Phosphorus (P) is a macronutrient for all microalgal species, and the main form of uptake is orthophosphate (PO4). In this chapter we present a colorimetric method for determining the PO4 concentration and dissolved organic phosphorus (DOP) based on total phosphorus (TP) measurements. We also describe a method for determining particulate organic phosphorus (POP) based on the same principles.
Keywords: Orthophosphate; Particulate organic phosphorus; Total phosphorus.