Ocean bacteria use light to grow through a process called photosynthesis. Photosynthesis is the process by which plants and other organisms use sunlight to convert carbon dioxide and water into energy-rich molecules, such as glucose.

Ocean bacteria are not the only organisms that use photosynthesis to grow. Plants, algae, and some species of protists also use photosynthesis. However, ocean bacteria are responsible for a significant portion of the Earth's oxygen production. In fact, it is estimated that ocean bacteria produce up to half of the Earth's oxygen.

Ocean bacteria use a variety of pigments to absorb light for photosynthesis. Some of the most common pigments are chlorophyll a, chlorophyll b, and carotenoids. These pigments are located in the cell membranes of the bacteria and they absorb light in specific wavelengths.

Once light is absorbed, it is used to power the chemical reactions of photosynthesis. These reactions include the splitting of water and the absorption of carbon dioxide from the atmosphere. The products of photosynthesis are glucose and oxygen.

The glucose produced by photosynthesis is used by the bacteria for energy. The oxygen produced by photosynthesis is released into the atmosphere and is used by all aerobic organisms, including humans.

Photosynthesis is essential for the survival of life on Earth. Without photosynthesis, plants, algae, and ocean bacteria would not be able to survive and without them, there would be no oxygen for animals to breath. Furthermore, phytoplankton - microscopic marine plants that do photosynthesis - help remove and store the greenhouse gas carbon dioxide, helping cool the planet. Therefore, ocean bacteria play a vital role in the global ecosystem.