The use of dispersants during the Deepwater Horizon oil disaster has been a thought- provoking, highly debatable issue. Speaking at a network lunch, Dr. Claire Paris-Limouzy from the University of Miami disagreed on using of dispersants to remove oil, saying that we have negligible knowledge about their impact on the ocean ecosystem. We also lack the basic knowledge about the chemical structure and what kind on dispersant to be used for a particular type of oil.
Thus, a lot of scientific research is required to understand and broaden our knowledge about dispersants, and how to use them at the right time, in the right way.
Many consider dispersants a never-use option, because they are harmful for the ocean ecosystem. In my opinion part of oil was dispersed from ocean was possible only due to the use of dispersants.
Dr. Paris-Limouzy further explained that some amount of oil in the Gulf might have evaporated, weathered and submerged. She further added that approximately 30 percent of oil is biodegradable and 40 percent is submerged and probably remains in the water column.
Several biological factors like microbes can help in degrading oil naturally. Thus, one needs to consider how these microbes help in degradation.
There are very few studies being done at present to find out the role of microbes in degradation of oil. I am working on one such project, with the objective to understand how microbial communities in near-shore environments respond to natural or anthropogenic exposure to hydrocarbons, and whether microbial communites in different habitats such as oyster beds, beach etc., respond in a similar way. The image above shows microbes degrading oil in the Gulf oil plume shown by Berkeley Lab.
The image on left shows an analysis with Berkeley Lab’s phyloChip (an analyzing tool), revealing that the dominant microbe in the dispersed Gulf of Mexico oil plume was a new species, closely related to members of Oceanospirillales.
The image below demonstrates use of phyloChip in one of the project.
In my opinion use of dispersants might be useful for oil dispersion, but has toxic effects on deep sea fishes, and even on some microorganisms that are primary producers of ocean ecosystems, such as like phytoplankton driving photosysnthesis.