When We Mess Up, Can Microbes Still Fix the Problem?

Humans greatly impact, and often harm, the environment by emitting greenhouse gases, destroying habitats, and by polluting the area, especially. Oil spills are a deadly and costly way that humans pollute the water ways. They are also quite notable, consider the Exxon Valdez spill near Alaska or the Deepwater Horizon spill in the Gulf of Mexico. Thankfully, nature is often able to fix our mistakes. Microbes play a huge role in degrading oceanic oil spills. However, microbes in the arctic seem to face particular challenges that are not experienced in warmer environments.

An article in Science Daily presents the challenges for oil-eating microbes in the Arctic. These difficulties are due to six things: low temperatures, sea ice, low nutrient content, particle formation, prolonged sunlight in the summer months, and potential lack of microbial adaptations.

Low temperatures cause the oil to become more viscous and thicker. This means it is harder for the oil to disperse into small droplets that can be consumed by a wide area of microbes. Sea ice inhibits wave formation and impact. This decreased power also makes it harder for the oil to disperse into small droplets. Few nutrients in the water cause decreased activity of the oil-consuming microbes, and high particle formation and concentrations allow the oil to clump and settle to the floor where microbial productivity is decreased. Furthermore, 24 hour arctic summer sunlight may make the oil more toxic to marine life, although it could make the oil easier to process as well; the answer is still unclear. Finally, lack of exposure to oil spills may promote microbes without the adaptations to digest and process oil. However, further research is required to determine this with certainty.

This article brings to light the importance of being cautious when handling harmful pollutants. Although microbes can help clean up the oil, they may not work efficiently in arctic environments causing the death of thousands of marine organisms. The effectiveness of microbes is important especially because mechanical removal of oil can only remove 15 to 25 percent of the oil. Therefore, it is crucial that people are careful with their actions and encourage research in microbial life in the oceans because microbes, although small, play a huge impact on the health of marine environments. 

Aarhus University. "Oil-eating microbes are challenged in the Arctic." ScienceDaily. ScienceDaily, 20 February 2018. .

Micro-Organismal Degradation of Oil Spills

BP Deepwater Horizon Oil Spill- Google Map Image (www.eoearth.org)

Oil spills like the Exxon-Valdez and BP Deepwater Horizon incidents are devastating to aquatic and terrestrial wildlife.  Much research has been done surrounding the most effective way of cleaning up oil slicks and/or plumes in the water and the shoreline.  With petroleum hydrocarbons occurring naturally in the environment, microorganisms are professionals at degrading these compounds.  Hundreds of species of bacteria and fungi are capable of breaking down petroleum hydrocarbons with the help of dispersants and fertilizers.  Although weathering processes and degradation by microorganisms are very effective, patches of highly weathered oil likely will remain in some environments.  In remediation, decisions to rely upon microbial oil biodegradation should be driven by risk to the environment and not just the presence of detectable hydrocarbons.    

In the first study I will reference in my talk, the researchers found that temperature had a greater effect than nutrient addition when degrading petroleum hydrocarbons.  They support the finding that there is an immediate change in bacterial community structure when crude oil is released into the water column.  They also noted that certain species that are “hydrocarbonoclastic” function at a range of 4-20°C, so organisms can be used to bioremediate the area seasonally.

The second study I found had a related author from the first paper, and this study quantified changes in concentrations of hydrocarbonoclastic bacteria in response to intervention strategies applied to external organisms.  Intervention strategies included adding nutrients, bioemulsifers, and bioaugmentation with other types of bacteria.  Overall, nutrient and bioemulsifier addition proved to be a synergistic mixture.  Alcanivorax enhanced degradation significantly over Thalassolituus, but the use of the synergistic mixture and the bacteria would improve mitigation strategies.

The third paper specifically relates the growth in population of λ-Proteobacteria to the Deepwater Horizon oil spill in the Gulf of Mexico.  With the spill being completely underwater as a plume rising to the surface, deep sea λ-Proteobacteria who degrade petroleum, increased due to the spill.  Changes in hydrocarbon composition with distance from the source and incubation experiments with environmental isolates demonstrated faster than expected hydrocarbon biodegradation rates at 5°C.  Based on these results, intrinsic bioremediation of the oil plume in the deep-water column without substantial oxygen drawdown is possible.

I am still researching some more primary literature to add to my talk.  This may include some supplementary information on other clean-up methods used besides bioremediation and more information about the biological implications of oil spills.

Harmful effects of oil spills on dolphins

With the recent oil spill in the Gulf of Mexico all over the news, I couldn’t help but wonder if dolphins could be hurt as bad as other marine organisms since they can at least swim away from the oil.

I was partially right. They can swim away from the spill, and their skin allows the oil to just run off them as they swim so it doesn’t cause any permanent harm.
However, they do need to breathe sometime. When they come up to the surface, if they happen to take in oil in their mouths or blowhole, it can cause serious damage to their airways, mucous membranes, or digestive tract (like a poison). Oil can also cause eye damage if it gets in their eyes.
Things only get worse from there because panicking or stressed dolphins will surface more often because they are breathing harder and need to breathe more often, which will expose them to more oil floating on the surface.

Source: www.amsa.gov

http://webcache.googleusercontent.com/search?q=cache:yneaqFyM5EcJ:www.amsa.gov.au/Marine_Environment_Protection/National_Plan/General_Information/Oiled_Wildlife/Oil_Spill_Effects_on_Wildlife_and_Non-Avian_Marine_Life.asp+oil+spill+effects+on+dolphins&cd=2&hl=en&ct=clnk&gl=us