Showing posts with label COP15. Show all posts
Showing posts with label COP15. Show all posts

12.18.2009

Toxic algae could be the next big threat



BY LES BLUMENTHAL
McClatchy Newspapers


WASHINGTON -- With a new theory surfacing that toxic algae rather than asteroids killed the dinosaurs, scientists are still trying to unravel the mystery of what caused a massive algae bloom off the Northwest Coast that left thousands of seabirds dead and may have sickened some surfers and kayakers.

The bloom, which stretches roughly 300 miles from Newport, Ore., north to the Canadian border, still persists, though it's a shadow of its September and October peak.

Whipped by waves and storms, the microscopic phytoplankton, which had turned the ocean a rust color, broke apart, releasing toxins and creating meringue-like foam that coated the feathers of birds like spilled oil. Up to 10,000 birds died of hypothermia in September, and researchers are still trying to come up with a count for October.

Researchers are also checking reports that surfers and kayakers who came in contact with the foam may have suffered cold-like symptoms, including temporary loss of smell and taste. The toxins also may have become aerosolized and affected beachcombers. In another strange twist, pathologists performing necropsies found that some of the birds lacked normal bacteria in their stomachs and other internal organs.

"It's definitely a warning sign of something," said Julia Parrish, a professor of aquatic and fishery sciences at the University of Washington. "We don't know what."

Blooms of the single-cell, saltwater algae species known as Akashiwo sanguinea have been found in Puget Sound, the Chesapeake Bay and elsewhere around the world. The bloom off the Northwest coast, however, is huge compared with others. At its height, there were 1.5 million algae cells per quart of water. The bloom was up to 65 feet deep and miles wide.

In only one other instance - a smaller bloom in 2007 in California's Monterey Bay - have the cells broken apart to create a toxic froth. And this particular specie of algae usually likes warmer water than that found off the Northwest Coast.

No one is sure what ignited the bloom. Some scientists think it could be caused by climate change, which has raised ocean temperatures and made the water more acidic - both conditions could favor this algae species. Others say it could be the result of such weather conditions as El Nino or the Pacific decadel oscillation, a long-lived El Nino-like pattern of Pacific climate variability.

The bloom could have been fed by nutrients washed down the Columbia River from farms in eastern Washington and Oregon, or from an ocean condition known as upwelling, where cold water rich with nutrients is pushed toward the surface by the wind.

Or, it could just be the rhythms of the ocean, which scientists are just starting to understand.

"The ocean does have a natural pulse," said Vera Trainer, a Seattle-based research oceanographer for the National Oceanic and Atmospheric Administration. "Is this part of the pulse or is this something different? We want to find out. But some of this is very unusual. We are looking at this very intensely."

Even as Trainer, Parrish and others study the bloom off the Northwest Coast, one of the scientists who developed the theory linking toxic algae to mass extinctions said it fit in with the research he and his partner were working on.

"That's exactly what we are talking about," said John Rodgers, an ecotoxicologist at Clemson University in South Carolina, who along with James Castle, a geologist at Clemson, developed the killer algae theory.

Rodgers was on the road last week in the Midwest, collecting samples of algae to analyze back in his lab. He said he and Castle have found ancient deposits of blue-green algae that produce toxins and deplete oxygen that coincide with five mass extinctions millions of years ago. Though he said algae may not have been the only cause for the extinctions, he said it was a major factor.

The blue-green algae was freshwater algae in ponds, lakes and rivers that could have been ingested by prehistoric animals. The toxins also may have been absorbed by plants that were later eaten by animals or become airborne and breathed in by animals.

"They certainly didn't die on the same day or week," Rodgers said. "This happened over hundreds of years."

Even though there are thousands of species of algae, only several hundred produce toxins, he said.

Though the bloom off the Northwest coast is in salt water rather than fresh water, Rodgers said such blooms were well worth keeping an eye on.

"They are changing, expanding their ranges into places never seen before and in densities never seen before," Rodgers said. "It's hard to ignore, and as the data grows, we are becoming more and more convinced."

Rodgers said his theory has been peer reviewed and is gaining acceptance among scientists.

Current climate conditions are becoming strikingly similar to those that existed during the time of the mass extinctions, he said.

In a paper published in March in the journal Environment Geosciences, Rodgers and Castle wrote that their findings "gives us cause for concern and underscores the importance of careful and strategic monitoring as we move into an era of global climate change."

Scientists studying the bloom off the Northwest are wary when asked about Rodgers' and Castle's theory.

"I would be cautious about it," Trainer said.

Raphael Kudela, a toxic algae expert and ocean sciences professor at the University of California at Santa Cruz, thinks algae blooms such as those off the Northwest Coast are becoming more frequent.

"It is consistent with climate change," Kudela said, adding that a bloom like this in the chilly waters of the Northwest was "very unusual."

As for the killer algae theory, Kudela said, "People who study harmful algae don't dismiss it. But it can't be proved."

Parrish doesn't quite know what to make of the theory that algae killed dinosaurs. Back when life was just starting, she said, algae and other single-cell organisms excreted oxygen that created the atmosphere.

"The claim algae had a humongous effect on the atmosphere is correct," Parrish said. "Whether it caused mass extinctions, I don't know."

Source: http://www.miamiherald.com/news/politics/AP/v-fullstory/story/1379798.html

12.15.2009

Copenhagen climate summit: ocean acidification an ‘underwater time-bomb’


Ocean acidification is an "underwater time-bomb" that threatens fish stocks, marine life and coastal communities around the world, a Natural England report has warned.

The summary of the latest science of the “souring” of the oceans found ocean acidity has increased by a third since pre-industrial times because of a rise in carbon dioxide in the atmosphere.

It is feared that if greenhouse gases continue to go up, sea water acidity could increase by 120 per cent by 2060 – greater than anything experienced in the past 21 million years.

This would destroy coral like the Great Barrier Reef as well as cold water corals around Britain.

The mass extinction of plants and animals on the ocean floor would lead to a fall in fish stocks, affecting the economy of coastal communities in many of the world’s poorest areas and threaten food shortages. Shell fish and fish larvae will also be affected.

Ocean Acidification: The Facts was presented at the UN Climate Change Conference in Copenhagen

Dr Helen Phillips, Chief Executive of Natural England, said the report highlighted the importance of bringing greenhouse gases under control.

“Acidification of our seas is being directly linked to the growing levels of carbon dioxide in the atmosphere and our oceans are struggling to cope,” she said.

“The threat to the delicate balance of the marine environment cannot be overstated - this is a conservation challenge of unprecedented scale and highlights the urgent need for effective marine management and protection.”

Source: http://www.telegraph.co.uk/earth/copenhagen-climate-change-confe/6777099/Copenhagen-climate-summit-ocean-acidification-an-underwater-time-bomb.html

12.08.2009

Earth More Sensitive to Carbon Dioxide Than Previously Thought


The temperature response of the Earth (in degrees C) to an increase in atmospheric carbon dioxide from pre-industrial levels (280 parts per million by volume) to higher levels (400 parts per million by volume). (a) shows predicted global temperatures when processes that adjust on relatively short-term timescales (for example sea-ice, clouds, and water vapour) are included in the model (b) includes additional long-tem processes that adjust on relatively long timescales (vegetation and land-ice). (Credit: Image courtesy of University of Bristol)

ScienceDaily — In the long term, the Earth's temperature may be 30-50% more sensitive to atmospheric carbon dioxide than has previously been estimated, reports a new study published in Nature Geoscience.

The results show that components of the Earth's climate system that vary over long timescales -- such as land-ice and vegetation -- have an important effect on this temperature sensitivity, but these factors are often neglected in current climate models.

Dan Lunt, from the University of Bristol, and colleagues compared results from a global climate model to temperature reconstructions of the Earth's environment three million years ago when global temperatures and carbon dioxide concentrations were relatively high. The temperature reconstructions were derived using data from three million-year-old sediments on the ocean floor.

Lunt said, "We found that, given the concentrations of carbon dioxide prevailing three million years ago, the model originally predicted a significantly smaller temperature increase than that indicated by the reconstructions. This led us to review what was missing from the model."

The authors demonstrate that the increased temperatures indicated by the reconstructions can be explained if factors that vary over long timescales, such as land-ice and vegetation, are included in the model. This is primarily because changes in vegetation and ice lead to more sunlight being absorbed, which in turn increases warming.

Including these long-term processes in the model resulted in an increased temperature response of the Earth to carbon dioxide, indicating that the Earth's temperature is more sensitive to carbon dioxide than previously recognised. Climate models used by bodies such as the Intergovernmental Panel on Climate Change often do not fully include these long-term processes, thus these models do not entirely represent the sensitivity of the Earth's temperature to carbon dioxide.

Alan Haywood, a co-author on the study from the University of Leeds, said "If we want to avoid dangerous climate change, this high sensitivity of the Earth to carbon dioxide should be taken into account when defining targets for the long-term stabilisation of atmospheric greenhouse-gas concentrations."

Lunt added: "This study has shown that studying past climates can provide important insights into how the Earth might change in the future."

(a) shows predicted global temperatures when processes that adjust on relatively short-term timescales (for example sea-ice, clouds, and water vapour) are included in the model

(b) includes additional long-tem processes that adjust on relatively long timescales (vegetation and land-ice).

This research was funded by the Research Council UK and the British Antarctic Survey.

Souce: http://www.sciencedaily.com/releases/2009/12/091206162955.htm