This project will develop and expand a stoichiometric Process Vector visualization and quantification approach to identify (on the timescale of hours) biogeochemical processes in streams and to quantify fundamental biogeochemical reaction rates. By developing methods to identify/quantify controlling metabolic processes for CO2 production, nitrification, denitrification and redox release of PO4 from FePO4 via multi-parameter measures at high frequencies, the hydrologic community will be better enabled to evaluate the spatial and temporal variability (time step 10-75min) of the water quality controls in shallow aquatic systems. The project will develop and deploy new instrumentation to quantify the biogeochemical water quality function of a small pond and two low order streams by combining a pumped-profiler/YSI system (O2, CO2, temperature, pH turbidity, fluorescence and specific conductivity) and an Envirotech Microlab nutrient analyzer system for NO3+NO2, NH3, and PO4 and a METS methane sampler. A measurement interval of 10mins is anticipated with week long deployments in ponds and multi-day deployments in streams. This suite of measurements covers the anticipated dominant metabolic reaction pathways for most streams/ponds over a wide Eh/pH range. The new suite of instrumentation will be deployed in a small suburban pond that undergoes a range of rapidly changing biogeochemical conditions driven in part by physical processes; this data will enable a broad range of biogeochemical processes to be observed and compared to theory. The equipment will also be deployed in two low order streams that cover a range of environments. The analysis will enable an elucidation of hydrologic, meteorologic, stratification and destratification controls on the biogeochemical function of detention ponds (a hydrologic component growing at 4%/yr) and the biogeochemical function of low order streams that represent an important component of the hydrologic network.
Intellectual Merit The major goal of this project was to examine how the day-night patterns in water chemistry could be used to assess the water quality function (e.g. nutrient filtration) of different habitats within fresh and estuarine ecosystems. This kind of information is fundamentally important for detecting change in aquatic and near-shore marine systems that may result from global change, or from localized human perturbation. Ideally this approach could be applied to habitats threatened by degradation, or ones that are considered keystone communities. The principal intellectual merit of this research was its ability to define the constraints and challenges that need to be addressed in order to best interpret time series chemical data in highly productive, tidal systems with a patchwork of disparate habitats. First – the size of the specific habitat matters. More reliable use of habitat-specific chemical data to predict water quality function occurs when these habitats (e.g. grass beds) are homogenous and large relative to the whole ecosystem (e.g. estuary). Second- in patchy systems, the key to interpreting the chemical patterns depends almost entirely on good estimates of water exchange between the habitat of interest and the rest of the ecosystem. Third – the addition of isotopic measurements to bulk chemical monitoring can help to refine the interpretation of the chemical patterns. The isotopic information also provides additional information on water quality function that the chemical data alone lacks. Broader Impacts Broader impacts of the work were realized through education and by the use of the results as a management tool. The work conducted can be generally placed in the category of trying to define service of a natural resource. Successfully achieving this goal speaks directly to valuation of these resources. Proper valuation is the key to sound management, prioritization of keystone habitat preservation, compensatory damages after environmental damage, and mitigation schemes including nutrient credits. Beyond the technical results, this project embodied the philosophy of integrating research into education and transfer of knowledge to practical real world problems. Six graduate students and four undergraduates received hands on training in the laboratory; including seven individuals from groups that are traditionally under-represented in the sciences. The research provided data that was directly incorporated into the classroom where it benefitted an additional 75 undergraduates and 10 graduate students. Results from the project have provided core pieces of information for water quality management in a process forum that brought together state and federal regulatory agencies, private industry, university researchers, and citizen scientists.
