西沙群岛地处海南岛到南海诸岛的中心位置, 是构造和生物交互作用形成的典型地质地貌体, 但西沙群岛又地处南海典型气候脆弱区, 是我国遭受台风、风暴潮等极端海洋灾害影响最严重的区域之一。未来推进西沙群岛的岛礁资源高质量发展, 势必会扩大西沙珊瑚礁海岸的使用规模, 加上全球气候日益恶化多重威胁所加重的海洋环境灾害风险, 使得西沙群岛珊瑚礁海岸的海洋防灾减灾挑战更加严峻。因此, 揭示珊瑚礁海岸对于海洋环境的地貌响应, 就成为了厘清珊瑚礁在未来海洋环境影响下生存前景和经略海洋可持续性迫切需要解决的关键问题。所以, 本文选取西沙群岛的18个珊瑚礁作为研究对象, 利用海洋卫星遥感数据获取了它们在2015和2023年的海岸地貌影像, 通过海洋地质和海岸地貌理论分析了珊瑚礁海岸地貌的演化特征, 利用物理海洋分析方法刻画了它们所处海域的海洋环境特征, 尝试利用海洋环境特征解释其海岸地貌演化空间差异性的原因, 关联性分析结果表明这些珊瑚礁海岸地貌演化与其区域海洋环境特征之间强关联性较弱(R2仅在0.06~0.21)。因此本文建议未来科学评判西沙珊瑚礁在全球海洋环境变化下的生存前景, 需要在融合考虑海洋环境要素的基础上, 加强对珊瑚礁所处地貌演化阶段、原始地形地貌、沉积动力过程、生物种群类型影响作用的考量。

Xisha Islands are located at the centre enroute from Hainan Island to other oceanic islands in the South China Sea (SCS). They are typical geological and geomorphological complexes formed by the coupling interaction between tectonic and biological processes. However, their exposed area is also subjected to a typical climate-vulnerable area in SCS, being severely influenced by extreme marine hazards, e.g., typhoons and storm surges. Coral reef coastal areas are expected to be broadly developed in the future, following the strategy of high-quality development of reef island resources in the Xisha Islands. With the aggravating risks and threats of marine environmental disasters due to global climate change considered, the challenges of marine hazards prevention and mitigation in Xisha Islands are further heightened. Hence, to reveal the geomorphic response of coral reef coasts to marine environments becomes a critical issue that urgently needs to be addressed. So that, the survival prospects of coral reefs under future marine environmental impacts could be fairly evaluated for sustainable maritime management. Therefore, this study employs 18 coral reefs in Xisha Islands as their research subjects, using marine satellite remote sensing data to acquire their coastal geomorphology images in 2015 and 2023. Morphological change of these coral reef coasts is characterized based upon marine geology and coastal geomorphology theories. Their surrounding marine environmental conditions are examined using physical oceanographic analysis methods. This study attempts to link the spatial difference of coastal morphological change among reef islands to environmental conditions. The coupled analysis demonstrates only a weak correlation (R2 between 0.06 and 0.21) the coastal morphological difference of these coral reefs and their regional marine environmental characteristics. Therefore, this work suggests that to scientifically asses the survival prospects of coral reefs in Xisha Islands, under the influence of global marine environmental changes, should not only comprehensively consider multiple marine environmental characteristics, but also strengthen the evaluation of their morphological evolution status, original geomorphology, sedimentary dynamics processes and the impact of marine biota of coral reefs.