The effects of runoff from land on nearshore ecosystems, including coral reef communities, are influenced by both sediment supply and removal by coastal processes. Integrated studies across the land-sea interface describing sources and transport of terrestrial sediment and its nearshore fate allow reef protection initiatives to target key onshore and offshore areas. Geochemical signatures in the fine fraction of terrestrial sediment from watersheds in southwest Puerto Rico were determined by multivariate principal component analysis and used to identify terrestrial sources of sediment runoff to nearshore coral reefs. Sediment settling out of suspension at reefs was collected at approximately 2 month-long intervals in bottom-mounted sediment traps from May 2017 to June 2018, a period that included Hurricanes Irma and Maria. Bulk sediment accumulation rates in traps exceeded a 10 mg/cm²/d threshold found to stress corals at 5 of 7 reef sites throughout the 13 month-long study. Geochemical signatures showed that watersheds 10s km to the east were a predominant, year-round source of fine sediment to reefs offshore of Guánica Bay and could have introduced sediment-bound contaminants due to a higher degree of industrialization and urbanization than the local watershed. Sediment runoff from the local watershed appeared to be constrained to a narrow band close to shore. During the 2.5 months after Hurricanes Irma and Maria, bulk sediment accumulation rates increased substantially and fine sediment geochemical signatures were indicative of predominantly distal sources, except outside of the mouth of Guánica Bay, which was strongly impacted by local runoff. Mass wasting, sediment runoff, and coastal turbidity persisted for months after Hurricane Maria and could account for the appearance of a small fraction of geochemical variance from a distal sediment source that appeared in reef traps 4 months post-hurricane and persisted through the end of the study 9 months post-hurricane. Sediment geochemical sourcing in temporally resolved records from sediment traps showed how landscape-scale changes after a major hurricane affected both near-term and long-term sediment delivery to reef communities. In addition, the importance of fine sediment advection from distal sources indicates that successful reduction of land-based pressures on nearshore ecosystems will require cross-jurisdictional strategies.

陆地径流对近岸生态系统（包括珊瑚礁群落）的影响受到海岸过程沉积物供应和清除的影响。陆海界面的综合研究描述了陆地沉积物的来源和运输及其近岸命运，使珊瑚礁保护举措能够针对关键的陆上和近海地区。通过多元主成分分析确定了波多黎各西南部流域陆地沉积物细粒部分的地球化学特征，并用于确定沉积物径流到近岸珊瑚礁的陆地来源。从 2017 年 5 月到 2018 年 6 月，在底部安装的沉积物捕集器中每隔大约 2 个月收集一次从珊瑚礁悬浮物沉淀出来的沉积物，这一时期包括飓风艾尔玛和玛丽亚。²在为期 13 个月的研究中，发现 /d 阈值对 7 个珊瑚礁中的 5 个珊瑚礁造成压力。地球化学特征表明，东部 10 公里处的流域是 Guánica 湾近海珊瑚礁的主要的全年细粒沉积物来源，并且由于比当地流域更高的工业化和城市化程度，可能会引入沉积物污染物。来自当地流域的沉积物径流似乎被限制在靠近海岸的狭窄地带。在飓风艾尔玛和玛丽亚之后的 2.5 个月内，大块沉积物积累率大幅增加，细沉积物地球化学特征表明主要是远端来源，但受当地径流影响的瓜尼卡湾口外除外。质量浪费，沉积物径流，和沿海浊度在飓风玛丽亚之后持续了数月，并且可以解释来自远端沉积物源的一小部分地球化学变化的出现，这种变化在飓风后 4 个月出现在珊瑚礁陷阱中，并持续到飓风后 9 个月的研究结束. 沉积物圈闭的时间解析记录中的沉积物地球化学来源显示了大型飓风后景观尺度的变化如何影响近期和长期向珊瑚礁群落输送的沉积物。此外，来自远端源头的细粒沉积物平流的重要性表明，成功降低近岸生态系统的陆上压力将需要跨辖区战略。