Tarball concentration and features have been used to assess the extent of oil spills and their composition can also be used to identify their sources of origin. They are slowly decomposed by microorganisms such as Chromobacterium violaceum, Cladosporium resinae, Bacillus submarinus, Micrococcus varians, Pseudomonas aeruginosa, Candida marina, and Saccharomyces estuari.