Carbon fixation and transfer in the Olavius spp. symbiosis studied with microautoradiography

<p>Microautoradiographic images of thin sections from <em>Olavius</em> spp. worms that were incubated with ¹⁴C-labelled bicarbonate in a pulse chase experiment. After 10 days chase, radioactive label is not only present in the outer region of the worm that harbors the chemosynthetic symbionts but is also detected over symbiont-free regions, i.e. the coelomic fluid (A) or the chloragogen tissue (B), indicating carbon transfer to the host.</p>