<p>Electronic Supplementary Material 1. R statistics and p-values from ANOSIM analyses based on Euclidean distances and using monthly nutrients concentrations and -3 DIN/P-PO4 ratio as variables. The combination island-type is used as single grouping factor. Significant p-value is set to α = 0.0056 after applying Bonferroni correction. MA: Majorca, MI: Minorca, IB: Ibiza and FO: Formentera</p><p>Factor (island-type) R Statistic p-value MA-oligohaline, MA-mesohaline 0.231 0.073 MA-oligohaline, MA-euhaline 0.231 0.026 MA-mesohaline, MA-euhaline 0.168 0.108</p><p>MI-mesohaline, MI-oligohaline -0.025 0.494</p><p>MA-oligohaline, MI-oligohaline 0.073 0.213 MA-mesohaline, MI-mesohaline -0.109 0.750</p><p>FO-euhaline, MA-euhaline 0.053 0.151</p><p>IB-euhaline, MA-euhaline 0.063 0.339</p><p>IB-euhaline, FO-euhaline 0.362 0.018</p>