Fig. 2
From: Chemosymbiotic bivalves contribute to the nitrogen budget of seagrass ecosystems
Results from freshly sampled bivalve specimens: a C:N ratio (± SE, n = 10) of symbiont-free (Symb-) and symbiont-hosting (Symb+) animal tissues; b Symbiotic tissue mass index—SMI. The SMI indicates the proportion of symbiont-hosting gill biomass (mg mm−1 ± SE, n = 10; see Supplementary Methods for details on how this index was calculated); c Biplot of the natural abundance of 13C and 15N isotopes showing the total amount of niche space occupied (total area, dashed polygons) and the isotopic niche width (standard ellipse area, solid ellipses) as proxies of trophic specialization of symbiont-free (squares) and symbiont-hosting (triangles) animal tissues. Sampling points are color-coded in purple (April) and cyan (October). Different lowercase letters indicate significant differences (p < 0.05, PERMANOVA)
