- _Spartina alterniflora_
- Commonly found in the mid-intertidal zone of estuaries
- Highly salt-tolerant due to specialized tissues that excrete excess salt
2. Mangroves
- Various species of the families Rhizophoraceae, Avicenniaceae, and Combretaceae
- Found in tropical and subtropical estuaries where salinities are high and temperatures are warm
- Adapted with aerial roots that help stabilizes sediment and extract oxygen
3. Phytoplankton
- Microalgae such as diatoms, dinoflagellates, and cyanobacteria
- Float freely in the water column and use sunlight for photosynthesis
- Contribute significantly to primary production in estuaries, especially in the upper water column