Abstract:

This dataset contains ammonium concentration measurements of porewater in Baffin Bay, Texas obtained over six seasons beginning from 2020-10-31 to 2022-05-26. Ammonium concentrations were determined by the use of the Ortho-phthaldialdehyde (OPA) method. A High-Performance Liquid Chromatography (HPLC) Ultimate 3000 model with a florescence detector was used to make measurements.

Suggested Citation:

Abdulla, Hussain. 2024. Ammonium concentration measurements in Baffin Bay's porewater obtained from 2020-10-31 to 2022-05-26. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/a1na953z

Purpose:

Used to calculate the benthic fluxes of ammonia in Baffin Bay, Texas during six different seasons from six sites.

Data Parameters and Units:

Latitude, longitude, Depth (cm), sampling date, Ammonium, NH4+ (umole/L).

Methods:

Ammonium (NH4+) concentrations were determined using the Ortho-phthaldialdehyde (OPA) method (Holmes et al., 1999) and measurements were conducted with the fluorescence detector in High-Performance Liquid Chromatography (HPLC) Ultimate 3000 model. OPA working solution (WS) is made up of 200mL borate buffer + 1mL sodium sulfite + 10mL OPA as the ratio is Borate : Na2SO3 : OPA = 200:1:10. Borate buffer solution: 8g of sodium tetraborate in 200 mL H2O makes up 200 mL of borate buffer for the WS. Sodium sulfite solution: 0.08g of Na2SO3 in 10 mL of H2O makes up 10 mL of sodium sulfite solution, then take only 1 mL for the WS. OPA fluorescence solution: 0.4g of OPA in 10mL of ethanol makes up 10 mL of OPA fluorescence solution for the WS. The WS will be stored in the dark for at least 1 day prior to reaction with samples. For the determination of ammonium (NH4+) concentration, 0.25 mL of a sample is mixed with 1mL of the WS then incubated in the dark for at least 2 hours prior to the detection by HPLC - fluorescence detector. The NH4+ concentration must be measured between 2-8 hours of incubation time. Ammonium chloride (NH4Cl) solutions were used as the calibration standard from 0.1 – 400 µM.

Provenance and Historical References:

Holmes, Robert M, Alain Aminot, Roger Kérouel, Bethanie A Hooker, and Bruce J Peterson. 1999. A simple and precise method for measuring ammonium in marine and freshwater ecosystems. Canadian Journal of Fisheries and Aquatic Sciences. 56(10): 1801-1808. https://doi.org/10.1139/f99-128

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