Seagrasses and bare sediment represent alternative stable states, with sediment resuspension being a key driver of system stability via the Seagrass–Sediment–Light (SSL) feedback. We explore the SSL feedback by quantifying the sediment stabilization by seagrass, and using these measurements to calculate under which conditions seagrass ends up in a turbid environment. We quantified in-situ sediment resuspension velocity thresholds (u_cr) for Zostera marina growing in medium to fine sand, using a field flume inducing near-bed wave motion. u_cr was determined for full length shoots, shoots clipped to 0.08 m, and removed shoots. We found that rhizomes did not influence u_cr of the top sediment layer. Overall, u_cr was linearly related to blade area, which became independent for sediment type when normalizing u_cr for the resuspension threshold after shoot removal. Comparing measured u_cr against natural wave conditions showed that the seagrass meadow at the study site is currently stable. Exploring the effects of changing hydrodynamic conditions revealed that effects of increasing storminess has limited influence on sediment resuspension and thus the SSL-feedback. Increasing mean wind velocity had a stronger influence on SSL-feedback dynamics by causing more frequent exceedance of u_cr. The response of seagrasses to increasing wind pressure depends on bay topography. A fully exposed Z. marina meadow under low initial turbidity pressure trended toward bistability, as turbidity pressure increased mainly on bare sediments. The study site and a fully exposed Z. marina meadow under high initial turbidity pressure saw an increase in turbidity across all blade areas.

中文翻译：

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风暴露和沉积物类型决定了海草草甸对气候变化的恢复力和响应

海草和裸露的沉积物代表了替代的稳定状态，沉积物再悬浮是通过海草-沉积物-光 (SSL) 反馈实现系统稳定性的关键驱动因素。我们通过量化海草对沉积物的稳定性来探索 SSL 反馈，并使用这些测量结果来计算海草在何种条件下最终会进入混浊环境。我们使用诱导近床波动的现场水槽量化了生长在中细砂中的Zostera marina的原位沉积物再悬浮速度阈值 ( u _cr ) 。u _cr是针对全长芽测定的，修剪到 0.08 m 的芽，并去除芽。我们发现根茎不会_影响你的顶部沉积层。总体而言，u _cr与叶片面积呈线性相关，当将u _cr归一化为去除枝条后的再悬浮阈值时，叶片面积与沉积物类型无关。将测量的u _cr与自然波浪条件进行比较表明，研究地点的海草草甸目前是稳定的。探索水动力条件变化的影响表明，暴风雨增加的影响对沉积物再悬浮和 SSL 反馈的影响有限。增加平均风速通过导致更频繁地超过u _{cr对 SSL 反馈动力学产生更大的影响}. 海草对增加的风压的反应取决于海湾的地形。在低初始浊度压力下完全暴露的Z. marina草甸趋向于双稳态，因为浊度压力主要在裸露的沉积物中增加。研究地点和在高初始浊度压力下完全暴露的Z. marina草甸看到所有叶片区域的浊度增加。