Title: Marine life
Content: appeared in the form of fish, which live exclusively in water. Some of these evolved into amphibians which spend portions of their lives in water and portions on land. Other fish evolved into land mammals and subsequently returned to the ocean as seals, dolphins or whales. Plant forms such as kelp and algae grow in the water and are the basis for some underwater ecosystems. Plankton, and particularly phytoplankton, are key primary producers forming the general foundation of the ocean food chain. Marine invertebrates exhibit a wide range of modifications to survive in poorly oxygenated waters including breathing tubes (see

Title: Tetraselmis
Content: discovered many species within the genera. Some notable contributors include R.W. Butcher, T. Hori, R.E. Norris, and M. Chihara. "Tetraselmis" species are found in both marine and freshwater ecosystems, and they occupy niches as primary producers in benthic and planktonic food webs. They can be found in many global waters, and their main enforcer of habitat range is light availability which restricts cells to the photic zone of the water column. The primary producers of aquatic ecosystems are mostly unicellular photosynthetic plankton, which includes "Tetraselmis". Planktonic photoautotrophs are important components of aquatic food webs because they form the first trophic

Title: Aquatic ecosystem
Content: 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%

Title: Marine biology
Content: the sea, where mangroves or cordgrass or beach grass might grow. As on land, invertebrates make up a huge portion of all life in the sea. Invertebrate sea life includes Cnidaria such as jellyfish and sea anemones; Ctenophora; sea worms including the phyla Platyhelminthes, Nemertea, Annelida, Sipuncula, Echiura, Chaetognatha, and Phoronida; Mollusca including shellfish, squid, octopus; Arthropoda including Chelicerata and Crustacea; Porifera; Bryozoa; Echinodermata including starfish; and Urochordata including sea squirts or tunicates. Invertebrates have no backbone. There are over a million species. Over 1500 species of fungi are known from marine environments. These are parasitic on marine algae or

Title: Phospholipid-derived fatty acids
Content: on bacteria, of polycyclic aromatic hydrocarbons on rice paddy bacteria and of methylene chloride on bacteria. Phytoplankton (eukaryotic algae) are microscopic photosynthesizing plants that inhabit the sunlit layers of oceans and bodies of freshwater. As the primary source of elaborated carbon compounds, they are vital to the aquatic food web. Phytoplankton produce considerable amounts of polyunsaturated fatty acids (PUFA), including Eicosapentaenoic acid (EPA, 20:5 w3c), with microalgae being the origin of omega-3 fatty acids in fish oil. The diverse taxonomic groups in algae vary in abundance dependent on environmental conditions such as temperature, salinity, sunlight, and nutrient availability. The PLFA

Question: Which microscopic organisms form the basis of marine and freshwater food chains?
Answer: Plankton