Marine petroleum hydrocarbon degrading bacteria : distribution and activity in the North Sea and Baltic Sea

In 1988 and 1989 data about the distribution and activity of petroleum hydrocarbon degrading bacteria in the North Sea and Baltic Sea were collected. Crude oil degrading bacteria and the number of bacteria which especially degrade naphthalene were quantified using a modified dilution (MPN) method. Crude oil degrading bacteria were present in all of about 100 water samples, with as many as 103 ml-1 in sum. Naphthalene degrading bacteria were present in at least tenfold fewer numbers which corresponded with petroleum hydrocarbon (PHC) concentrations (ultraviolet fluorescence spectroscopy method, UVF) in more highly polluted areas. There is obviously a greater connection between this bacteria group and PHC pollutiori determined by UVF than between the more nonspecific group of crude oil degrading bacteria and UVF-determined PHC pollution. Data from the North Sea show an extremely high abundance of hydrocarbon degrading bacteria, even in winter, while in the southern Baltic Sea low numbers of bacteria were found and a slower crude oil degradation was observed