Britannica Educational Publishing 
Investigating Earth’s Oceans [PDF ebook] 

Contained in the immensity and depths of the Earth’s oceans, many of the planet’s species and resources thrive far away from the reaches of human civilization. With expanses that have yet to be discovered and enormous reservoirs of untapped potential, oceans provide fodder for all manners of research. This informative volume describes the features and properties of the bodies of water that make up 70 percent of the world’s surface as well as the various branches of oceanography dedicated to studying all aspects of the ocean and its life forms.