Oceanography is a very important discipline for understanding the oceans, which are essential for all life on Earth and cover the majority of the Earth's surface. Oceanography is extremely multidisciplinary, covering the physics, chemistry, geology and biology of the world's oceans. No understanding of Earth's climate or the chemical cycles essential to life is complete without the insights of oceanography.
Oceanography covers both the deep oceans and the much shallower coastal regions. The breadth of knowledge in oceanography means oceanographers tend to be rather specialized around one specific subject. Many different sorts of tools and instruments are used in oceanography. While ships are certainly a part of this, other methods, such as stationary underwater observatories, are also used to study the ocean. Modern oceanographers also use automated underwater vehicles and sophisticated scanning devices to uncover information more quickly than direct human effort could accomplish.
The importance of oceans to life cannot be overstated, even on land. Oceans are a critical source and absorber of heat, moderating worldwide temperatures. Also, the majority of oxygen generation comes from single-celled algae in the oceans, not from land plants. As the bodies containing the vast majority of water on Earth, oceans are also the major source of cloud formation and thus, a driver of weather.