: Like land plants, phytoplankton use sunlight, carbon dioxide ( CO2cap C cap O sub 2

The ocean is far more than just a body of water; it is often referred to as the "lungs of the planet," responsible for producing roughly of the world's oxygen . While the vast majority of this comes from surface-level photosynthesis, recent groundbreaking discoveries have revealed that the deep ocean also produces its own "dark oxygen". 1. The Surface Engine: Photosynthesis

), and water to create energy, releasing oxygen as a byproduct. :

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.