Based on this NY Times article that presents opposing points of view: William F. Martin says that the Last Universal Common Ancestor can be traced back to deep sea vents...
** Commentary **
Everybody wants life to spring up around these thermal vents- because that sort of implies that life might arise around similar environments on other planets. If life did arise around and because of thermal vents, then there is going to be a whole lot of life in the universe.
But life did not arise around or because of these thermal vents. At least not according to my speculations about the generation of life. I think life can only arise in a thermally fluctuating environment- far from thermal equilibrium. I think fluctuation in available energy is a primary dynamic in the emergence of life. In a system close to constant thermal equilibrium- like around deep-sea thermal vents- everything is going to settle down, stop changing. Complex physical structure is not going to naturally evolve in systems close to thermal equilibrium.
I think a significant factor in the emergence of life on Earth is our constantly fluctuating bath of energy. Because of the Earth's rotation and because of our elliptical revolution around the sun, temperatures are constantly fluctuating in a range that our particular organic mix finds conducive to reaction- stimulating constant flux, chemicals mixing themselves up, higher frequency of generations and mutations and natural selection.
I think life needs thermal fluctuation to arise and temperatures stay relatively constant around those thermal vents. Plus, I don't think regions of these vents last long enough- geologically- for life to have time to arise. A lot of the ocean floor is stable now, but, over the course of the millions of years it would take for life to emerge around any particular region of vents, the vents are going to come and go. It's the other side of the equation- the fluctuation needed for life to emerge needs to happen in an environment that is going to stay stable long enough for life to emerge/evolve.
I think life arose elsewhere on our planet and- maybe very early on- adapted to finding energy around these thermal vents.
I am pretty sure there is like almost zero probability of finding any life on Titan or other places that may have undersea thermal vents. There might be some geological or gravitational tidal heating/fluctuation but- all things considered- the ocean floor on Titan remains close to thermal equilibrium- not much going on there- in terms of chemical reactions. I think we could spend our space dollars on more promising endeavors.
Your thoughts Steemianites?