Oscillating redox environment of the hyporheic zone of tidally forced rivers

下弗雷泽河三角洲地表含水层的地下水含有高浓度的铁和其他与溶解氧不相容的物质。大部分地下水从含水层通过所谓的潜流区（河水和地下水混合的地下区域）排入弗雷泽河的底部。这种混合部分是由弗雷泽河的潮汐作用驱动的。在潜流区，弗雷泽河水中的氧气预计会导致地下水中的铁氧化并形成低溶解度的氧化铁（锈状）沉淀物，已知这些沉淀物会吸附水中的微量金属。 本研究的目的是研究在潜流带发生的物理和地球化学过程，并研究在弗雷泽河三角洲含水层的地下水获得其溶解负荷的过程。这项研究是重要的，因为在潜流带和弗雷泽河三角洲地表含水层的地球化学过程可以有很大的影响，污染物在地下水和营养负荷的地表沃茨。

The groundwater in the Lower Fraser River Delta surface aquifer contains high concentrations of iron and other species that are not compatible with dissolved oxygen. Much of this groundwater discharges from the aquifer into the base of Fraser River through the so-called hyporheic zone, the zone of the subsurface where river water and groundwater mix. This mixing is driven in part by the tidal action of the Fraser River. In the hyporheic zone, the oxygen in the Fraser River water is expected to cause the iron in the groundwater to oxidize and form low-solubility iron-oxide (rust-like) precipitates, which are known to adsorb trace metals from the water. The objective of this research is to study the physical and geochemical processes that occur in the hyporheic zone, and to study the processes that by which the groundwater in the Fraser River Delta aquifers acquire their dissolved loads. The research is important because the geochemical processes in the hyporheic zone and the Fraser River Delta surface aquifer can have a strong effect on contaminants in groundwater and nutrient loading to surface waters.