Plankton Types to Know for Marine Biology

Plankton are tiny organisms that play a huge role in marine ecosystems. They include phytoplankton, which produce oxygen, and zooplankton, which transfer energy through the food web. Understanding these types helps us grasp the ocean's complex dynamics.

1. Phytoplankton

   • Microscopic, photosynthetic organisms that form the base of the marine food web.
   • Produce approximately 50% of the Earth's oxygen through photosynthesis.
   • Key players in carbon cycling, absorbing carbon dioxide and influencing climate regulation.

2. Zooplankton

   • Heterotrophic plankton that feed on phytoplankton and other small organisms.
   • Includes a diverse range of organisms, from tiny protozoa to larger jellyfish.
   • Essential for transferring energy from primary producers (phytoplankton) to higher trophic levels, such as fish.

3. Bacterioplankton

   • Composed of bacteria and archaea, playing a crucial role in nutrient cycling and decomposition.
   • Important for the breakdown of organic matter, recycling nutrients back into the ecosystem.
   • Can influence the health of marine environments by regulating microbial communities.

4. Holoplankton

   • Organisms that spend their entire life cycle in the planktonic stage.
   • Includes both phytoplankton and zooplankton, such as copepods and krill.
   • Vital for maintaining the structure of marine ecosystems and food webs.

5. Meroplankton

   • Organisms that are planktonic only during a part of their life cycle, typically in larval stages.
   • Includes the larvae of fish, mollusks, and crustaceans, which eventually settle to the ocean floor.
   • Contributes to biodiversity and population dynamics in marine environments.

6. Microplankton

   • Small planktonic organisms ranging from 20 to 200 micrometers in size.
   • Includes both phytoplankton and small zooplankton, such as ciliates and small copepods.
   • Plays a significant role in primary production and nutrient cycling in marine ecosystems.

7. Nanoplankton

   • Extremely small plankton, typically ranging from 2 to 20 micrometers in size.
   • Composed mainly of small phytoplankton and bacteria, contributing to primary production.
   • Important for the microbial food web and nutrient dynamics in aquatic systems.

8. Picoplankton

   • The smallest plankton, measuring less than 2 micrometers in size.
   • Primarily consists of cyanobacteria and small heterotrophic bacteria.
   • Plays a critical role in nutrient cycling and serves as a food source for larger plankton.

9. Macroplankton

   • Larger planktonic organisms, typically ranging from 200 micrometers to 2 centimeters.
   • Includes larger zooplankton like jellyfish and some larval fish.
   • Important for energy transfer within marine food webs and can impact fish populations.

10. Megaplankton

    • The largest planktonic organisms, exceeding 2 centimeters in size.
    • Includes large jellyfish and some species of planktonic larvae.
    • Can have significant ecological impacts, including predation on smaller plankton and competition for resources.