A metabolically active transient storage model for predicting nutrient retention in streams

This collaboration among Drs. Roy Haggerty and Alba Argerich (Geosciences), David Myrold, Eugènia Martí (Centre d’Estudis Avançats de Blanes, Spain), and Nancy B. Grimm (Arizona State University) has been completed.

Transient storage has become one of the most important concepts in hydrology in the past 25 years, helping to predict solute and heat transport in streams, and it is one of the most frequently quantified processes in stream ecology. However, recent research shows that transient storage has minimal explanatory power for nutrient retention in streams. This is a paradox because nutrient retention is closely tied to aerobic metabolism, which in turn is very strongly tied to hyporheic exchange, a major component of transient storage. Further, other processes that retain nutrients (sorption of phosphorus, and anaerobic microbial processes) also should happen preferentially in transient storage zones. Consequently, it is surprising that transient storage has not been a better predictor for nutrient retention. We hypothesize that nutrient retention is mostly associated with transient storage that is metabolically active. Metabolically active transient storage (MATS) is defined as water with velocity much slower than the mean in which there is significant primary production or respiration. Given known mechanistic relationships between nutrient transformations and metabolism, we predict that MATS zones will also be hotspots for nutrient retention. We tested the efficacy of using resazurin, which quickly reduces to resorufin in the presence of aerobic respiration, as a measure of MATS in column and mesocosm experinments. We also applied resazurin in streams to measure MATS.

The project has produced the following publications:

  • González-Pinzón, R., R. Haggerty, and D.D. Myrold. 2012. Measuring aerobic respiration in stream ecosystems using the resazurin-resorufin system. J. Geophys. Res. 117:G00N06. (doi:10.1029/2012JG001965)
  • Argerich, A., R. Haggerty, E. Martí, F. Sabater, and J. P. Zarnetske. 2011. Quantification of metabolically active transient storage (MATS) in two reaches with contrasting transient storage and ecosystem respiration. J. Geophys. Res. 116:G03034. (doi:10.1029/2010JG001379)
  • Argerich, A., E. Martí, F. Sabater, M. Ribot, and R. Haggerty. 2011. Influence of transient storage on stream nutrient uptake based on substrata manipulation. Aquatic Sci. 73:365-376. (doi:10.1007/s00027-011-0184-9)
  • Haggerty, R., E. Martí, A. Argerich, D. von Schiller, and N. B. Grimm. 2009. Resazurin as a “smart” tracer for quantifying metabolically active transient storage in stream ecosystems. J. Geophys. Res. 114”g03014. (doi:10.1029/2008JG000942)
  • Haggerty, R., A. Argerich, and E. Martí. 2009. Development of a ''smart'' tracer for the assessment of microbiological activity and sediment-water interaction in natural waters: The resazurin-resorufin system. Water Resour. Res. 44:W00D01. (doi:10.1029/2007WR006670)