荷兰皇家海洋研究所Grandjean, Tim J.团队成员在研究全球河口潮滩维持的临界浊度阈值中取得新进展。相关论文于2024年5月6日发表在《自然—地球科学》杂志上。

研究人员通过对4,939张卫星图像的分析，评估了1986-2011年间40个全球分布河口的潮坪形态动力学变化。研究考虑了有植被和无植被的潮间带区域。通过与遥感得出的浊度估算值的比较，研究确定了一个临界浊度阈值，该阈值指示了最小沉积物供应以及水动力，这是维持潮滩所必需的。低浊度河口潮间带潮滩呈后退趋势，随着潮幅的增大，临界浊度阈值增大。

相比之下，浊度高的河口则倾向于呈现横向或纵向扩张的潮滩。然而，尽管潮差有限的河口具有相对较低的浊度阈值，但环境或人为变化仍然会对潮滩的形态产生不利影响。研究结果表明，需要在综合河口管理策略中考虑沉积物供应，以保持潮滩的生态完整性和防洪功能。

据悉，全球的潮滩面积正在缩小。河口潮滩对全球环境变化的响应动力学尚不清楚。潮滩的形态是由波浪和潮汐力、河流流量和沉积物供应的相互作用形成的，潮滩的保存需要保持侵蚀和沉积过程之间的平衡。

附：英文原文

Title: Critical turbidity thresholds for maintenance of estuarine tidal flats worldwide

Author: Grandjean, Tim J., Weenink, Roland, van der Wal, Daphne, Addink, Elisabeth A., Hu, Zhan, Liu, Shuai, Wang, Zheng B., Lin, Yuan, Bouma, Tjeerd J.

Issue&Volume: 2024-05-06

Abstract: Tidal flats are shrinking in extent globally. The dynamics of the response of estuarine tidal flats to global environmental changes remain unclear. Tidal-flat morphology is shaped by the interplay among wave and tidal forces, river discharge and sediment supply, and preservation of tidal flats requires a balance between erosional and depositional processes be maintained. Here we assess tidal-flat morphodynamic changes of 40 globally distributed estuaries with contrasting tidal amplitudes between 1986 and 2011 from analyses of 4,939 satellite images. We consider both vegetated and unvegetated intertidal areas. From comparisons with remote-sensing-derived turbidity estimates, we identify a critical turbidity threshold indicative of a minimum sediment supply along with the hydrodynamic forces, which is necessary to maintain tidal flats. Tidal flats in intertidal areas in estuaries with low turbidity face retreat, with the critical turbidity threshold increasing with increasing tidal amplitudes. By contrast, estuaries with high turbidity tend to exhibit laterally or vertically expanding tidal flats. However, despite estuaries with limited tidal ranges having relatively low turbidity thresholds, environmental or anthropogenic alterations can still adversely affect the morphology of tidal flats. Our findings demonstrate the need to consider sediment supply in integrated estuarine management strategies to maintain the ecological integrity and flood defence function of tidal flats.

DOI: 10.1038/s41561-024-01431-3

Source: https://www.nature.com/articles/s41561-024-01431-3