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Methods for reproducible shipboard SFA nutrient measurement using RMNS and automated data processing
Author(s) -
Rees Christine,
Pender Lindsay,
Sherrin Kendall,
Schwanger Cassie,
Hughes Peter,
Tibben Stephen,
Marouchos Andreas,
Rayner Mark
Publication year - 2019
Publication title -
limnology and oceanography: methods
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.898
H-Index - 72
ISSN - 1541-5856
DOI - 10.1002/lom3.10294
Subject(s) - nutrient , certified reference materials , nitrate , environmental science , ocean chemistry , seawater , silicate , remote sensing , oceanography , engineering , chemistry , geology , detection limit , organic chemistry , chromatography , chemical engineering
Ocean observations are critical in developing our understanding of the interaction between the ocean and climate. Detailed information about the nutrient composition of the ocean is achieved using in situ sensing and the collection and analysis of physical samples from research vessels. The analysis of nutrients underpins work in understanding both the carbon cycle and biological productivity in oceans. Although in situ sensors are becoming more common for some nutrients, the best and most reliable method for making these measurements is to conduct analysis of physical samples at sea. This article discusses the analysis and data processing methods developed by the hydrochemistry team at Commonwealth Scientific and Industrial Research Organisation (CSIRO) to provide repeatable and accurate analysis of nutrient samples at sea. Nutrients are measured by segmented flow analysis and data are processed using in‐house software (Hydrology Processor [HyPro]). These methods were used during the Global Ocean Ship‐based Hydrographic Investigations Program (GO‐SHIP) P15S voyage in 2016. Accuracy and precision of the analyses during the voyage was determined from measurement of the certified reference material for nutrients in seawater (RMNS) for silicate, phosphate, nitrate, and nitrite and is presented and discussed here. The accuracy of the silicate and phosphate RMNS measurements was within 1–3% of the certified values, and nitrate + nitrite within 1–2%. The precision for silicate, nitrate + nitrite, and phosphate was greater than 0.2%. The hydrochemistry team has established a standard operating procedure which assures the quality of nutrient data obtained is accurate and precise.