Phytoplankton are microscopic, photosynthetic organisms that drift in bodies of water and play a crucial role in the marine and freshwater ecosystems. They are a primary producer at the base of the food chain, converting sunlight into energy through photosynthesis. Phytoplankton are a diverse group of organisms, including diatoms, dinoflagellates, and cyanobacteria. They are sensitive to changes in environmental conditions such as nutrient levels, temperature, and light availability, making them important indicators of ecosystem health. Research on phytoplankton focuses on their abundance, diversity, distribution, and ecological roles in aquatic environments. Additionally, phytoplankton play a key role in the global carbon cycle, as they are responsible for a significant portion of carbon fixation in the oceans. Studying phytoplankton is essential for understanding and predicting the impacts of climate change on marine ecosystems.