2010-08-25

Microbes ate BP oil deep-water plume: study

Microbes ate BP oil deep-water plume: study

By Deborah Zabarenko, Environment Correspondent
Tue Aug 24

WASHINGTON (Reuters) – A Manhattan-sized plume of oil spewed deep into the Gulf of Mexico by BP's broken Macondo well has been consumed by a newly discovered fast-eating species of microbes, scientists reported on Tuesday.

The micro-organisms were apparently stimulated by the massive oil spill that began in April, and they degraded the hydrocarbons so efficiently that the plume is now undetectable, said Terry Hazen of Lawrence Berkeley National Laboratory.
These so-called proteobacteria -- Hazen calls them "bugs" -- have adapted to the cold deep water where the big BP plume was observed and are able to biodegrade hydrocarbons much more quickly than expected, without significantly depleting oxygen as most known oil-depleting bacteria do.

Oxygen is essential to the survival of commercially important fish and shellfish; a seasonal low-oxygen "dead zone" forms most summers in the Gulf of Mexico, caused by farm chemical run-off that flows down the Mississippi River.
Hydrocarbons in the crude oil from the BP spill actually stimulated the new microbes' ability to degrade them in cold water, Hazen and his colleagues wrote in research published on Tuesday in the journal Science.

In part, Hazen said, this is because these new "bugs" have adjusted over millions of years to seek out any petroleum they can find at the depths where they live, which coincides with the depth of the previously observed plume, roughly 3000 feet. At that depth, water temperature is approximately 41 degrees F (5 degrees C).

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Long before humans drilled for oil, natural oil seeps in the Gulf of Mexico have put out the equivalent of an Exxon Valdez spill each year, Hazen said.

Another factor was the consistency of the oil that came from the Macondo wellhead: light sweet Louisiana crude, an easily digestible substance for bacteria, and it was dispersed into tiny droplets, which also makes it more biodegradable.
These latest findings may initially seem to be at odds with a study published last Thursday in Science by researchers from Woods Hole Oceanographic Institution, which confirmed the existence of the oil plume and said micro-organisms did not seem to be biodegrading it very quickly.

However, Hazen and Rich Camilli of Woods Hole both said on Tuesday that the studies complement each other.
The Woods Hole team used an autonomous robot submarine and a mass spectrometer to detect the plume, but were forced to leave the area in late June, when Hurricane Alex threatened. At that time, they figured the plume was likely to remain for some time.

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But that was before the well was capped in mid-July. Hazen said that within two weeks of the capping, the plume could not be detected, but there was a phenomenon called marine snow that indicated microbes had been feasting on hydrocarbons.
As of Tuesday, there was no sign of the plume, Hazen said.

That doesn't mean there is no oil left from the 4.9 million barrels of crude that spilled into the Gulf after the April 20 blowout at BP's Deepwater Horizon rig. The U.S. government estimated on August 4 that 50 percent of the BP oil is gone from the Gulf and the rest is rapidly degrading.

Newly discovered microbe helped disperse oil, study finds

Newly discovered microbe helped disperse oil, study finds
By Vivian Kuo, CNN
August 25, 2010

(CNN) -- A new study finds oil spilled into the Gulf of Mexico from a ruptured BP well degraded at a rate that was "much faster than anticipated," thanks to the interaction of a newly-found and unclassified species of microbes with the oil particles.

Berkeley Lab's Earth Sciences Division and the Energy Biosciences Institute examined a dispersed oil plume that was formed at a depth of between 3,600 and 4,000 feet and extended some 10 miles out from the wellhead.

"Our findings show that the influx of oil profoundly altered the microbial community by significantly stimulating deep-sea psychrophilic (cold-temperature) gamma-proteobacteria that are closely related to known petroleum-degrading microbes," said Terry Hazen, a microbial ecologist and principal investigator on the study.
The cold-temperature bacteria "appears to be one of the major mechanisms behind the rapid decline of the deepwater dispersed oil plume that has been observed," Hazen said.

Researchers believe the light, sweet, nature of this particular crude, plus the Gulf's hardy adaptation to "frequent episodic leaks from natural seeps" may have contributed to its improved microbial ability to break the oil down.
The use of Corexit, a controversial commercial oil dispersant widely used during operations in response to the BP oil spill, "may have also accelerated biodegradation because of the small size of the oil particles and the low overall concentrations of oil in the plume," according to the study.

Additionally, the report noted the microbial degradation of the oil appeared to "take place without a significant level of oxygen depletion." Scientists had been concerned the microbes would consume large portions of oxygen in plumes, creating "dead zones" where it would be difficult to sustain sea life. The study found that oxygen saturation outside the plume was 67 percent while within the plume it was 59 percent, only a slight drop.

Hazen said the report is "the first data ever on microbial activity from a deepwater dispersed oil plume," and the microbes' speedy rate of degradation showed that the bacteria plays "a significant role in controlling the ultimate fates and consequences of deep-sea oil plumes in the Gulf of Mexico."

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Scientists began the study on May 25, just a little more than a month after the Deepwater Horizon rig exploded, killing 11 workers and precipitating the world's largest accidental oil spill.

According to Berkeley Lab, the Gulf of Mexico's deep waters are a relatively unexplored microbial habitat, where temperatures hover around 5 degrees Celsius, the pressure is enormous, and there little carbon is normally present.
The findings of the report will appear in the journal Science on Thursday.

Home sales plunge 27 pct. to lowest in 15 years

Home sales plunge 27 pct. to lowest in 15 years

By ALAN ZIBEL and J.W. ELPHINSTONE, AP Real Estate Writers
52 mins ago

WASHINGTON – Sales of previously occupied homes plunged last month to the lowest level in 15 years, despite the lowest mortgage rates in decades and bargain prices in many areas.
July's sales fell by more than 27 percent to a seasonally adjusted annual rate of 3.83 million, the National Association of Realtors said Tuesday. It was the largest monthly drop on records dating back to 1968, and sharp declines were recorded in all regions of the country.

The plunge in home sales also magnified fears about the broader economy.
"The housing market is undermining the already faltering wider economic recovery," said Paul Dales, U.S. economist with Capital Economics. "With the increasingly inevitable double-dip in prices yet to come, things could yet get a lot worse."
Sales were particularly weak among homes in the lower- to mid-priced ranges. For example, in the Midwest, homes priced between $100,000 and $250,000 tumbled nearly 47 percent.

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The weakness follows a strong spring, when now-expired government tax credits sparked sales, especially among first-time buyers of lower-priced homes.
The tax credits caused many of those buyers to speed up their home purchases. Sales have weakened since the credits expired on April 30.

As sales have slowed, the inventory of unsold homes on the market grew to nearly 4 million in July. That's a 12.5 month supply at the current sales pace, the highest level in more than a decade. It compares with a healthy level of about six months.

One reason the market is hurting is that buyers and sellers are in a standoff over prices. Many sellers are reluctant to lower their prices. And buyers are hesitating because they think home prices haven't bottomed out.
Laurie Salaman has been trying to sell her home in New York City for a year so she can move to the suburbs. She's had no offers, even after cutting her listing price on the three-bedroom Bronx home from $475,000 to $449,900.
She notes that she has upgraded the kitchen and bathrooms, refinished the basement and put in new decks and patios. Her goal is to take about $100,000 from the sale and put it toward the purchase of the new house. She said she won't lower her price any further.

"That's my bottom price," said Salaman, 55. "If I don't get that price, then I will hold off until the market gets a little better," she said.
The housing market is also being hampered by the weakening economic recovery. Unemployment remains stuck at 9.5 percent and many potential buyers worry they might not have a job to pay the mortgage.
Prices have fallen in part because foreclosures are running about 10 times higher than before the housing bust. Though the average rate for a 30-year fixed mortgage has sunk to 4.42 percent, many people can't qualify because banks have tightened their lending standards.

Home sales picked up in the spring when the government was offering tax credits. But sales have sputtered since the tax credits expired.
The drop in July's sales was led by 35 percent plunge in the Midwest. Sales were down 30 percent in the Northeast, 25 percent in the West and 23 percent in the South.
The median sale price was $182,600, up 0.7 percent from a year ago, but down 0.2 percent from June.