Hii bright thinker!!!

Firstly greetings for having different thoughts regarding your career, now if you are pursuing your 10+2 studies in Science, with Biology as a stream then to know the Under Ocean world the best course would be B.Sc in Marine Biology. But it is not confined to only one course rather you have few others like

Master of Science (M.Sc) in Oceanography.

M. Tech in Ocean Engineering.

M. Tech in Ocean Technology.

For all the above cases you need Physics, Chemistry, Biology or Mathematics as career objective. You can explore the best course of your choice, after profound knowledge you can earn even more than 20 LPA based on your expertise,

Good luck!!!