Decomposers, as the name suggests, decompose dead plants or animals into simple compounds. They feed on dead producers from the first levels or consumers from other three levels. Breaking them down, decomposers release nutrients that producers can use. In an ecosystem with four levels, the first level are producers, such as plants and algae. On the second trophic level, there are primary consumers, herbivores that eat plants, for example, a deer, a rabbit, a grasshopper. The next trophic level belongs to secondary consumers that eat herbivores, for example, a wolf, a fox. The highest level is tertiary consumers that eat carnivores, for example, a bear, an eagle.
