Details zur Publikation

Referenztyp Zeitschriften
DOI / URL Link
Titel (primär) High frequency measurements of reach scale nitrogen uptake in a fourth order river with contrasting hydromorphology and variable water chemistry (Weiße Elster, Germany)
Autor Kunz, J.V.; Hensley, R.; Brase, L.; Borchardt, D.; Rode, M.;
Journal / Serie Water Resources Research
Erscheinungsjahr 2017
Department ASAM;
Band/Volume 53
Heft 1
Sprache englisch;
POF III (gesamt) T31;
Keywords time series; longitudinal sampling; nutrient retention; stream metabolism; high frequency measurements; quantitative methods
UFZ Querschnittsthemen RU2;
Abstract River networks exhibit a globally important capacity to retain and process nitrogen. However direct measurement of in-stream removal in higher order streams and rivers has been extremely limited. The recent advent of automated sensors has allowed high frequency measurements, and the development of new passive methods of quantifying nitrogen uptake which are scalable across river size. Here we extend these methods to higher order streams with anthropogenically elevated nitrogen levels, substantial tributaries, complex input signals, and multiple N species. We use a combination of two station time-series and longitudinal profiling of nitrate to assess differences in nitrogen processing dynamics in a natural versus a channelized impounded reach with WWTP effluent impacted water chemistry. Our results suggest that net mass removal rates of nitrate were markedly higher in the unmodified reach. Additionally, seasonal variations in temperature and insolation affected the relative contribution of assimilatory versus dissimilatory uptake processes, with the latter exhibiting a stronger positive dependence on temperature. From a methodological perspective, we demonstrate that a mass balance approach based on high frequency data can be useful in deriving quantitative uptake estimates, even under dynamic inputs and lateral tributary inflow. However, uncertainty in diffuse groundwater inputs and more importantly the effects of alternative nitrogen species, in this case ammonium, pose considerable challenges to this method.
ID 18306
dauerhafte UFZ-Verlinkung https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=18306
Kunz, J.V., Hensley, R., Brase, L., Borchardt, D., Rode, M. (2017):
High frequency measurements of reach scale nitrogen uptake in a fourth order river with contrasting hydromorphology and variable water chemistry (Weiße Elster, Germany)
Water Resour. Res. 53 (1), 328 - 343