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Phosphorus (P) fractions were quantified in water samples collected on four occasions from sites at the lower tidal limit of seven Scottish East Coast rivers. Individual catchment characteristics ranged from those dominated by semi-natural land use to those where agriculture predominated. Together the rivers displayed attributes ranging from nearly...
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... the seven catchments situated along the Scottish East Coast possessed a diverse range of attributes and river types and were subjected to varying degrees of human impact. Individual land areas ranged between 369 km 2 and 4590 km 2 (Fig- ure 1) and the dominant land cover varied widely ( Figure 2). Agriculture typically included extensive sheep/beef grazing in the uplands progressively giving way to more intensive mixed arable and livestock farms in the lower coastal areas. ...
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Twenty-five fog/cloud water samples were collected at the weather station at summit of Mount Huangshan in summer 2009. Chemical characteristics, source of pollutants and microphysical properties of fog/cloud are analyzed based on the surface observational data at Guangmingding Station and the fog/cloud samples. Results show that the fog/clouds at M...
Citations
... Ernstberger et al. (2004), who claimed that, although the regulation measures of inorganic 443 nutrients are concerned, the TN and TP flowing into streams were dominated by the organic 444 forms. 445 ...
Hydrological models are effective tools for assessing the effects of soil and nutrient losses on land degradation. SWAT (Soil and Water Assessment Tool) model is widely used to simulate soil and nutrient losses caused by various management regimes. However, its performance of predicting nutrient loss has not been assessed adequately on the Loess Plateau. This study proposed a modified SWAT model by incorporating the modified Soil Conservation Service curve number method, the storm-based Chinese soil loss equation and the nutrient loss model. The observed daily data of runoff and sediment over 16 years and the monthly soluble phosphorus (P) and nitrate losses over 9 years and 4 years, respectively at the outlet of the upper Beiluo river (UBR) basin were used to assess the model performances. Global sensitivity and uncertainty analyses of parameters to runoff, sediment, soluble P and nitrate in the modified SWAT were conducted. The findings during calibration and validation showed that the modified SWAT was highly accurate in terms of model efficiency (calibration: 0.83, 0.83, 0.48, and 0.49; validation: 0.58, 0.57, 0.53, and 0.65) for runoff, sediment, soluble P loss and nitrate loss, respectively. High model efficiency indicated that the modified SWAT could accurately predict soil and nutrient losses at the river basin scale for the Loess Plateau. Moreover, the temporal variations from month to year and the spatial variations at the sub-basin scale for soil loss and the total N and P losses were analysed using the data simulated by the modified SWAT. The results indicated that the critical loss period occurred in July and August, and the Grain for Green project significantly affected the hydrological behaviour and reduced the soil and nutrient losses in the UBR basin.
... Scanning electron microscopy (SEM) and energydispersive X-ray microanalyses (EDX) inspection of solid particles is usually applied on water samples for investigation of the mineralogical and geochemical composition of suspended particulate matter (Leipe et al. 2000). In some studies, SEM-EDX was already used to characterize especially P-bearing particles in water samples from different regions (e.g., Ernstberger et al. 2004;Nausch et al. 2017). SEM-EDX enables direct visual evaluation and thereby gives a representative overview about the morphologies of single particles in the samples (Dellwig et al. 2010) combined with elemental analyses and, thus, a speciation at the single particle level. ...
Purpose
Phosphorus (P) is a crucial element for living organisms at both land and sea, but simultaneously, it can cause environmental problems especially in marine ecosystems. The pathway of P from soils through riverine and coastal systems to sea sediments has not been clarified to date. Thus, the main aim of this study was to characterize P species in sediments along a gradient from the coast of Northern Germany to the Baltic Proper.
Materials and methods
Six sediment samples along a transect from river outlets into the Baltic Sea in northeastern Germany to the deep basins at the Baltic Proper were analyzed. Four complementary methods were applied to explore the different sedimentary P compounds: (i) the sequential P fractionation to extract P from sediment pools of different solubility; (ii) P K-edge X-ray absorption near edge structure (XANES) spectroscopy as an element-specific method for speciation analyses of complex environmental samples; (iii) ³¹P nuclear magnetic resonance (³¹P NMR) spectroscopy as a capable technique distinguishing especially different organic P compounds based on their characteristic resonance frequencies and (iv) scanning electron microscopy (SEM) combined with energy-dispersive X-ray microanalyses (EDX) to identify certain solid particles and their elemental composition.
Results and discussion
Sequential P fractionation revealed a decrease in labile P pools (resin-P; NaHCO3-P) along with an increase in more stable P fractions (H2SO4-P; residual-P) from near-coastal sediments towards the Baltic Proper with increasing water depths of sediment deposits. In comparison, XANES analysis indicated a decline of Fe-associated P compounds in favor of Ca-bound P with increasing distance of sediments from the coastline into the Baltic Sea. Results of ³¹P NMR spectroscopy showed that the variety of different mono- and diester P compounds decreased with increasing distance from the coast and that high proportions of orthophosphate (ortho-P) were present especially in greater water depths. The SEM-EDX analysis supported most of these results by retriving Fe phosphate particles especially in the sediments near the coast.
Conclusions
The integration of several P-specific methods enabled improved insights into P speciation. A trend towards more stable Ca-P compounds towards the Gotland basin was found with sequential fractionation and P-XANES. In the future, different types of sediments will be analyzed with respect to their interactions with adjacent soils to find out a common principle of P-transformations and derive approaches for capturing P before entering susceptible marine systems.
... This indicates that precipitation is the main control factor of hydrological parameters in natural water, and the response of the flow rate and sediment to precipitation is significant [25][26][27]. Precipitation drives the hydrological regime, P flows to the surface water from the sources, while the flow rate, sediment, and other hydrological parameters are the carriers of TP transport [28][29][30]. The temporal changes of soil particle sizes in the YLZB River Basin also prove this conclusion: the median sizes of soil at some stations at the upstream of the mainstream of the YLZB River are 0.044 mm in April, 0.082 mm in August, and 0.041 mm in November. ...
Phosphorus is an important limiting biogenic material. The special topography and climate of the Yarlung Zangbo River Basin generate unique distribution and transport characteristics of total phosphorus (TP). A survey of TP concentration, precipitation, runoff, sediment content, suspended load discharge, and relevant data was carried out for the Yarlung Zangbo River Basin in the last ten years. In combination with the regional geography and social economies, the basic spatial-temporal characteristics of P-water-sediment were analyzed by using the correlation and time series analysis methods. Furthermore, the transport characteristics of P and the main control factors were also studied. The results show that the TP concentration in this basin displays the characteristics of interannual cyclical variation and annual phasic variation, and the peak value appears in the wet season. Among the Yarlung Zangbo River, Nyangqu River, Lhasa River, and Nyang River, the TP concentration is the highest in the Nyangqu River, exceeding 0.4 mg/L several times in the wet season. In this basin, the distribution patterns of the TP concentration are similar to those of the rainfall, runoff, suspended load discharge, and sediment concentration. The coupling property of the TP concentration is the strongest with the suspended load discharge among the meteorological and hydrological parameters. The spatial variation of dissolved P in the wet and dry seasons in 2016 responded to the distribution patterns of the population density, environmental factors, farming, and animal husbandry. This indicates that the TP in the water is mainly from non-point sources and is affected by agricultural, geographical, and ecological factors. The transport of TP is mainly controlled by the suspended load discharge due to precipitation.
... However, integrated analyses of multi-scale sediment, C and nutrient loss analyses are generally lacking. The yields vary spatially and temporally, while the elements also change forms (Gentine at al., 2012;Battin et al., 2008;Ernstberger et al., 2004;Dent et al., 2001;Blöschl and Sivapalan, 1995). Past elucidation of yield-area relationships involving multiple scales relied, mostly, on data from different environments (Hoffmann et al., 2013;Nadal-Romero et al., 2011;Vanmaercke et al., 2011;de Vente and Poesen, 2005). ...
Water erosion provides major links in global cycles of carbon (C), nitrogen (N) and phosphorus (P). Although significant research on erosion mechanisms has been done, there is still little knowledge on C, N and P fluxes across landscapes to the ocean and their controlling factors in subtropical climates. A four-year study quantifying and comparing particulate and dissolved C, N and P from multiple scales (microplot, plot, microcatchment, subcatchment, catchment, sub-basin and basin) was performed in Thukela basin (≈30 000km²), South Africa. The basin climate was largely subtropical-humid [mean annual precipitation (MAP) > 980mm yr⁻¹], but temperate (MAP >2000mm yr⁻¹) on the highlands. Open grassland, cropland and bushland were the major land uses. On average, 65, 24 and 4g m⁻²yr⁻¹ C, N and P were displaced from original topsoil positions, but only 0.33, 0.005 and 0.002mg m⁻²yr⁻¹ were, respectively, exported to the ocean. The fluxes decreased by 95, 97 and 84%, respectively, from plot to microcatchment outlet; and decreased further in downstream direction by >99% from microcatchment to basin outlet. The hillslope (microplot to microcatchment) fluxes correlated strongly with rainfall parameters. Particulate contributions dominated hillslope fluxes at 73, 81 and 76% of total annual C, N and P, respectively. Although particulate C dominated in the microcatchment-catchment reach (55%), N (54%) and P (69%) were dominated by dissolved forms. The lower basin zone was dominated by dissolved flux contributions at 93, 81 and 78% for C, N and P for the sub-basin outlet. These results suggested spatially varying drivers of C, N and P losses from the landscape to the ocean, via the river network. Deposition was envisaged the dominant hillslope level loss process, which gradually gave way to mineralization and biotic uptake in the river network as flux contributions shifted from being predominantly particulate to dissolved forms.
... The elemental composition of SPM was consistent at all stations and throughout the study period, but the P content tended to increase downstream, ranging from 0.75 to 1.57% (Table 3). This range was similar to that reported by Ernstberger et al. (2004) for rivers on the east coast of Scotland (0.27 and 2.07%). ...
... In addition to Fe(hydr)oxides, P can interact with aluminum and manganese oxides, but with a lower affinity (Withers and Jarvie, 2008). In our study the Al-content of P-enriched suspended particles was a mean 10 times lower than that of Fe and there was no relationship between Al and P. Al binding mostly varies between rivers whereas Fe and Ca binding is also subject to seasonal variation (Ernstberger et al., 2004). ...
Understanding phosphorus (P) dynamics, from inland sources to the sea, is essential for developing strategies to reduce P loads. In this study, we examined concentrations, fractions, and association of P with other elements at a tile-drain outlet, the adjacent ditch and brook, further downstream from the brook, and in the river itself. The study was conducted in a sub-basin of the Warnow River catchment from 1 November 2013 to 30 April 2014 covering a mild and dry winter. Total phosphorus (TP) concentrations were lowest at the tile-drain effluent and increased in the ditch and brook, as a result of elevated dissolved reactive phosphorus (DRP), particulate reactive (PRP) and organic (POP) phosphorus. Dissolved organic phosphorus (DOP) concentrations remained constant. Further increase of TP along the brook and in the river reflected the increase in DRP + DOP along the first 2.5 km and the doubling of PRP along the 6.5 km thereafter. In the river, phytoplankton growth transformed P into POP in early spring. Total loads of DRP, PRP + POP, and DOP emitted during the study period were 4.3–5.6, 3–7, and 1–2 g ha−1 respectively, with an increasing tendency downstream. Despite their low P content (0.7–3.9%), clay minerals and Fe(hydr)oxides particles were the most important carriers because they formed 68–90% of all P-containing particles. A shift from Ca-phosphate to Fe-phosphate occurred from winter to spring and there was a variation in composition of P-containing particles along the flow course. Our results underline the importance of particulate P in discharge and show that the brook Zarnow following the drain outlet and the ditch is a location of P-enrichment and modification probably due to other inputs. The entire flow course has to be considered to assess nutrient inputs from agricultural land because P-composition and loads are changing in time and space.
... (i) Hydrological characteristics determine the physical pathways and timing of nutrient transfer at different scales. On the catchment scale, the transportation of SM and sediment-associated P via surface runoff due to intense precipitation has long been recognized as a major hydrological pathway for P delivery to surface waters (Ernstberger et al., 2004;Ballantine et al., 2009;Doody et al., 2010). On a floodplain scale, the role of the seasonal hydrological patterns for nutrient turnover and exchange between river and its floodplain is explained by the Flood Pulses Concept (Junk et al., 1989). ...
Riverine selfpurification regulates concentrations of phosphorus (P) and suspended matter (SM) in rivers, thus determine water quality in the rivers, downstream reservoirs and estuaries. This study tests a hypothesis, that ecohydrological dynamics of aquatic ecosystems, including their selfpurification, are controlled by two top-drivers: hydrological characteristics and temperature. The paper proposes a model explaining the changing hierarchy of these two top-drivers in a temperate river (Pilica, Poland), which supplies an eutrophication-sensitive lowland reservoir with accidents of toxic cyanobacterial blooms. Statistical analyses of the 4-year observation of the P and SM dynamics at the inflow to the reservoir, in a matrix of high/low discharge and high/low temperature ranges show that the hydrological drivers regulate nutrient concentrations stronger during cold months. During summers, temperature seriously disturbs this pattern. The effect of the rapid rise in discharge (24 h ΔQ) is also weaker in the growing season when compared to winters. The results indicate that the general management strategies for nutrient control, especially in the face of climate changes, should differ seasonally: they should focus on enhancement of physical selfpurification processes (e.g. discharge control by floodplains rehabilitation) in the winters, and enhancement of temperature-dependent selfpurification processes (including biological trapping) during growing seasons. Both strategies are based on green infrastructure, ecological engineering and ecohydrology concepts, and enhance supporting ecosystem services of catchments.
... Total phosphate (TP (mg L −1 )), was analysed, within three weeks of sample collection, using an air segmented flow analyser (Bran & Luebbe AA3) after persulphate digestion (Mackay et al., 2011). There is evidence that SRP may represent from <5% to >90% of TP (e.g., Ernstberger et al., 2004), but as a general rule of thumb, using empirical evidence from the literature (e.g., Tarapchak and Rubitschun, 1981;Jeppesen et al., 2000) TP is usually about an order of magnitude greater than SRP concentration. In consequence we divided TP values from unfiltered samples by 10 to achieve a rough equivalence with the SRP data held for the bulk of the Zambian sites. ...
The Zambian Macrophyte Trophic Ranking system (ZMTR) is a new bioassessment scheme to indicate the trophic status of tropical southern African river systems. It was developed using a dataset of 218 samples of macrophytes and water chemistry, collected during 2009–2012, from river sites located in five world freshwater ecoregions primarily represented in Zambia. A typology based on these ecoregions, and three stream order categories, was used to determine soluble reactive phosphate (SRP) reference conditions. Zambian Trophic Ranking Scores (ZTRSsp) were calculated for 156 species, using direct allocation from SRP data for 80 species, in samples for which sufficient available SRP data existed. An indirect quantitative procedure, based upon occurrence of species in six sample-groups, of differing mean SRP status, produced by TWINSPAN classification, allocated provisional ZTRSsp values for the remaining 76 species. Additional data for nitrate, pH, alkalinity and conductivity were used to help assess the trophic preferences of macrophyte species showing differing ZTRSsp values. ZMTRsample values were calculated as the mean ZTRSsp score of species present per sample. ZMTR indicated trophic status reasonably accurately for 83.1% of Zambian samples, and for all samples within a test dataset from Botswanan rivers. Examples of application of the methodology, and its potential for hindcasting river trophic status are provided. The scheme currently underestimates highly-enriched conditions, and, to a lesser extent, overestimates the trophic status of some very low-nutrient rivers, but at this pilot stage of development it generally predicts the trophic status of tropical southern African river systems quite well.
... Dissolved P tends to dominate total P content during low flow conditions (Ernstberger et al., 2004), whilst for C the increased production over the summer leads to accumulations that can be flushed out during wetter periods (Stutter et al., 2012). Leaching of other solutes is likely to follow a similar temporal pattern, with projected increases in autumn or winter precipitation liable to increase loads. ...
... Particulate phosphorus is not immediately available for uptake by algae but between 23% and 69% of particulate phosphorus has been estimated to be biogeochemically active by Howarth et al. (1995). This suggests that this could become labile and enter biogeochemical cycles (Ernstberger et al., 2004). In lakes however, particulate P can provide a long-term source of phosphorus to algae through desorption to the surrounding lake water (Sharpley and Menzel, 1987). ...
Windrowing is widely practised, across Europe and North America, in bole-only harvested coniferous forest plantations before replanting. Forest harvesting has been shown to significantly increase sediment and nutrient losses to watercourses in other studies but windrowing effects, which are as bad, have not been investigated in detail. To determine physico-chemical impacts on water quality and to help inform forest managers, the effects of windrowing were investigated in a headwater catchment. Water samples were collected from storm events pre- (PWR), during (DWR) and after windrowing (AWR). Total suspended solids (TSS), total phosphorus (TP), soluble reactive phosphorus (SRP), total ammonia, nitrate, stream discharge, water level and velocity were measured. Results showed that peak and flow weighted mean concentrations (FWMC) of TSS concentrations increased significantly during windrowing when compared to pre-windrowing concentrations. Peak TSS increased from 88mg/l (PWR) to 502mg/l (DWR) and decreased to 163mg/l (one year AWR) and 225mg/l (two years AWR). Peak and FWMC of TP also increased during windrowing when compared to pre-windrowing concentrations. Peak TP concentrations increased from 0.1mg/l (PWR) to 0.4mg/l (DWR) and decreased to 0.1mg/l (AWR). SRP and nitrate concentrations increased during windrowing when compared to pre-windrowing but remained low overall. TSS and TP concentrations were highest when flows greater than 0.3m(3)/s (exceeded 6.3% of time) were recorded in the channel. It was highlighted that high-resolution sampling of storm events is important, where precise measurements of windrowing-sourced outputs are required. Windrowing was shown to generate very high concentrations of TSS and TP, comparable to those recorded during harvesting. This research helps to identify potential impacts on physico-chemical water quality that arise during windrowing and demonstrates the need for measures to minimize impacts on surface waters as required by the EU Water Framework Directive and similar legislation elsewhere.
Copyright © 2015 Elsevier B.V. All rights reserved.
... C, N, and P cycles are inherently linked to water availability and hydrologic transport through overland flow and subsurface runoff (Manzoni and Porporato, 2011). These three key environmental nutrients may be exported in the form of dissolved inorganic chemicals, organic complexes, or in association with particulate materials (Ernstberger et al., 2004), all of which may produce differing effects on aquatic ecosystems. Understanding the composition and transport of C, N, and P in surface water flow is essential not only in practical terms, such as enabling quantitative constraint of riverine export flux, but also in theoretical terms, such http://dx.doi.org/10.1016/j.jhydrol.2014.02.005 0022-1694/Ó 2014 Elsevier B.V. All rights reserved. ...
summary As global warming and extreme weather events increase and intensify across the globe, it becomes ever more urgent to study and understand the effects of extreme rainfall events on carbon (C), nitrogen (N), and phosphorus (P) export from terrestrial to riverine ecosystems. There is still much to learn regarding C, N, and P non-point source discharge that results from extremely heavy rainfall as well as their effects on downstream ecosystems. This study aimed to shed light on C, N, and P biogeochemical and hydrolog-ical coupling processes. Long-term and short-term water composition monitoring research was carried out within a purple soil watershed in China's Sichuan Province. This study captured both base flow from long-term observations and dynamic runoff under extreme rainfall events that took place during the 2012 rainy season. Dissolved total nitrogen (DTN) was the largest percentage of total nitrogen (TN) in storm runoff. DTN exceeded particulate nitrogen (PN), which itself exceeded dissolved organic nitrogen (DON). Under site conditions, particulate phosphorus (PP) formed the largest constituent of total phosphorus (TP) followed by dissolved total phosphorus (DTP) and dissolved organic phosphorus (DOP). Furthermore, results showed that C, N, and P loads increased sharply in response to heavy rainfall. Although P abundance in purple soils is limited, it was nevertheless shown that C:N:P ratios measured during rainstorms corresponded much more closely to the Redfield ratio than to ratios measured in base flows. This adds to the evidence that suggests that increased storm runoff will increase eutrophication likelihood in ecosystems further downstream. Ó 2014 Elsevier B.V. All rights reserved.
