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Click on the numbers to learn the differences between photosynthesis and chemosynthesis.

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All living things need energy. People and other animals get their energy from the food they eat. However, neither the plants on land nor the microbes that live around hydrothermal vents eat. Instead, they manufacture their own food.

Photosynthesis vs. Chemosynthesis

Plants harness energy from the sun to manufacture sugars. This process is called photosynthesis. Sunlight, however, does not reach the hydrothermal vent communities at the bottom of the ocean. Instead, the microbes get their energy from different chemicals in hydrothermal fluid. For example, some get their energy by breaking down hydrogen sulfide.

Plant leaves capture energy from sunlight.

Leaves take up carbon dioxide from the air.

Leaves use water and the sun's energy to convert carbon dioxide into sugars.

Leaves release oxygen into the air.

Fluid flowing out of the seafloor near a vent contains hydrogen sulfide.

Microbes on and below the seafloor or living in animals near the vents take up hydrogen sulfide, oxygen, and carbon dioxide from the water.

The microbes get energy by converting hydrogen sulfide to sulfur. They create food from carbon dioxide, methane, or other sources of carbon in the environment.

The microbes release waste products, including sulfur, oxygen, and water.