Survival of free-living symbionts

by Teresa Winter

I am Teresa and I want to help to understand how Endoriftia survives once they escaped the dead host. When host associated, Endoriftia has a chemoautotrophic metabolism, however genes that are coding for enzymes necessary for heterotrophy are present as well! To show that they are indeed able to switch from host associated to free living lifestyle, but also from chemoautotrophy to heterotrophy, I put trophosome tissue with living symbionts in a small capsule and incubate it with sugars and amino acids in high pressure vessels. After the cruise we will check using fluorescence in situ hybridization how many symbionts managed to escape and evaluate using transcriptomics if they switched their metabolism. If Endoriftia is indeed a mixotroph it might explain why this symbiosis is that successful and widespread at vents. The escaped free-living symbionts seed the environment and enhance the probability that both partners find each other, which is crucial to establish the symbiosis for new host generations. Additionally it might help to reach also more distant vent sites and hosts.