Description: These data represent nutrient data that were obtained from the Bio-ORACLE project and represent a long-term composite of data from 2000 to 2014. The map layer represents mean silicate concentration (micromoles per liter) in surface waters of the U.S. Exclusive Economic Zone. Additional data available for download here provide six nutrient concentrations at three different depths within the water column (surface, mean depth, and maximum depth). Data have a common spatial resolution of 5 arc minutes and were assessed using a cross-validation framework against in situ quality-controlled data.