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Scientists may look at oil-eating bacteria cleaning Rena spill

Posted in Expert Reactions on October 14th, 2011.

The black tide of contamination pouring from the container ship Rena, in New Zealand’s biggest fuel oil spill, may yet offer  a silver lining in terms of knowledge to be gained by the nation’s scientists and researchers.

Two quite different American oil spills — Alaska’s  Exxon Valdez grounding  in 1989, and Louisiana’s  BP Deepwater Horizon spill in  2010 — both highlighted the environmental clean-up provided by micro-organisms  able to “eat”  petroleum hydrocarbons. In both those spills, bacteria and other  micro-organisms played a significant role in reducing
the overall environmental impacts.

Half the world’s total oil “spills” have been estimated to come from natural seeps such as those at New Plymouth’s Ngamotu Beach, which triggered the nation’s first commercial exploration.  Microbes which degrade hydrocarbons are widespread in the environment — partly because algae and cyanobacteria of the type used to produce biodiesel also produce similar alkanes and aromatic compounds.

Researchers say the Rena spill provides an opportunity for a natural experiment by scientists such as those at Auckland University and Landcare Research with who already have a track record of  investigating microbes breaking down  hydrocarbons in Antarctic soils.

The SMC asked scientists whether “bio-augmentation” such introducing oil-eating bacteria from natural  oil seeps, or adding nutrients could boost the biodegradation of oil in the polluted areas.

Soil scientist Dr Jackie Aislabie (Landcare Research), who has investigated how Antarctic bacteria break down hydrocarbons, comments:

“Researchers from Landcare Research and Auckland University could potentially  take an interest in the microbial populations that may contribute to hydrocarbon degradation following the Rena spill. Once the physical removal from the beaches has finished there will be a need to understand what remains in the sand (residual hydrocarbons). We could identify the oil-eating microbes in the BOP.

“Laboratory studies could check whether  nutrient addition would enhance biodegradation of the residual fuel (both alkanes and polyaromatic hydrocarbons). At the same time there would need to be discussion on the form of nutrients to be applied … and the potential environmental consequences of nutrient application. It would be important to ensure that the nutrients stayed where the oil was and did not get washed off with the tide and were not toxic”.

Kentucky biologist, Professor Ron Atlas from the University of Louisville,  worked on both the Exxon Valdez and Deepwater Horizon spills and said:

“I am not aware of any demonstration that bio-augmentation could help. There are lots of commercial claims and laboratory experiments that claim that adding bacteria can greatly help…many claim 100 percent removal within hours,  but none of these claims have been verified in field experiments.   That does not stop the claims from gaining lots of press and political support when there is a spill.

“There are indigenous microorganisms that are undoubtedly at work degrading the oil…Adding nutrients might be able to stimulate their activities on oiled shorelines.  That was done extensively following physical cleanup of Prince William Sound shorelines after the Exxon Valdez spill.  It sped up the rates of biodegradation three to five times.  No biological treatment was carried out in the Gulf of Mexico following the BP Deepwater Horizon spill. Burning and physical cleaning have been the main method for cleanup.   The addition of nutrients could and probably should be evaluated to see if there would be a net environmental benefit.”

“There should be a variety of studies that will help define the impact (environmental damage) from the spill and also the factors that were involved in the natural removal (weathering) of the oil.  In the case of the BP Deepwater Horizon spill the studies have included extensive characterizations of the microbial communities as well as detailed chemical analyses of oil in the environment.  Over 10,000 Gulf of Mexico water samples have been subjected to detailed chemical analysis to determine what happened to the oil and what role microbes played in its destruction”.

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