Nitrogen loss rates in streams: Scale-dependence and up-scaling methodology

2004 ◽  
Vol 31 (13) ◽  
pp. n/a-n/a ◽  
Author(s):  
G. A. Lindgren ◽  
G. Destouni
Keyword(s):  
Nitrogen Loss ◽  
Scale Dependence ◽  
Up Scaling ◽  
Loss Rates

scholarly journals Comparison of Active Nitrogen Loss in Four Pathways on a Sloped Peanut Field with Red Soil in China under Conventional Fertilization Conditions

2019 ◽  
Vol 11 (22) ◽  
pp. 6219
Author(s):  
Zheng ◽  
Liu ◽  
Nie ◽  
Zuo ◽  
Wang
Keyword(s):  
Water Conservation ◽  
Nitrogen Loss ◽  
N2o Emission ◽  
Red Soil ◽  
N Leaching ◽  
Nh3 Volatilization ◽  
Leakage Loss ◽  
Active Nitrogen ◽  
Nitrogen Levels ◽  
Loss Rates

Active nitrogen loss mainly includes ammonia (NH3) volatilization, nitrous oxide (N2O) emission, NO3−-N and NH4+-N deep leakage (N leaching), and NO3−-N and NH4+-N surface runoff (N runoff), resulting in serious environmental problems. To analyze the characteristics of active nitrogen loss in the four pathways on sloped farmland under conventional fertilization, six lysimeters with a slope of 8° were used. Losses due to NH3 volatilization, N2O emission, N leaching, and N runoff were investigated after urea application on a peanut field with red soil in China during the growing season from 2017–2018. Results reveal that at conventional nitrogen levels of 150 and 172 kg hm−2, the total active nitrogen loss caused by fertilization accounting for the total nitrogen applied was 5.57% and 14.21%, respectively, with the N2O emission coefficients of 0.18% and 0.10%, respectively; the NH3 volatilization coefficients of 2.24% and 0.31%, respectively; the N leakage loss rates of 3.07% and 10.50%, respectively; and the N runoff loss rates of 0.08% and 3.30%, respectively. The dry year was dominated by leaching and NH3 volatilization, while the wet year was dominated by leaching and runoff; the base fertilizer period was dominated by leakage, while the topdressing period was dominated by leakage and runoff, which suggests that the loss of active nitrogen in the soil-peanut system on a sloped red soil was mainly affected by rainfall and fertilization methods. Taken together, reasonable fertilization management and soil and water conservation measures appear to be effective in minimizing the loss of active nitrogen from nitrogen fertilizer.

scholarly journals Controls of terrestrial ecosystem nitrogen loss on simulated productivity responses to elevated CO<sub>2</sub>

2018 ◽  
Vol 15 (18) ◽  
pp. 5677-5698 ◽  
Author(s):  
Johannes Meyerholt ◽  
Sönke Zaehle
Keyword(s):  
Plant Growth ◽  
Elevated Co2 ◽  
Large Scale ◽  
Nitrogen Availability ◽  
Carbon Sink ◽  
Nitrogen Loss ◽  
Terrestrial Ecosystem ◽  
Turnover Rates ◽  
Terrestrial Biosphere ◽  
Loss Rates

Abstract. The availability of nitrogen is one of the primary controls on plant growth. Terrestrial ecosystem nitrogen availability is not only determined by inputs from fixation, deposition, or weathering, but is also regulated by the rates with which nitrogen is lost through various pathways. Estimates of large-scale nitrogen loss rates have been associated with considerable uncertainty, as process rates and controlling factors of the different loss pathways have been difficult to characterize in the field. Therefore, the nitrogen loss representations in terrestrial biosphere models vary substantially, adding to nitrogen cycle-related uncertainty and resulting in varying predictions of how the biospheric carbon sink will evolve under future scenarios of elevated atmospheric CO2. Here, we test three commonly applied approaches to represent ecosystem-level nitrogen loss in a common carbon–nitrogen terrestrial biosphere model with respect to their impact on projections of the effect of elevated CO2. We find that despite differences in predicted responses of nitrogen loss rates to elevated CO2 and climate forcing, the variety of nitrogen loss representation between models only leads to small variety in carbon sink predictions. The nitrogen loss responses are particularly uncertain in the boreal and tropical regions, where plant growth is strongly nitrogen-limited or nitrogen turnover rates are usually high, respectively. This highlights the need for better representation of nitrogen loss fluxes through global measurements to inform models.

Linkages between anammox and denitrifying bacterial communities and nitrogen loss rates in high‐elevation rivers

2020 ◽  
Author(s):  
Sibo Zhang ◽  
Wei Qin ◽  
Yubei Bai ◽  
Zhenrui Zhang ◽  
Junfeng Wang ◽  
...  
Keyword(s):  
Bacterial Communities ◽  
Nitrogen Loss ◽  
High Elevation ◽  
Loss Rates

scholarly journals Controls of terrestrial ecosystem nitrogen loss on simulated productivity responses to elevated CO<sub>2</sub>

2018 ◽  
Author(s):  
Johannes Meyerholt ◽  
Sönke Zaehle
Keyword(s):  
Plant Growth ◽  
Large Scale ◽  
Nitrogen Availability ◽  
Carbon Sink ◽  
Nitrogen Loss ◽  
Terrestrial Ecosystem ◽  
Turnover Rates ◽  
Terrestrial Biosphere ◽  
Considerable Uncertainty ◽  
Loss Rates

Abstract. The availability of nitrogen is one of the primary nutritional controls on plant growth. Terrestrial ecosystem nitrogen availability is not only determined by inputs of fixation, deposition, and mineralization, but also regulated by the rates with which nitrogen is lost through various pathways. Large-scale nitrogen loss rates have been associated with considerable uncertainty, as process rates and controlling factors of the different loss pathways have been difficult to characterize in the field. Therefore, the nitrogen loss representations in terrestrial biosphere models vary substantially, adding to nitrogen cycle-related uncertainty and resulting in varying predictions of how the biospheric carbon sink will evolve under future scenarios of elevated atmospheric CO2. Here, we test three published approaches to represent ecosystem level nitrogen loss in a common carbon-nitrogen terrestrial biosphere model with respect to their impact on projections of the carbon effect of elevated CO2. We find that despite differences in predicted responses of nitrogen loss rates to biogeochemical and climate forcing, the variety of nitrogen loss representation between models only leads to small variety in carbon sink predictions. The nitrogen loss responses are particularly uncertain in the boreal and tropical regions, where plant growth is strongly nitrogen limited or nitrogen turnover rates are usually high, respectively. This highlights the need for better resolution of nitrogen loss fluxes through global measurements to inform models.

scholarly journals Carbon and nitrogen loss rates during aging of lake sediment: Changes over 27 years studied in varved lake sediment

2008 ◽  
Vol 53 (3) ◽  
pp. 1076-1082 ◽  
Author(s):  
Veronika Gälman ◽  
Johan Rydberg ◽  
Sara Sjöstedt de-Luna ◽  
Richard Bindler ◽  
Ingemar Renberg
Keyword(s):  
Lake Sediment ◽  
Nitrogen Loss ◽  
Carbon And Nitrogen ◽  
Varved Lake Sediment ◽  
Loss Rates

Ex Situ Loss Rates from ACZA Treated and Wrapped Piles

Ports 2010 ◽  
2010 ◽  
Author(s):  
Rolf Schottle ◽  
Katherine Prickett
Keyword(s):  
Ex Situ ◽  
Loss Rates

scholarly journals Three-component modelling of C-rich AGB star winds – V. Effects of frequency-dependent radiative transfer including drift★

2020 ◽  
Vol 499 (2) ◽  
pp. 1531-1560
Author(s):  
Christer Sandin ◽  
Lars Mattsson
Keyword(s):  
Radiative Transfer ◽  
Mass Loss ◽  
Density Ratio ◽  
Mie Scattering ◽  
Speed Ratio ◽  
Exponential Dependence ◽  
Frequency Dependent ◽  
Wind Velocities ◽  
Drift Models ◽  
Loss Rates

ABSTRACT Stellar winds of cool carbon stars enrich the interstellar medium with significant amounts of carbon and dust. We present a study of the influence of two-fluid flow on winds where we add descriptions of frequency-dependent radiative transfer (RT). Our radiation hydrodynamic models in addition include stellar pulsations, grain growth and ablation, gas-to-dust drift using one mean grain size, dust extinction based on both the small particle limit (SPL) and Mie scattering, and an accurate numerical scheme. We calculate models at high spatial resolution using 1024 gridpoints and solar metallicities at 319 frequencies, and we discern effects of drift by comparing drift models to non-drift models. Our results show differences of up to 1000 per cent in comparison to extant results. Mass-loss rates and wind velocities of drift models are typically, but not always, lower than in non-drift models. Differences are larger when Mie scattering is used instead of the SPL. Amongst other properties, the mass-loss rates of the gas and dust, dust-to-gas density ratio, and wind velocity show an exponential dependence on the dust-to-gas speed ratio. Yields of dust in the least massive winds increase by a factor 4 when drift is used. We find drift velocities in the range $10\!-\!67\, \mbox{km}\, \mbox{s}^{-1}$, which is drastically higher than in our earlier works that use grey RT. It is necessary to include an estimate of drift velocities to reproduce high yields of dust and low wind velocities.

scholarly journals Scale dependence of galaxy biasing investigated by weak gravitational lensing: An assessment using semi-analytic galaxies and simulated lensing data

2018 ◽  
Vol 613 ◽  
pp. A15 ◽  
Author(s):  
Patrick Simon ◽  
Stefan Hilbert
Keyword(s):  
Gravitational Lensing ◽  
Spatial Scales ◽  
Scale Dependence ◽  
Reconstruction Technique ◽  
Weak Gravitational Lensing ◽  
Physical Scale ◽  
The Galaxy ◽  
Galaxy Bias ◽  
The Impact ◽  
Lens Galaxies

Galaxies are biased tracers of the matter density on cosmological scales. For future tests of galaxy models, we refine and assess a method to measure galaxy biasing as a function of physical scalekwith weak gravitational lensing. This method enables us to reconstruct the galaxy bias factorb(k) as well as the galaxy-matter correlationr(k) on spatial scales between 0.01hMpc−1≲k≲ 10hMpc−1for redshift-binned lens galaxies below redshiftz≲ 0.6. In the refinement, we account for an intrinsic alignment of source ellipticities, and we correct for the magnification bias of the lens galaxies, relevant for the galaxy-galaxy lensing signal, to improve the accuracy of the reconstructedr(k). For simulated data, the reconstructions achieve an accuracy of 3–7% (68% confidence level) over the abovek-range for a survey area and a typical depth of contemporary ground-based surveys. Realistically the accuracy is, however, probably reduced to about 10–15%, mainly by systematic uncertainties in the assumed intrinsic source alignment, the fiducial cosmology, and the redshift distributions of lens and source galaxies (in that order). Furthermore, our reconstruction technique employs physical templates forb(k) andr(k) that elucidate the impact of central galaxies and the halo-occupation statistics of satellite galaxies on the scale-dependence of galaxy bias, which we discuss in the paper. In a first demonstration, we apply this method to previous measurements in the Garching-Bonn Deep Survey and give a physical interpretation of the lens population.

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