Here's a really cool article on the prominence of endospores along the ocean floor.
(A Constant Flux of Diverse
Thermophilic Bacteria into the
Cold Arctic Seabed)
Many thermophilic bacteria have been found in and around seemingly inhospitable areas for these heat loving creatures (the arctic). These bacteria have been surviving as endospores rolling along the ocean floor until they reach warmer climate more suitable for thermophiles. Most likely these bacteria have been popping up out of Petroleum-bearing sediments and fractured ocean crust. It is interesting how these methods of protection have shaped the marine biome.