Fine sediment and organic matter interactions: bio-physical effects of aggregated sediments on streams

絮凝或聚集的土壤和沉积物是营养物和污染物转移到水生系统和水生系统内的已知载体。 它们在水生系统中的行为和停留时间是河流、湖泊和海洋中物质输送和保留的调节因素。 在公元前北方，大规模的松甲虫流行改变了许多流域的水文功能。 各国政府提出了一项建议，即收获这些地区并改为农业。这一点，再加上预测的气候变暖，意味着在许多流域增加田间耕作和施肥。这些潜在变化通过土壤侵蚀对陆地-水生连通性的影响表明，河流将接收更多的沉积物和有机物。 这些物质中的一些将作为土壤聚集体被输送到河流中，但也会发生絮凝的瞬时过程。 这些复合颗粒可以在砾石床中保留和分解，将营养物质输送到次表层水和上覆水。 最近的工作表明，沉积物鱼类生物量反馈回路有助于调节营养状态，因此鲑鱼产卵，砾石床河流的生态功能。我建议调查这个过程是否在其他河流系统中运行，主要是不同类型的有机物（农业肥料，藻类水华，森林凋落物）。 我将量化人工溪流（水槽）中聚集体的生成、沉降、储存和低渗释放产物。 可以确定每种有机源材料的生物物理过程的幅度和意义，然后在天然河流中进行实地工作，将允许对水槽模拟结果进行比较。 将利用沉积学和显微镜技术进行调查河流絮凝物/聚合物的产生、归宿和影响的基础研究，同时将测试利用微生物脱氧核糖核酸作为水文地貌示踪剂开发新的沉积物示踪方法的应用研究。 该项目提供流域管理和水生生境恢复的关注，需要结合沉积物转移的地貌知识和水生营养转移的生态信息。

Flocculated or aggregated soils and sediment are a known vector for nutrient and contaminant transfers to and within aquatic systems. Their behavior and residence time in aquatic systems is a regulating factor in the delivery and retention of materials in rivers, lakes and oceans. In northern BC the massive pine beetle epidemic has altered the hydrologic functioning of many watersheds. A suggestion to harvest these regions and change to an agricultural has been suggested by governments. This, in combination with predicted climate warming, implies an increase in field tillage and fertilization in many watersheds. The effect of these potential changes on terrestrial-aquatic connectivity, via soil erosion, suggests that streams will be receiving increased loads of sediment and organic matter. Some of this material will be delivered to the streams as soil aggregates but as well an instream process of flocculation will occur. These composite particles can be retained and decomposed in the gravel bed delivering nutrients to the hyporeic and overlying water. Recent work indicates that a sediment-fish biomass feedback loop helps regulate the nutrient status, and therefore ecological functioning of salmon spawning, gravel-bed rivers. I propose to investigate if this process operates in other stream systems, dominated by different types of organic matter (agricultural fertilizers, algal blooms, forest litter). I will quantify the generation, settling, storage, and hyporeic release products of aggregates in artificial streams (flumes). The magnitude and significance of the bio-physical processes for each of the organic source materials can be determined and then field work in natural rivers will allow a comparison of the flume simulated results. Basic research investigating riverine floc/aggregate generation, fate and effect will use sedimentological and microscopic techniques, while applied research into the development of a new sediment tracing method using microbial DNA as a hydro-geomorphic tracer will be tested. This project delivers to watershed management and aquatic habitat restoration concerns that require combined geomorphic knowledge of sediment transfers and ecological information regarding aquatic nutrient transfers.