Principal component (PC) analysis for the biogeochemical subprovinces of the Mediterranean Sea.

<p>The (a) biogeochemical subprovinces of the Mediterranean Sea, as defined by the 5% threshold for the full multivariate array, and the (b–f) PC analysis arrow plots and time series of the retained PCs for each of the subprovinces, derived from the mean of all pixels in the subprovince for each month of the data set. Arrows that align well with an axis are well-explained by that axis. The longer the arrow, the more it contributes to explaining the variability of an axis. Variable abbreviations are as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0111251#pone-0111251-g004" target="_blank">Figure 4</a>.