Seasonal variations in heterotrophic bacterial populations in waters off Sydney

Abstract

Viable counts were made of heterotrophic bacteria in seawater samples taken from 0, 25, 50, 75, and 100 m at one station off Sydney over a period of 2 years. Populations, which fell largely within the range of 10-1000/ml, tended to be higher in spring and early summer than at other times. Some evidence was obtained of a negative correlation between bacterial population and chlorinity. There was no evidence of a correlation between bacterial populations and several other variables which were examined. A (presumed) species of Chromobacterium occurred intermittently at the lower depths with some suggestion of a correlation with season and total bacterial count.