Phytoplankton

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

1. Phytoplankton are primary producers, converting sunlight into chemical energy through photosynthesis.
2. They contribute to about 50% of the global oxygen supply.
3. Phytoplankton populations can be affected by nutrient availability, light conditions, and water temperature.
4. Diatoms and dinoflagellates are two major groups of phytoplankton.
5. Phytoplankton are integral to the carbon cycle as they absorb CO2 during photosynthesis and can sequester carbon when they die and sink.

Review Questions

• What role do phytoplankton play in the marine food web?
• How do phytoplankton contribute to global oxygen production?
• Name two major groups of phytoplankton.

Related terms

Zooplankton: Small aquatic organisms that feed on phytoplankton.

Photosynthesis: The process by which green plants and certain microorganisms use sunlight to synthesize foods with the aid of chlorophyll.

Carbon Cycle: 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.