Estuary food webs begin with the conversion of the sun’s energy to food energy by plants and plankton. Simplified feeding relationships are shown in this diagram.There are two main feeding pathways. One begins with large plants such as mangroves, seagrass and rushes. When they die their leaves and roots are broken down by bacteria and fungi to become detritus. Detritus is eaten by small animals such as snails, worms and shellfish and they, in turn, are eaten by larger creatures such as fish and birds. A second pathway begins with microscopic phytoplankton. They are eaten by tiny zooplankton which then become food for snails and shellfish.