Bacteria in intertidal sediments: Factors related to their distribution1

Direct counts of bacteria from intertidal deposits support previous suggestions of a strong relationship between bacterial numbers and sediment properties. Bacteria were counted after acridine orange staining. Numbers ranged from 1.17 × 10 8 to 9.97 × 10 9 g −1 of dry sediment and were highly correlated with grain size and other granulometric properties. Sediment organic carbon and total nitrogen were correlated with bacterial numbers beyond what would be expected from the relationships of these properties to grain size; yet grain size alone accounts for over 80% of the variance in bacterial numbers. Bacterial biomass to a depth of 10 cm varied from 5.5 to 26.8 g m −2 , in the same range as previously reported for meiofauna and mixed macrofauna in sediments.