Relationships between suspended solids and standing crops and activities of bacteria in an estuary during a neap-spring-neap tidal cycle.

During a neap-spring-neap tidal cycle in the Humber estuary concentrations of suspended solids and oxygen depletion were greatest at spring tides. Most bacteria were attached to particles and attached bacteria (counted using epifluorescence microscopy) increased as solids increased. Concentrations of free bacteria however were unrelated to suspended solids. Heterotrophic activities of bacteria per unit volume of water (measured using 14C glucose uptake and Michaelis-Menton kinetics) varied irregularly and were not related to bacterial crops, suspended solids or oxygen depletion. Activity per bacterium however decreased as suspended solids increased.