Search results
Results From The WOW.Com Content Network
Humans often aggregate near coastal habitats to take advantage of ecosystem services. For example, coastal capture fisheries from mangroves and coral reef habitats are estimated to be worth a minimum of $34 billion per year. [64] Yet, many of these habitats are either marginally protected or not protected.
Only 46% of the world's reefs could be currently regarded as in good health [4] and about 60% of the world's reefs may be at risk due to destructive, human-related activities. The threat to the health of reefs is particularly strong in Southeast Asia , where 80% of reefs are endangered .
Reef types include fringing reefs, barrier reefs, and atolls. A fringing reef is a reef that is attached to an island. Whereas, a barrier reef forms a calcareous barrier around an island, resulting in a lagoon between the shore and the reef. Conversely, an atoll is a ring reef with no land present.
Each ecoregion possesses a unique combination of biotic and abiotic conditions and hosts a unique community of neustonic organisms. Yet these ecoregions have been largely forgotten. [1] But there is another reason to study neuston: The ocean's surface is on the front line of human impacts, from climate change to pollution, oil spills to plastic.
A reef is a ridge or shoal of rock, coral or similar relatively stable material, lying beneath the surface of a natural body of water. [55] Many reefs result from natural, abiotic processes but there are also reefs such as the coral reefs of tropical waters formed by biotic processes dominated by corals and coralline algae.
Canton Island typifies the isolated coral atolls dotting the Pacific Ocean. The Structure and Distribution of Coral Reefs, Being the first part of the geology of the voyage of the Beagle, under the command of Capt. Fitzroy, R.N. during the years 1832 to 1836, was published in 1842 as Charles Darwin's first monograph, and set out his theory of the formation of coral reefs and atolls.
The off-reef floor is the shallow sea floor surrounding a reef. This zone occurs next to reefs on continental shelves. Reefs around tropical islands and atolls drop abruptly to great depths and do not have such a floor. Usually sandy, the floor often supports seagrass meadows which are important foraging areas for reef fish.
The most common evaporite minerals found within modern and ancient deposits are gypsum, anhydrite, and halite. These minerals can occur as crystalline layers, isolated crystals, or clusters of crystals. [2] Approximately 75% of surface sediments are in shallow marine environments, holding most Phanerozoic and Precambrian sedimentary rock. [3]