Reaeration in open-channel flow

Bennett, James P.; Rathbun, R.E.

doi:10.3133/pp737

Cited by 148 publications

(105 citation statements)

References 56 publications

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“…The calculated piston velocity remains rather constant over the entire estuary, with a mean value and standard deviation of 13.5 + 4.9 cm h-l. This value is of the same order of magnitude as the range reported for marine systems (Liss and Merlivat 1986;Wanninkhof 1992) and is typical for moderately turbulent rivers (Bennet and Rathbun 1972;Wilcock 1984) at low wind speeds (~3.6 m s-l). Clark et al (1994) determined the gas exchange rate in the Hudson River with a dual tracer technique and proposed values of K ranging from 1 to 9 cm h-l for a Schmidt number (SC) normalized to 600.…”

supporting

confidence: 70%

Atmospheric CO₂ fluxes in a highly polluted estuary (the Scheldt)

Frankignoulle¹,

Bourge²,

Wollast³

1996

Limnology & Oceanography

157

105

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Dissolved CO2 concentration and exchange with the atmosphere were investigated simultaneously in the Scheldt estuary. CO2 partial pressures as high as 5,700 µatm, corresponding to oversaturation with respect to the atmosphere of 1,600%, were observed in the upper estuary. The corresponding atmospheric CO2 fluxes reached values of up to 1.2 mol m−2 d−1. The estimated flux for the entire estuary amounts to 600 t of C d−1 for a river discharge of <1×106 m3 d−1.

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supporting

confidence: 70%

Atmospheric CO₂ fluxes in a highly polluted estuary (the Scheldt)

Frankignoulle¹,

Bourge²,

Wollast³

1996

Limnology & Oceanography

157

105

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“…Exchange coefficients are a function of molecular activity (D i ) of gases and coefficients for two gases are related as k 1 / k 2 = [D 1 /D 2 ] n where n is a exponent ranging from 0.5 to 1.0 [Bennett and Rathbun, 1972;Genereux and Hemond, 1992]. Assuming organic matter is decomposed as C 6 H 12 O 6 + 6O 2 !…”

Section: Chemical Analysesmentioning

confidence: 99%

Long‐term decline in carbon dioxide supersaturation in rivers across the contiguous United States

Jones

Stanley

Mulholland

2003

Geophysical Research Letters

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[1] The partial pressure CO 2 ( pCO 2 ) in streams and rivers reflects both internal carbon dynamics and external biogeochemical processes in terrestrial ecosystems. CO 2 is typically supersaturated in streams because rates of organic matter decomposition exceed photosynthetic uptake, and because of inflow of CO 2 supersaturated ground waters. Using the U.S. Geological Survey's NASQAN database, we calculated pCO 2 and dissolved inorganic carbon (DIC) concentration in 417 streams and rivers distributed across the contiguous United States over a 22-year period. In addition to demonstrating widespread supersaturation and distinct regional variation in pCO 2 across the U.S., our analysis revealed that pCO 2 significantly declined 78.4 ppmv y À1 from 1973 to 1994. This decline is not attributable to changes in terrestrial weathering or instream processes, but instead suggests large-scale declines in terrestrial CO 2 production and import into aquatic ecosystems during this 22-year period.

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“…We selected the models of O'Connor and Dobbins [1958], Owens et al [1964], and Bennett and Rathburn [1972], which were developed for conditions similar to those of our study streams [Cox, 2003]. Our flux estimates are based on equation (1), using [14] We assessed whether tile drains present in the catchments of three of our study streams (Layton Creek, Black River, and Mariposa Brook) were likely to affect gas concentrations using a first-order gas loss equation [Chapra and di Toro, 1991] to define the length of reach over which 95% of the gases input by a tile drain will be dissipated:…”

Section: Unknownmentioning

confidence: 99%

Nitrogen enrichment and the emission of nitrous oxide from streams

Baulch¹,

Schiff²,

Maranger³

et al. 2011

Global Biogeochem. Cycles

125

101

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[1] Nitrous oxide (N 2 O) is a potent greenhouse gas produced during nitrogen cycling. Global nitrogen enrichment has resulted in increased atmospheric N 2 O concentrations due in large part to increased soil emissions. There is also a potentially important flux from streams, rivers and estuaries; although measurements of these emissions are sparse, and role of aquatic ecosystems in global N 2 O budgets remains highly uncertain. Using the longest-term measurements of N 2 O fluxes from streams to date, we found annual fluxes from 14 sites in five streams of south-central Ontario, Canada varied widely-from net uptake of 3.2 ± 0.2 (standard deviation) mmol N 2 O m −2 d −1 to net release of 776 ± 61 mmol N 2 O m −2 d −1 . N 2 O consumption was associated with very low nitrate concentrations (<2.7 mM). Mean annual (log-transformed) N 2 O emissions from our study streams (across sites and years) were positively related to nitrate concentrations (r 2 = 0.59).This nitrate-N 2 O relationship can be generalized across all 20 streams (in Canada, Japan, Mexico, and the midwestern United States) for which published data now exist and could provide a new basis for the IPCC to calculate agricultural emissions from streams. In addition to predicting annual emissions, we present the first measurements of N 2 O concentrations under ice in streams. Nitrate was a strong predictor of N 2 O % saturation during periods of ice cover (r 2 = 0.89), when gas exchange is negligible. Given the small surface area of streams within a catchment and the fact our measured areal fluxes are comparable to reported fluxes from agricultural soils, this suggests streams are a small regional N 2 O source.Citation: Baulch, H. M., S. L. Schiff, R. Maranger, and P. J. Dillon (2011), Nitrogen enrichment and the emission of nitrous oxide from streams, Global Biogeochem. Cycles, 25, GB4013,

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Reaeration in open-channel flow

Cited by 148 publications

References 56 publications

Atmospheric CO₂ fluxes in a highly polluted estuary (the Scheldt)

Atmospheric CO₂ fluxes in a highly polluted estuary (the Scheldt)

Long‐term decline in carbon dioxide supersaturation in rivers across the contiguous United States

Nitrogen enrichment and the emission of nitrous oxide from streams

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Reaeration in open-channel flow

Cited by 148 publications

References 56 publications

Atmospheric CO2 fluxes in a highly polluted estuary (the Scheldt)

Atmospheric CO2 fluxes in a highly polluted estuary (the Scheldt)

Long‐term decline in carbon dioxide supersaturation in rivers across the contiguous United States

Nitrogen enrichment and the emission of nitrous oxide from streams

Contact Info

Product

Resources

About

Atmospheric CO₂ fluxes in a highly polluted estuary (the Scheldt)

Atmospheric CO₂ fluxes in a highly polluted estuary (the Scheldt)