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种。这些地下水中的大部分通过所谓的地下水位带从含水层排放到弗雷泽河底部，地下水位带是河水和地下水混合的区域。这种混合在一定程度上是由弗雷泽河的潮汐作用驱动的。在潜水带，弗雷泽河水中的氧气预计会导致地下水中的铁被氧化，并形成低溶解度的氧化铁(铁锈状)沉淀物，众所周知，这些沉淀物可以从水中吸附微量金属。这项研究的目的是研究潜水带中发生的物理和地球化学过程，并研究弗雷泽河三角洲含水层中地下水获得其溶解负荷的过程。这项研究很重要，因为潜水带和弗雷泽河三角洲地表含水层中的地球化学过程可以对地下水中的污染物和地表水的营养负荷产生强烈的影响。

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.