Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025
Definition
Phytoplankton are microscopic, photosynthetic organisms found in aquatic environments. They form the base of the marine food web and play a crucial role in biogeochemical cycles, particularly carbon cycling.
5 Must Know Facts For Your Next Test
Phytoplankton are primary producers, converting sunlight into chemical energy through photosynthesis.
They contribute to about 50% of the global oxygen supply.
Phytoplankton populations can be affected by nutrient availability, light conditions, and water temperature.
Diatoms and dinoflagellates are two major groups of phytoplankton.
Phytoplankton are integral to the carbon cycle as they absorb CO2 during photosynthesis and can sequester carbon when they die and sink.
Review Questions
Related terms
Zooplankton: Small aquatic organisms that feed on phytoplankton.
The series of processes by which carbon compounds are interconverted in the environment, involving the incorporation of CO2 into living tissue by photosynthesis and its return to the atmosphere through respiration, decay, and combustion.