Winter surface concentrations of nitrates in sea water

Classification is not related to background values. In addition, the results of trend analyses of time series 1985-2000 (with at least three years data in the period 1995-2000) are shown for each country by a pie diagram. Pie diagrams are based on statistical trend assessments of nutrient concentrations at individual stations and show the percentage of stations with increasing, decreasing or no trend respectively.