A source of inaccuracy in many methods of estimating biomass is the difficulty of distinguishing living from non-living tissue. In samples containing appreciable amounts of non-living organic matter there are possibilities of greater accuracy from biomass estimates based on measurements of the adenosine triphosphate (ATP) content, as this is a constituent of all live protoplasm but is virtually absent from dead cells. The technique measures the amount of light emitted when ATP is added to an appropriate preparation of luciferin and luciferase. Calibrated against known amounts of ATP, the method can measure very small amounts of ATP if photo-multiplier tubes are used. For plankton studies raw samples of seawater are filtered to collect particulate matter, which is then treated chemically to extract ATP. This extract can be stored deep-frozen for several months without loss of activity prior to measurement.
Was this article helpful?