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BP oil spill dispersants may have hurt Gulf of Mexico food chain, study finds
Published: Tuesday, July 31, 2012, 10:00 PM Updated: Wednesday, August 01, 2012, 8:20 AM
By The Associated PressThe Associated Press
...
For the study, Alabama researchers pumped water from Mobile Bay into 53-gallon drums, then added oil, dispersant or both in proportions found during the oil spill to simulate the spill's effects on microscopic water-life in the bay.
Over more than 12 weeks in 2010, BP's well spewed nearly 200 million gallons of oil into the Gulf of Mexico. The company used more than 1.8 million gallons of dispersants -- more than 770,000 gallons of it at the oil's source on the ocean floor -- to break up the oil into tiny droplets. Earlier research hadn't found significant problems for the environment and marine life, but dispersants had never before been used a mile underwater or in such large amounts.
The researchers found that, within days, the numbers of plant-like phytoplankton and ciliates -- plankton that use hairlike cilia to move -- increased under an oil slick. But they dropped significantly in the drums with dispersant or dispersed oil, while the numbers of bacteria increased.
The study was published Tuesday in PLoS ONE, one of the peer-reviewed journals in the online Public Library of Science.
...
Full text:
http://www.nola.com/news/gulf-oil-spill/index.ssf/2012/07/bp_oil_spill_dispersants_may_h.html
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Dispersed Oil Disrupts Microbial Pathways in Pelagic Food Webs
Alice C. Ortmann<SUP>1</SUP><SUP>,</SUP><SUP>2</SUP><SUP>*</SUP>, Jennifer Anders<SUP>2</SUP>, Naomi Shelton<SUP>2</SUP>, Limin Gong<SUP>3</SUP>, Anthony G. Moss<SUP>3</SUP>, Robert H. Condon<SUP>2</SUP>
1 Department of Marine Sciences, University of South Alabama, Mobile, Alabama, United States of America, 2 Dauphin Island Sea Lab, Dauphin Island, Alabama, United States of America, 3 Department of Biological Sciences, Auburn University, Auburn, Alabama, United States of America
Abstract Top
Most of the studies of microbial processes in response to the Deepwater Horizon oil spill focused on the deep water plume, and not on the surface communities. The effects of the crude oil and the application of dispersants on the coastal microbial food web in the northern Gulf of Mexico have not been well characterized even though these regions support much of the fisheries production in the Gulf. A mesocosm experiment was carried out to determine how the microbial community off the coast of Alabama may have responded to the influx of surface oil and dispersants. While the addition of glucose or oil alone resulted in an increase in the biomass of ciliates, suggesting transfer of carbon to higher trophic levels was likely; a different effect was seen in the presence of dispersant. The addition of dispersant or dispersed oil resulted in an increase in the biomass of heterotrophic prokaryotes, but a significant inhibition of ciliates, suggesting a reduction in grazing and decrease in transfer of carbon to higher trophic levels. Similar patterns were observed in two separate experiments with different starting nutrient regimes and microbial communities suggesting that the addition of dispersant and dispersed oil to the northern Gulf of Mexico waters in 2010 may have reduced the flow of carbon to higher trophic levels, leading to a decrease in the production of zooplankton and fish on the Alabama shelf.
More...
http://www.plosone.org/article/info:doi/10.1371/journal.pone.0042548
Published: Tuesday, July 31, 2012, 10:00 PM Updated: Wednesday, August 01, 2012, 8:20 AM
By The Associated PressThe Associated Press
...
For the study, Alabama researchers pumped water from Mobile Bay into 53-gallon drums, then added oil, dispersant or both in proportions found during the oil spill to simulate the spill's effects on microscopic water-life in the bay.
Over more than 12 weeks in 2010, BP's well spewed nearly 200 million gallons of oil into the Gulf of Mexico. The company used more than 1.8 million gallons of dispersants -- more than 770,000 gallons of it at the oil's source on the ocean floor -- to break up the oil into tiny droplets. Earlier research hadn't found significant problems for the environment and marine life, but dispersants had never before been used a mile underwater or in such large amounts.
The researchers found that, within days, the numbers of plant-like phytoplankton and ciliates -- plankton that use hairlike cilia to move -- increased under an oil slick. But they dropped significantly in the drums with dispersant or dispersed oil, while the numbers of bacteria increased.
The study was published Tuesday in PLoS ONE, one of the peer-reviewed journals in the online Public Library of Science.
...
Full text:
http://www.nola.com/news/gulf-oil-spill/index.ssf/2012/07/bp_oil_spill_dispersants_may_h.html
---------------------------------------------------------------------------------
Dispersed Oil Disrupts Microbial Pathways in Pelagic Food Webs
Alice C. Ortmann<SUP>1</SUP><SUP>,</SUP><SUP>2</SUP><SUP>*</SUP>, Jennifer Anders<SUP>2</SUP>, Naomi Shelton<SUP>2</SUP>, Limin Gong<SUP>3</SUP>, Anthony G. Moss<SUP>3</SUP>, Robert H. Condon<SUP>2</SUP>
1 Department of Marine Sciences, University of South Alabama, Mobile, Alabama, United States of America, 2 Dauphin Island Sea Lab, Dauphin Island, Alabama, United States of America, 3 Department of Biological Sciences, Auburn University, Auburn, Alabama, United States of America
Abstract Top
Most of the studies of microbial processes in response to the Deepwater Horizon oil spill focused on the deep water plume, and not on the surface communities. The effects of the crude oil and the application of dispersants on the coastal microbial food web in the northern Gulf of Mexico have not been well characterized even though these regions support much of the fisheries production in the Gulf. A mesocosm experiment was carried out to determine how the microbial community off the coast of Alabama may have responded to the influx of surface oil and dispersants. While the addition of glucose or oil alone resulted in an increase in the biomass of ciliates, suggesting transfer of carbon to higher trophic levels was likely; a different effect was seen in the presence of dispersant. The addition of dispersant or dispersed oil resulted in an increase in the biomass of heterotrophic prokaryotes, but a significant inhibition of ciliates, suggesting a reduction in grazing and decrease in transfer of carbon to higher trophic levels. Similar patterns were observed in two separate experiments with different starting nutrient regimes and microbial communities suggesting that the addition of dispersant and dispersed oil to the northern Gulf of Mexico waters in 2010 may have reduced the flow of carbon to higher trophic levels, leading to a decrease in the production of zooplankton and fish on the Alabama shelf.
More...
http://www.plosone.org/article/info:doi/10.1371/journal.pone.0042548