GUAM — Only a scattering of light penetrates the deep water, more than 300 feet beneath the ocean surface off the coast of Guam. It's like twilight to the human eye, even in the middle of the day.

(CNN) — Only a scattering of light penetrates the deep water, more than 300 feet beneath the ocean surface off the coast of Guam. It’s like twilight to the human eye, even in the middle of the day.

Divers supporting ocean conservation are going to unusual lengths (or depths) to do it. These are not marketing stunts or travel fantasies. They are the real-world experiences driving participation in ...