This study shows that riverine riparian (shoreline) zones — and plant management decisions made therein — can measurably influence the availability of silica delivered to lower reaches of rivers, estuaries, and some coastal oceans. The aims were to determine how much silica is sequestered by riparian vegetation in a river, and what processes govern that effect. We used the invasion and rapid spread of the non‐native grass Phragmites australis (common reed) in the Platte River (central United States) to quantify the biochemical and physical mechanisms by which silica is removed from the river flow and stored in sediments. Specifically, we measured bioavailable silica in sediment, native and non‐native vegetation biomass, and river water over a period of four years. The robust biomass production and high silica content of Phragmites led to biochemical production of amorphous silica particles (ASi) that was 1.5× higher than native willow and 2× higher than native Phragmites. And, the denser growth habit of non‐native Phragmites contributed to more rapid physical sequestration of ASi than with other vegetation. Altogether, the rapid vegetation change due to this invasion caused sequestered silica to increase 1.5× in this reach, which is ~7% of the Platte’s annual silica load. Subsequent Phragmites eradication efforts, wherein the plants were sprayed with herbicide and left physically intact, allowed rapid silica remobilization but it was highly variable.

中文翻译：

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广泛传播的非本地草类入侵导致下游生物利用二氧化硅的减少

这项研究表明，河流河岸（海岸线）区及其中的植物管理决策可以显着影响输送到下游河流，河口和一些沿海海洋的二氧化硅的可用性。目的是确定河流中的河岸植被隔离了多少二氧化硅，以及由什么过程控制这种作用。我们使用了非本地草芦苇的入侵和快速传播（位于美国中部）的普拉特河（常见芦苇），以量化生物化学和物理机制，从而从河水中去除二氧化硅并将其存储在沉积物中。具体来说，我们在四年的时间内测量了沉积物，本地和非本地植被生物量以及河水中的生物有效性二氧化硅。鲁棒的生物质生产和高硅石含量芦苇导致生化生产，这是比天然柳树高1.5倍和比天然高2×无定形二氧化硅颗粒（ASI）的芦苇。而且，非本地芦苇的生长习惯更密集与其他植被相比，有助于更快地物理隔离ASi。总而言之，由于这种入侵而造成的快速植被变化导致隔离的二氧化硅在该范围内增加了1.5倍，约为Platte年度二氧化硅负荷的7％。随后的芦苇根除工作（其中对植物喷洒了除草剂并保持完好无损）可以使二氧化硅快速迁移，但变化很大。