In most terrestrial ecosystems, green plants are the producers. In aquatic ecosystems, most of the producers are phytoplankton, consisting of various species of of floating and drifting bacteria and protist. Most producers make their organic nutrients they need through photosynthesis . These producers are called chemosynthesis . An example of this is around the hydrothermal vents in some parts of the deep ocean.
Bacteria carry out chemosynthesis by converting inorganic hydrogen sulfide to organic nutrients.
There are several classes of of consumers, depending on there food source. Omnivores can eat both plants and animals. Examples are pigs, rats, cockroaches, and humans. Decomposers digest detritus by breaking down the complex organic molecules in these materials into simpler, inorganic compounds. Decomposers consist of various bacteria and fungi .