Sediment transport-based metrics of wetland stability
Sediment transport-based metrics of wetland stability
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DOI：
10.1002/2015gl065980
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发表时间：
2015-10-16
影响因子：
5.2
通讯作者：
Kroeger, Kevin D.
中科院分区：
文献类型：
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作者：
Ganju, Neil K.;Kirwan, Matthew L.;Kroeger, Kevin D.
尽管沉积物的可用性对湿地稳定性的重要性，脆弱性评估很少考虑时空变化的沉积物输送。模型预测，海平面上升的最大速率沼泽可以生存是成比例的悬浮泥沙浓度（SSC）和加积。相比之下，我们发现，SSC和加积是在一个不稳定的沼泽比在相邻的稳定沼泽，这表明这些指标不能描述湿地的脆弱性。因此，我们提出了更好的脆弱性指标的涨潮/落潮SSC差和有机无机悬浮泥沙比。不稳定沼泽有利于沉积物输出（落潮时高18 mgL（-1）），而稳定沼泽则有利于沉积物输入（涨潮时高12 mgL（-1））。在不稳定的沼泽中，有机-无机SSC比高出84%，稳定同位素表明与沼泽衍生物质一致的来源。这些简单的度量尺度与沉积物通量，整合时空变化，并指出沉积物来源。
Despite the importance of sediment availability on wetland stability, vulnerability assessments seldom consider spatiotemporal variability of sediment transport. Models predict that the maximum rate of sea level rise a marsh can survive is proportional to suspended sediment concentration (SSC) and accretion. In contrast, we find that SSC and accretion are higher in an unstable marsh than in an adjacent stable marsh, suggesting that these metrics cannot describe wetland vulnerability. Therefore, we propose the flood/ebb SSC differential and organic-inorganic suspended sediment ratio as better vulnerability metrics. The unstable marsh favors sediment export (18mgL(-1) higher on ebb tides), while the stable marsh imports sediment (12mgL(-1) higher on flood tides). The organic-inorganic SSC ratio is 84% higher in the unstable marsh, and stable isotopes indicate a source consistent with marsh-derived material. These simple metrics scale with sediment fluxes, integrate spatiotemporal variability, and indicate sediment sources.