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Liuyi Zhang - One of the best experts on this subject based on the ideXlab platform.
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ambient concentration and dry deposition of major Inorganic Nitrogen species at two urban sites in sichuan basin china
Environmental Pollution, 2016Co-Authors: Huanbo Wang, Fumo Yang, Guangming Shi, Mi Tian, Leiming Zhang, Liuyi ZhangAbstract:Abstract To assess pollution levels of major Inorganic Nitrogen species and their atmospheric deposition input to sensitive ecosystems in Sichuan Basin, southwest China, ambient concentrations of oxidized (NO y ∼ NO 2 , HNO 3 , NO 3 − ) and reduced (NH x = NH 3 , NH 4 + ) Nitrogen species were collected at two urban sites during four one-month periods, each in a different season from July 2014 to April 2015. Estimated annual mean concentration of NO y was 20.3 and 13.5 μg N m −3 in Chengdu and Wanzhou, respectively, and NH x was 16.9 and 13.6 μg N m −3 , respectively. Back trajectory cluster analysis indicated that high levels of NO y and NH x in Chengdu were mainly caused by local emissions while those in Wanzhou were caused by both the local emissions and long-range transport of pollutants. On annual basis, NO 2 contributed the most to NO y , followed by NO 3 − and HNO 3 , accounting for 87.5%, 10.5% and 2.0%, respectively, of NO y in Chengdu, and 91.4%, 6.9% and 1.7%, respectively, in Wanzhou. NH 3 was the predominant contributor to NH x , contributing 65.6% and 72.2% in Chengdu and Wanzhou, respectively. Dry deposition fluxes were estimated using the inferential method with measured ambient concentrations and modelled dry deposition velocities. The total Inorganic Nitrogen dry deposition flux was estimated to be 21.4 and 8.5 kg N ha −1 yr −1 , with 44.3% and 41.4% from NO y in Chengdu and Wanzhou, respectively. NO 2 and NH 3 each contributed about 80% of NO y and NH x dry deposition, respectively. Wet deposition was only collected in Wanzhou, where the annual wet deposition of NO 3 − and NH 4 + was 4.5 and 15.7 kg N ha −1 yr −1 , respectively. The total wet plus dry deposition was 28.7 kg N ha −1 yr −1 in Wanzhou with 72.2% from reduced Nitrogen. Therefore, controlling NH 3 emissions from agricultural, traffic, waste containers and sewage system sources would be effective to reduce the total Nitrogen deposition in the Sichuan Basin area.
Nancy B. Dise - One of the best experts on this subject based on the ideXlab platform.
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Predicting dissolved Inorganic Nitrogen leaching in European forests using two independent databases
Science of The Total Environment, 2009Co-Authors: Nancy B. Dise, James J. Rothwell, Vincent Gauci, C. Van Der Salm, W. De VriesAbstract:Abstract Regional-scale databases can be particularly useful for identifying relationships between dissolved Inorganic Nitrogen (N) leaching in forests and environmental drivers, which in turn allow an assessment of the risk of ecosystem damage, such as forest acidification and eutrophication of downstream water bodies. However, detecting the ‘signal’ of a significant correlate to N leaching against a background of wide variability in other factors requires a large number of sites, and the validation of models developed requires a similarly large number of independent sites. Here we use two large and fully independent databases of forest ecosystems across Europe to develop and validate indicators of N saturation and leaching. One database was used for model development and the other for validating these models. Among 35 variables considered, the most significant indicators of N leaching in the model development database were: the flux of dissolved Inorganic N in deposition, mean annual temperature, mean altitude, the site drainage (plot vs catchment), needle- and litter-N concentration, organic horizon C:N ratio, and subsoil pH. Altitude was not a consistent predictor (it was significant in the development database but not in the validation database), and needle and litter N concentration, plot vs catchment, and subsoil pH all showed high intercorrelation with N deposition and so were not significant in models already including N deposition. The most consistent and useful indicators of N leaching were throughfall N deposition, organic horizon C:N ratio and mean annual temperature. Sites receiving low levels of N deposition ( − 1 y − 1 ) showed very low output fluxes of N and were simulated separately from more polluted forests. In general, the models successfully predicted N leaching (mean of ± 5 kg N ha − 1 y − 1 between observed and predicted) from forests at early to intermediate stages of Nitrogen saturation but not from Nitrogen-saturated sites. Thus, simple relationships developed from combining (1) external drivers (deposition, temperature) and (2) site conditions (Nitrogen status of soils) can successfully estimate Nitrogen leaching from forests that have not yet been highly damaged by N deposition.
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A classification and regression tree model of controls on dissolved Inorganic Nitrogen leaching from European forests.
Environmental Pollution, 2008Co-Authors: James J. Rothwell, Martyn N. Futter, Nancy B. DiseAbstract:Often, there is a non-linear relationship between atmospheric dissolved Inorganic Nitrogen (DIN) input and DIN leaching that is poorly captured by existing models. We present the first application of the non-parametric classification and regression tree approach to evaluate the key environmental drivers controlling DIN leaching from European forests. DIN leaching was classified as low ( 15 kg N ha � 1 year � 1 ) at 215 sites across Europe. The analysis identified throughfall NO3 deposition, acid deposition, hydrology, soil type, the carbon content of the soil, and the legacy of historic N deposition as the dominant drivers of DIN leaching for these forests. Ninety four percent of sites were successfully classified into the appropriate leaching category. This approach shows promise for understanding complex ecosystem responses to a wide range of anthropogenic stressors as well as an improved method for identifying risk and targeting pollution mitigation strategies in forest ecosystems. 2008 Elsevier Ltd. All rights reserved.
A. Subandar - One of the best experts on this subject based on the ideXlab platform.
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laminaria culture for reduction of dissolved Inorganic Nitrogen in salmon farm effluent
Journal of Applied Phycology, 1993Co-Authors: A. Subandar, Royann J. Petrell, Paul HarrisonAbstract:Finfish culture is a growing industry, and it causes a nutrient loading problem. To investigate the feasibility of an integrated culture of kelp and salmon, 15-cm long kelp (Laminaria saccharina) was grown in salmon culture effluent. The objectives were to test the effects of flow rate and kelp density on dissolved Inorganic Nitrogen removal (DIN), and DIN uptake and growth by the kelp. NH 4 + , NO 3 − and DIN (NH 4 + + NO 3 − ) loadings were in the ranges 6.2–25.4, 12.9–40.0, 19.7–52.7 μmol 1−1, respectively, over the experimental period. Surplus uptake of Nitrogen was not evident, because the C:N ratio (10–11) was constant in all experiments. During light periods, the kelp removed from 170–339 μmol 1−1 h−1, and approximately 26–40% of the incoming DIN. The DIN uptake rate, based on daylight sampling periods, ranged between 6.1–22.5 μmol g−1 dry mass h−1. The highest-flow rate, lowest-density tank had the highest DIN uptake rate. Debris from the fish effluent settling on the kelp thalli in the low-flow rate tanks affected uptake. Mean DIN uptake rate based on 3 days of growth for all flow-density combinations ranged between 5.4–8.3 μmol g−1 dry mass h−1. The kelp utilized NH 4 + and NO 3 − equally. The growth ranged between 6.5–9% d−1. The biomass production ranged from 1–2 g per sampling period. The highest growth rate and biomass production were achieved by kelp in the highest-flow rate, lowest-density tank. Lower DIN concentrations due to higher DIN removal rates in the other tanks and light limitation due to self-shading in the high-density tanks were probably responsible for the reduced growth rate in these tanks.
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Laminaria culture for reduction of dissolved Inorganic Nitrogen in salmon farm effluent
Journal of Applied Phycology, 1993Co-Authors: A. Subandar, Royann J. Petrell, Paul J. HarrisonAbstract:Finfish culture is a growing industry, and it causes a nutrient loading problem. To investigate the feasibility of an integrated culture of kelp and salmon, 15-cm long kelp (Laminaria saccharina) was grown in salmon culture effluent. The objectives were to test the effects of flow rate and kelp density on dissolved Inorganic Nitrogen removal (DIN), and DIN uptake and growth by the kelp. NH 4 + , NO 3 − and DIN (NH 4 + + NO 3 − ) loadings were in the ranges 6.2–25.4, 12.9–40.0, 19.7–52.7 μmol 1−1, respectively, over the experimental period.
James J. Rothwell - One of the best experts on this subject based on the ideXlab platform.
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Predicting dissolved Inorganic Nitrogen leaching in European forests using two independent databases
Science of The Total Environment, 2009Co-Authors: Nancy B. Dise, James J. Rothwell, Vincent Gauci, C. Van Der Salm, W. De VriesAbstract:Abstract Regional-scale databases can be particularly useful for identifying relationships between dissolved Inorganic Nitrogen (N) leaching in forests and environmental drivers, which in turn allow an assessment of the risk of ecosystem damage, such as forest acidification and eutrophication of downstream water bodies. However, detecting the ‘signal’ of a significant correlate to N leaching against a background of wide variability in other factors requires a large number of sites, and the validation of models developed requires a similarly large number of independent sites. Here we use two large and fully independent databases of forest ecosystems across Europe to develop and validate indicators of N saturation and leaching. One database was used for model development and the other for validating these models. Among 35 variables considered, the most significant indicators of N leaching in the model development database were: the flux of dissolved Inorganic N in deposition, mean annual temperature, mean altitude, the site drainage (plot vs catchment), needle- and litter-N concentration, organic horizon C:N ratio, and subsoil pH. Altitude was not a consistent predictor (it was significant in the development database but not in the validation database), and needle and litter N concentration, plot vs catchment, and subsoil pH all showed high intercorrelation with N deposition and so were not significant in models already including N deposition. The most consistent and useful indicators of N leaching were throughfall N deposition, organic horizon C:N ratio and mean annual temperature. Sites receiving low levels of N deposition ( − 1 y − 1 ) showed very low output fluxes of N and were simulated separately from more polluted forests. In general, the models successfully predicted N leaching (mean of ± 5 kg N ha − 1 y − 1 between observed and predicted) from forests at early to intermediate stages of Nitrogen saturation but not from Nitrogen-saturated sites. Thus, simple relationships developed from combining (1) external drivers (deposition, temperature) and (2) site conditions (Nitrogen status of soils) can successfully estimate Nitrogen leaching from forests that have not yet been highly damaged by N deposition.
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A classification and regression tree model of controls on dissolved Inorganic Nitrogen leaching from European forests.
Environmental Pollution, 2008Co-Authors: James J. Rothwell, Martyn N. Futter, Nancy B. DiseAbstract:Often, there is a non-linear relationship between atmospheric dissolved Inorganic Nitrogen (DIN) input and DIN leaching that is poorly captured by existing models. We present the first application of the non-parametric classification and regression tree approach to evaluate the key environmental drivers controlling DIN leaching from European forests. DIN leaching was classified as low ( 15 kg N ha � 1 year � 1 ) at 215 sites across Europe. The analysis identified throughfall NO3 deposition, acid deposition, hydrology, soil type, the carbon content of the soil, and the legacy of historic N deposition as the dominant drivers of DIN leaching for these forests. Ninety four percent of sites were successfully classified into the appropriate leaching category. This approach shows promise for understanding complex ecosystem responses to a wide range of anthropogenic stressors as well as an improved method for identifying risk and targeting pollution mitigation strategies in forest ecosystems. 2008 Elsevier Ltd. All rights reserved.
Andreas Krein - One of the best experts on this subject based on the ideXlab platform.
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Hydrogeologic and landscape controls of dissolved Inorganic Nitrogen (DIN) and dissolved silica (DSi) fluxes in heterogeneous catchments
Journal of Hydrology, 2012Co-Authors: Milan Onderka, Sebastian Wrede, Marek Rodný, Laurent Pfister, Lucien Hoffmann, Andreas KreinAbstract:Summary This paper examines the combined effects of catchment complexity in terms of physiography, land use patterns, and lithology on the export of dissolved Inorganic Nitrogen and dissolved silica from heterogeneous nested catchments in the Grand-Duchy of Luxembourg. Using results from water quality monitoring at 24 sampling sites, we determined the first-order controls on these fluxes. Land cover with four classes (forest, agriculture, grassland and urban), dominant lithology (schist, marls, sandstone, limestone, alluvial sediments), physiographic indices (elevation, flow path length, ratio of flow path length to flow path gradient, topographic wetness index, and other), and a suite of hydrological indices (baseflow, flashiness index and runoff coefficient), were calculated and used as potential controls. Given the high co-dependence of the predictors, Partial Least Square Regression was used to shed light on the linkages between export fluxes and the metrics composed of the 19 selected catchment characteristics. The first-order controls were determined by calculating the Variable Influence on Projection (VIP). These values revealed that the overall dissolved Inorganic Nitrogen fluxes are controlled primarily by lithology, land cover, topographic wetness index and flow path length. The first-order controls of dissolved silica fluxes are runoff coefficient, average topographic slope and land cover. Fluxes of dissolved Inorganic Nitrogen and dissolved silica did not show any strong relation to catchment scale. Apart from the widely accepted effect of land cover, our results indicate that catchment topography has an essential impact on the fluxes of dissolved Inorganic Nitrogen. The ratio of flow path length and flow path gradient, previously suggested as a proxy of mean water transit time, exerted a relatively strong control on dissolved Inorganic Nitrogen fluxes (VIP > 1) with a negative relation to dissolved Inorganic Nitrogen fluxes, suggesting that dissolved Inorganic Nitrogen fluxes decrease with an increasing flow path gradient.