Many of the biological indicators that give us clues on the health of a pond are microscopic. Since they rely on the surrounding water for its survival it can easily die when conditions are not just right. Microscopic algae is very sensitive to added nutrients that can cause "blooms" which can cause problems to other organisms. Turbidity, or when sediments "cloud" up the water, can prevent light from penetrating the surface. Lack of light can shut down the energy making (photosynthesis) part of the plant, which will reduce the abundance of water plants.
Microscopic algae is at the bottom of the food chain. They feed larger protozoa, invertebrates, and even some fish. Protozoa like paramecium and amoebae are abundant in the ponds. Invertebrates from the arthropod Phylum are also abundant, especially the larval stages of flies and mosquitoes which require water to survive.
The following have been observed in the Tule Ponds: