Though people like to refer to their cars as gas guzzlers, organisms that eat alkanes more literally do indeed exist. They are also media whores.
Yes, oil consuming microbes have been in the spotlight quite a bit these recent days as the gulf coast waits not only for the Macondo well to be permanently killed, but for the oil to go away. Alcanivorax borkumensis is a feisty little guy, the first hydrocarbonoclastic bacterium to be genetically sequenced, and is found worldwide. Though there are other species of Alcanivorax, A. borkumensis is a favorite in the world of bioremediation because it synthesizes not just one, but several potent enzymes that assist in the degradation of alkanes. Naturally, they tend to dominate microbial populations in areas with ambient oil/gas seeps and those with high pollution rates.
It’s never a bad idea to look on the bright side of life, and surely these must be good times for Alcanivorax. Not only is there a large amount of oil spewing into their neighborhood, it has been broken up into tiny pieces with the use of chemical dispersants. Just imagine yourself pulling into Golden Corral for all you can eat filet mignon night and you are issued your own personal waitstaff to cut your meat. Alcanivorax colonies form biofilms that coat small droplets of oil for maximum surface contact with its primary food source and has adaptations that allow it to take advantage of low trace nutrient conditions. But here’s the catch… they do need oxygen.
We know they consume oxygen during the metabolic process and a ~30% reduction in oxygen saturation is sometimes used as a proxy indicator of their presence and activity. Unfortunately, large portions of the Gulf of Mexico become hypoxic, or low in oxygen, seasonally. Rapid runoff of excess fertilizers from agricultural activity in the Midwest bathes the Mississippi river delta in nutrients needed for algae to grow, like phosphorous and nitrogen. When these limitations are removed, the algae populations take off, resulting in blooms that suck all of/or most of the dissolved oxygen from the water column, killing everything nearby that can’t swim away fast enough. The dead include fish, benthos, and our limited mobility friend Alcanivorax. Only time will tell who wins out in the end… I’m rooting for the alkane-o-vores!