Featured Research

from universities, journals, and other organizations

How gas and temperature controlled bacterial response to Deepwater Horizon spill

Date:
October 4, 2011
Source:
University of California - Santa Barbara
Summary:
Scientists used DNA to identify microbes present in the Gulf of Mexico following the Deepwater Horizon oil spill, and then identified the microbes responsible for consuming the large amount of natural gas present immediately after the spill. They have also explained how water temperature played a key role in the way bacteria reacted to the spill.

Flaring of captured gas (left) and oil (right) at the Deepwater Horizon spill site in June 2010.
Credit: Image courtesy of David L. Valentine

In a new study, UC Santa Barbara scientists explain how they used DNA to identify microbes present in the Gulf of Mexico following the Deepwater Horizon oil spill, and how they identified the microbes responsible for consuming the large amount of natural gas present immediately after the spill. They also explain how water temperature played a key role in the way bacteria reacted to the spill.

The results of their research are published in the Proceedings of the National Academy of Sciences. The study was led by David Valentine, a geochemist and professor of earth science at UCSB, and Molly Redmond, a postdoctoral scholar in Valentine's laboratory. The research was supported by the National Science Foundation and the Department of Energy.

The Deepwater Horizon oil spill was unique, according to the scientists, because it happened at such great depth and contained so much natural gas -- predominantly methane, ethane, and propane. Those factors influenced the way bacteria responded to the spill. In earlier studies, Valentine, Redmond, and their colleagues showed that ethane and propane were the major hydrocarbon compounds being consumed in June 2010, two months after the start of the April spill. By September 2010, the scientists found that these gases and all of the methane had been consumed.

In May and June of 2010, the scientists found that bacterial communities in the Deepwater Horizon submerged plume were dominated by just a few types -- Oceanospirillales, Colwellia, and Cycloclasticus -- and were very different from control samples without large concentrations of oil or gas, and also from the communities in surface oil slicks collected at the same time.

"It's much warmer at the surface than in the deep water -- around 80 degrees (Fahrenheit) versus 40 degrees, which is pretty close to the temperature in your refrigerator," said Redmond, the study's lead author. "There was very little natural gas in the surface samples, suggesting that both temperature and natural gas could be important in determining which bacteria bloomed after the spill. The bacteria we saw in the deep-water samples in May and June were related to types of psychrophilic, or cold-loving bacteria. Most bacteria grow more slowly at cooler temperatures -- that's why we keep our food in the refrigerator. But psychrophilic bacteria actually grow faster at cold temperatures than they would at room temperature."

To provide additional evidence of the importance of temperature, the scientists added oil to water from the Gulf and incubated it at 40 degrees and at room temperature (about 70 degrees), and looked at which bacteria grew at the different temperatures. In the 40-degree samples, Colwellia were most abundant, but were only found in low numbers in the room temperature samples, suggesting that these particular bacteria have an advantage in cold water.

"To figure out which bacteria were consuming methane, ethane, and propane, we used a technique called stable isotope probing, where we incubated fresh seawater samples from the Gulf with isotopically labeled methane, ethane, or propane," Redmond said. "The bacteria that grew as they consumed the methane, ethane, or propane converted the isotopically labeled gases into biomass, including their DNA. By sequencing the labeled DNA, we were able to identify the bacteria that had consumed the methane, ethane, or propane. The bacteria that consumed the ethane and propane were the same Colwellia that we saw at high abundance in the environmental samples from May and June, when ethane and propane consumption rates were high, and that were abundant when we incubated oil at 40 degrees, but not at room temperature."

This suggests that the Colwellia were abundant because they grow well at low temperatures and because they could consume ethane and propane, which were very abundant during the spill, the researchers said. The bacteria that consumed methane were a group of bacteria called Methylococcaceae -- the same bacteria that were abundant in September after the methane had been consumed, suggesting that they were, in fact, important in consuming methane.

"The ability of oil-eating bacteria to also grow with natural gas as their foodstuff is important, because these bacteria may have grown to high numbers by eating the more-abundant gas, and then turned their attention to other components of the oil," said Valentine. "With this work, we have revealed some of the relationships between hydrocarbons released from Deepwater Horizon and the bacteria that responded. But numerous questions remain as to how the bacteria interacted with one another, and how this ecology impacted the fate of the released oil."


Story Source:

The above story is based on materials provided by University of California - Santa Barbara. Note: Materials may be edited for content and length.


Journal Reference:

  1. Molly C. Redmond and David L. Valentine. Science Applications in the Deepwater Horizon Oil Spill Special Feature: Natural gas and temperature structured a microbial community response to the Deepwater Horizon oil. PNAS, October 3, 2011 DOI: 10.1073/pnas.1108756108

Cite This Page:

University of California - Santa Barbara. "How gas and temperature controlled bacterial response to Deepwater Horizon spill." ScienceDaily. ScienceDaily, 4 October 2011. <www.sciencedaily.com/releases/2011/10/111003180432.htm>.
University of California - Santa Barbara. (2011, October 4). How gas and temperature controlled bacterial response to Deepwater Horizon spill. ScienceDaily. Retrieved July 30, 2014 from www.sciencedaily.com/releases/2011/10/111003180432.htm
University of California - Santa Barbara. "How gas and temperature controlled bacterial response to Deepwater Horizon spill." ScienceDaily. www.sciencedaily.com/releases/2011/10/111003180432.htm (accessed July 30, 2014).

Share This




More Earth & Climate News

Wednesday, July 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Thousands Flocking to German Crop Circle

Raw: Thousands Flocking to German Crop Circle

AP (July 30, 2014) Thousands of people are trekking to a Bavarian farmer's field to check out a mysterious set of crop circles. (July 30) Video provided by AP
Powered by NewsLook.com
In Virginia, the Rise of a New Space Coast

In Virginia, the Rise of a New Space Coast

AP (July 30, 2014) Every summer, tourists make the pilgrimage to Chincoteague Island, Va. to see wild ponies cross the Assateague Channel. But, it's the rockets sending to supplies to the International Space Station that are making this a year-round destination. (July 30) Video provided by AP
Powered by NewsLook.com
Climate Change Could Cost Billions, According To White House

Climate Change Could Cost Billions, According To White House

Newsy (July 29, 2014) A report from the White House warns not curbing greenhouse gas emissions could cost the U.S. billions. Video provided by Newsy
Powered by NewsLook.com
Climate Change Could Cost Billions According To White House

Climate Change Could Cost Billions According To White House

Newsy (July 29, 2014) A report from the White House warns not curbing greenhouse gas emissions could cost the U.S. billions. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

    Environment News

    Technology News



      Save/Print:
      Share:

      Free Subscriptions


      Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

      Get Social & Mobile


      Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

      Have Feedback?


      Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
      Mobile: iPhone Android Web
      Follow: Facebook Twitter Google+
      Subscribe: RSS Feeds Email Newsletters
      Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins