What mysterious underwater nosie is not easily explained by natural phenomena, (Bloop, Train, Whistle, Slowdown)?

Barrow boy

All of these sounds are not yet fully explained. Bloop is believed to emanate from a 'monster of the deep' as yet undiscovered. Train and Whistle are likely to derive from dolphins. Slowdown (along with the unmentioned Julia and Upsweep) are still not adequately explained. I have had to visit a number of sites to piece this together. Jul 21 02, 3:23 PM

birch

Thank u barrow boy for your effort in finding the answer, tell me how did you go about finding the answer? Jul 21 02, 6:30 PM

Barrow

I like working with search engines, it's a bit like detective work. When I put your four words into the search engine along with 'noise'. I took me to a site that listed all these sounds, but said they were all unexplained. Then I found a link to a news item that said the bloop might be from a giant animal very deep in the ocean. I then had to put in various combinations of the words and came up with a research report which was trying to link trains and whistles to dolphins. I couldn't really find slowdown linked to anything. Jul 21 02, 8:23 PM

birch

thank you barrow i shall do what you had suggested your answer is very helpful thank you. Jul 22 02, 4:33 AM