To learn about being a marine biologist, you should first know the definition of marine biology. Marine biology is the study of plants and animals that live in salt water. There are thousands of marine species, and marine biology may include the study of any of them, from tiny plankton to huge blue whales.
Tools used to study the biology of marine organisms include sampling tools such as plankton nets and trawls, underwater equipment such as video cameras, remotely operated vehicles, hydrophones and sonar, and tracking methods such as satellite tags and photo-identification research.
This article describes in more detail what a marine biologist does, where they work, and what they get paid.
As described above, the term "marine biologist" is very general - an actual marine biologist likely has a more specific title. Titles include "ichthyologist" (someone who studies fish), "cetologist" (someone who studies whales), marine mammal trainer, or microbiologist (someone who studies microscopic organisms).
Marine biologists may work at colleges or universities, government agencies, non-profit organizations, or privately-owned businesses. This work may occur "in the field" (outside), in a laboratory, in an office, or a combination of all three. Their pay range depends on their position, their qualifications, and where they work.
There are many online resources for job-hunting, including career web sites. You can also go directly to the source - including web sites for government agencies (e.g., related agencies such as NOAA's career web site) and career departments for universities, colleges, organizations or aquariums where you'd like to work.
The best way to get a job, though, is by word-of-mouth or working your way up to a position. Through volunteering, interning, or working in an entry-level position, you're more likely to learn about available job opportunities, and the people in charge of hiring might be more likely to hire you if they've worked with you before, or if they get a stellar recommendation about you from someone they know.