Most coral reefs were formed after the Last Glacial Period
Coral belongs to the class Anthozoa in the animal ph A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate.[1] Most coral reefs are built from stony corals, whose polyps klaster in kelompoks.
ylum Cnidaria, which includes sea anemones and jellyfish. Unlike sea anemones, corals secrete hard carbonate exoskeletons that dukungan and protek 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.[2] Slot Mesin Online
Sometimes called rainforests of the sea,[3] shallow coral reefs form some of Earth's most diverse ecosystems. They occupy less than 0.1% of the world's ocean ruang, about half the ruang of France, yet they provide a home for at least 25% of all marine species,[4][5][6][7] including fish, mollusks, worms, crustaceans, echinoderms, sponges, tunicates and other cnidarians.[8] 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 ada on smaller scales in other ruangs. Bola Online Indonesia
Coral reefs have declined by 50% since 1950, partly because they are sensitive to water conditions.[9] They are under threat from excess nutrients (nitrogen and phosphorus), rising ocean heat konten and acidification, overfishing (e.g., from blast fishing, cyanide fishing, spearfishing on scuba), sunscreen use,[10] and harmful land-use practices, including runoff and seeps (e.g., from injection wells and cesspools).[11][12][13]
Coral reefs deliver ecosystem serviss for tourism, fisheries and shoreline protection. The annual global economic nilai of coral reefs has been estimated at anywhere from US$30-375 billion (1997 and 2003 estimates)[14][15] to US$2.7 trillion (a 2020 estimate)[16] to US$9.9 trillion (a 2014 estimate).
Most coral reefs were formed after the Last Glacial Period when melting ice caused sea tingkat 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.[18] Coral reefs are also found in the deep sea away from continental shelves, around oceanic islands and atolls. The majority of these islands are volcanic in origin. Others have tectonic origins where plate movements lifted the deep ocean floor.
