DISTRIBUTION OF THERMOPHILIC MARINE SULFATE REDUCERS IN NORTH-SEA-OILFIELD WATERS AND OIL-RESERVOIRS

The distribution of thermophilic marine sulfate reducers in produced o il reservoir waters from the Gullfaks oil field in the Nonwegian secto r of the North Sea was investigated by using enrichment cultures and g enus-specific fluorescent antibodies produced against the genera Archa eoglobus, Desulfotomaculum, and Thermodesulforhabdus. The thermophilic marine sulfate reducers in this environment could mainly be classifie d as species belonging to the genera Archaeoglobus and Thermodesulforh abdus. In addition, some unidentified sulfate reducers were present. C ulturable thermophilic Desulfotomaculum strains were not detected. Spe cific strains of thermophilic sulfate reducers inhabited different par ts of the oil reservoir. No correlation between the duration of seawat er injection and the numbers of thermophilic sulfate reducers in the p roduced waters was observed. Neither was there any correlation between the concentration df hydrogen sulfide and the numbers of thermophilic sulfate reducers. The results indicate that thermophilic and hyperthe rmophilic sulfate reducers are indigenous to North Sea oil field reser voirs and that they belong to a deep subterranean biosphere.