Bacteria are important for decomposition and release of nutrients. They are important for converting ammonia and nitrogen into nitrates and nitrites. Protista are single-celled organisms with a nucleus. This kingdom includes plants and animals such as the foraminifera, coccoliths, diatoms, and radiolarians. These groups are responsible for most deep sea oozes.
Fungi are abundant in the intertidal zone and are important in decomposition.
Metaphyta are the plants that grow attached to the sea floor. This kingdom includes the red, brown, and green algae and the advanced plants of the salt marshes and coastal swamps. They are only found in shallow areas where the bottom is in the photic zone. Metazoa include all multicellular animals in the ocean. Plankton are the organisms which float in the water and have no ability to propel themselves against a current.