Plankton Biologist


Plankton are relatively small organisms whose movements are dominated by currents, though many can swim. They come in all shapes and sizes, the smallest of which are the bacteria, which are too small to be seen without a microscope. Phytoplankton include all kinds of microscopic plants, like diatoms and dinoflagellates. These tiny plants are critical primary producers that form the base of the ocean food chain. Zooplankton (animal plankton) graze on phytoplankton, or may eat other zooplankton. They are an important food source for many other marine animals, including fish, seals, and whales.

Studying plankton helps scientists understand many other things about the ocean, such as changes in fish stocks, pollution, and climate. Most phytoplankton are harmless, however, a few species can produce toxic chemicals. Shellfish like clams, mussels, and oysters are filter feeders that can consume these harmful plankton, causing the poisons to build up in their flesh. If other animals—including humans—eat these shellfish, they can get sick. It is important to monitor harmful algal blooms and understand the organisms that cause them.

Education Requirements

Estimated Salary

  • B.S. in biology, ecology, oceanography, or related field
  • Master’s degree in microbiology, marine biology, or biological oceanography often needed for advanced positions (PhD usually required)

For salary information, please visit the United States Bureau of Labor Statistics

Tasks and Duties

Plankton biologists may have a variety of responsibilities depending on the specific nature of their job. These could include:

  • Research the growth, development, and other characteristics of phytoplankton and/or zooplankton
    • Harmful algal blooms
  • Identify and classify plankton
  • Study how plankton interact with the ocean environment
    • Investigate trophic relationships/food web dynamics
    • Assess phytoplankton diversity in different water bodies
    • Identify toxic species of plankton; research harmful algal blooms
    • Climate change
  • Prepare technical reports, research papers, presentations, and recommendations based on research findings
  • Make recommendations on management systems and planning
  • Teaching undergraduate and graduate courses (if in academia)

Knowledge and Skills

Basic skills might include:

  • Laboratory skills
    • Analysis and experimentation not limited to plankton culture and maintenance
    • Plankton identification/ species compositional differences
    • Experience with laboratory equipment such as microscopes, gas chromatographs, electrophoresis gels, fluorescent cell sorters, particle counters, splitters, and various chemicals and/or dyes
  • Field research skills
    • Experience with oceanographic sampling techniques
    • Experience with field sampling equipment including pumps, bottle samplers, nets, high-frequency acoustics, and optics
    • Plankton identification
  • Interpersonal Skills
    • Many plankton biologists work on teams in the laboratory and field. They must be able to work effectively with others to achieve their goals

May need knowledge in:

  • Biology
  • Chemistry/Biochemistry
  • Ecology
  • Oceanography
  • Marine Botany/Microbiology/and/or Zoology
  • Physics
  • Statistics/Statistical Modeling

Basic skills may also include:

  • Research and analytical skills
    • Data organization, processing, and analytics
    • Willingness to work long hours in a laboratory or in the field
    • Shipboard experience may be useful
  • Written and oral communication skills
    • Preparation of technical reports and presentations
    • Authoring research articles
    • Drafting grant proposals
  • Computer skills
    • Use of computer applications
  • Interpersonal skills
    • Coordination and supervision of research personnel
    • Ability to teach and mentor undergraduate and graduate students (university-level teaching positions)
    • Ability to cooperate and collaborate with others
    • Public interactions and public speaking (ability to explain things to diverse audiences)

Connections to Underwater Acoustics

Studying plankton helps scientists understand many other things about the ocean, such as changes in fish stocks, pollution, and climate. Acoustics have become an important part of plankton research. Sonar systems, similar to fish finding sonars, can be used to study zooplankton. These systems measure the echoes produced when sound bounces off layers or even individual zooplankton. Sonar has helped scientists watch the vertical movement of zooplankton layers in response to light, nutrients, food, and other physical and chemical characteristics of the water and to determine how other animals, such as whales, respond to these movements. Sound can also be used to estimate the biomass of plankton. By knowing the depth of the layer, the salinity and temperature of the water, the frequency of the sound wave, the type of zooplankton, and the return time, scientists can quantify how much plankton is gathered in the water . Zooplankton are typically too small and too close together for individual animals to be identified using ship-borne sensors; however, acoustic mapping can be used to calculate their overall abundance and distribution. New, very high frequency acoustic sensors that are lowered into plankton patches are beginning to allow observations of the behavior of individual animals.

Plankton biologists and other scientists are also studying the sound detection capabilities of coral reef and invertebrate larvae (which are zooplankton). There is evidence these larvae use acoustic cues to guide them to coastal areas and identify suitable settlement sites. If anthropogenic sounds are masking natural reef sounds, coral reef fish (and invertebrate) populations may be negatively impacted. More research is needed on the hearing abilities of early life history stages of fishes and invertebrates and the special characteristics of natural reef sounds to which fish and/or invertebrates may be attracted.

Example of someone in this career

Dr. Kelly Benoit-Bird

Dr. Kelly Benoit-Bird is an Associate Professor in the College of Earth, Ocean, and Atmospheric Sciences at Oregon State University. She examines a wide range of animals including zooplankton, fish, squid, and marine mammals using active acoustics (sonar) to understand the role of spatial heterogeneity (patches) and temporal patterns in pelagic marine ecosystems. She is particularly interested in the role of animal behavior in the formation of patches in the ocean and the effects of behavior like schooling, cooperation, and other ‘group’ processes on inter-individual and predator-prey interactions. In order to address complex, four-dimensional problems she often develops new acoustic techniques and integrates these tools with other approaches including optical sampling, animal tagging, and behavioral modeling, typically as part of interdisciplinary research programs.

Related Careers

  • Biological Oceanographer
  • Microbiologist
  • Marine biologist
  • Marine ecologist


People and Sound
Investigate Marine Animals > How is sound used to measure plankton?

Resources Microbiology careers

Arizona State University, School of Life Sciences: Ask a Biologist 

United States Bureau of Labor Statistics