I was watching some newscast about a local naval observatory working with marine biologists tracking whales. For the “color” aspect of what they do (listening for submarines using sound monitors throughout the oceans) - they played recordings of whales, etc.
The biologist played the various sounds and would say “that is a Blue Whale near the surface in the South Pacific,...that is a humpback off the coast of Japan, etc.
The last sound was REALLY weird - sounded partly organic like the whales, but also had an almost electric synthesised, high frequency tone mixed in. The biologist let in run and said it was in the Indian Ocean, at a depth of 15,000 ft (some really great depth anyway),.....”and we have NO IDEA what the heck it is!”
I have searched youtube for it (it is several years old now I imagine) to see if it ever made it onto the internet, but no luck.
It gives me chills just thinking about it again. On one hand it is cool that it is probably just some creature that hasn’t been discovered yet. But that synthetic tone gives me the chills that it might be something else.
Maybe you should take a trip on over to the observatory and see what you can find out. Do you know where the marine biologist were stationed out of because maybe you can talk to them to. Certainly might be interesting.