Alkaline phosphatase activity over bioassay experiments with seawater collected during R/V Savannah cruise SAV-19-02 from March to April of 2019 in the Northwestern Atlantic from the surface to 50 m depth.
Sampling and analytical procedures:
Bioassay Experiments consisted of incubating, over an incubation period of 48h, surface seawater (5m) with inorganic and organic phosphate compounds (20 µM; final concentration of P) including, polyphosphate (polyp), inorganic phosphate (Pi), nucleotides (ATP, AMP) and phosphonate (Mepn). In each incubation experiment, a control treatment (surface seawater) was considered as well in each bioassay experiment alongside a treatment amended with nitrogen (NH4Cl, NaNO3). These bioassay experiments were conducted at station 1 and stations 3. At each station, inorganic and organic phosphate amendments were performed on seawater with and without nitrogen enrichment.
Alkaline phosphatase activity was determined fluorometrically using 4-methylumbelliferyl phosphate (MUF-P), as representative of phosphomonoesterase activity. Total APA was measured in each experimental bottles in triplicate. Hydrolysis rates were determined by separately incubating 200 µL of seawater with 8 different concentrations (0, 0.1, 0.2, 0.5, 1, 5, 10, 20 µM; final concentrations) of MUF-P in 96-well black microtiter plates. To ensure linearity of the hydrolysis rate, the increase of fluorescence was measured (excitation/emission wavelength: 359/449 nm) at multiple time points over an incubation period of 24 h. Maximum hydrolysis rate (Vmax) was determined, using a nonlinear regression based on the rectangular hyperbolic function following V=Vmax x S/ Km+ S, where S and V are the concentrations of the substrate and the hydrolysis rates, respectively.
Location: Northwestern Atlantic surface waters. Depth: surface-50 m.
Instruments: Reading of fluorescence was performed on a plate reader (SpectraMax® M2, Molecular Devices).
Duhamel, S., Diaz, J. (2021) Alkaline phosphatase activity over bioassay experiments with seawater from R/V Savannah cruise SAV-19-02 in the NW Atlantic Ocean in Spring of 2019. Biological and Chemical Oceanography Data Management Office (BCO-DMO). (Version 1) Version Date 2021-11-02 [if applicable, indicate subset used]. http://lod.bco-dmo.org/id/dataset/864258 [access date]
Terms of Use
This dataset is licensed under Creative Commons Attribution 4.0.
If you wish to use this dataset, it is highly recommended that you contact the original principal investigators (PI). Should the relevant PI be unavailable, please contact BCO-DMO (info@bco-dmo.org) for additional guidance. For general guidance please see the BCO-DMO Terms of Use document.