On-line fluorometry of multiple reactive and conservative tracers in streams

Lemke, Dennis; Schnegg, Pierre-André; Schwientek, Marc; Osenbrück, Karsten; Cirpka, Olaf A.

doi:10.1007/s12665-013-2305-3

Cited by 36 publications

(56 citation statements)

References 22 publications

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“…Because unequal numbers of moles were injected for fluorescein and resazurin, respectively, the tracer concentrations were normalized by the number of injected moles to allow for a better comparability of the respective BTCs. The turbidity of the river water never exceeded five nephelometric turbidity units (NTU) during the experiment, indicating good conditions for the separation of tracer signals [see Lemke et al ., ]. We injected the tracers significantly upstream of our monitoring stations following the suggestions in Barsby [] to allow for complete lateral mixing.…”

Section: Resultsmentioning

confidence: 99%

“…This is supported by the narrow parameter uncertainties derived from the maximum‐likelihood approach suggesting reliable identification of the model parameters. The low parameter uncertainty is partly due to the high temporal resolution of the measurements (10 s intervals) using the recently introduced field fluorometer [ Lemke et al ., ]. The online measurements significantly increased the quality of the BTC simulations compared to data obtained by manual sampling [ Gooseff and McGlynn , ; Wagner and Harvey , ].…”

Section: Discussionmentioning

confidence: 99%

“…The BTCs of the tracers fluorescein, resazurin, and resorufin as well as the temperature and turbidity of the river water were measured online at three monitoring stations denoted MS1, MS2, and MS3 at 830, 1075, and 1210 m distance downstream of the injection site (Figure ), using portable field fluorometers of the type GGUN FL‐30 [ Lemke et al ., ; Schnegg , ; Schnegg and Flynn , ] with a temporal resolution of 10 s. The devices were placed in the thalweg of the river to ensure an optimal oncoming flow. The pH of the river water was monitored at MS2.…”

Section: Methodsmentioning

confidence: 99%

“…Corrections of tracer concentrations due to temperature fluctuations during the experiment were performed following the procedures described by Lemke et al . [].…”

Section: Methodsmentioning

confidence: 99%

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Concurrent conservative and reactive tracer tests in a stream undergoing hyporheic exchange

Lemke

Liao

Wöhling

et al. 2013

Water Resources Research

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[1] Knowledge about the strength and travel times of hyporheic exchange is vital to predict reactive transport and biogeochemical cycling in streams. In this study, we outline how to perform and analyze stream tracer tests using pulse injections of fluorescein as conservative and resazurin as reactive tracer, which is selectively transformed to resorufin when exposed to metabolically active zones, presumably located in the hyporheic zone. We present steps of preliminary data analysis and apply a conceptually simple mathematical model of the tracer tests to separate effects of in-stream transport from hyporheic exchange processes. To overcome the dependence of common parameter estimation schemes on the initial guess, we derive posterior parameter probability density functions using an adaptive Markov chain Monte Carlo scheme. By this, we can identify maximum-likelihood parameter values of instream transport, strength of hyporheic exchange, distribution of hyporheic travel times as well as sorption and reactivity coefficients of the hyporheic zone. We demonstrate the approach by a tracer experiment at River Goldersbach in southern Germany (60 L/s discharge). In-stream breakthrough curves were recorded with online fluorometers and jointly fitted to simulations of a one-dimensional reactive transport model assuming an exponential hyporheic travel-time distribution. The findings show that the additional analysis of resazurin not only improved the physical basis of the modeling, but was crucial to differentiate between surface transport and hyporheic transient storage of stream solutes. Parameter uncertainties were usually small and could not explain parameter variability between adjacent monitoring stations. The latter as well as a systematic underestimation of the tailing are due to structural errors of the model, particularly the exponential hyporheic travel-time distribution. Mean hyporheic travel times were in the range of 12 min, suggesting that small streambed structures dominate hyporheic exchange at the study site.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

“…Corrections of tracer concentrations due to temperature fluctuations during the experiment were performed following the procedures described by Lemke et al . [].…”

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Concurrent conservative and reactive tracer tests in a stream undergoing hyporheic exchange

Lemke

Liao

Wöhling

et al. 2013

Water Resources Research

Self Cite

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“…Samples were extracted by 25 ml syringe and analyzed twice a day (10 am and 17 pm) in experiment 1 and once a day (10 am) in experiment 2, for a period of five days. Measurements of resazurin and resorufin fluorescence were conducted immediately after sampling with an Albilla GGUN-FL 30 fluorimeter28. After measurements the water samples were transferred from the fluorometer chamber back into the respective microcosm.…”

Section: Methodsmentioning

confidence: 99%

Effects of bioirrigation of non-biting midges (Diptera: Chironomidae) on lake sediment respiration

Baranov

Lewandowski

Romeijn

et al. 2016

Sci Rep

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Bioirrigation or the transport of fluids into the sediment matrix due to the activities of organisms such as bloodworms (larvae of Diptera, Chironomidae), has substantial impacts on sediment respiration in lakes. However, previous quantifications of bioirrigation impacts of Chironomidae have been limited by technical challenges such as the difficulty to separate faunal and bacterial respiration. This paper describes a novel method based on the bioreactive tracer resazurin for measuring respiration in-situ in non-sealed systems with constant oxygen supply. Applying this new method in microcosm experiments revealed that bioirrigation enhanced sediment respiration by up to 2.5 times. The new method is yielding lower oxygen consumption than previously reported, as it is only sensitive to aerobic heterotrophous respiration and not to other processes causing oxygen decrease. Hence it decouples the quantification of respiration of animals and inorganic oxygen consumption from microbe respiration in sediment.

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Hyporheic zone hydrologic science: A historical account of its emergence and a prospectus

Cardenas

2015

Water Resources Research

137

107

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The hyporheic zone, defined by shallow subsurface pathways through river beds and banks beginning and ending at the river, is an integral and unique component of fluvial systems. It hosts myriad hydrologically controlled processes that are potentially coupled in complex ways. Understanding these processes and the connections between them is critical since these processes are not only important locally but integrate to impact increasingly larger scale biogeochemical functioning of the river corridor up to the river network scale. Thus, the hyporheic zone continues to be a growing research focus for many hydrologists for more than half the history of Water Resources Research. This manuscript partly summarizes the historical development of hyporheic zone hydrologic science as gleaned from papers published in Water Resources Research, from the birth of the concept of the hyporheic zone as a hydrologic black box (sometimes referred to as transient storage zone), to its adolescent years of being torn between occasionally competing research perspectives of interrogating the hyporheic zone from a surface or subsurface view, to its mature emergence as an interdisciplinary research field that employs the wide array of state-of-the-art tools available to the modern hydrologist. The field is vibrant and moving in the right direction of addressing critical fundamental and applied questions with no clear end in sight in its growth. There are exciting opportunities for scientists that are able to tightly link the allied fields of geology, geomorphology, hydrology, geochemistry, and ecology to tackle the many open problems in hyporheic zone science.

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On-line fluorometry of multiple reactive and conservative tracers in streams

Cited by 36 publications

References 22 publications

Concurrent conservative and reactive tracer tests in a stream undergoing hyporheic exchange

Concurrent conservative and reactive tracer tests in a stream undergoing hyporheic exchange

Effects of bioirrigation of non-biting midges (Diptera: Chironomidae) on lake sediment respiration

Hyporheic zone hydrologic science: A historical account of its emergence and a prospectus

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