We conducted two isotope experiments (described in Gibbin et al. 2018) to determine how the presence of pathogens influences resource partitioning in the coral holobiont. Specifically, we quantified: 1) 13C-assimilation in Symbiodinium and the amount of 13C-labelled photosynthates that are assimilated by the host; 2) the metabolic turnover of 13C in Symbiodinium and in their host and 3) the incorporation of bacterial-derived N within the tissues of the coral holobiont.NanoSIMS images (either 40×40 or 50×50 µm in size) were obtained by rasterizing a 16 keV Cs+ primary ion beam, focused to a spot-size of 150 nm, across the sample surface. Settings (dwell time = 5 ms; number of pixels = 256×256, layers = 5) were kept constant between images. Data was extracted from drift-corrected images using L'IMAGE (Dr. Larry Nittler, Carnegie Institution of Washington). Regions of interest (ROIs) were drawn around individual symbiont cells and the host gastrodermis (excluding symbionts), using the contour lines on the 12C14N- image. These ROIs were then used to quantify the average enrichment of 13C and 15N in each partner. Our measured values are expressed as Atom Percent Excess (APE, in %).

Supplement to: Gibbin, Emma M; Gavish, Assaf; Krueger, Thomas; Kramarsky-Winter, Esti; Shapiro, Orr; Guiet, Romain; Jensen, Louise; Vardi, Assaf; Meibom, Anders (2018): Vibrio coralliilyticus infection triggers a behavioural response and perturbs nutritional exchange and tissue integrity in a symbiotic coral. The ISME Journal