In a pond ecosystem, producers include phytoplankton ($e.g.$, diatoms, Chlorella, Spirogyra, Chlamydomonas, etc), free floating macrophytes($e.g.$,Lemna, Azolla), suspended macrophytes($e.g.$, Utricularia, Hydrilla), submerged plants (Vallisneria), floating leaved plants ($e.g.$, Nelumbo), emergent plants (Sagittaria) etc.