Size‐Fractionated Alkaline Phosphatase Activity in the Hypereutrophic Villerest Reservoir (Roanne, France)

Abstract

Seasonal changes in size-fractionated alkaline phosphatase activity (APA) were studied in the hypereutrophic Villerest reservoir (Roanne, France) to determine whether the APA showed seasonal variations coupled to abiotic and biotic variables. Samples were collected at different depths from November 1992 to October 1993. The phosphatase activities were measured spectrophotometrically with pnitrophenyl phosphate as the substrate and related to protein concentrations. No correlations were found between APA and soluble reactive phosphorus concentrations during an annual cycle. Free phosphatases were particularly high in the epilimnion (54.5% of total activity was at 5 m) and decreased with depth (4% of total APA at 40 m). The contribution of small microorganisms to APA increased with depth. It was concluded that APA is not a valid quantitative test of the phosphorus status of aquatic microorganisms. Water Environ. Res., 73, 132 (2001).

Physiological regulation of Cylindrospermopsis raciborskii (Nostocales, Cyanobacteria) in response to inorganic phosphorus limitation

“…When P is scarce, phytoplankton can produce alkaline phosphatase (APA) to hydrolyze organic phosphorus to compensate for the ambient P deficiency (Feuillade et al, 1990;Gillor et al, 2002). Therefore, APA is often recommended as an indicator of P status (Thingstad et al, 1998;Jamet et al, 2001). When phosphatases are present, an enzyme-labeled fluorescence phosphate (ELFP) substrate is cleaved to form an intense green fluorescent insoluble product, ELF alcohol (ELFA), which tags individual algal cells at or near the sites of enzymatic activity (Gonzá lez-Gil et al, 1998).…”

Extracellular Enzyme Activity in the River Elbe during a Spring Flood Event

“…The spatiotemporal dynamics of the ratio between the two can be very high even in the same study areas, and reverse on seasonal scales (e.g., [54,56]), vertically ( [57]) and from day to day ( [55]). Therefore, very complex processes must be assumed to be involved in the dynamics of breakdown, the breakdown pattern, and the respective contributions of free dissolved enzymes and ectoenzymes.…”

Limitations of using extracellular alkaline phosphatase activities as a general indicator for describing P deficiency of phytoplankton in Chinese shallow lakes

“…When ambient available P is scarce, phytoplankton can produce extracellular phosphatase to hydrolyze organic phosphorus for compensation of P deficiency (Gillor et al 2002;Spijkerman and Coesel 1998;Feuillade et al 1990). Therefore, algal alkaline phosphatase activity (APA), roughly represented by that associated with larger particles (Nedoma et al 2006) or total APA (Pettersson 1985;Chrost et al 1984) was inversely proportional to phosphorus concentration, such as total P (Berman 1970;Smith and Kalff 1981) or soluble reactive phosphorus (SRP) concentration (Pettersson 1985; (Healey and Hendzel 1980;Thingstad et al 1998;Jamet et al 2001;Rose and Axler 1997;Istvanovics et al 1992) or in periphyton (Burkholder et al 1990;Rejmankova and Komarkova 2000;Newman et al 2003). Furthermore, some rectified APA, such as chlorophyll-specific total APA (Istvanovics et al 1992), surface-area-specific APA (Newman et al 2003) was sensitive enough to show changes in the P status of algae.…”