Understanding the coupling between sediment availability and sea-level change is important for forecasting coastal-barrier (barrier islands and barrier spits) response to future sea-level rise (SLR). An extensive data set of sediment cores, seismic profiles, and a high-resolution chronology from the Wadden Sea (southeastern North Sea) documents that long-term barrier-chain progradation was interrupted by a period of widespread barrier deterioration between ca. 3.5 and 2.0 ka. The decay of the barrier islands resulted from a decrease in littoral drift triggered by regional-scale coastal reconfiguration. The formation of a large cuspate foreland updrift caused the depositional locus to shift away from the barrier coast. Our results demonstrate that the resulting reduction in marine sediment availability substantially decreased the stability of the barrier chain, causing the regional SLR thresholds to fall from between 2 and 9 mm yr–1 to ~0.9 mm yr–1, and thus below contemporary rates of SLR. Hence, we argue that predicting the response of barrier coasts to ongoing SLR requires consideration of possible changes in sediment availability and the role of large-scale geomorphological feedbacks due to human and natural causes.

中文翻译：

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由于沉积物供应不足，丹麦瓦登海暂时晚全新世屏障链退化

了解沉积物可用性与海平面变化之间的耦合对于预测沿海屏障（屏障岛和屏障喷口）对未来海平面上升 (SLR) 的响应非常重要。来自瓦登海（北海东南部）的大量沉积物岩心数据、地震剖面和高分辨率年代学记录表明，长期的屏障链进积被约 10 至 200 年之间的广泛屏障退化时期中断。3.5 和 2.0 ka。障壁岛的衰败是由区域尺度的海岸重构引发的沿海漂移减少造成的。大的尖角前陆隆起的形成导致沉积轨迹远离屏障海岸。我们的结果表明，由此导致的海洋沉积物可用性的减少大大降低了屏障链的稳定性，导致区域 SLR 阈值从 2 到 9 mm yr-1 下降到 ~0.9 mm yr-1，因此低于当代速率单反。因此，我们认为预测屏障海岸对正在进行的 SLR 的响应需要考虑沉积物可用性的可能变化以及由于人类和自然原因导致的大规模地貌反馈的作用。