The primary source of phytoplankton productivity in the ocean is sunlight, which facilitates photosynthesis. Phytoplankton play a vital role as primary producers, converting solar energy into organic compounds that form the base of the marine food web. Nutrient availability, particularly nitrogen and phosphorus, also significantly influences their productivity. Understanding phytoplankton dynamics is essential for assessing ocean health, supporting fisheries, and mitigating the impacts of climate change on marine ecosystems.