Respiration

B. tuberatus, just like any other ascidian, uses the branchial basket as a mode for respiration as well.  As mentioned under the section 'Feeeding mechanisms', fresh seawater flows from the incurrent aperture of the individual zooids, through the branchial basket whereby gaseous exchange occurs, and out of the excurrent aperture into the common cloacal aperture, and then expelled (Kott 1989).  The arrangement of the zooids is such that the incurrent apertures of the individual B. tuberatus zooids are facing away from the common cloacal aperture, so as to minimize the amount of water re-entering the organism before it could be carried away by the currents (Kott 1985).