Determination of stream reaeration coefficients by use of tracers

Kilpatrick, F.A.; Rathbun, R.E.; Yotsukura, Nobuhiro; Parker, G.; DeLong, Lewis L.

doi:10.3133/ofr87245

Cited by 58 publications

(96 citation statements)

References 6 publications

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“…Both respiration (R) and reaeration (K) are corrected for temperature changes at each time step (i). Specifically, R includes a temperature-dependence factor of 1.072, which represents a doubling in respiration with each 10uC increase in temperature, and K includes a temperature-dependence factor of 1.024 as in Kilpatrick et al (1989). The diel DO curve is modeled using light (as PAR in this study); temperature; and initial (i 5 0) DO concentration (as % saturation); and the values of A, r, R, and K are iteratively solved by minimizing the sums of squares between the modeled and the measured DO concentrations (Atkinson et al 2008) using a Marquardt algorithm in ModelMaker 4.0 (AP Benson).…”

Section: Methodsmentioning

confidence: 99%

Agricultural land use alters the seasonality and magnitude of stream metabolism

Griffiths

Tank

Royer

et al. 2013

Limnology & Oceanography

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We present a comprehensive data set of gross primary production (GPP) and ecosystem respiration (ER) in open-canopy, nutrient-rich streams draining row-crop agriculture in the midwestern United States. We used two approaches to characterize temporal and spatial variation in whole-stream metabolism: continuous measurements in one agricultural stream for 1 yr, and periodic daily measurements in six agricultural streams on six dates spanning summer, autumn, and winter. Continuous measurements revealed high rates of GPP (range: 0.1 to 22.0 g O 2 m 22 d 21 ) and ER (range: 20.9 to 234.8 g O 2 m 22 d 21 ) that varied seasonally with light availability and temperature. GPP and ER were correlated during periods of high autotrophic production, suggesting that autotrophic respiration comprised a large portion of ER; however, the GPP : ER ratio exceeded 1 for only 4% of the year. While there were distinct temporal patterns in metabolism in one agricultural stream, rates of GPP and ER were similar among six streams when assessed via periodic daily measurements, and 26% of all periodic daily measurements were autotrophic with GPP : ER . 1. However, these periodic measurements were collected under baseflow conditions and may have overestimated the extent of autotrophy in agricultural streams. Overall, the open canopy and elevated nutrients of agricultural streams resulted in higher rates of GPP and ER compared with more pristine systems. Estimates of metabolism are needed from underrepresented systems to accurately quantify carbon fluxes from fluvial ecosystems.

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Section: Methodsmentioning

confidence: 99%

Agricultural land use alters the seasonality and magnitude of stream metabolism

Griffiths

Tank

Royer

et al. 2013

Limnology & Oceanography

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“…To compensate for daily temperature fluctuation, ER was assumed to double with a 10°C increase in temperature (Phinney and McIntire 1965), whereas k was assumed to increase by 2.41%/°C (Kilpatrick et al 1989). Daily GPP (g m…”

Section: Sitementioning

confidence: 99%

Land use affects temporal variation in stream metabolism

Clapcott¹,

Young²,

Neale³

et al. 2016

Freshwater Science

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Stream metabolism (gross primary production and ecosystem respiration) is increasingly used to assess waterway health because mean values are responsive to spatial variation in land use, but little is known about how human land use influences the temporal variability of stream metabolism. We investigated daily variation in dissolved O 2 (DO) concentrations and calculated mean and within-season variation in gross primary production (GPP) and ecosystem respiration (ER) rates at 13 stream sites across a landuse intensity gradient in the Auckland region, New Zealand, over 9 y. Based on generalized linear mixed models, mean daily GPP (0.1-12.6 g O 2 m −2 d ) and seasonal variation in stream metabolism were significantly related to landuse intensity with higher variability associated with higher values of a landuse stress score. Overall, mean daily rates and day-to-day variation in GPP and ER were greatest in summer and least in winter. We recommend summer monitoring over a minimum 5-d period to assess stream health. Our results show that human land use affects the mean and the temporal variability of DO and stream metabolism. This finding has important consequences for characterizing in-stream processes and the resilience of stream ecosystems. Only long-term temporal monitoring provides the data needed to assess fully how streams function.

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“…technique within systems of low water mass (see Hibbs et al 1998;Kilpatrick et al 1989). Various other methods exist for estimating the gas transfer coefficient, each with their own inherent assumptions and errors.…”

Section: Assessment and Discussionmentioning

confidence: 99%

Revisiting the application of open‐channel estimates of denitrification

Baulch

Venkiteswaran

Dillon

et al. 2010

Limnology & Ocean Methods

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Development of an open-channel method for measurement of denitrification, without the use of expensive isotopic tracers, has generated considerable interest among researchers attempting to quantify N loss from lotic systems. Membrane inlet mass spectrometry allows measurement of small changes in N 2 concentrations, facilitating calculation of whole reach denitrification rates using an N 2 mass balance corrected for gas exchange. The method has been applied successfully within numerous rivers ranging widely in size and denitrification rate. Previous model-based analyses suggest that the method can be applied in a broader suite of ecosystems, and specifically, that it is well suited to shallow streams where denitrification rates as low as 30-100 µmol N m -2 h -1 may be measurable. This coupled with increasing availability of necessary equipment, relatively low cost of measurements, and the ability to measure denitrification at environmentally relevant spatial scales suggests that broad adoption of the method is likely. In this paper, we revisit this model-based analysis using alternate models of gas exchange and demonstrate that benthic turbulence-induced gas exchange will restrict the suite of suitable study streams. Specifically, we note that within shallow streams and fast-flowing systems denitrification may be measurable only at moderate or high rates. To help facilitate further application of the method, we extend our discussion beyond site selection to discuss assumptions of the open-channel method, options for estimating the error in denitrification rates, and recommended practices for future studies.

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Determination of stream reaeration coefficients by use of tracers

Cited by 58 publications

References 6 publications

Agricultural land use alters the seasonality and magnitude of stream metabolism

Agricultural land use alters the seasonality and magnitude of stream metabolism

Land use affects temporal variation in stream metabolism

Revisiting the application of open‐channel estimates of denitrification

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