Subdisciplines

Phycology - Study of algae
Mycology - Study of fungi (mushrooms, molds, yeast)
Protozoology - Study of protozoa
Virology - Study of viruses
Bacteriology - Study of bacteria
Medical microbiology - Study of the relationship between disease and micro-organisms
Parasitology - Study of protozoa, helminths, some insects that act as vectors (mosquitoes)
Immunology - Study of defense mechanism, antibodies, antigens. Includes allergy and hypersensitivities
Molecular biology - DNA/RNA sequencing for the purposes of identification of the organism and its genetic relationship with other organisms
Microbial ecologist - Study of how organisms act in the soil, water, or other habitats. Study of their part in the carbon and nitrogen cycles
Microbial physiologist - Study of metabolic pathways such as fermentation