ANCHORAGE, Alaska (Reuters) – A wildfire that burned over 400 square miles of Alaska tundra in the scorching summer of 2007 poured as much carbon into the atmosphere as the entire Arctic normally absorbs each year, according to a new study in the scientific journal Nature.

The tundra fire, near the Anaktuvuk River of Alaska’s North Slope, was considered an unprecedented event at the time. It was, by far, the largest single wildfire on treeless Arctic tundra ever recorded, and was twice as big as all previously recorded Alaska tundra fires combined.

But it may be an ominous sign of climate problems in the future, according to the study and the researchers who conducted it.

The study, published on Thursday, measured the volume of carbon emitted by the months-long fire — although massive it covered only a tiny portion of the vast North Slope — at 2.1 million metric tons.

“It was the same order of magnitude as what the Arctic takes up and stores in plant biomass,” said Syndonia Bret-Harte of the Institute of Arctic Biology at the University of Alaska, Fairbanks, one of the study’s authors.

That creates the potential for a “positive feedback” loop that would reinforce the warming trend in the far north, according to the study.

Repeated large fires might even cancel out any potential carbon-absorption benefits from increased plant growth in the Arctic that has been made possible by the region’s warming climate, the researchers said.

ANCHORAGE, Alaska (Reuters) – Alaska scientists have discovered the fossil of a rare, prehistoric marine reptile that is likely the most complete remnant of the creature ever found in North America.

The nearly complete fossilized skeleton is of a thalattosaur, a long-tailed sea creature that plied warm, shallow waters in the early days of dinosaurs and became extinct at the end of the Triassic period some 200 million years ago.

The discovery of the fossil, found during an extreme low tide along the shore of the Tongass National Forest, was announced this week by the Museum of the North at the University of Alaska, Fairbanks.

“We were just having our morning coffee out on the outcropping when somebody said, ‘What’s that?’” Jim Baichtal, the U.S. Forest Service’s Tongass geologist and part of the discovery team, said on Thursday.

Geologists had been conducting field surveys at the site when the fossil was spotted.

Unlike most thalattosaur discoveries, which are fossilized remnants of individual bones and bone fragments, this specimen appeared to be a nearly full skeleton.

“In North America, this may be the most articulated specimen that we have right now,” Baichtal said.

ANCHORAGE, Alaska (Reuters) – Six small, rural newspapers in Alaska published by a Yupik Eskimo company are slated to go out of business next month, falling victim to rising costs of materials and operations.

Calista Corp, one of 12 regional Native corporations in the state, announced last Friday it plans to close and liquidate its Alaska Newspapers Inc subsidiary, along with the Native-themed magazine, First Alaskans.

The last publication date for the six newspapers, all weeklies, has yet to be determined, Calista spokesman Thom Leonard said this week, adding, “Right now, we’re just focusing on our employees.”

The chain employs 38 people, Leonard said. Workers will be provided opportunities for other jobs within Calista and offered assistance in making the transition, he said.

The chain’s newspapers, averaging about 2,000 subscribers each, serve readers in Barrow and northwestern Alaska, the Yukon-Kuskokwim Delta of southwestern Alaska, the Aleutian Islands, Bristol Bay and the fishing ports of Cordova and Seward.

Calista owns a diversified portfolio of businesses, with subsidiaries involved in government contracting, engineering, oil-field services, construction and telecommunications. The company bought the struggling Alaska Newspapers chain in 1992.

Loss of the publications will leave a large void in the state, some prominent Alaskans said.

ANCHORAGE, Alaska, July 25 (Reuters) – A spill of about 200 gallons of an oil-water mixture has prompted a temporary shutdown of an oil-separation facility at the BP(BP.L: Quote, Profile, Research, Stock Buzz)-operated Prudhoe Bay oil field, the Alaska Department of Environmental Conservation reported on Monday.

The spilled material amounts to about 70 percent produced water and 30 percent crude oil, the department said in a statement. The material flowed into gravel-bermed, water-filled containment pits that encircle the flow station’s flares.

The spill was discovered on Thursday, but only made public on Monday. The cleanup launched in response required shutdown of the facility, known as Flow Station 2, the Department of Environmental Conservation said. The shutdown is expected to last for at least another four days, the department said.

The facility is one of three flow stations on the eastern operating area of Prudhoe Bay. The flow stations, along with the three gathering stations on the western side of Prudhoe Bay, separate the crude oil, gas and water that are pumped out of wells.

A BP spokesman said there will be a small reduction in overall field output, but that it will be difficult to quantify. “We expect that there will be some minor short-term impact here. But production impacts are going to be minimal due to other ongoing maintenance activities,” BP spokesman Steve Rinehart said.

Several facilities are undergoing annual maintenance in the brief North Slope summer, he said. “This is the time of year when facilities are going off-line and coming on-line all summer,” he said.

Total North Slope production has averaged 453,351 barrels per day so far in July, according to the Alaska Oil and Gas Conservation Commission. That is roughly 70 percent of normal winter production rates, according to state records. (Editing by Bill Rigby and Carol Bishopric)

ANCHORAGE, Alaska (Reuters) – Alaska wildlife managers have no plans to hunt down a bear that attacked a group of seven young backpackers over the weekend in a remote stretch of backcountry, a state biologist said on Monday.

The bear, believed to be a female with a cub nearby, probably acted to defend its young against a perceived threat when it attacked teenagers participating in a National Outdoor Leadership School expedition, said Lem Butler, a wildlife biologist with the Alaska Department of Fish and Game.

“The bear does not pose an immediate risk to public safety, so we do not have any plans to locate or remove it,” he said.

That could change if Alaska fish and game officials learn the animal, which was either a grizzly or a brown bear, was unusually aggressive. But so far experts believe the attack was a result of a specific scenario that is unlikely to be repeated, he said.

Also, the area where the mauling occurred is so remote that authorities were not confident they could find the bear.

The bear attacked the teenagers on Saturday evening as they were attempting to cross a rushing river in a remote area east of Denali National Park, according to state police. Four of the seven teens were injured seriously enough to be hospitalized.

Joshua Berg, 17, of New York, and Samuel Gottsegen, 17, of Colorado, were the two expedition members who bore the brunt of the attack. Berg remained hospitalized in Anchorage on Monday in serious condition, while Gottsegen was in good condition, a hospital spokeswoman said.

ANCHORAGE, Alaska (Reuters) – A grizzly bear has attacked seven teenagers in Alaska, injuring four of them, Alaska State Troopers said on Sunday.

The teens were hiking in the Talkeetna Mountains east of Denali National Park and were trying to cross a river when the grizzly attacked Saturday night, the troopers said.

The two 17-year-old students in the lead, Joshua Berg of New York and Samuel Gottsegen of Denver, bore the brunt of the attack, the troopers said.

Other members were able to activate an emergency beacon and the group was rescued on Sunday morning by the Alaska Air National Guard, the troopers said.

While Berg and Gottsegen were the most severely mauled, two other students, 16-year-old Noah Allaire of Albuquerque and 18-year-old Victor Martin of Richmond, California, also were hospitalized with injuries.

Martin was released late Sunday but the other three remained hospitalized. Their conditions were not available.

The three other teens received minor injuries or suffered from exposure-related ailments, the troopers said.

ANCHORAGE, Alaska (Reuters) – Recent satellite images of a remote Alaska volcano along a flight route for major airlines show the mountain may be poised for its first big eruption in 10 years, scientists said on Thursday.

The Alaska Volcano Observatory has issued an eruption advisory for the 5,676 foot-tall Cleveland Volcano, located on the uninhabited island of Chuginadak in the Aleutian chain about 940 miles southwest of Anchorage.

The advisory was based on “thermal anomalies” detected by satellite, the observatory said. Those measurements indicate the volcano could erupt at any moment, spewing ash clouds up to 20,000 feet above sea level with little further warning, the observatory said.

A major eruption could disrupt international air travel because Cleveland Volcano, like others in the Aleutians, lies directly below the commercial airline flight path between North America and Asia, said John Power, scientist-in-charge at the Alaska Volcano Observatory.

The volcano’s last major eruption came in 2001, when it blasted ash more than 5 miles into the sky and spilled lava from the summit crater. Cleveland has experienced several smaller eruptions or suspected eruptions since then.

So far, airlines have not changed their flight patterns because of Cleveland’s heat emissions, said Steve McNutt, a University of Alaska Fairbanks scientist who works at the observatory.

Scientists are not always certain about what is happening at the remote volcano, observatory officials said. The town of Nikolski, the nearest settlement to Cleveland Volcano, is 45 miles away.

ANCHORAGE, Alaska, July 19 (Reuters) – Chevron Corp (CVX.N: Quote, Profile, Research, Stock Buzz) said on Tuesday it has reached an agreement to sell all of its interests in Alaska’s Cook Inlet basin to Texas-based independent oil firm Hilcorp Energy [HILCO.UL].

Financial terms of the sale were not disclosed. The sale is expected to be completed by the end of the year, pending regulatory reviews, Chevron said.

Current net daily production from the assets in the sale total 3,900 barrels of oil and 85 million cubic feet of natural gas, Chevron said.

The assets to be sold comprise Chevron’s interests in the Granite Point, Middle Shoals, Trading Bay and MacArthur fields; the company’s interests in 10 offshore platforms and onshore gas fields; two gas-storage facilities and Chevron’s interests in the Cook Inlet Pipe Line Co and Kenai Kachemak Pipeline LLC.

Chevron initially announced its plans to sell the Cook Inlet assets in October, explaining at the time that the oil and gas facilities there no longer fit into the company’s global portfolio.

Chevron said it will retain its interests in several Alaska North Slope fields and its 1.36 percent interest in the Trans Alaska Pipeline System.

Cook Inlet is Alaska’s oldest producing oil and gas basin, with production starting in the 1950s. Chevron had been an early explorer and producer there. The company sold its assets in 1992, but then re-entered the Alaska business in 2005, when it acquired Unocal, a company very active in Cook Inlet.

ANCHORAGE/LONDON (Reuters) – BP reported another pipeline leak at its Alaskan oilfields, frustrating the oil company’s attempts to rebuild its reputation after last year’s disastrous Gulf of Mexico oil spill.

BP said on Monday that a pipeline at its 30,000 barrel-per-day Lisburne field, currently closed for maintenance, had ruptured during testing and spilled a mixture of methanol and oily water onto the tundra.

The London-based company has a history of oil spills at its Alaskan pipelines, including lines servicing Lisburne. The accidents have tarnished BP’s public image in the United States, where around 40 percent of its assets are based.

The Alaska Department of Environmental Conservation said the spill occurred on Saturday and amounted to 2,100 to 4,200 gallons, affecting 4,960 square feet of gravel pad and about 2,040 square feet of wet and aquatic tundra.

Production from the entire Lisburne field remains shut off while the spill is addressed, Alaska officials said.

A BP spokesman said the cleanup was under way and the company would determine the cause “in due course.”

The federal Pipeline and Hazardous Materials Safety Administration, which oversees most U.S. pipelines, said late on Monday that it does not have jurisdiction over the BP pipeline.

ANCHORAGE, Alaska (Reuters) – A breached pipeline at one of BP’s Alaska oilfields spilled a mixture of methanol and oily produced water, Alaska environmental officials said Sunday.

The affected pipeline, which runs underground, failed during a pressure test that was conducted while the BP-operated Lisburne field was shut in for summer maintenance, the Alaska Department of Environmental Conservation said.

Lisburne, managed as part of the Greater Prudhoe Bay Unit, has daily production that usually averages about 30,000 to 32,000 barrels, according to Alaska Oil and Gas Conservation Commission records. But the field has produced no oil since June 18, according to AOGCC records, suggesting maintenance work requiring a prolonged shutdown.

The spill occurred on Saturday, the department said. It was estimated at 2,100 to 4,200 gallons, the department said.

BP officials were not immediately available Sunday night to comment.

A rig explosion unleashed millions of barrels of oil from BP’s Macondo well into the Gulf of Mexico last year.

The breached pipeline in Alaska serves one of Lisburne’s eight drill pads, department officials said. Production from the entire Lisburne field remains shut off while the spill is addressed, officials said.