- Algae: Algae are a type of plant that can synthesize their own food through photosynthesis. They absorb sunlight and use it to convert carbon dioxide and water into glucose, which they use for energy.
- Bacteria: Bacteria are single-celled organisms that lack a nucleus. They can be either photosynthetic or heterotrophic. Photosynthetic bacteria use sunlight to convert carbon dioxide and water into glucose, while heterotrophic bacteria consume other organic matter for energy.
- Protozoa: Protozoa are single-celled organisms that are heterotrophic. They consume other organisms, such as bacteria, algae, and other protozoa, for energy.
Some pond scum also obtains nutrients from decomposing plant matter and animal waste in the pond.