A method for determining enzymatically hydrolyzable phosphate (EHP) in natural waters1

Abstract

A method for determining enzymatically hydrolyzable phosphate (EHP) in natural waters is described, based on the determination of released inorganic phosphate after the hydrolysis of organophosphoric esters by free, dissolved phosphohydrolases (mainly phosphatase) produced by the biota. The method gives higher values in highly eutrophic waters than the classical procedure of Strickland and Parsons; in samples from less eutrophic habitats the two methods give similar results. The new method is simple, accurate, and can be used in both freshwater and marine studies. It is particularly recommended for determination in hypereutrophic waters, when Pi concentrations exceed 25 µg P liter−1. Representative field data from the euphotic zone of seven lakes and two marine habitats are presented.

A Protocol to Assess the Enzymatic Release of Dissolved Organic Phosphorus Species in Waters under Environmentally Relevant Conditions

“…This is due to the difficulties involved in accurate detection of the usually low concentrations of DOP in natural waters and the subsequent orthophosphate produced by enzymatic hydrolysis. Moreover, although rarely reported, it is not uncommon to observe that (a) the amounts of inorganic P measured in samples incubated with the enzyme are sometimes lower than before the enzyme treatment (7,20), and (b) a specific enzyme may hydrolyze less organic P in natural samples, despite hydrolyzing greater proportions of P model compounds (12), suggesting that enzymatic methods are subject to matrix interferences.…”

“…They directly impact on natural waters by exchange at the sediment-water interface or via effluent discharge. Because there is considerable evidence that a sizable fraction of DOP in natural waters is amenable to hydrolysis by microbial populations, phytoplankton, and/or zooplankton (6,7), the characterization and determination of DOP is of primary importance.…”

Total Alkaline Phosphatase Activity in Bottom Sediments of Szmaragdowe Lake in the City of Szczecin (North-West Poland)

“…Littoral sediment was sampled with a Kajak core sampler with a surface of 20 cm 2 , while sublittoral sediment with Borucki apparatus with the surface of 225 cm 2 . Activity of that enzyme in bottom sediments was established in accordance with Tabatabai and Bremmer [29], using the aforementioned buffer solution.…”

“…One of the important processes impacting on the level of available mineral phosphorous is enzymatic hydrolysis of organic bonds of this element [11,[14][15][16][17][19][20][21][22][23][24][25][26]29,30]. A majority of previous studies shows that alkaline phosphatase is chiefly responsible for the rate of organic phosphorous mineralization, both in the pelagic zone and in the bottom sediment of water bodies with pH > 7 [1][2][3][4][5][6][7][8][9][11][12][13][14][15]27,30]. However, some authors report, e.g.…”

Total Alkaline Phosphatase Activity in Water of Szmaragdowe Lake in the City of Szczecin in Poland

“…One of the important processes impacting on the level of available mineral phosphorous is enzymatic hydrolysis of organic bonds of this element [11][12][13]19,[22][23][24][25]. A majority of previous studies shows that alkaline phosphatase is chiefly responsible for the rate of organic phosphorous mineralization, both in the pelagic zone and in the bottom sediment of water bodies with pH > 7 [1][2][3][4][5][6][7][8][9][11][12][13][14][15]20,23]. However, some authors report, e.g.…”