In an ocean ecosystem which is necessary to begin a food web?

In an ocean ecosystem, phytoplankton are essential for initiating a food web. These microscopic plants perform photosynthesis, converting sunlight into energy and forming the base of the food chain. They are consumed by small marine organisms like zooplankton, which in turn serve as food for larger species, establishing a complex network of energy flow throughout the ecosystem. Without phytoplankton, the entire marine food web would collapse.