FIG 1.

Composition of microbial symbionts in the colonial ascidian Clavelina oblonga and ambient seawater, showing the average relative abundances of microbial taxa by source (ambient seawater, C. oblonga) and range (native versus invasive) (a) and by sampling location: North Carolina (NC) and Florida (FL) from the native range and Cadis, Spain (CS), Ebro Delta, Spain (DS), Italy (IT), and Brazil (BR) from the invasive range (b). Symbionts are classified at the phylum level, except Proteobacteria, which are classified at the class level, and rare microbial taxa (contributing <1% to the average abundance across all sites) are classified as “Other.”