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

---

About Oceanic Defense
We are an international non-profit organization with members in over 60 countries, spanning 6 continents with 1 mission; healthy aquatic ecosystems free from human abuse and neglect. Oceanic Defense teaches people to protect our oceans by acting responsibly as consumers and by making smart decisions in our daily lives. Whether we are buying groceries, commuting to work, planning a vacation or advocating within our own communities; each action we take or decision we make either helps or hurts our oceans. We empower people to be part of the solution rather than part of the problem and work together to protect our blue planet.

Join us on Facebook: www.facebook.com/OceanicDefense
Visit our official website: www.oceanicdefense.org
Follow us on Twitter: www.twitter.com/OceanicDefense
Our YouTube Channel: www.youtube.com/OceanicDefense

Acidifying Oceans Dramatically Stunt Growth of Already Threatened Shellfish, Research Finds

ScienceDaily — New research shows that global warming and its effects -- in particular, ocean acidification have descended upon shellfish reefs, particularly those formed by the Olympia oyster.

More than one-third of the world's human-caused carbon dioxide emissions have entered the oceans, according to Brian Gaylord, a biological oceanographer at the Bodega Marine Laboratory of the University of California at Davis.

"Similar to what happens in carbonated soda," says Gaylord, "increasing carbon dioxide in seawater makes it more acidic."

Even with small changes in acidity, seawater becomes corrosive to the shells of aquatic organisms.

That's not good news for most marine life, especially for oysters.

Gaylord is investigating the consequences of this increasing ocean acidity on the growth of larval and juvenile Olympia oysters native to the U.S. West Coast.

"Such early life stages can be extremely sensitive to environmental stresses like ocean acidification," says Gaylord.

"These stages operate as bottlenecks that drive overall population numbers. If larval and juvenile Olympia oysters decline as a result of an acidifying ocean, what does that mean for the species as a whole?"

Likely nothing good, he and colleagues say.

"Changes now happening in the ocean's chemistry are expected to continue far into the foreseeable future," says David Garrison, director of the National Science Foundation (NSF)'s biological oceanography program, which funds Gaylord's research. "They may have myriad effects on marine animals."

Gaylord conducted experiments on larvae and juveniles produced by adult oysters in Tomales Bay, California. Adults were collected in the bay, then held at the Bodega Marine Laboratory until they released larvae.

In the lab, the free-swimming larvae were reared into early juvenile life.

Carbon dioxide concentrations in laboratory seawater were controlled to match present-day conditions in the oceans, 380 parts per million (ppm), as well as two carbon dioxide scenarios projected to occur by the year 2100 (540 and 970 ppm).

Mid-way through the larval phase at day nine, oysters in the high carbon dioxide treatment had shells that were 16 percent smaller than those reared in control, or ambient, conditions.

These effects continued through the time the larval oysters settled onto hard substrate at day 12. Shell size was seven percent smaller for oysters in the 970 ppm treatment than in the control group.

By a week later, the effects were dramatically magnified. The bottom-dwelling juveniles in the 970 ppm treatment had grown 41 percent less than juveniles under control conditions.

The consequences persisted, even after the juveniles from all treatments had been returned to present-day conditions.

"One and a half months after being transferred back to normal seawater," says Gaylord, "juveniles that had come from the high carbon dioxide environment were still 28 percent smaller than oysters reared for the entire experiment in control conditions."

The results strongly suggest that the effects of ocean acidification on oyster larvae persist well into the juvenile phase, he says, with potential consequences for oyster populations.

"If similar impacts happen to species beyond the Olympia oyster, there could be repercussions for oysters around the world."

Globally, 85 percent of shellfish reefs have been lost, making oyster reefs one of the most severely threatened marine habitats on the planet.

"Shellfish reefs in some places are at less than 10 percent of their former abundance," says Garrison. "Oysters have gone extinct in many areas, especially in North America, Australia and Europe."

Just as coral reefs are critical to tropical marine habitats, shellfish like oysters are the ecosystem engineers of bays and estuaries, creating dwelling places for countless plants and animals that find refuge in their three-dimensional structure.

The surface area of an oyster bed across its dips and folds and crevices may be 50 times greater than that of an equally extensive flat mud bottom.

Shellfish reefs also provide important services to people by filtering water, and serving as natural coastal buffers from boat wakes, sea-level rise and storms.

Oysters have supported civilization for millennia, from the ancient Romans to railroad workers in California in the 1880s. In the 1870s, eastern oyster reefs extended for miles along the James River in Chesapeake Bay. By the 1940s, they had largely disappeared.

"It's unclear whether we will ever be able to return to that by-gone era," says Gaylord. "The constellation of environmental and other pressures on oysters--including the consequences of ocean acidification--places them at grave risk."

Gaylord and colleagues presented early results of their research at the Ocean Sciences Meeting in Portland, Oregon, in February. They plan to publish a paper with updated findings later this year.

Source: http://www.sciencedaily.com/releases/2010/04/100420152841.htm

---

About Oceanic Defense We are an international non-profit volunteer organization with members in over 60 countries, spanning 6 continents with 1 mission; healthy aquatic ecosystems free from human abuse and neglect. Oceanic Defense teaches people to protect our oceans by acting responsibly as consumers and by making smart decisions in our daily lives. Whether we are buying groceries, commuting to work, planning a vacation or advocating within our own communities; each action we take or decision we make either helps or hurts our oceans. We empower people to be part of the solution rather than part of the problem and work together to protect our blue planet.

Join us on Facebook:www.facebook.com/OceanicDefense
Visit our official website:www.oceanicdefense.org
Follow us on Twitter:www.twitter.com/OceanicDefense

Your Trash Found in Dead Gray Whale

OLYMPIA, Wash. —

A gray whale that died after stranding on a West Seattle beach had a large amount of trash in its stomach, ranging from a pair of sweat pants to a golf ball, said biologists who examined the animal.

Scientists with the Cascadia Research Collective said Monday that the examination did not immediately determine why the 37-foot near-adult male died, but it was found to be in better nutritional condition than some other gray whales that have died recently. Starvation was not considered a major contributor to its death.

In a news release, the research organization said the animal found on the beach Thursday had more than 50 gallons of material in its stomach. Most was algae - typical of the bottom-feeding whales - but "a surprising amount of human debris" also was found.

Besides the pants and golf ball, the trash included more than 20 plastic bags, small towels, surgical gloves, plastic pieces and duct tape.

The debris made up only 1 percent to 2 percent of the stomach contents and there was no clear indication it caused the whale's death. But Cascadia said the junk showed the whale had tried to feed in industrial waters.

Gray whales feed by sucking in sediment in shallow waters and filtering out small organisms that live there.

Cascadia said the whale had cuts on the head, possibly from a boat propeller, but they did not appear fresh or deep enough to have contributed to its death. A large number of samples were taken and will be analyzed, but results will not be known for weeks or months, the organization said.

So far this year, five gray whales have died in Washington waters, four of them in Puget Sound in the last two weeks. That number is far below the 50 that died in Washington waters in 1999 and 2000, The Olympian newspaper reported.

"I'd say we are concerned but not alarmed yet," Cascade Research biologist John Calambokidis told the newspaper.

Three of the four whales to die in April appeared emaciated and all four apparently were stragglers from the nearly 20,000 gray whales that typically migrate north each spring from breeding grounds in Mexico to feeding grounds in Alaska. Whales that didn't get enough to eat in Alaska last year may now be running low on reserves, researchers told The Olympian.

State Department of Fish and Wildlife biologists also participated in the examination. Moving the animal to the remote examination site was coordinated by NOAA Fisheries with the help of Highline Community College, which hopes to preserve the whale's skeleton.

---

Information from: The Olympian, http://www.theolympian.com

Source: http://seattletimes.nwsource.com/html/localnews/2011649627_apwastrandedwhale1stldwritethru.html

---

About Oceanic Defense
We are an international non-profit organization with members in over 60 countries, spanning 6 continents with 1 mission; healthy aquatic ecosystems free from human abuse and neglect. Oceanic Defense teaches people to protect our oceans by acting responsibly as consumers and by making smart decisions in our daily lives. Whether we are buying groceries, commuting to work, planning a vacation or advocating within our own communities; each action we take or decision we make either helps or hurts our oceans. We empower people to be part of the solution rather than part of the problem and work together to protect our blue planet.

Join us on Facebook:
www.facebook.com/OceanicDefense
Visit our official website:
www.oceanicdefense.org
Follow us on Twitter:
www.twitter.com/OceanicDefense