title: Importance of acidic phosphatase activity in P supply and Gonyostomum semen Ehrenbergh (Raphidophyta) occurrence in a Hungarian peat bog, Keleméri Kis-Mohos (Ne Hungary).
abstract: Phosphatase enzymes are capable of releasing phosphate through cleavage of phosphoester bonds. The seasonal importance of this process was examined by using a model substrate paranitrophenylphosphate and the Michaelis-Menten equation to estimate the release rate of PO 4 -P from phosphomonoesters. The seasonal occurrence of phosphomonoesters and acid phosphatase activity was used to estimate the velocity of phosphate release from these compounds. Filter fractionation of phosphatase activity demonstrated that most activity (>60%) was in size fractions less than 0.45 microm. The release rates were highest in May and June (15 to 25 nmol L -1 min -1 ) during the Gonyostomum semen (Raphidophyta) bloom and decreased to less than 2 nmol L -1 min -1 in two weeks and remained low throughout the summer and the fall. Fractionation of 32 P-H 3 PO 4 labelled dissolved organic phosphorus showed this fraction to vary considerably through the year. Potential phosphate release declined through the summer and into the fall. Significance of the co-occurrence of phosphomonoesters and acid phosphatase activity maxima and Gonyostomum semen (Raphidophyta) bloom is discussed.
authors.affiliation: Department of Hydrobiology, University of Debrecen, H-4010 Debrecen, Egyetem tér 1, Hungary. gege@puma.unideb.hu
authors.forename: I
authors.initials: I
authors.lastname: Grigorszky
authors.forename: G
authors.initials: G
authors.lastname: Dévai
authors.forename: K T
authors.initials: KT
authors.lastname: Kiss
authors.forename: B
authors.initials: B
authors.lastname: Tóthmérész
authors.forename: M
authors.initials: M
authors.lastname: Gligora
authors.forename: A
authors.initials: A
authors.lastname: Plenkovic-Moraj
authors.forename: Koraljka
authors.initials: K
authors.lastname: Kraj
authors.forename: V B
authors.initials: VB
authors.lastname: Béres
authors.forename: C
authors.initials: C
authors.lastname: Schnitchen
authors.forename: G
authors.initials: G
authors.lastname: Borics
authors.forename: A S
authors.initials: AS
authors.lastname: Nagy
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism*; D002734:Chlorophyll / Q000378:metabolism; D000077194:Chlorophyll A; D004777:Environment; D056890:Eukaryota / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D012621:Seasons; D012987:Soil; D014867:Water / Q000737:chemistry
chemical_list: D012987:Soil; D014867:Water; D002734:Chlorophyll; D000135:Acid Phosphatase; D000077194:Chlorophyll A