In photic zones benthic diatoms dominate as photosynthetic organisms. Food inclusions contain bacteria, bluegreen algae, small dinoflagellates, diatoms, ciliates, and other dinoflagellates. Juveniles feed on phytoplankton like diatoms and small zooplankton including cladocerans and ostracods. Its food consists of crustacean larvae, small copepods, diatoms, algae and detritus. The most important groups of phytoplankton include the diatoms and dinoflagellates. Phytobenthos comprises the plants belonging to the benthos, mainly benthic diatoms and macroalgae (seaweed). Some species of brown algae (Fucales, Laminariales and diatoms) contain apparent polyploid genomes. Tadpoles feed on algae, including diatoms filtered from the water through the gills. In contrast, Copeland's term included nucleated eukaryotes such as diatoms, green algae and fungi. The biogeochemical silica cycle is regulated by the algae known as the diatoms. Hydroxyproline is also found in the walls of oomycetes, fungus-like protists related to diatoms. Diatomaceous earth consists of fossilized remains of diatoms, a type of hard-shelled protist. Silica forms the exoskeleton in the microscopic diatoms and radiolaria. Rhamnose is also produced by microalgae belonging to class Bacillariophyceae (diatoms). Thalassiosira pseudonana is a species of marine centric diatoms.