Sediment and Salmon Interactions: Implications for nutrient storage and downstream lake productivity

流经河道的沉积物就像一个载体，将营养物和污染物沿着同一条路线运送到下游的湖泊。 一些可溶性化学物质松散地吸附在沉积物上，而其他物质则物理地附着在细沉积物上。 被定义为小于63微米的细小无机沉积物容易与水柱中的有机颗粒结合以形成聚集或絮凝的颗粒，这些颗粒较大并且具有与其组成材料不同的沉降特性。这导致沉积物和附着的有机物的运输和沉降速率变化不定，因此预测不佳。 使用鲑鱼腐烂产物作为当代的例子，本研究探讨了沉积物和鲑鱼的相互作用，改变鲑鱼衍生的营养物质（SDN）从产卵场到下游苗圃湖泊的交付。 在不列颠哥伦比亚省的内陆，鲑鱼育苗湖需要初级生产水平，以维持食物网，以支持鲑鱼鱼苗。 返回产卵鱼的腐烂产物在多大程度上有助于下游育苗湖的初级生产，这是不确定的。 鲑鱼腐烂营养物的命运对产卵场的管理有影响，并可能对未来种群的成功产生影响。 在5年的时间内，捕获高密度和低密度产卵器返回，我建议i）估计产卵场和苗圃湖之间的河流排放中转移的通道存储SDN的数量和时间，ii）量化SDN的上游河道和洪泛区存储，以及iii）测量和模拟与产卵流排空到苗圃湖相关的物理混合过程，以确定SDN负载对苗圃湖初级生产力

Sediment moving through river channels acts as a vector, moving nutrients and contaminants along the same route to downstream lakes. Some soluble chemicals are loosely adsorbed to the sediment while other material is physically attached to the fine sediment. Fine inorganic sediment, defined as being smaller than 63 microns, readily combines with organic particles in the water column to form aggregated or flocculated particles which are larger and have different settling properties than their constituent materials. This results in variable, and therefore poorly predicted, transport and settling rates for both the sediment and the attached organic matter. Using salmon decay products as a contemporary example, this study investigates the interaction of sediment and salmon in altering the delivery of salmon-derived nutrients (SDN) from the spawning grounds to the downstream nursery lakes. In the interior of BC, salmonid nursery lakes require levels of primary production that can maintain the food web to support salmon fry. It is uncertain to what degree the decay products of returning spawners contribute to primary production in downstream nursery lakes. The fate of salmon decay nutrients has implications in the management of the spawning grounds and potentially for the success of future stocks. Over a 5-year period, which captures high- and low-density spawner returns, I propose to i) estimate the amount and timing of channel-stored SDN transferred in river discharge between the spawning grounds and nursery lake, ii) quantify the upstream river channel and floodplain storage of SDN, and iii) measure and model the physical mixing processes associated with a spawning stream emptying into a nursery lake in order to determine the effects of SDN loads on nursery lake primary productivity.