A marine biologist's day involves collecting animal and plant samples underwater, organizing samples in a lab, analyzing data on a computer, and monitoring experiments. The document provides an example schedule of a marine biologist who collects samples for 9 hours, analyzes data and eats lunch from 12-2pm, then tags animals and monitors experiments in the afternoon. It also outlines the education and training needed to become a marine biologist, as well as average salaries of $40,000 to $100,000 depending on the field and employer.