Answer
Approximately 200 years ago the ocean become an important area of study.
Explanation.
The study of physical and biological aspects of the sea.On earth there are four major oceans which are the pacific,Atlantic, Indian and arctic.
About years ago oceanographers covered the wide range of topics including the marine life and the ecosystems,the circulation of the ocean,plate tectonics and the geology of the sea floor.and the chemical and the physical properties of the ocean.
