Temperature dependence of naphthalene biodegradation in seawater (0.5-15ºC)

Abstract

The polar areas are very vulnerable to exposure to contaminants. An oil spill in polar areas could be a disaster to large areas. The recovery from contamination takes longer time in arctic areas than in more temperate areas due to the low temperatures. In this research a relationship between growth factor (k1) and temperature for bacterial degradation of naphthalene in seawater is being found. Different analyses was utilized to monitor degradation: Chemical analysis for substrate concentration, automated OxiTop® method for BOD monitoring, and DAPI bacterial cell counting. The consistency between the results from the different analysis methods was mostly good, even for the biological analysis. But the bacterial cells were very different in size, which made it difficult to make good estimations of biomass concentration in the system. The k1 value was found to be 0.021d-1 at 0.5ºC, 0.035d-1 at 4ºC, 0.056d-1 at 8ºC and 0.112d-1 at 15ºC. A relation between k1 and temperature (t) can then be written like this: k1 = 0.0002t2 + 0.0029t + 0.0196. These results gives some information regarding how much faster the naphthalene biodegradation process goes at high than at low temperature within the temperature area of the research.