Natural gas and temperature structured a microbial community response to the Deepwater Horizon oil spill

Abstract

Microbial communities present in the Gulf of Mexico rapidly responded to the Deepwater Horizon oil spill. In deep water plumes, these communities were initially dominated by members of Oceanospirillales, Colwellia, and Cycloclasticus. None of these groups were abundant in surface oil slick samples, and Colwellia was much more abundant in oil-degrading enrichment cultures incubated at 4°C than at room temperature, suggesting that the colder temperatures at plume depth favored the development of these communities. These groups decreased in abundance after the well was capped in July, but the addition of hydrocarbons in laboratory incubations of deep waters from the Gulf of Mexico stimulated Colwellia's growth. Colwellia was the primary organism that incorporated 13 C from ethane and propane in stable isotope probing experiments, and given its abundance in environmental samples at the time that ethane and propane oxidation rates were high, it is likely that Colwellia was active in ethane and propane oxidation in situ. Colwellia also incorporated 13 C benzene, and Colwellia's abundance in crude oil enrichments without natural gas suggests that it has the ability to consume a wide range of hydrocarbon compounds or their degradation products. However, the fact that ethane and propane alone were capable of stimulating the growth of Colwellia, and to a lesser extent, Oceanospirillales, suggests that high natural gas content of this spill may have provided an advantage to these organisms. methane | biodegradation | marine bacteria | archaea | alkane

Science in support of the Deepwater Horizon response

“…(The total amount of dispersed oil was originally estimated at 24% and later revised to 29%.) iii) As we reported in early August, to the disbelief of many people, much of the oil that had been dispersed (either naturally or chemically) was rapidly being consumed by bacteria (23,26,48,49). iv) Fishery closures plus newly developed and rigorously implemented protocols for testing of seafood for the components of hydrocarbons and dispersant that were of potential concern seem to have been successful, because no tainted seafood was reported to have entered the seafood supply.…”

“…Scientific revelations from the DWH spill are many, and we continue to be surprised by numerous aspects, such as the discovery of novel microbial communities (48) and the conditions that led to rapid decomposition of hydrocarbons during this event (49). Full conclusions about the impact of the oil on species, ecosystems, and people will necessarily await ongoing analyses for detecting long-term impacts.…”

Hydrocarbon biodegradation by Arctic sea-ice and sub-ice microbial communities during microcosm experiments, Northwest Passage (Nunavut, Canada)

“…Members of the genus Colwellia, which are oil-degrading Gammaproteobacteria (Yakimov et al 2004;Redmond & Valentine 2012), were also stimulated by the presence of oil in sub-ice seawater (Fig.9). Like Polaribacter (Bacteroidetes), Colwellia are known psychrophiles and may have benefited from the low incubation temperature (< -1°C), like previously observed in cold marine environments (Yakimov et al 2004;Brakstad et al 2008).…”

Amphiphilic siderophore production by oil-associating microbes

“…3 One strategy for the remediation 20 of the deep underwater plume has been to use the intrinsic hydrocarbon-degrading potential of marine microorganisms to break down the oil. 1,4,5 Crude oil is a complex mixture containing thousands of different hydrocarbon compounds which differ in solubility and volatility and are degraded at different rates. 4 25 Effective microbial biodegradation is dependent on a variety of environmental factors, including a favourable response by the indigenous microorganisms.…”

“…4 25 Effective microbial biodegradation is dependent on a variety of environmental factors, including a favourable response by the indigenous microorganisms. Reports profiling the most dominant oil-degraders in plume samples following the spill revealed an abundance of γ-proteobacteria in both deep water, surface water 30 and oil-contaminated sand samples; Oceanospirillales, Colwellia and Cycloclasticus dominated the deep water samples, Pseudoalteromonas, Vibrio, Acinetobacter and Alteromonas prevailed in the surface samples, 4,5 while the famously ubiquitous oil-degrader Alcanivorax borkumensis was the dominant 35 hydrocarbon-degrading bacterial group enriched by oil contamination of Gulf beach sands. 6 These results indicate a dynamic population of hydrocarbon-degraders with different compound preferences existing in the Gulf.…”