What are zooplankton?

Zooplankton are indeed classified as planktonic animals that primarily feed on phytoplankton, which are plant-like organisms that float in aquatic environments. This distinction is essential because zooplankton play a crucial role in aquatic ecosystems as they serve as a vital food source for larger marine animals, such as fish and whales.

Unlike planktonic plants, which are responsible for photosynthesis and contribute to the primary production of the aquatic food web, zooplankton are heterotrophic. They consume organic material, primarily phytoplankton, enabling energy transfer through different trophic levels in the ecosystem. Zooplankton can include a variety of organisms, ranging from tiny microscopic creatures like copepods to larger jellyfish. This feeding relationship underlines their importance in nutrient cycling and energy flow in marine environments.

In context, free-floating microorganisms typically refer to phytoplankton or bacteria, not zooplankton, while bottom-dwelling organisms are associated with a different ecological niche and are not part of the zooplankton category. Understanding this distinction clarifies the roles that these different organisms play in their respective habitats and the overall ecosystem.