Explanation:

Phytoplankton serve as the major primary producers in the marine ecosystem. These microscopic, single-celled plants, bacteria, algae and other organisms harvest sunlight through photosynthesis and store it as chemical energy before becoming food for tiny creatures called zooplankton. The phytoplankton rest at the base of these food chains because all the energy used by these larger organisms comes from them. phytoplankton ?also require inorganic nutrients such as nitrates, phosphates andsulpher which convert in to protiens, fats, and carbohydrates.