Supplementary material to "Effects of photosymbiosis and related processes on planktic foraminifera-bound nitrogen isotopes in South Atlantic sediments"

Size-specific δ 18 O relationship.It has been proposed that due to persistently shallower depth habitats throughout ontogeny of symbiont-bearing foraminifera, their size-specific δ 18 O relationship should be minimal in comparison to symbiont-barren foraminifera species with a larger potential range of depth habitats (Rebotim et al., 2017).The five species analysed in this study generally follow the data compilation-averaged species-specific predictions of size-specific δ 18 O trends for dinoflagellate-bearing, chrysophyte-bearing, and symbiont-barren species in (Ezard et al., 2015) (Fig. S2) with G.truncatulinoides showing the biggest variation in δ 18 O across the size fractions and G. ruber ruber showing the least variation.However, both G. ruber ruber and G. siphonifera seem to diverge from the general pattern in the size-specific stable isotope compilation (Fig. S2 b,c,e) by up to 0.5‰.A possible explanation for this could be the cooler waters at our site in comparison to the more tropical sites used in the compilation.