Bacterioplankton counting methods

Bacterioplankton counting is the estimation of the abundance of bacterioplankton in a specific body of water, which is useful information to marine microbiologists. Various counting methodologies have been developed over the years to determine the number present in the water being observed. Methods used for counting bacterioplankton include epifluorescence microscopy, flow cytometry, measures of productivity through frequency of dividing cells (FDC), thymidine incorporation, and leucine incorporation.

Factors such as salinity, temperature, latitude, various nutrient levels, water movement and the presence of other organisms can affect bacterioplankton enumeration. Changes in these factors affect the bacterioplankton count, causing it to vary by body of water, location, distance from shore and season.

Bacterioplankton count is usually expressed in cells per ml (cells ml⁻¹).