Also, several different home video versions, as well as a director's cut (1997) supervised by Petersen, have been released.Īn adaptation of Lothar-Günther Buchheim's 1973 German novel based on his experiences aboard German submarine U-96, the film is set during World War II and follows U-96 and her crew, as they set out on a hazardous patrol in the Battle of the Atlantic. It has been exhibited both as a theatrical release (1981) and a TV miniseries (1985). The tower of the submarine, Bavaria Studios, Munichĭas Boot ( German pronunciation:, The Boat) is a 1981 West German war film written and directed by Wolfgang Petersen, produced by Günter Rohrbach, and starring Jürgen Prochnow, Herbert Grönemeyer and Klaus Wennemann. A coral reef is an underwater ecosystem characterized by reef-building corals.DM 32 million (equivalent to €34 million 2021) Reefs are formed of colonies of coral polyps held together by calcium carbonate. Most coral reefs are built from stony corals, whose polyps cluster in groups.Ĭoral belongs to the class Anthozoa in the animal phylum Cnidaria, which includes sea anemones and jellyfish. Unlike sea anemones, corals secrete hard carbonate exoskeletons that support and protect the coral. Most reefs grow best in warm, shallow, clear, sunny and agitated water. Coral reefs first appeared 485 million years ago, at the dawn of the Early Ordovician, displacing the microbial and sponge reefs of the Cambrian. Sometimes called rainforests of the sea, shallow coral reefs form some of Earth's most diverse ecosystems. They occupy less than 0.1% of the world's ocean area, about half the area of France, yet they provide a home for at least 25% of all marine species, including fish, mollusks, worms, crustaceans, echinoderms, sponges, tunicates and other cnidarians. Coral reefs flourish in ocean waters that provide few nutrients. They are most commonly found at shallow depths in tropical waters, but deep water and cold water coral reefs exist on smaller scales in other areas.Ĭoral reefs have declined by 50% since 1950, partly because they are sensitive to water conditions. They are under threat from excess nutrients (nitrogen and phosphorus), rising ocean heat content and acidification, overfishing (e.g., from blast fishing, cyanide fishing, spearfishing on scuba), sunscreen use, and harmful land-use practices, including runoff and seeps (e.g., from injection wells and cesspools). Ĭoral reefs deliver ecosystem services for tourism, fisheries and shoreline protection. The annual global economic value of coral reefs has been estimated at anywhere from US$30–375 billion (19 estimates) to US$2.7 trillion (a 2020 estimate) to US$9.9 trillion (a 2014 estimate). 13.5.1 Invasive algae in Caribbean reefs. Most coral reefs were formed after the Last Glacial Period when melting ice caused sea level to rise and flood continental shelves. ![]() ![]() Most coral reefs are less than 10,000 years old. As communities established themselves, the reefs grew upwards, pacing rising sea levels. Reefs that rose too slowly could become drowned, without sufficient light. Coral reefs are found in the deep sea away from continental shelves, around oceanic islands and atolls. The majority of these islands are volcanic in origin.
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