When did the ocean become an important area of study?

First of all the ocean makes up 97% of our planet's water. They also produce more than half of the oxygen in the atmosphere, and absorb most carbon from it.
If this did not become an important study, we wouldn't know any of this information that could lead us to even more incredible facts about planet Earth.

It is useful for historians to write narratives so that history can be passed on from their point of view.  think about a story being told in third person, then think about it again being told in first person, by someone who actually experienced the event.

100% tortilla. it is the only possible answer