Methanotrophic symbiont location and fate of carbon incorporated from methane in a hydrocarbon seep mussel

14C Tissue autoradiographic study was utilized to analyze the mechanism of carbon transfer from symbiont to host in the Seep Mytilid Ia association. Results indicated that host digestion of symbionts occurred and resulted in carbon transfer. Translocation of products of early stage of carbon fixation was an additional means of host nutrition. It was found that acid phosphatase was present in SMIa bacteriocytes and was critical in the digestion of symbionts.