Phytoplankton nutrient-addition bioassays

Holmboe, N., Jensen, H. S., and Andersen, P.0. (1999). Nutrient addition bioassays as indicators of nutrient hmitation of phytoplankton in an eutrophic estuary. Mar. Ecol. Prog. Ser. 186, 95-104. 

Figure ll.ll Results from a set of in situ nutrient addition bioassays conducted at three locations along the axis of the Neuse River Estuary that was routinely monitored for ambient nutrient (ammonium, nitrate, phosphate) concentrations and chlorophyll a as an indicator phytoplankton biomass. All nitrogen forms were added at 20 jlM-N, while phosphate was added at 5 pM-P. The locations of bioassays are shown (symbols) on the map (A) just upstream of the chlorophyll a maximum (Cniax)l ( ) the Cmax i d (C) downstream of the Cmax- Strong N limitation was encoun-... 

Fisher, T. R., and Gustafson, A. B. (2004). Nutrient-Addition Bioassays in Chesapeake Bay to Assess Resources Limiting Phytoplankton Growth, Progress Report Aug. 1990—Dec. 2003. Rep. Maryland Dept. Natural Resources, Annapolis, MD. p. 50. 

The measurement of alkaline phosphatase activity (APA) of target phytoplankton is a recently developed bioassay that has been used to determine the algicidal effects of polyphenols from Eurasian watermilfoil (Myriophyllum spicatum) [80]. Phytoplankton produce extracellular enzymes, such as alkaline phosphatase, to provide additional sources of nutrients. Fluorescence spectrometry is used to measure APA, with methylumbeliferyl-phosphate used as substrate and mixed with the algal or cyanobacterial suspension and the suspected inhibitor. 

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