The comparability and traceability of nutrients data in the world’s oceans are fundamental issues in marine science, and particularly for studies of global change. Our community has been continuing to improve comparability of the nutrients data in the world ocean in many ways, including international　linter-comparison experiments and also development of nutrients reference materials. However, as Climate Change 2007 – The Physical Science Basis(IPCC2007) report sated, adequate comparability and traceability have not yet been achieved.

The IPCC2007 report comments as follows on the nutrients comparability:
　"Using the same data set extended to the world, large regional changes in nutrient ratios were observed (Li and Peng, 2002) but no consistent basin-scale patterns. Uncertainties in deep ocean nutrient observations may be responsible for the lack of coherence in the nutrient changes. Sources of inaccuracy include the limited number of observations and the lack of compatibility between measurements from different laboratories at different times (Bindoff et al., 2007)".

In 1990s, Ridout (1999) pointed out that in 1993 the IOC-IAEA-UNEP Group of Experts on Standards and Reference Materials (GESREM, 1993) drew attention to an urgent need for the development of certified reference seawater for dissolved nutrients. Dickson (2001) also pointed out the need to develop of certified reference seawater which can cover several determinants all in one bottle.
　During the WOCE periods, WHPPC recognized the importance of comparability of WOCE nutrients data world wide. They recommended to all WOCE cruise PIs to participant ICES 6th inter-comparison (WOCE WHPPC, 199x), however, it could not done because ICES 6th inter-comparison was canceled.
　

In the 1990s a number of studies were organized under the ICES umbrella. These studies were well documented (see Aminot et al.,1995 and Aoyama, 2006 in details). In Europe this lead into the setting up of QUASIMEME (Topping, 1997). QUASIMEME is useful from the point of validating the procedures of individual laboratories for a wide range of determinands. However, this system is inadequate for supporting the traceability that is required to link measurements from day to day in order to improve the overall precision within a laboratory or to achieve a known level of comparability between different laboratories.
　In 2000 and 2002, the National Oceanic and Atmospheric Administration, USA and the National Research Council of Canada (NOAA/NRC) had conducted two inter-comparison exercises to certify MOSS-1 ( Willie and Clancy, 2000; Clancy and Willie, 2003).

However, despite individual efforts, adequate comparability and traceability of nutrient data have not yet been achieved. Various efforts have been made to change it, but these have been on too small a scale to meet the needs of the global community in measuring nutrients in seawater.

In 2003 Michio Aoyama, of the Meteorological Research Institute, Japan, organized an inter-compariosn study which include 18 laboratories (Aoyama, 2006, Aoyama et. al, 2007). In 2006 Michio Aoyama, of the Meteorological Research Institute, Japan working with Hidekazu Ota, of the General Environmental Technos Co., Ltd. (KANSO) organized second inter-comparison study which included 55 different laboratories world wide (Aoyama, 2007 in preparation). Both inter-comparison studies clearly show that global use of reference materials of nutrients in seawater would greatly improve the comparability of nutrients data in the world’s oceans.

In early 2007 Michio Aoyama had visited NOC in Southampton. One of the reasons for their visit was to discuss the results of the inter-calibration. This was extended to an invitation to the European participants in the inter-calibration and other interested nutrient chemists to attend a discussions meeting at NOC.

Following on from this an International Workshop on Chemical Reference Materials in Ocean Science was held in Tsukuba, Japan, on 29 October to 1 November 2007. It focused on the measurement of nutrients and of ocean CO2 parameters, and the current status of available chemical reference materials, particularly for nutrient references in ocean science were discussed. The participants agreed to start a collaborative program, called the International Nutrients Scale System (INSS), with the aim to establish global comparability and traceability of nutrient data. The agreements at this workshop in Tsukuba 2007 marked an epoch in the history of nutrient comparability.

The 2009 INSS workshop in Paris is a follow-up meeting of 2007 workshop in Tsukuba to advance international collaboration in establishing global comparability of nutrient data in the world ocean.