The magical forest realm hiding at the bottom of the ocean

scuba

the sport of swimming underwater with special breathing equipment

aquanaut

a person who swims under water using an aqualung.

naval

relating to a navy or navies

dredge

clear the bed of (a harbour, river, or other area of water) by scooping out mud, weeds, and rubbish with a dredge

subsist

to get enough food or money to stay alive, but no more

swing

change

detritus

waste material or rubbish, especially left after a particular event: