Oxygen production primarily occurs through the process of photosynthesis, where plants, algae, and some bacteria convert sunlight, carbon dioxide, and water into glucose and oxygen. During this process, chlorophyll in plant cells captures sunlight, enabling the conversion of carbon dioxide from the air and water from the soil into energy-rich compounds. In addition to plants, oceans play a significant role in oxygen production. Marine organisms, particularly phytoplankton, contribute to about 50% of the Earth's oxygen supply. These tiny, photosynthetic organisms thrive in sunlight-rich waters, producing oxygen as a byproduct of their energy-making processes.