The primary source of ocean oxygen is microscopic organisms known as . These tiny, plant-like drifters live in the "photic zone"—the top 200 meters of the ocean where sunlight can reach.
: Like land plants, phytoplankton use sunlight, carbon dioxide ( CO2cap C cap O sub 2 Oxygene - The Ocean
), and water to create energy, releasing oxygen as a byproduct. : The primary source of ocean oxygen is microscopic