Saturday, August 15, 2009
Warming Ocean Contributes to Global Warming
The warming of an Arctic current over the last 30 years has triggered the release of methane, a potent greenhouse gas, from methane hydrate stored in the sediment beneath the seabed. Although this had been predicted as a possible consequence of climate change, it is very worrying that the process has already started.
Scientists at the National Oceanography Centre Southampton working in collaboration with researchers from the University of Birmingham, Royal Holloway London and IFM-Geomar in Germany have found that more than 250 plumes of bubbles of methane gas are rising from the seabed of the West Spitsbergen continental margin in the Arctic, in a depth range of 150 to 400 metres.
Methane released from gas hydrate in submarine sediments has been identified in the past as an agent of climate change.
The data were collected from the royal research ship RRS James Clark Ross, as part of the Natural Environment Research Council’s International Polar Year Initiative. The bubble plumes were detected using sonar and then sampled with a water-bottle sampling system over a range of depths.
The results indicate that the warming of the northward-flowing West Spitsbergen current by 1 degree over the last thirty years has caused the release of methane by breaking down methane hydrate in the sediment beneath the seabed.
Professor Tim Minshull, Head of the University of Southampton’s School of Ocean and Earth Science based at the National Oceanography Centre, says: “Our survey was designed to work out how much methane might be released by future ocean warming; we did not expect to discover such strong evidence that this process has already started.”
Graham Westbrook Professor of Geophysics at the University of Birmingham, warns: “If this process becomes widespread along Arctic continental margins, tens of megatonnes of methane per year – equivalent to 5-10% of the total amount released globally by natural sources, could be released into the ocean.”
Journal Reference:
Westbrook, G. K., et al. (2009), Escape of methane gas from the seabed along the West Spitsbergen continental margin, Geophys. Res. Lett., 36, L15608, doi:10.1029/2009GL039191.
Scientists at the National Oceanography Centre Southampton working in collaboration with researchers from the University of Birmingham, Royal Holloway London and IFM-Geomar in Germany have found that more than 250 plumes of bubbles of methane gas are rising from the seabed of the West Spitsbergen continental margin in the Arctic, in a depth range of 150 to 400 metres.
Methane released from gas hydrate in submarine sediments has been identified in the past as an agent of climate change.
The data were collected from the royal research ship RRS James Clark Ross, as part of the Natural Environment Research Council’s International Polar Year Initiative. The bubble plumes were detected using sonar and then sampled with a water-bottle sampling system over a range of depths.
The results indicate that the warming of the northward-flowing West Spitsbergen current by 1 degree over the last thirty years has caused the release of methane by breaking down methane hydrate in the sediment beneath the seabed.
Professor Tim Minshull, Head of the University of Southampton’s School of Ocean and Earth Science based at the National Oceanography Centre, says: “Our survey was designed to work out how much methane might be released by future ocean warming; we did not expect to discover such strong evidence that this process has already started.”
Graham Westbrook Professor of Geophysics at the University of Birmingham, warns: “If this process becomes widespread along Arctic continental margins, tens of megatonnes of methane per year – equivalent to 5-10% of the total amount released globally by natural sources, could be released into the ocean.”
Journal Reference:
Westbrook, G. K., et al. (2009), Escape of methane gas from the seabed along the West Spitsbergen continental margin, Geophys. Res. Lett., 36, L15608, doi:10.1029/2009GL039191.
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Labels: environment, research, SCUBA News
Friday, August 14, 2009
Healthiest US Coral Reef is in Gulf of Mexico
Flower Garden Banks National Marine Sanctuary is among the healthiest coral reef ecosystems in the US Caribbean and Gulf of Mexico, according to a new NOAA report.Sanctuary managers will use the report to track and monitor changes in the marine ecosystem located 70 to 115 miles off the coasts of Texas and Louisiana.
“We found that 50 percent of the area surveyed for this report is covered by live coral,” said Chris Caldow, a NOAA marine biologist and lead author on the report. “This is significant because such high coral cover is a real rarity and provides critical habitat for many different types of fish and other animals that live in these underwater systems.”
The sanctuary also is unusual in that it is dominated by top-level predators, including large grouper, jacks, and snappers that are virtually absent throughout the U.S. Caribbean. Researchers looked at the relationship between physical measures of the sanctuary’s habitat such as depth, slope and geographic location, and the nature of the fish community in each location.
The report cautions that despite the sanctuary’s relatively healthy condition, it may be more susceptible to environmental impacts than previously thought. For example, scientists observed high levels of coral bleaching and corals severely impacted from hurricane activity.
NOAA predicts changes in the Earth's environment, from the depths of the ocean to the surface of the sun, and conserves and manages the US coastal and marine resources.
For more on Flower Garden Banks see the NOOA site.
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Labels: America, coral reef, environment, SCUBA News
Monday, August 10, 2009
Earthquake off Andaman Islands
An earthquake measuring 7.6 on the Richter scale has struck the Andaman Islands off the coast of India. It has triggered a tsunami watch for India, Myanmar (Burma), Indonesia, Thailand and Bangladesh.
According to the The U.S. Geological Survey, the earthquake happened 160 miles (260 km) north of Port Blair in the Andaman Islands, India and 510 (825 km) miles west of Bangkok, Thailand. It was 20 miles (33 km) deep.
See the location of the earthquake on a map...
According to the The U.S. Geological Survey, the earthquake happened 160 miles (260 km) north of Port Blair in the Andaman Islands, India and 510 (825 km) miles west of Bangkok, Thailand. It was 20 miles (33 km) deep.
See the location of the earthquake on a map...
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Labels: India, SCUBA News
