Mesoscale Shoreline Evolution on a Carbonate Sand Island: Anegada, British Virgin Islands
Anegada, the easternmost island of the Virgin Islands group (Caribbean Sea), is a low Pleistocene carbonate platform surrounded by Horseshoe Reef, the world’s third-largest fringing reef. The western part of the island consists of an extensive beachridge plain (>40 ridges). The sandy carbonate sh...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-09-01
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| Series: | Journal of Marine Science and Engineering |
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| Online Access: | https://www.mdpi.com/2077-1312/11/9/1725 |
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| author | Anna Lisa Cescon J. Andrew G. Cooper Derek W. T. Jackson Antoine Collin Shannon Gore |
| author_facet | Anna Lisa Cescon J. Andrew G. Cooper Derek W. T. Jackson Antoine Collin Shannon Gore |
| author_sort | Anna Lisa Cescon |
| collection | DOAJ |
| description | Anegada, the easternmost island of the Virgin Islands group (Caribbean Sea), is a low Pleistocene carbonate platform surrounded by Horseshoe Reef, the world’s third-largest fringing reef. The western part of the island consists of an extensive beachridge plain (>40 ridges). The sandy carbonate shoreline exists in three morphodynamic domains that exhibit distinctive behaviour over the 59-year study period (1953 to 2012). The northern shore is dominated by westerly longshore drift under fair-weather conditions and cross-shore sediment transport during high-energy events. Storm wave run-up and high nearshore sediment availability contribute to the construction of shore-parallel beachridges. The western end of the island is affected by refracted waves that drive strong erosion and sediment transport. This is reflected in a succession of alternating rapid shoreline recession and progradation phases over the study period. The south–central shoreline is exposed to low wave energy and is stable and colonised by mangroves. The fringing reef plays a dominant role in mesoscale shoreline morphodynamics, both as a sediment source and in wave energy dissipation. Quasi-stable points and embayments suggest a strong influence of the reef framework in controlling the shoreline’s morphology and position. Sediment transfer from the reef to the shoreline appears to take place via shore-oblique, linear sediment transport pathways that develop across the lagoon in response to the modification of incoming waves. Cannibalisation of the shoreline sediment over the past 50 years is leading to straightening of the shoreline planform. This is counter to the long-term (Holocene) development of beachridges and suggests a change from a strongly positive to negative sediment budget. |
| first_indexed | 2024-03-10T22:35:04Z |
| format | Article |
| id | doaj.art-5128b498d6a04fb4932b8fa5dba309c3 |
| institution | Directory Open Access Journal |
| issn | 2077-1312 |
| language | English |
| last_indexed | 2024-03-10T22:35:04Z |
| publishDate | 2023-09-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Journal of Marine Science and Engineering |
| spelling | doaj.art-5128b498d6a04fb4932b8fa5dba309c32023-11-19T11:26:33ZengMDPI AGJournal of Marine Science and Engineering2077-13122023-09-01119172510.3390/jmse11091725Mesoscale Shoreline Evolution on a Carbonate Sand Island: Anegada, British Virgin IslandsAnna Lisa Cescon0J. Andrew G. Cooper1Derek W. T. Jackson2Antoine Collin3Shannon Gore4School of Geography and Environmental Sciences, University of Ulster, Coleraine BT52 1SA, UKSchool of Geography and Environmental Sciences, University of Ulster, Coleraine BT52 1SA, UKSchool of Geography and Environmental Sciences, University of Ulster, Coleraine BT52 1SA, UKLaboratoire de Géomorphologie et Environnement Littoral, École Pratique de Hautes Études, 35800 Dinard, FranceCoastal Management Consulting, Road Town, Tortola VG1110, UKAnegada, the easternmost island of the Virgin Islands group (Caribbean Sea), is a low Pleistocene carbonate platform surrounded by Horseshoe Reef, the world’s third-largest fringing reef. The western part of the island consists of an extensive beachridge plain (>40 ridges). The sandy carbonate shoreline exists in three morphodynamic domains that exhibit distinctive behaviour over the 59-year study period (1953 to 2012). The northern shore is dominated by westerly longshore drift under fair-weather conditions and cross-shore sediment transport during high-energy events. Storm wave run-up and high nearshore sediment availability contribute to the construction of shore-parallel beachridges. The western end of the island is affected by refracted waves that drive strong erosion and sediment transport. This is reflected in a succession of alternating rapid shoreline recession and progradation phases over the study period. The south–central shoreline is exposed to low wave energy and is stable and colonised by mangroves. The fringing reef plays a dominant role in mesoscale shoreline morphodynamics, both as a sediment source and in wave energy dissipation. Quasi-stable points and embayments suggest a strong influence of the reef framework in controlling the shoreline’s morphology and position. Sediment transfer from the reef to the shoreline appears to take place via shore-oblique, linear sediment transport pathways that develop across the lagoon in response to the modification of incoming waves. Cannibalisation of the shoreline sediment over the past 50 years is leading to straightening of the shoreline planform. This is counter to the long-term (Holocene) development of beachridges and suggests a change from a strongly positive to negative sediment budget.https://www.mdpi.com/2077-1312/11/9/1725coral reefextreme wave eventsshoreline change analysisbeachridgecarbonate beach |
| spellingShingle | Anna Lisa Cescon J. Andrew G. Cooper Derek W. T. Jackson Antoine Collin Shannon Gore Mesoscale Shoreline Evolution on a Carbonate Sand Island: Anegada, British Virgin Islands Journal of Marine Science and Engineering coral reef extreme wave events shoreline change analysis beachridge carbonate beach |
| title | Mesoscale Shoreline Evolution on a Carbonate Sand Island: Anegada, British Virgin Islands |
| title_full | Mesoscale Shoreline Evolution on a Carbonate Sand Island: Anegada, British Virgin Islands |
| title_fullStr | Mesoscale Shoreline Evolution on a Carbonate Sand Island: Anegada, British Virgin Islands |
| title_full_unstemmed | Mesoscale Shoreline Evolution on a Carbonate Sand Island: Anegada, British Virgin Islands |
| title_short | Mesoscale Shoreline Evolution on a Carbonate Sand Island: Anegada, British Virgin Islands |
| title_sort | mesoscale shoreline evolution on a carbonate sand island anegada british virgin islands |
| topic | coral reef extreme wave events shoreline change analysis beachridge carbonate beach |
| url | https://www.mdpi.com/2077-1312/11/9/1725 |
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