Biodegradation of crude oil in cold climatic conditions

Although crude oil is a natural product, it can have considerably harmful impacts when released in large quantities into the environment. The Arctic marine environment is especiaUy sensitive in this respect. Temperature affects the physical properties of oil; at low temperatures the viscosity of oil increases, thus reducing the degree of spreading in soil and aquatic matrices. Volatilization of short-chain alkanes is also reduced at low temperatures, thus increasing their solubility in the aqueous phase and increasing the degree of toxicity to microbes. This, in turn, may cause a delay in the onset of biodegradation (Atlas, 198 I; Leahy and Colwell, 1990). Most long-chain alkanes are solid at temperatures below IO°C, which also decreases their bioavailability and hence degradation (Whyte et aI., 1998). Although microbial activity is generally reduced at low temperatures, many of the components in crude oil can in fact be degraded at low-temperature subarctic, Arctic, Antarctic, and alpine sites (Atlas, 1981; Bossert and Bartha, 1984; Leahy and Colwell, 1990; Margesin and Sehinner, 1997a, 1997b; Westlake et aI., 1974; Whyte et aI., 1998).