The Antarctic food web: the food web is an interconnected system in which organisms eat other organisms to obtain the energy they need to survive. Generally, smaller creatures are food for larger animals. Explore the Antarctic food web to see how each orange arrow leads from food to its predator.PHYTOPLANKTON phytoplankton Flora of freely floating, often minute organisms that drift with water currents. Like land vegetation, phytoplankton uses carbon dioxide, releases oxygen, and converts minerals to a form animals can use. At the base of the food web are phytoplankton, or tiny plants and plantlike organisms that drift through the ocean. Phytoplankton obtain energy through photosynthesis: They convert sunlight, water, and carbon dioxide carbon dioxide, chemical compound, CO2, a colorless, odorless, tasteless gas that is about one and one-half times as dense as air under ordinary conditions of temperature and pressure. gas into food. ZOOPLANKTON zooplankton: see marine biology. zooplankton Small floating or weakly swimming animals that drift with water currents and, with phytoplankton, make up the planktonic food supply on which almost all oceanic organisms ultimately depend (see Zooplankton are a large variety of small animals hat cannot swim well against the current. KRILL krill: see crustacean. krill Any member of the crustacean suborder Euphausiacea, comprising shrimplike animals that live in the open sea. The name also refers to the genus Euphausia within the suborder and sometimes to a single species, E. superba. Krill is a type of zooplankton. What sets it apart? This shrimplike crustacean--or animal with an external skeleton, segmented body, and paired, jointed legs--is a keystone species. Its presence influences the survival of other species in the food web. BALEEN WHALES The blue whale is one of six species of baleen whales found in Antarctic waters. They have comblike plates in their mouths used for filtering plankton plankton: see marine biology. plankton Marine and freshwater organisms that, because they are unable to move or are too small or too weak to swim against water currents, exist in a drifting, floating state. . SINKING MATTER After marine life dies, it decays into nutrients that sink to the seafloor (yellow arrows). TOOTHED WHALES The killer whale killer whale or grampus, a large, rapacious marine mammal, Orcinus orca, of the dolphin family. Male killer whales may reach a length of 30 ft (9 m) and females half that length. , a toothed whale, is the top predator in the Antarctic food web. It has no natural predators. SEABIRDS Petrels scan the ocean surface, and dive in to nab prey. PENGUINS Emperor penguins can dive to a depth of 565 meters (1,854 feet) to find food. SQUID Antarctic squid species can range from 15 centimeters (6 inches) to 4m (13 ft) in length. SMALL FISH Antarctic silverfish grow to approximately 15 cm (6 in.) in length. They are one of the most abundant fish in Antarctic waters. LARGE FISH The largest Antarctic fish species is the 25 kilogram (55 pound) Antarctic cod. It lives between the depths of 90 m and 1,600 m (300 ft and 5,000 ft). SEALS Most seals eat squid and fish. The leopard seal, however, prefers penguins. BOTTOM DWELLERS The Antarctic seafloor is rich with sea stars and sea urchins. They thrive on nutrients that sink from above (yellow arrows). The Antarctic icefish (left) is the world's only vertebrate, or backboned animal, that lacks red blood cells Red blood cells Cells that carry hemoglobin (the molecule that transports oxygen) and help remove wastes from tissues throughout the body. Mentioned in: Bone Marrow Transplantation red blood cells . It preys on smaller bottom-dwelling fish. |
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