Petroleum hydrocarbons inhibit decomposition of organic matter in seawater

MOTILE marine bacteria, like higher animals, have the capacity to detect and be attracted to organic substances¹, including living microbial prey². Mitchell et al.³ found that this chemotactic response was inhibited by low concentrations of hydrocarbons such as toluene, phenol and crude oil. The bacterial population was not killed but did lose its ability to detect non-living substrates as well as living prey, such as algae and enteric bacteria^3-5. It seems that the ability of a marine bacterium to degrade a substrate is augmented by its attraction to that substance. This report describes the role of bacterial chemotaxis in organic matter decomposition in seawater and its inhibition by sublethal concentrations of petroleum hydrocarbons.