Application of targeted transcriptomics for determining early nutrient sediment retention capacity (NSRC)****

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Nutrient mitigation and their interception is a primary goal of source water protection and a main objective for effective sewage treatment, engineered water retention basins and agricultural best practice. Emphasis is often placed on monitoring nutrient sources and concentrations in water. However, the risks associated with nutrients mobilization from long-term sequestration in sediment reservoirs are not well understood in lakes, wetlands, and engineered systems (e.g. retention ponds, constructed wetlands, drainage ditches). These sediment-nutrient dynamics can significantly impact internal nutrient loading in shallow eutrophic systems and can cause delayed recovery after external loads have been abated. Nutrient cycling in sediment is driven largely by microbial processes, either directly by conversion of bound-nutrients to bioavailable forms or indirectly by regulating the physical/chemical conditions that control nutrient speciation and solubility. Classic approaches to measuring nutrient flux from sediments often overlook the dynamic and complex set of microbial pathways involved in regulating sediment nutrient retention capacity. With our Collaborators and Industrial Partners, this project will develop a rapid and cost effective technology to diagnose surficial sediment nutrient retention capacity as it relates to microbial gene expression (function) and microbial community composition. Specifically, this project will develop a targeted transcriptomic assay system capable of detecting diagnostic microbial gene expression profiles indicative of active nutrient flux and can serve as a proxy for more expensive and laborious classic chemical approaches. The assay will be system designed by generating novel gene expression libraries calibrated to in-situ microbial communities derived from several sediment environments including agricultural tributaries/drainage ditches, engineered retention systems and tributaries receiving wastewater treatment effluents. Such information will provide new insights for evaluating the health/potential risk of sediment-nutrient release leading to internal load, a current major concern for Lake Erie and a anticipated major stress vector in other Canadian and global watersheds related to climate change.