Figure 8. Mean partial dependence plots for the environmental variables describing the N₂ fixation rates.

Mean partial dependence plots with 95% confidence intervals (light grey, based on bootstrapping of 30 BRT runs and indicating robustness of model performance) for the 10 environmental variables which explain the variation in N₂ fixation rates best. The environmental variables are A) C-fix rate, B) phosphate, C) nitrate + nitrite, D) sigma-PSII, E) DON, F) oxygen, G) DFe, H) picoeukaryotes, I) Chl a, and J) temperature. The y-axis is centered to have zero mean over the distribution of fitted N₂ fixation rates. A common scale is used for the x-axis. Rug plots at inside top of plots show the distribution of sites across that variable, in deciles.