2010 Gulf Oil Leak Remediation Brainstorm

The Gulf (waters and coastal areas) is now the largest Brownfield in the world, and if the leak is not stopped, the disaster will far exceed the largest Superfund site in the world. The leak is now, by far, the largest oil spill in the history of the United States. While this disaster is raising oil awareness of the need to reduce and eliminate our need for petroleum product as they come to us at a tremendous environmental and social cost, there is a pressing need for cleanup solutions.

I am challenged and humbled by the scale of this disaster. Creative solutions are needed to respond effectively to this disaster. 

Bioremediation is a process that harnesses the innate ability of certain bacteria and fungi to destroy pollutants in place. There have been applications developed for marine oil spills as well as spills on land. The interest in these technologies increased greatly after the Exxon Valdez spill (see 1991 report and 1996 review article).  A number of different technologies may fall into the category of biological methods; these include the use of straw or plant material as an absorbent for oil, biosurfactants to clean oiled surfaces, biological polymers to coat surfaces to prevent oil adhesion, the addition of materials to encourage microbiological biodegradation of oil, and the addition of non-indigenous natural or engineered microbes to a contaminated environment.

These technologies are often limited by environmental factors to do the work necessary to restore the contaminated environment. These factors are, including others:
 

• temperature - microbial cells are active within specific temperature ranges, depending on the species.

• availability of nutrients - the oil is a food source for the microbes, however, it does not contain all of the nutrients that microbes require to grow - and we need them to grow quickly if there is any hope of success for this strategy. For example, iron is very limited in the marine environment, but is essential for growth.

• metabolic cofactors - certain chemicals that are resistant to microbial metabolism - known as recalcitrance- can be digested by microbes in the presence of other natural compounds. This phenomenon is called co-metabolic biodegradation and is very common around the roots of plants, who employ microbial groups to supply them with nutrients otherwise locked up in organic matter or rocks.

• bioavailability - this is one of the most limiting factors in treating  contaminated environments with living organism, but can also be a blessing. If a chemical has very low bioavailability it cannot be easily attacked by hungry microbes, but fortunately is not going to be absorbed by sensitive organisms. However, at the scale that this disaster the impacts are beyond the toxicological and entering into the physical. Cancer is not a concern when you are being suffocated. 

• diversity - no microbe is an island. There are very few examples (despite the hopes and dreams of reductionist scientists) of a single microbe that is capable of completely mineralizing (complete breakdown of the molecule - not to some daughter product) a recalcitrant pollutant alone. There have been oodles and oodles of attempts to make "superbugs" through genetic engineering. These super bugs have genes pulled out of other species that infer the ability to break down the pollutant in less time than the native, wild-type bug. Papers are published in high impact-factor rate journals and the authors get their next big NSF grant.  However (with a big H) invariably, these superbugs never perform when release into the wild to do their magic. Leaving aside the moral questions surrouding the release of genetically modified organisms into the environment, the failure of the superbugs to treat the problem they were supposedly created to address, leaves much to be desired about the scientific processes that lead to this sort of scenario, but also leaves us with few tools that are ready for prime-time in the event of a disaster. Umm hello, all you PIs with your flasks of superbugs, what have you done for me lately? Some of us advocate for a different approach: if we can understand how nature does it, we can promote the natural, indigenous processes in times of need. There are consortia of microbes that have evolved to work together to use crude oil as a food source. Studying these in their natural environment will provide us with the tools needed to promote their activity in times of need (today for example).

Next time: Floating ecological restorers