If you're interested in marine sounds, the SANCTSOUND portal is what you want to explore. You can't upload sounds there, but there are some nice sounds of animals as well as anthropogenic sounds that comes from 4 years of recordings in the MPA across USA. The portal is nicely organized and easy to access.
You can download the sounds, as the portal is mentioned to be free access for people. You can also enquire them, if you have a project in mind, and ask if you can have access to certain kind of sounds. I've followed the conference where they presented the project, results and portal and found to be a large sample of great sounds.