A rare intercomparison of nutrient analysis at sea: lessons learned and recommendations to enhance comparability of open-ocean nutrient data
<p>An intercomparison study has been carried out on the analysis of inorganic nutrients at sea following the operation of two nutrient analysers simultaneously on the GO-SHIP A02 trans-Atlantic survey in May 2017. Both instruments were Skalar San<span class="inline-formula"><...
Main Authors: | , , , , , , |
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Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2019-03-01
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Series: | Earth System Science Data |
Online Access: | https://www.earth-syst-sci-data.net/11/355/2019/essd-11-355-2019.pdf |
Summary: | <p>An intercomparison study has been carried out on the analysis of inorganic
nutrients at sea following the operation of two nutrient analysers
simultaneously on the GO-SHIP A02 trans-Atlantic survey in May 2017. Both
instruments were Skalar San<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M1" display="inline" overflow="scroll" dspmath="mathml"><msup><mi/><mrow><mo>+</mo><mo>+</mo></mrow></msup></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="13pt" height="6pt" class="svg-formula" dspmath="mathimg" md5hash="a615832409df034f0149a854c5d3d1d0"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="essd-11-355-2019-ie00001.svg" width="13pt" height="6pt" src="essd-11-355-2019-ie00001.png"/></svg:svg></span></span> Continuous Flow Analyzers, one from the
Marine Institute, Ireland and the other from Dalhousie University, Canada,
each operated by their own laboratory analysts following GO-SHIP guidelines
while adopting their existing laboratory methods. There was high
comparability between the two data sets and vertical profiles of nutrients
also compared well with those collected in 1997 along the same A02 transect
by the World Ocean Circulation Experiment. The largest differences between
data sets were observed in the low-nutrient surface waters and results
highlight the value of using three reference materials (low, middle and high
concentration) to cover the full range of expected nutrients and identify
bias and non-linearity in the calibrations. The intercomparison also raised
some interesting questions on the comparison of nutrients analysed by
different systems and a number of recommendations have been suggested that we
feel will enhance the existing GO-SHIP guidelines to improve the
comparability of global nutrient data sets. A key recommendation is for the
specification of clearly defined data quality objectives for oceanic nutrient
measurements and a flagging method for reported data that do not meet these
criteria.</p>
<p>The A02 nutrient data set is currently available at the National
Oceanographic Data Centre of Ireland: <a href="https://doi.org/10.20393/CE49BC4C-91CC-41B9-A07F-D4E36B18B26F">https://doi.org/10.20393/CE49BC4C-91CC-41B9-A07F-D4E36B18B26F</a> and
<a href="https://doi.org/10.20393/EAD02A1F-AAB3-4F4E-AD60-6289B9585531">https://doi.org/10.20393/EAD02A1F-AAB3-4F4E-AD60-6289B9585531</a>.</p> |
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ISSN: | 1866-3508 1866-3516 |