking two packs of cigarettes a day", said the report's lead-author Australian marine scientist Professor Ove Hoegh-Guldberg.

The Australia-U.S. report published in Science magazine on Friday, studied 10 years of marine research and found that climate change was causing major declines in marine ecosystems.

Oceans were rapidly warming and acidifying, water circulation was being altered and dead zones within the ocean depths were expanding, said the report.

There has also been a decline in major ocean ecosystems like kelp forests (left) and coral reefs (below right) and the marine food chain was breaking down, with fewer and smaller fish and more frequent diseases and pests among marine organisms.

"If we continue down this pathway we get into conditions which have no analog to anything we've experienced," said Hoegh-Guldberg, director of the Global Change Institute at The University of Queensland.

Hoegh-Guldberg said oceans were the Earth's "heart and lungs", producing half of the world's oxygen and absorbing 30 percent of man-made carbon dioxide.

"We are entering a period in which the very ocean services upon which humanity depends are undergoing massive change and in some cases beginning to fail," said Hoegh-Guldberg.

"Quite plainly, the Earth cannot do without its ocean. This is further evidence that we are well on the way to the next great extinction event."

More than 3.5 billion people depend on the ocean for their primary source of food and in 20 years this number could double, the report's authors say.

The world's climate has remained stable for several thousand years, but climate change in the past 150 years is now forcing organisms to change rapidly -- changes that through evolution would normally take a long time, said the report.

"We are becoming increasingly certain that the world's marine ecosystems are approaching tipping points. These tipping points are where change accelerates and causes unrelated impacts on other systems," said co-author marine scientist John F. Bruno at the University of North Carolina.

Last week, the head of the United Nations Environment Program, Achim Steiner, said it was crucial the world responded to the loss of coral reefs, forests and other ecosystems "that generate multi-trillion dollar services that underpin all life-including economic life-on Earth".


Source:
Reuters,"Oceans choking on CO2, face deadly changes: study", accessed June 20, 2010

Whale poo helps offset carbon footprint

Southern Ocean sperm whales offset their carbon footprint by defecating, scientists said on Wednesday, releasing tons of iron a year that stimulates the growth of phytoplankton which in turn absorb carbon dioxide.

Each whale releases about 50 tons of iron a year after digesting the fish and squid they hunt. Their natural fertilization stimulates the process of photosynthesis, removing the equivalent carbon emissions from 40,000 cars each year. The cetaceans have been previously fingered as climate culprits because they breathe out carbon dioxide (CO2), the commonest greenhouse gas.

An estimated 12,000 sperm whales that inhabit the Southern Ocean absorb about 400,000 tons of carbon each year, twice the amount they release by breathing, said scientists from Flinders University in South Australia.

"They eat their diet, mainly squid, in the deep ocean, and defecate in the upper waters where phytoplankton can grow, having access to sunlight," marine biologist Trish Lavery, who led the scientific study at Flinders University, said in a statement.

"Sperm whale poo is rich in iron, which stimulates phytoplankton to grow and trap carbon. When the phytoplankton die, the trapped carbon sinks to the deep ocean," Lavery said.

"They've well and truly bypassed being carbon neutral. They've actually gone one step further," she said. The whale study was published in the Royal Society's biological research journal, Proceedings of the Royal Society, Biological Sciences.

Before industrial whaling, the population of this species was about 10 times bigger, which meant around two million tons of CO2 were removed annually, said the paper.

The Southern Ocean is rich in nitrogen but poor in iron, which is essential for phytoplankton. The scientists suspect that because sperm whales cluster in specific areas of the Southern Ocean there is a clear link between food availability and cetacean feces.

This could explain the "krill paradox," they believe. Researchers have previously found that when balleen whales are killed, the amount of krill in that sea area declines, which thus affects the entire food chain.

Source:
Reuters, "Whale poo helps offset carbon footprint", accessed June 16, 2010
Yahoo News, "Faecal attraction: Whale poop fights climate change", accessed June 16, 2010