CREST-PRF: Constraining Spatiotemporal Nutrient Dynamics Along An Arid-Land River Continuum

Regier Peter, North Miami FL

Investigators

Abstract

The Centers of Research Excellence in Science and Technology-Postdoctoral Research Fellowship (CREST-PRF) track within the CREST program supports beginning CREST Center investigators with significant potential and provides them with training and research experiences that will broaden perspectives, facilitate interdisciplinary interactions and establish them in positions of leadership within the scientific community. This CREST-PRF project is aligned with the research focus of the CREST Center for Water and the Environment (CWE) at the University of New Mexico. The objective of this project is to determine how longitudinal changes in the composition of dissolved organic carbon control nutrient uptake dynamics and export in arid-land river networks at multiple spatial (reach to river) and temporal (hours to years) scales. Arid lands support approximately a third of the world's population and half of the world's agriculture. Due to multiple competing stressors (e.g., dams, constant dewatering, fire ash inputs and increased evapotranspiration), and overreliance on water resources, arid-land river systems are typically less resilient and more vulnerable to water quality degradation, including eutrophication. Results from this project will provide tools to assess the fate and transport of carbon and nutrients in arid river systems, and scientific knowledge to support the development of multi-sector solutions aimed at improving nutrient recycling in arid metropolitan areas, within the context of the food, water and energy nexus. The proposed research will continuously monitor nitrate, phosphate, dissolved organic carbon, and ancillary water quality parameters using state-of-the-art sensor technology for two years along a river continuum spanning four orders of magnitude in mean annual discharge, ~2000 m in altitude and ~500 km of stream length. High-information-yield experiments to quantify carbon and nutrient uptake rates will be conducted every three weeks at the sensor sites along with laboratory analysis of dissolved organic carbon composition. The research approach harnesses the power of "big data" by combining continuous sensor data, field experiments, and laboratory measurements with time-series analysis and data-based modeling techniques. Spatiotemporally comprehensive information about the interconnections between chemistry, biology, hydrology and ecology along an entire river network collected by this project will generate datasets and modeling approaches to inform adaptive management of freshwater resources and establish guidelines for total maximum daily loads in arid land rivers. Development of novel proxy relationships correlating continuous measurements to complex environmental parameters holds great potential to transform current understanding of watershed nutrient cycling and advance freshwater biogeochemistry.