When
the Deepwater Horizon suffered a devastating explosion and ruptured
an oil well on April 20 of this year, BP executives spent
months trying to figure out a way to stop it, and eventually clean up
the mess. What they might not have known was that something had
already begun
cleaning up the oil only a month after it started spilling
into the Gulf of Mexico.
The
clean-up crew was a series of bacteria, like Alcanivorax,
which is an oil-eating bacteria found
in the ocean. This bacteria only "blooms" when oil is
present, and then it feeds on chemicals found in crude oil. According
to a team of scientists working on the study, there were large
numbers of these types of bacteria present in the Gulf just one month
after the leak began, and they had quite a feast.
Terry
Hazen led a team of American scientists on an expedition to collect
samples of water on two ships in the Gulf between May 25 and June 2
looking for different types of oil-eating bacteria. They found 16
types of bacteria within a deep-sea oil plume about 1,100 meters
below surface.
Richard
Camilli from the Woods Hole
Oceanographic Institution recently announced that this plume
had "persisted" for months after the oil leak began,
insinuating that bacteria wasn't breaking down the oil plume as Hazen
suggested. Also, Camilli stated that oxygen levels near the plume
were stable, and if bacteria were eating the oil, these levels would
fall.
Hazen
argued that his team was looking directly for the bacteria themselves
rather than just traces of their presence, and the results were that
oxygen levels inside the plume were lower than the outside,
indicating the presence of bacteria. Twice as many bacteria were
found inside the plume than outside.
Of
the 16 types of bacteria found, Oceanospirllales (which
is a group that includes the Alcanivorax) were the most prominent.
All the groups on the inside of the plume had oil-eating
capabilities, breaking down hydrocarbons within the oil. These groups
of bacteria were "genetically distinct" from bacteria
outside of the plume, and according to Hazen, salinity, pressure,
temperature or any other cause besides the oil would cause this
difference. Hence, Hazen and his team believe these bacteria
were there strictly to clean up the oil.
Now
Hazen is saying that the plume has been undetectable for
approximately two to three weeks now, and that it disappeared shortly
after the leak
was capped July 12. While the various types of bacteria
found supposedly "ate" the oil, there are some components
of the oil that cannot be broken down by bacteria. Only the
hydrocarbons are digested by the bacteria.
