If you are interested in Oceanography or you want to specialize in marine species, then Marine Biology is an ideal subject for you. In fact, a PhD. in Marine Biology is for those students who want to discover untouched areas of marine species. If you want to contribute something new to this field, then this kind of research oriented subject is required. This subject is highly pursued in various parts of North America. You will learn various aspects of Environmental Science in this subject. In some universities Marine Biology is studied as a category of Ocean Studies. You will learn new techniques of saving the creatures of the ocean. Here one can understand the effects of environmental pollution on the ocean. You will discover new organisms thriving in the ocean's depth. This PhD. may require around 6 years in completing. In these six years, you will become an expert in this subject.