Showing posts with label offshore oil drilling. Show all posts
Showing posts with label offshore oil drilling. Show all posts

5.01.2010

Bird Habitats Threatened by Oil Spill


The American Bird Conservancy (ABC) has released a list of key bird sites most immediately threatened by the ongoing Deepwater Horizon oil spill in the Gulf of Mexico (as of Friday, April 30). The sites previously had been designated Globally Important Bird Areas by the organization, and they are directly in the path of the advancing oil slick.

“This spill spells disaster for birds in this region and beyond,” said ABC President George Fenwick. “It is ironic that next weekend is International Migratory Bird Day. At a time when we should be celebrating the beauty and wonder of migratory birds, we could be mourning the worst environmental disaster in recent U.S. history.”

The Gulf Coast is extremely important for hundreds of species of migrants, which variously breed, winter and rest here during migration. The population effects on birds from this spill will be felt as far north as Canada and Alaska and as far south as South America.

The complexity of the Gulf coastline, with numerous bays, estuaries, inlets, marshes and creeks, will make cleanup extremely difficult; impacts could last for decades for much of the habitat, and some species may suffer significant long-term population declines.

All coastal nesting species (herons, terns, skimmers, plovers, gulls, rails, ducks) are currently present on the Gulf Coast, including several species on the U.S. WatchList of birds of conservation concern. The impact to these species depends on how long the leak lasts and what happens with weather and currents. The leak could persist for weeks or months, and end up being the worst environmental disaster in U.S. history.

For species with long life spans and low reproductive rates (such as reddish egrets and least terns), acute mortality events such as this can have long-term population-level impacts if they affect a large proportion of the breeding population. This is because adults that survive do not produce young quickly enough for populations to recover quickly.

Species where large proportions of populations concentrate in a few, discreet locations (including species with only a few breeding colonies and species that concentrate en masse during migration stopovers) are particularly vulnerable to these events.

Compounding problems for songbirds, not normally directly affected by oil spills, is smoke billowing skywards from the burning oil that was set alight to try to minimize damage to marine life.

“Millions of our songbirds are crossing the Gulf now, and will arrive stateside perilously weak and undernourished from their journey. The smoke may well compound their precarious situation and potentially lead to birds failing to make it to shore, or arriving so weakened that they are unable to survive,” said Fenwick.

The Top Ten Sites at Most Immediate Risk from the Deepwater Horizon Oil Spill

  1. Gulf Coast Least Tern Colony
    One of the world’s largest colonies of the threatened least tern.

  2. Lower Pascagoula River – including the Pascagoula River Coastal Preserve
    The coastal marshes at the mouth of the river support yellow and black rails, snowy plovers and endangered wintering piping plovers.

  3. Gulf Islands National Seashore
    Hosts thousands of wintering shorebirds, including endangered piping plover, Wilson’s plover and American oystercatcher (above) as well as brown pelican, black-crowned night-heron, white ibis and black skimmer.

  4. Breton National Wildlife Refuge – including the Chandeleur Islands
    Largest tern colony in North America, predominantly of sandwich, royal, and caspian terns. Also American oystercatcher, brown pelican, reddish egret and endangered piping plover. Also an important wintering area for magnificent frigatebird, and stopover site for redhead and lesser scaup.

  5. Dauphin Island
    An important stopover site for migrant birds including shorebirds, gulls, terns, herons and rails.

  6. Fort Morgan Historical Park
    An important stopover site for migratory birds including shorebirds, gulls, terns, herons and rails.

  7. Bon Secour National Wildlife Refuge
    An important stopover site for thousands of trans-Gulf migrants.

  8. Eglin Air Force Base
    Best known for its inland population of red-cockaded woodpeckers, Elgin also has significant coastal habitat for shorebirds and wading birds.

  9. Delta National Wildlife Refuge
    Large numbers of wading birds nest here, including white ibis, snowy egrets and herons; thousands of shorebirds use the mudflats in winter and during migration, including dunlin, long-billed dowitcher and western sandpiper as well as endangered piping plover.

  10. Baptiste Collette Bird Islands
    This artificial barrier island, created from dredge spoil, is one of the many Louisiana coastal islands that could be affected. Birds found here include caspian tern, brown pelican, gull-billed tern and black skimmer.



Source: http://www.nwf.org/News-and-Magazines/National-Wildlife/Birds/Archives/2010/Oil-Spill-Birds.aspx



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4.26.2010

Scientists find ancient asphalt domes off California coast


High-resolution bathymetry shows extinct asphalt volcanoes on the sea-floor off California. Credit: Dana Yoerger, WHOI

About 35,000 years ago, a series of apparent undersea volcanoes deposited massive flows of petroleum 10 miles offshore. The deposits hardened into domes that were discovered recently by scientists from the Woods Hole Oceanographic Institution (WHOI) and UC Santa Barbara (UCSB).

Their report—co-authored with researchers from UC Davis, the University of Sydney and the University of Rhode Island—appears online today (April 25) in the Journal Nature Geoscience. The work was funded by the National Science Foundation, U.S. Department of Energy and the Seaver Institute.

"It was an amazing experience, driving along…and all of a sudden, this mountain is staring you in the face," said Christopher M. Reddy, director of WHOI's Coastal Ocean Institute and one of the study's senior authors, as he described the discovery of the domes using the deep submersible vehicle Alvin. Moreover, the dome was teeming with undersea life. "It was essentially an oasis," he said, "almost like an artificial reef."

What really piqued the interest of Reddy—a marine geochemist who studies oil spills—was the chemical composition of the dome: "very unusual asphalt material," he said. "There aren't that many opportunities to study oil that's been sitting around on the bottom of the ocean for 35,000 years."

Reddy's unique chance came courtesy of UCSB earth scientist and lead author David L. Valentine, who first came upon the largest of the structures—named Il Duomo—and brought back a chunk of the brittle, black material in 2007 from an initial dive in Alvin, which WHOI operates for the US Navy. Valentine and Reddy were on a cruise aboard the WHOI-operated research vessel Atlantis, following up on undersea mapping survey by the Monterey Bay Aquarium Research Institute (MBARI) and the work of UCSB earth scientist Ed Keller.

"The largest [dome] is about the size of two football fields, side by side and as tall as a six-story building," Valentine said. Alvin's robotic arm snapped off a piece of the unusual formation, secured it in a basket and delivered it to Reddy aboard Atlantis.

"I was sleeping," Reddy chuckled. "Somebody woke me up and wanted me to look at the rocks and test them."

It turned out to be quite an awakening. "I was amazed at how easy it was to break," Reddy recalls, "which confirmed it wasn't solid rock" and lent credence to Keller's theory that these structures might be made of asphalt.

Without access to the sophisticated equipment in his Woods Hole lab, Reddy employed a "25-cent glass tube, the back of a Bic pen and a little nail polish remover" to analyze the crusty substance. He used the crude tools like a mortar and pestle to grind the rock, "and literally within several minutes, it became a thick oil."

"This immediately said to me that this was asphalt," Reddy said. "And I remember turning to Dave [Valentine] and saying, 'We've got to back. Please take me back there'" to the dome.


Diagram showing formation of an asphalt volcano and associated release of methane and oil. Credit: Jack Cook, UCSB

After making some schedule changes, Valentine cleared the way for him and Reddy to take Alvin back to several sites in 2007. This work also set the stage for a follow-up study in September 2009, when the investigators returned to the domes with Alvin and the Autonomous Undersea Vehicle (AUV) Sentry to study the unique structures. They were joined by, among others, WHOI collaborators Dana Yoerger, Richard Camilli and Robert K. Nelson and Oscar Pizarro, now at the University of Sydney.

"With that combination, we were able to go in and do very detailed mapping of the site and very detailed sampling at the seafloor," Valentine said. Using mass spectrometers and radiocarbon dating in their respective laboratories, the scientists were able to confirm the nature and age of the domes.

"To me, as an oil-spill chemist, this was very exciting," said Reddy. "I got to find out what oil looks like after… 35,000 years."

What it looked like was "incredibly weathered," said Reddy. "That means nature had taken away a lot of compounds. These mounds of black material were the last remnants of oil that exploded up from below. To see nature doing this on its own was an unbelievable finding."

A few asphalt-like undersea structures have been reported, says Valentine, "but not anything exactly like these…no large structures like we see here." He estimates that the dome structures contain about 100,000 tons of residual asphalt and compares them to an underwater version of the La Brea Tar Pits in Los Angeles, complete with the fossils of ancient animals.

The researchers are not sure exactly why sea life has taken up residence around the asphalt domes, but one possibility is that because the oil has become benign over the years that some creatures are able to actually feed off it and get energy from it. They may also be "thriving" on tiny holes in the dome areas that release minute amounts of methane gas, Reddy says.

The scientists plan to continue studying the domed structures. "We have some very fundamental questions that remain," Valentine says. "It would be nice to know what is going on deep down under these things.

"One future direction is to try and actually drill into them," he says. "We also need to turn it over to some geologists to figure out where this oil is really coming from. More fundamentally, we're going to look at the actual degradation of the oil by microorganisms and maybe even see what organisms are trapped in this…very much like the La Brea Tar Pits."

From a chemical point of view, Reddy says he will continue to probe the question of exactly which of the chemicals that make up the domes "stayed around" all these years.

"Instead of this taking place at a refinery, nature used a variety of its own tools," he said, to manufacture the asphalt substance. With some heating and a few chemical tweaks, he added, this is essentially the same material that paves highways and parking lots. After all, it is California.

Provided by Woods Hole Oceanographic Institution

Source: http://www.physorg.com/news191397828.html



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