Nutrient dynamics in a created desert wetland: Implications for the Rio Bosque Wetlands Park

Rio Bosque Wetland Park is an arid wetland currently under restoration, which primarily receives water inputs from the Bustamante Waste Water Treatment Plant (WWTP) during the non-irrigation season. Understanding the ability of a desert wetland to remove nutrients from the water column through uptake by primary producers or sediment transformations is key to justifying the protection and creation of other similar wetland sites. Nitrate concentrations tended to be reduced, relative to the inflow, near the outflow of the wetland. To further understand these trends, sediment nutrient release experiments and algal nutrient limitation experiments were completed. Sediment phosphorus release experiments indicated that Soluble Reactive Phosphorus (SRP) release rates at the sites were positively correlated with average well color development (r=0.90, p=0.0347), indicating greater phosphorus release at sites with higher levels of bacterial activity. Nutrient limiting experiments completed in the last 2 years of the study indicated that algae tended towards limitation by nitrogen at the outflow, with no nutrient limitation at the inflow. The presence of water year round, which is currently lacking from the Rio Bosque, and the increased growth of wetland plants it would promote, could have a substantial effect on the removal rates of nutrients from the wetland through not only the direct uptake of nutrients by plants but also by alterations in redox potential, denitrification, microbial activity, and sediment phosphorus dynamics