Joppien Marlena, Morgan Kyle
Asian School of the Environment, Nanyang Technological University, Singapore; Earth Observatory of Singapore, Nanyang Technological University, Singapore.
Asian School of the Environment, Nanyang Technological University, Singapore; Earth Observatory of Singapore, Nanyang Technological University, Singapore.
Mar Pollut Bull. 2025 Mar;212:117596. doi: 10.1016/j.marpolbul.2025.117596. Epub 2025 Jan 23.
Turbid coral reefs are characterised by high turbidity and sedimentation. However, the impacts of terrestrial sediment inputs on coral communities, as well as their interactions with reef-derived carbonate sediment, remain poorly understood. Here we examine the physical properties of mixed carbonate-siliciclastic benthic sediments from six turbid reefs in southern Singapore, which exhibit coral covers ranging from 15 % to 65 %. Coral was the dominant contributor to sand and gravel sediment on reefs (mean ± SE: 57 ± 1 %), followed by molluscan grains (21 ± 1 %). Mud content ranged from 0 to 26 % between sites and there was a positive correlation (r = 0.4) between terrigenous mud and coral-derived sand, while coral cover significantly decreased with increasing mud. Results suggest that losses in coral cover may initially cause an increase in bioclastic carbonate sediment as the reef structure degrades. However, long-term declines in coral cover will ultimately reduce sediment supply, as live coral sources diminish on reefs. Our findings highlight the importance of mitigating high sediment loads on coral reefs, even within naturally turbid environments, to ensure continued bioclastic sand generation and ecosystem functioning. Mud content on reefs was also a strong predictor of reef recovery following major coral bleaching underscoring the need for holistic transboundary management of coral reefs as coastal urbanisation continues to intensify.
浑浊的珊瑚礁具有高浊度和高沉积的特点。然而，陆地沉积物输入对珊瑚群落的影响，以及它们与珊瑚礁衍生的碳酸盐沉积物的相互作用，仍知之甚少。在此，我们研究了新加坡南部六个浑浊珊瑚礁中碳酸盐-硅质碎屑混合底栖沉积物的物理性质，这些珊瑚礁的珊瑚覆盖率在15%至65%之间。珊瑚是珊瑚礁上砂和砾石沉积物的主要贡献者（平均值±标准误差：57±1%），其次是软体动物颗粒（21±1%）。不同地点的泥质含量在0%至26%之间，陆源泥与珊瑚衍生砂之间存在正相关（r = 0.4），而珊瑚覆盖率随着泥质增加而显著降低。结果表明，随着珊瑚礁结构退化，珊瑚覆盖率的损失可能最初会导致生物碎屑碳酸盐沉积物增加。然而，随着珊瑚礁上活珊瑚来源减少，珊瑚覆盖率的长期下降最终将减少沉积物供应。我们的研究结果强调了减轻珊瑚礁高沉积物负荷的重要性，即使在自然浑浊的环境中，以确保生物碎屑砂的持续生成和生态系统功能。珊瑚礁上的泥质含量也是重大珊瑚白化事件后珊瑚礁恢复的有力预测指标，这突出表明随着沿海城市化的持续加剧，需要对珊瑚礁进行全面的跨界管理。
