Guidelines for monitoring of chlorophyll a

Abstract

Increase in phytoplankton biomass is a direct consequence of advancing eutrophication. For monitoring purposes, phytoplankton biomass is estimated by chlorophyll a (Chl a) concentration. The amount of Chl a is not a direct proxy for phytoplankton biomass because of a highly variable ratio of cellular carbon to Chl a in phytoplankton (Geider 1987). Phytoplankton biomass, except for picoplankton, is more accurately assessed by quantitative taxonomical analysis. It is, however, laborious and thus provides with a smaller amount of data than the Chl a method, which lowers the status confidence of any taxonomybased indicator. Regardless of its shortcomings, the Chl a method ‒ being easy to sample and fast to analyze ‒ is the method of choice for environmental studies. The scope of this guideline is the determination of Chl a concentration; measured from water samples using wet analytics as well as estimated from in vivo Chl a fluorescence recordings.