Indirect Method - Bacterial mass can be determined by measuring the turbidity of cell suspensions. Metabolic functions such as production of carbon dioxide, oxygen uptake or production of acid can also be related to microbial mass. These methods are particularly useful with very low concentration of cells. Chlorophyll determination is also an useful method, especially for algae.
Synthesis of ATP can also be determined as a function of rate of microbial activity or total biomass.
