"Oil is still detrimental to the environment, " she said, "because the molecules that are not accessible to microbes persist and could have toxic effects." These are the kinds of molecules that can get into the food web of both offshore and shoreline environments, Edwards and Van Mooy said. "They could say, 'Look, we can put oil into the environment and the microbes will eat it,'" she said.Įdwards, a graduate student in the joint MIT/WHOI program, pointed out that this is not completely the case, because oil is composed of a complex mixture molecules, some of which the microbes are unable to break down. "It's not what we expected to see." She added that she was also "a little afraid" that oil companies and others might use the results to try to convince the public that spills can do relatively little harm. "By a lot."īethanie Edwards, a biochemist in Van Mooy's lab and lead author of the paper, said she too was "very surprised" by the amount of oil consumption by the microbes. "We found that the answer was 'quick,'" Van Mooy said. If the microbes were respiring slowly, then oxygen levels would decrease slowly if they respired quickly, the oxygen would decrease quickly. They discovered this by using a special sensor called an oxygen optode to track the changing oxygen levels in water samples taken from the slick. "We thought the microbes would not be able to respond," Van Mooy said.īut the WHOI researchers found, to the contrary, that the bacteria not only responded, but did so at a very high rate. Going into the study, he said, "We thought microbe respiration was going to be minimal." This was because nutrients such as nitrogen and phosphorus - usually essential to enable microbes to grow and make new cells - were scarce in the water and oil in the slick. Van Mooy and his team were nearly equally taken aback by the ability of the microbes to chow down on the oil in the first place. "What did they do with the energy they gained from this increased respiration?" asked WHOI chemist Benjamin Van Mooy, senior author of the study. In this process, respiration combines food (oil in this case) and oxygen to create carbon dioxide and energy. They found that bacterial microbes inside the slick degraded the oil at a rate five times faster than microbes outside the slick - accounting in large part for the disappearance of the slick some three weeks after Deepwater Horizon's Macondo well was shut off.Īt the same time, the researchers observed no increase in the number of microbes inside the slick - something that would be expected as a byproduct of increased consumption, or respiration, of the oil. 2 online edition of Environmental Research Letters, the WHOI team studied samples from the surface oil slick and surrounding Gulf waters. In research scheduled to be published in the Aug.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |