There is a TV show by that marine explorer who is also a adventure novelist that documents some human habitation deep in the current depths of the Blace Sea. Can't rememember his name off hand. Maybe google "NUMA" (National underwater marine archeology???)
Couple of possible links to what you're looking for higher in this thread.
Is that the same guy who believes that Sodom and Gomorrah were located either on the banks of the Dead Sea or perhaps in the low areas now covered by the Dead Sea?