Fig 4. Boxplot of phytoplankton baseline isotope signatures at the study’s six sampling sites.

Plankton samples were collected in five size fractions at each sampling site. Significant differences were found between the <20μm size class and all other size classes for δ¹³C and δ¹⁵N. Significant differences were found between the grassy gulf and open lake sites for δ¹³C.