Producer, in an ecosystem, is an organism that can produce its own food. An ecosystem is made up of all the living and nonliving things in a particular environment and the interactions that occur among them. Plants and algae are examples of producers. They use sunlight to combine carbon dioxide and water to make food in a process called photosynthesis . Ecologists also call producers autotrophs.
The sun provides most producers with the energy they use. But not all of the sun’s energy reaches producers. Some of it is reflected, scattered, or absorbed in the atmosphere. Some falls on such surfaces as rocks, ice, or soil. Also, the availability of sunlight for photosynthesis varies with latitude. Sunlight is most available in the tropics. The tropics are the regions of Earth that lie close enough to the equator that the sun shines directly overhead at some time during the year. Even in the tropics, only about 1 percent of the light that reaches a plant’s leaves is converted into food energy by photosynthesis.
Some bacteria and other producers that are microbes use a process known as chemosynthesis to make food. Chemosynthesis uses energy released from chemical reactions involving such compounds as hydrogen sulfide. This process does not rely on the sun. Bacteria that use chemosynthesis live in such places as hot springs and in hydrothermal vents on the ocean floor.
Producers have an essential role in ecosystems. They make food energy available to other organisms, called consumers . Consumers cannot make their own food. Instead, they get their energy by eating producers or by eating other consumers. Only energy not used by the producers themselves can be used by consumers.
