plankton

2. Planktonic organisms that spend only a part of their life cycle as plankton.
4. Extremely small-sized plankton, smaller than microplankton.
7. Organisms that produce their own food through processes like photosynthesis.
8. Zooplankton that remain in the planktonic phase throughout their entire life cycle.
10. Microscopic organisms that drift or float in aquatic environments.
11. Small animals that feed on phytoplankton or other zooplankton.
12. The position an organism occupies in a food chain, indicating its feeding relationship to other organisms.
14. A close and long-term interaction between different biological species.
16. Unicellular algae that can be both phytoplankton and sometimes bioluminescent.
17. Organisms that obtain their energy by consuming other organisms.
18. Larger-sized plankton, visible under a microscope.
20. Planktonic organisms that spend their entire life cycle in the planktonic phase.

1. Small crustaceans that are a common type of zooplankton.
3. A bloom of harmful, often toxic, phytoplankton that can lead to the discoloration of water.
5. Microscopic, photosynthetic organisms that form the base of the aquatic food chain.
6. A rapid increase in the population of planktonic organisms, often causing discoloration of the water.
9. A type of phytoplankton with a silica-based cell wall, often shaped like a glass shell.
13. The depth in the water column where the rate of photosynthesis equals the rate of respiration.
15. Pertaining to the bottom of a body of water; organisms living on or in the substrate.
19. Free-swimming aquatic organisms, such as fish and squid, capable of active movement.