There are many different types of biologists. They study areas that are very different. Aquatic biologists study plants and animals that live in water. Marine biologists study salt water organisms. Limnologists study fresh water organisms.
Biochemists study the chemicals that make up living things.
Botanists study plants and their environment. Ecologists study the relationship between organisms and their environments. Medical microbiologists study the relationship between organisms and diseases. Microbiologists investigate the growth and characteristics of microscopic organisms. Bacteria, algae, or fungi are examples of such organisms.