Alexander, S.K.; Schropp, S.J.; Schwarz, J.R.Contributions in Marine Science2010-02-152010-02-151982Alexander, S.K.; Schropp, S.J.; Schwarz, J.R. 1982. Spatial and seasonal distribution of hydrocarbon-utilizing bacteria of sediment from the northwestern Gulf of Mexico. Contributions in Marine Science 25: 13-19.http://hdl.handle.net/1969.3/19060pages 13-19Hydrocarbon-utilizing bacteria were enumerated in sediment collected seasonally from four sites representative of offshore, using the most-probable-number (MPN) method, were detected in 438 of 448 samples in numbers that ranged from 8.0 x 10 to 1.1 x 10 exp 8 per ml wet sediment. The total viable heterotrophic population in 70% of the sediment samples contained less than 2% hydrocarbon utilizers. Analysis of spatial variations revealed that populations were most abundant in estuarine sediment and decreased with increasing distance from shore. Significant seasonal differences were observed at all four sites, with highest numbers in summer or fall. Spatial variations in population levels may be related to hydrocarbon input, while seasonal changes may be controlled primarily by temperature. Results from the present study indicate that sediments from the northwestern Gulf of Mexico contain a dynamic resident population of bacteria capable of utilizing hydrocarbons.bacteria; microbiology; seasonal distribution; spatial variations; hydrocarbons; sediment analysis; sedimentsArticle