Words about the ocean that begin with J

I need a word that begins with J that has to do with oceanography, but it can't be an animal. I have only found two and they aren't very good. Thanks in advance!

The best I can think of is JOIDES.
Not a word as such; but an acronym, meaning: "Joint Oceanographic Institute for Deep Earth Sampling"
This was a ship used for deep ocean drilling and was superseded by the Glomar Challenger; but JOIDES would be a well-understood term by all oceanographers.

Jellyfish. It's not an animal, look it up. It's not a fish either. Or jelly.