4th UF Water Institute Symposium Abstract

Submitter's Name Alexandra Rozin
Session Name Poster Session: Water quality protection and treatment
Poster Number 32
Author(s) Alexandra Rozin,  Soil and Water Science, University of Florida (Presenting Author)
  Mark Clark,  Soil and Water Science, University of Florida
  Exploring in situ optical sensors for the measurement of nitrate
  Assessing the impact of nutrient concentrations on aquatic ecosystems requires an in depth understanding of dynamic biogeochemical cycles that are often a challenge to monitor at the high spatial and temporal resolution necessary to understand these complex processes. Traditional sampling approaches involving discrete samples and laboratory analyses can be constrained by analytical costs, field time, and logistical details that can fail to accurately capture both spatial and temporal changes. Optical in situ instruments may provide the opportunity to continuously monitor a variety of water quality parameters at a high spatial or temporal resolution. This work explores the suitability of a Submersible Ultraviolet Nitrate Analyzer (SUNA) produced by Satlantic, to accurately assess in situ nitrate concentration in several freshwater systems in north Florida. SUNAs with different path lengths were deployed to measure nitrate at five different water bodies selected to represent a range of watershed land uses and water chemistry in the region. In situ nitrate measurements were compared to standard laboratory methods to evaluate the effectiveness of the SUNA’s operation and the difference in path length. Other optical sensors were used to measure the spectral properties of absorbance, fluorescence, and turbidity (scatter) in the same Florida water bodies. Data from these additional sensors were collected to quantify possible interferences that may affect SUNA performance and guide instrument specification recommendations. A better understanding of the capabilities and possible limitations of differing path lengths associated with these relatively new analytical instruments will allow researchers to more effectively investigate biogeochemical processes and nutrient transport and enhance decision-making to protect our water bodies.