* Algae: Algae are a diverse group of microscopic organisms that are found in all freshwater environments. They are important primary producers, meaning that they convert sunlight into energy that can be used by other organisms.
* Protozoa: Protozoa are single-celled organisms that are found in all freshwater environments. They are typically predators or scavengers, and they play an important role in the decomposition of organic matter.
* Rotifers: Rotifers are microscopic animals that are found in all freshwater environments. They are filter feeders, and they play an important role in the removal of suspended particles from the water.
* Cladocerans: Cladocerans are small, crustacean zooplankton that are found in all freshwater environments. They are filter feeders, and they play an important role in the removal of suspended particles from the water.
* Copepods: Copepods are small, crustacean zooplankton that are found in all freshwater environments. They are predators, and they play an important role in the control of phytoplankton populations.
Microscopic Organisms in Marine Environments
* Phytoplankton: Phytoplankton are a diverse group of microscopic organisms that are found in all marine environments. They are important primary producers, meaning that they convert sunlight into energy that can be used by other organisms.
* Zooplankton: Zooplankton are microscopic animals that are found in all marine environments. They are typically predators or scavengers, and they play an important role in the decomposition of organic matter.
* Ichthyoplankton: Ichthyoplankton are the eggs and larvae of fish. They are found in all marine environments, and they play an important role in the recruitment of new fish to the population.
* Meroplankton: Meroplankton are the larvae of benthic invertebrates. They are found in all marine environments, and they play an important role in the recruitment of new benthic invertebrates to the population.
* Holoplankton: Holoplankton are microscopic organisms that spend their entire lives in the plankton. They are found in all marine environments, and they play an important role in the transfer of energy between different trophic levels.