Export of nitrogen from catchments: A worldwide analysis

Álvarez‐Cobelas, Miguel; Angeler, David G.; Sánchez-Carrillo, Salvador

doi:10.1016/j.envpol.2008.02.016

Cited by 124 publications

(113 citation statements)

References 85 publications

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“…Several studies have reported that DON accounted for the dominant fraction of N flux in undisturbed forested watersheds (Alvarez-Cobelas et al, 2008;Frank et al, 2000;Kaushal and Lewis, 2003;Pellerin et al, 2006). Substantial fluxes of NO 3 -N and the dominance of NO 3 -N over DON in runoff are likely due to a certain degree of N saturation (N supply > N demand) of these forested watersheds (Aber et al, 1998;Compton et al, 2003).…”

Section: Organic and Inorganic Nitrogen In Runoffmentioning

confidence: 99%

Variability in runoff fluxes of dissolved and particulate carbon and nitrogen from two watersheds of different tree species during intense storm events

et al. 2016

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Abstract. Heavy storm events may increase the amount of organic matter in runoff from forested watersheds as well as the relation of dissolved to particulate organic matter. This study evaluated the effects of monsoon storm events on the runoff fluxes and on the composition of dissolved (< 0.45 µm) and particulate (0.7 µm to 1 mm) organic carbon and nitrogen (DOC, DON, POC, PON) in a mixed coniferous/deciduous (mixed watershed) and a deciduous forested watershed (deciduous watershed) in South Korea. During storm events, DOC concentrations in runoff increased with discharge, while DON concentrations remained almost constant. DOC, DON and NO 3 -N fluxes in runoff increased linearly with discharge pointing to changing flow paths from deeper to upper soil layers at high discharge, whereas nonlinear responses of POC and PON fluxes were observed likely due to the origin of particulate matter from the erosion of mineral soil along the stream benches. The integrated C and N fluxes in runoff over the 2-month study period were in the order of DOC > POC and NO 3 -N > DON > PON. The integrated DOC fluxes in runoff during the study period were much larger at the deciduous watershed (16 kg C ha −1 ) than at the mixed watershed (7 kg C ha −1 ), while the integrated NO 3 -N fluxes were higher at the mixed watershed (5.2 kg N ha −1 ) than at the deciduous watershed (2.9 kg N ha −1 ). The latter suggests a larger N uptake by deciduous trees. Integrated fluxes of POC and PON were similar at both watersheds. The composition of organic matter in soils and runoff indicates that the contribution of near-surface flow to runoff was larger at the deciduous than at the mixed watershed. Our results demonstrate different responses of particulate and dissolved C and N in runoff to storm events as a combined effect of tree species composition and watershed specific flow paths.

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Section: Organic and Inorganic Nitrogen In Runoffmentioning

confidence: 99%

Variability in runoff fluxes of dissolved and particulate carbon and nitrogen from two watersheds of different tree species during intense storm events

et al. 2016

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“…A worldwide assessment (946 rivers) showed that, although most rivers displayed nitrogen export profiles (N fraction distributions) reflecting pristine conditions, nitrate export to rivers that passed through human settlements was related to human population density (Alvarez-Cobelas et al, 2008). Although P discharges into coastal waters have stabilised or reduced in Western Europe, after unprecedented contamination during the second half of the 20 th century, N trends have not attenuated and are still increasing in some places (Thieu et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Long-term nitrate and phosphate loading of river water in the Upper Manyame Catchment, Zimbabwe

Nyamangara¹,

Jeke²,

Rurinda³

2013

WSA

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Urbanisation and agriculture represent a dramatic example of human interference in catchment hydrology. The impact of agricultural, domestic, industrial and municipal activities on river flow and water quality within the Upper Manyame Catchment Area (UMCA) was assessed using 7-year nitrate, phosphate and water flow rate data, collected by the Environmental Management Agency (EMA). Water samples for nitrate and phosphate analysis were collected at 8 points along the Manyame (2 points), Marimba (2 points) and Mukuvisi (4 points) rivers, and runoff volume was recorded at the mouth of each river. Annual runoff of each river was closely related to rainfall amount, with the lowest runoff being recorded during drought years. High nitrate and phosphate concentrations were recorded directly downstream of residential, municipal and industrial areas suggesting that these were the major sources of the pollutants found in the river water. For example, phosphate concentration at 2 sites along Mukuvisi River (downstream of domestic and industrial areas) exceeded the statutory limit (0.5 mg/ℓ) for 'safe' or good quality water ('blue' category) according to the Zimbabwe Water (Waste and Effluent Disposal) Regulations, and ranged from 0.78 mg/ℓ during the dry season to 2.23 mg/ℓ during the wet season. In the Marimba River phosphate concentration at Site 4 (downstream of domestic, industrial and sewage processing plant) also exceeded the safe water quality standard by 4-6 times. Although Marimba River contributes the lowest proportion of runoff (relative to the other two rivers sampled) entering Lake Chivero, it contributed the highest nitrate (114 840 kg/yr) and phosphate (84 324 kg/yr) loading. It was concluded that anthropogenic activities within the UMCA were the major sources of nitrate and phosphate pollution in the three rivers and pose a serious threat to the ecological sustainability of the rivers and lakes downstream, and to the economic wellbeing of nearby cities which rely on the water for potable uses.

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“…These factors should be evaluated carefully to improve our understanding of downstream N eutrophication. Upland forests have been commonly regarded as having negligible NPSs for downstream eutrophication [6,7]. However, elevated atmospheric N deposition resulting from human activities may potentially cause N saturation in forested ecosystems, defined as an excess of biotic demand [8], which causes high levels of NO 3 − leaching from upland forested ecosystems to be observed [8,9].…”

Section: Introductionmentioning

confidence: 99%

Differences in Stream Water Nitrate Concentrations between a Nitrogen-Saturated Upland Forest and a Downstream Mixed Land Use River Basin

et al. 2017

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Nitrogen (N) saturation of upland forests has been assumed to be a substantial N source downstream. However, removal processes of N, including assimilation and denitrification in the downstream area, have not been clarified. To evaluate the N removal processes, nitrate and organic N concentrations, as well as nitrogen isotope ratio (δ 15 N) and oxygen isotope ratio (δ 18 O) of NO 3 − were measured along three rivers of Tatara River Basin, Japan where upland forests have already been N-saturated. Geographic information system (GIS) based topographical analysis was also conducted to evaluate the land use as urban area in relation to topography. In two of the three rivers, NO 3 − concentrations did not increase from upstream to downstream, despite the potential non-point N sources of urban areas. In another river, NO 3 − concentrations rather decreased.The values of δ 15 N and δ 18 O of NO 3 − and organic N concentrations suggested the presence of denitrification and assimilation over N pollutants in the river whose watersheds have a lower percentage of urban area. The lower percentage of urban area could be explained by the lower topographic index. This study concluded that the NO 3 − leaching from upland N-saturated forests was substantially assimilated or denitrified in the downstream area.

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Export of nitrogen from catchments: A worldwide analysis

Cited by 124 publications

References 85 publications

Variability in runoff fluxes of dissolved and particulate carbon and nitrogen from two watersheds of different tree species during intense storm events

Variability in runoff fluxes of dissolved and particulate carbon and nitrogen from two watersheds of different tree species during intense storm events

Long-term nitrate and phosphate loading of river water in the Upper Manyame Catchment, Zimbabwe

Differences in Stream Water Nitrate Concentrations between a Nitrogen-Saturated Upland Forest and a Downstream Mixed Land Use River Basin

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