Pandoravirus sediments. Pandoraviruses, like other marine viruses, prey on plankton, which are organisms that live in the water column and form the basis of the food chain for other marine species. More study and research needs to be done in order to confirm the prevalence of Pandoraviruses in different environments. Currently, not much is known about their role in marine ecosystems. Pandoraviruses do have approximately 93% of their genes that are unidentifiable with any other microbes, suggesting they may belong to an as of yet undescribed "fourth domain" aside from Bacteria, Archaea, and Eukaryotes. Viruses as a whole are not popularly
Aquatic ecosystem lagoons and mangrove swamps. In the deep water, hydrothermal vents may occur where chemosynthetic sulfur bacteria form the base of the food web. Classes of organisms found in marine ecosystems include brown algae, dinoflagellates, corals, cephalopods, echinoderms, and sharks. Fishes caught in marine ecosystems are the biggest source of commercial foods obtained from wild populations. Environmental problems concerning marine ecosystems include unsustainable exploitation of marine resources (for example overfishing of certain species), marine pollution, climate change, and building on coastal areas. Freshwater ecosystems cover 0.78% of the Earth's surface and inhabit 0.009% of its total water. They generate nearly 3%