Protista are an important kingdom to all life on Earth. Protists include algae. They produce most of the oxygen on Earth via the process of photosynthesis. Besides that, the chemical energy that they produce is available to primary consumers in ocean food chains. Without algae, there would be no ocean food chains and all the fisheries in the world would die off. Protists make up the plankton in the ocean that other organisms rely on as a source of nutrition. Some protists are important as disease vectors. For example, amebic dysentery is a serious illness that affects and kills humans. The protist Plasmodium falciparum causes malaria is a disease that kills millions of people every year in the tropics and is carried by Anopheles mosquitoes.