World ocean atlas 2013. Volume 4, Dissolved inorganic nutrients (phosphate, nitrate, silicate)

This atlas consists of a description of data analysis procedures and horizontal maps of climatological distribution fields of dissolved inorganic nutrients (phosphate, nitrate, and silicate) at selected standard depth levels of the World Ocean on a one-degree latitude-longitude grid. The aim of the maps is to illustrate large-scale characteristics of the distribution of these nutrients. The oceanographic data fields used to generate these climatological maps were computed by objective analysis of all scientifically quality-controlled historical nutrient data in the World Ocean Database 2013. Maps are presented for climatological composite periods (annual, seasonal, monthly, seasonal and monthly difference fields from the annual mean field, and the number of observations) at 102 standard depths.