What is plankton?

What is plankton?

• A. Small organisms that drift in water and are a crucial food source for many aquatic animals.
• B. Large nektonic predators that actively swim.
• C. Benthic organisms living on the seafloor.
• D. Floating debris that accumulates in currents.

Answer: (A)

Plankton are organisms that cannot swim against the current very effectively, so they drift with the water. They form the base of aquatic food webs, delivering energy up from the tiniest producers to a wide range of creatures. Phytoplankton are photosynthetic, making their own food using sunlight, while zooplankton are small animals that eat phytoplankton or other tiny organisms. This combination is why plankton are such a crucial food source for many aquatic animals, from small fish to large filter feeders.

The other options describe different things: nekton are actively swimming animals, like fish and squid; benthic organisms live on the seafloor; and floating debris is not living organisms.