Inorganic nutrient salts in seawater are determined by SFA (Segmented Flow Autoanalyzer) (Aminot & Kérouel, 2007) with a SEAL Analytical QuAAtro analyzer using colorimetric methods (Hydes et al., 2010 & Becker et al., 2020).
Nitrate is measured with Cu-Cd reduction Naphthylenediamine method. Nitrite is determined with Naphthylenediamine method. Silicate is analyzed according to Molybdenum blue method. These methods were described by Grasshoff et al (1983). Phosphate is measured with Molybdenum blue photometric method from Murphy & Riley (1962). Concentrations are given in µmol Kg-1.

KANSO-JAMSTEC RMNs (Reference Material for Nutrients in seawater) with different ranges of concentration are used to control de accuracy of our analysis, the RMN  cover the maximum concentration found in the samples. Low Nutrient Seawater (surface seawater filtered and aged) is also used to control low nutrient concentrations. A first quality control procedure is usually performed (if available time) assigning flags to the results (2= good, 3=probably bad, 9= not sampled/analysed).



Aminot, A. and R. Kérouel. 2007. Dosage automatique des nutriments dans les eaux marines. 188p. In Methodes d’analyse en milieu marin. Ifremer, ed. Editions 25 Quae.  

Becker, S.; Aoyama, M.; Woodward, E.M.S.; Bakker, K.; Coverly. S.; Mahaffey, C. and Tanhua, T. (2019) GO-SHIP Repeat Hydrography Nutrient Manual: The precise and accurate determination of dissolved inorganic nutrients in seawater, using Continuous Flow Analysis methods. In: GO-SHIP Repeat Hydrography Manual: A Collection of Expert Reports and Guidelines. Version 1.1, [56pp.]. DOI: Available online at:

Becker S, Aoyama M,Woodward EMS, Bakker K,Coverly S, Mahaffey C and Tanhua T(2020) GO-SHIP Repeat HydrographyNutrient Manual: The Preciseand Accurate Determinationof Dissolved Inorganic Nutrientsin Seawater, Using Continuous FlowAnalysis Methods.Front. Mar. Sci. 7:581790. doi: 10.3389/fmars.2020.581790

Grasshoff, K., Kremling, K., and Ehrhardt, M. (eds), 1983. Determination of nutrients. In Methods of seawater analysis, Germany: Wiley-VCH.

Hydes, D. J., Aoyama, M., Aminot, A., Bakker, K., Becker, S., Coverly, S., et al. (2010). Determination of dissolved nutrients (N, P, Si) in seawater with high precision and inter-comparability using gas-segmented continuous flow analysers. GO-SHIP Repeat Hydrography Manual: A collection of expert reports and guidelines. IOCCP report #14, ICPO publications series no.134, Version 1. Updated by Becker et al. (2019) above.

Murphy, J. and Riley, J.P., 1962. A modified single solution method for the determination of phosphate in natural waters. Anal. Chim. Acta, 27: 31-36.




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