{"title":"Wind-Generated Waves","authors":"R. Davidson-Arnott","doi":"10.1017/CBO9780511841507.005","DOIUrl":"https://doi.org/10.1017/CBO9780511841507.005","url":null,"abstract":"Synopsis Wind-generated waves are the most important energy input into the littoral zone and, together with wave-generated currents, they are responsible for coastal erosion and sediment transport. They are thus the primary force leading to modification of the coast and the creation of erosional and depositional landforms A wind wave is simply a vertical displacement of the surface of a body of water that results from the transfer of energy from the wind to the water surface. Wind-generated waves are periodic, in that they appear as undulations on the water surface characterised by a high point, or crest, followed by a low point, or trough. They are also progressive in that the wave form travels across the water surface in the direction that the generating wind blows. The energy transferred from the wind is expressed in the potential energy resulting from the displacement of the crest and trough of the wave above and below the original still-water surface, and in the kinetic energy of the circular motion of water particles within the wave. In addition to waves generated by winds, a variety of other waves are found in oceans and lakes ranging from very long period waves, such as the tidal waves generated by the gravitational force of the moon and sun, to waves with much shorter periods, such as the standing waves produced by reflection of wind waves from seawalls.","PeriodicalId":102210,"journal":{"name":"Introduction to Coastal Processes and Geomorphology","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114592958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Coral Reefs and Atolls","authors":"W. Hobbs","doi":"10.1017/9781108546126.013","DOIUrl":"https://doi.org/10.1017/9781108546126.013","url":null,"abstract":"Coral reefs are calcium carbonate (limestone) structures which are created by colonies of polyps that create a hard exoskeleton (the coral), which then becomes home to zooxanthellae which give the corals their colour. The zooxanthellae and corals live in a rela onship which is mutually beneficial, called a symbio c rela onship. Coral bleaching refers to the loss of the zooxanthellae, reducing the stability of the coral; they also lose their colour. Coral reefs have three main structure types. The first is a fringing reef, which forms along the shoreline of most tropical islands. The Barrier Reef is created through the sinking of land below the sea surface, due to a lack of volcanic ac vity. Lastly the third is an atoll, which is created similarly to the Barrier Reef, but the land sinks quicker, and the reef grows upwards to be near the sunlight.","PeriodicalId":102210,"journal":{"name":"Introduction to Coastal Processes and Geomorphology","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129986658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}