Some bacteria use oil as their source. Before the oil spill waters of gulf has many bacteria of different phyla, immediately after the spill the bacteria of several phyla became less whereas bacteria of a particular phyla has increased. This shows that several phyla of bacteria were sensitive to bacteria whereas some able to persist the high doses of oil. Scientists after research identified the bacteria which is growing in the presence of oil and found that some bacteria feed on aromatic compounds which are very hard to break. Some examples of these bacteria are Colwellia, Neptuniibacter etc. Dispersants are used when workers want to stop the oil from spreading to a covered area like harbour or marsh. These dispersants are useful because oil is moved away from the habitat of the marine animals. The dispersant-oil mixture was colonised rapidly and was broken down by the bacteria that sunk towards the bottom. The dispersants helped the bacteria by exposing more oil to them.