Question

larger producer of food in the ocean

Answer 1

They are algae and then comes the phytoplanktons

Answer 2

World's Biggest Oxygen Producers Living in Swirling Ocean Waters. Oceanographers probe the impact of deep swirling vortices on phytoplankton. Plankton are not just one species of sea creature but, rather, a large variety of tiny organisms. Algae, bacteria, crustaceans, mollusks, and more are all considered plankton.