scholarly journals Carbon and nutrient export regimes from headwater catchments to downstream reaches

2017 ◽  
Author(s):  
Rémi Dupas ◽  
Andreas Musolff ◽  
James W. Jawitz ◽  
P. Suresh C. Rao ◽  
Christoph G. Jäger ◽  
...  
Keyword(s):  
Point Source ◽  
Soluble Reactive Phosphorus ◽  
Low Flow ◽  
Spatial And Temporal Variability ◽  
River Continuum ◽  
Headwater Catchments ◽  
Freshwater Bodies ◽  
Source Signal ◽  
Reactive Phosphorus ◽  
Stream Transport

Abstract. Excessive amounts of nutrients and dissolved organic matter in freshwater bodies affect aquatic ecosystems. In this study, the spatial and temporal variability in nitrate (NO3), dissolved organic carbon (DOC) and soluble reactive phosphorus (SRP) was analyzed in the Selke (Germany) river continuum from headwaters draining 1–3 km2 catchments to downstream reaches representing spatially integrated signals from 184–456 km2 catchments. Three headwater catchments were selected as archetypes of the main landscape units (land use x lithology) present in the Selke catchment. Export regimes in headwater catchments were interpreted in terms of NO3, DOC and SRP land-to-stream transfer processes. Headwater signals were subtracted from downstream signals, with the differences interpreted in terms of in-stream processes and contribution of point-source emissions. The seasonal dynamics for NO3 were opposite those of DOC and SRP in all three headwater catchments, and spatial differences also showed NO3 contrasting with DOC and SRP. These dynamics were interpreted as the result of the interplay of hydrological and biogeochemical processes, for which riparian zones were hypothesized to play a determining role. In the two downstream reaches, NO3 was transported almost conservatively, whereas DOC was consumed and produced in the upper and lower river sections, respectively. The natural export regime of SRP in the three headwater catchments mimicked a point-source signal (high SRP during summer low flow), which may lead to overestimation of domestic contributions in the downstream reaches. Monitoring the river continuum from headwaters to downstream reaches proved effective to investigate jointly land-to-stream and in-stream transport and transformation processes.

scholarly journals Carbon and nutrient export regimes from headwater catchments to downstream reaches

2017 ◽  
Vol 14 (18) ◽  
pp. 4391-4407 ◽  
Author(s):  
Rémi Dupas ◽  
Andreas Musolff ◽  
James W. Jawitz ◽  
P. Suresh C. Rao ◽  
Christoph G. Jäger ◽  
...  
Keyword(s):  
Soluble Reactive Phosphorus ◽  
Point Sources ◽  
Low Flow ◽  
Spatial And Temporal Variability ◽  
River Continuum ◽  
Headwater Catchments ◽  
Freshwater Bodies ◽  
Source Signal ◽  
Reactive Phosphorus ◽  
Stream Transport

Abstract. Excessive amounts of nutrients and dissolved organic matter in freshwater bodies affect aquatic ecosystems. In this study, the spatial and temporal variability in nitrate (NO3−), dissolved organic carbon (DOC) and soluble reactive phosphorus (SRP) was analyzed in the Selke (Germany) river continuum from three headwaters draining 1–3 km2 catchments to two downstream reaches representing spatially integrated signals from 184–456 km2 catchments. Three headwater catchments were selected as archetypes of the main landscape units (land use  ×  lithology) present in the Selke catchment. Export regimes in headwater catchments were interpreted in terms of NO3−, DOC and SRP land-to-stream transfer processes. Headwater signals were subtracted from downstream signals, with the differences interpreted in terms of in-stream processes and contributions from point sources. The seasonal dynamics for NO3− were opposite those of DOC and SRP in all three headwater catchments, and spatial differences also showed NO3− contrasting with DOC and SRP. These dynamics were interpreted as the result of the interplay of hydrological and biogeochemical processes, for which riparian zones were hypothesized to play a determining role. In the two downstream reaches, NO3− was transported almost conservatively, whereas DOC was consumed and produced in the upper and lower river sections, respectively. The natural export regime of SRP in the three headwater catchments mimicked a point-source signal (high SRP during summer low flow), which may lead to overestimation of domestic contributions in the downstream reaches. Monitoring the river continuum from headwaters to downstream reaches proved effective to jointly investigate land-to-stream and in-stream transport, and transformation processes.

Sediment Control of Soluble Reactive Phosphorus in Hoxie Gorge Creek, New York

1988 ◽  
Vol 45 (11) ◽  
pp. 2026-2034 ◽  
Author(s):  
R. L. Klotz
Keyword(s):  
New York ◽  
Stream Water ◽  
Soluble Reactive Phosphorus ◽  
Low Flow ◽  
Phosphorus Concentration ◽  
Sediment Control ◽  
Al Content ◽  
Exchangeable Al ◽  
Reactive Phosphorus ◽  
Highly Correlated

Stream sediments were found to regulate the soluble reactive phosphorus (SRP) of stream water by geochemical processes. This conclusion was based on sediment analysis, laboratory sorption experiments, and measurement of the equilibrium phosphorus concentration (EPC). EPC is the concentration of P in the water at which there is neither sorption nor desorption of P by the sediments. At low flow conditions, streamwater SRP was highly correlated with EPC at six sites along Hoxie Gorge Creek (r = 0.979). EPC was inversely related to the ionic strength of the equilibrating solution, with Ca2+ producing larger changes than Na+. Minimum EPC values occurred near the neutral pH of the stream water and increased sharply in acidic and basic solutions. Also, EPC was negatively correlated with the exchangeable Al content of the sediments at the six sites. These data are consistent with a mechanism previously verified for soils in which solution cations displace exchangeable Al(III) from sediments; hydrolyzed Al(III) reacts with phosphate and removes it from solution. EPC and streamwater SRP were lower at sites with sediments that had higher concentrations of P-binding sites, despite also having higher sediment P.

Cumulative effects of pulp mill and municipal effluents on epilithic biomass and nutrient limitation in a large northern river ecosystem

2000 ◽  
Vol 57 (7) ◽  
pp. 1342-1354 ◽  
Author(s):  
Garry J Scrimgeour ◽  
Patricia A Chambers
Keyword(s):  
Point Source ◽  
Nutrient Limitation ◽  
Large Scale ◽  
Function Analysis ◽  
Inorganic Nitrogen ◽  
Soluble Reactive Phosphorus ◽  
Pulp Mill ◽  
Nutrient Status ◽  
Dissolved Inorganic Nitrogen ◽  
Reactive Phosphorus

Large-scale patterns in epilithic biomass and nutrient status were evaluated at 33 sites located upstream and downstream of point-source anthropogenic effluents in the Athabasca and Wapiti-Smoky rivers in Alberta, Canada. Multiple regression showed that epilithic chlorophyll a was significantly (p < 0.0001) related to concentrations of dissolved inorganic nitrogen and marginally (p = 0.06) significantly related to soluble reactive phosphorus. Epilithic biomass was up to 50 times higher immediately downstream of point-source inputs compared with sites upstream and those 20-150 km downstream. Data from nutrient diffusing substrata showed that the epilithon at 18 of the 33 sites was nutrient limited, while 14 sites showed no nutrient limitation; interpretation of the remaining site was inconclusive. Of the 18 nutrient-limited sites, six were nitrogen limited, five were phosphorus limited, and seven were co-limited. Multiple discriminant function analysis showed that the combined concentration of soluble reactive phosphorus and dissolved inorganic nitrogen was a significant discriminator between deplete and replete sites.

Major controls of base flow soluble reactive phosphorus losses in humid temperate headwater streams

2020 ◽  
Author(s):  
Michael Rode ◽  
Remi Dupas
Keyword(s):  
Land Use ◽  
Headwater Streams ◽  
Soluble Reactive Phosphorus ◽  
Low Flow ◽  
Temperate Climate ◽  
Redox Processes ◽  
Temperature Dependent ◽  
P Release ◽  
Reactive Phosphorus

&lt;p&gt;Long-term Soluble Reactive Phosphorus (SRP) monitoring in headwater streams in central Europe revealed a seasonal pattern of SRP concentrations during low flow periods, with highest concentrations in summer and lowest in winter. These seasonal concentration amplitudes often exceed the eutrophication threshold during the summer eutrophication-sensitive period. It is assumed that temperature dependent biogeochemical processes control the underlying P release mechanism, where redox processes may be responsible for this increase. Several studies have highlighted the crucial role of reactive zones such as riparian wetlands in controlling solute export regimes. Moreover especially in forest headwater streams, in-stream assimilatory uptake shows a distinct seasonal behaviour because of varying shading conditions. This can also lead to seasonal SRP amplitudes. Furthermore sorption and desorption processes are temperature dependent which may alter in-stream SRP release during the year.&lt;/p&gt;&lt;p&gt;Often SRP concentrations are higher in agricultural streams than in more pristine headwaters. It is not clear how land use (e.g. P status of soils) may impact the baseline SRP concentrations and which factors control the seasonal change in SRP stream concentration (riparian groundwater heads and redox processes, temperature, in-stream release and uptake processes). Therefore the objective of this study is to disentangle land use impacts from hydrological and biogeochemical controls of low flow SRP losses.&amp;#160; A comparative study on seasonal SRP concentration patterns will be presented comprising around 53 long term monitored headwater catchments in humid temperate climate of northern Europe and the United States. Based on hydrological and SRP headwater signals and catchment properties, P release processes are discussed. The results of the study will allow to target SRP mitigation strategies based on knowledge of the dominating control of SRP loss from headwater streams.&amp;#160;&lt;/p&gt;

scholarly journals Along-stream transport and transformation of dissolved organic matter in a large tropical river

2016 ◽  
Vol 13 (9) ◽  
pp. 2727-2741 ◽  
Author(s):  
Thibault Lambert ◽  
Cristian R. Teodoru ◽  
Frank C. Nyoni ◽  
Steven Bouillon ◽  
François Darchambeau ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Water Discharge ◽  
High Water ◽  
Large River ◽  
Low Flow ◽  
River Continuum ◽  
Fluorescence Measurements ◽  
Tropical Areas ◽  
Stream Transport

Abstract. Large rivers transport considerable amounts of terrestrial dissolved organic matter (DOM) to the ocean. However, downstream gradients and temporal variability in DOM fluxes and characteristics are poorly studied at the scale of large river basins, especially in tropical areas. Here, we report longitudinal patterns in DOM content and composition based on absorbance and fluorescence measurements along the Zambezi River and its main tributary, the Kafue River, during two hydrological seasons. During high-flow periods, a greater proportion of aromatic and humic DOM was mobilized along rivers due to the hydrological connectivity with wetlands, while low-flow periods were characterized by lower DOM content of less aromaticity resulting from loss of connectivity with wetlands, more efficient degradation of terrestrial DOM and enhanced autochthonous productivity. Changes in water residence time due to contrasting water discharge were found to modulate the fate of DOM along the river continuum. Thus, high water discharge promotes the transport of terrestrial DOM downstream relative to its degradation, while low water discharge enhances the degradation of DOM during its transport. The longitudinal evolution of DOM was also strongly impacted by a hydrological buffering effect in large reservoirs in which the seasonal variability of DOM fluxes and composition was strongly reduced.

scholarly journals Along-stream transport and transformation of dissolved organic matter in a large tropical river

2016 ◽  
Author(s):  
Thibault Lambert ◽  
Cristian R. Teodoru ◽  
Frank C. Nyoni ◽  
Steven Bouillon ◽  
François Darchambeau ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Water Discharge ◽  
Large River ◽  
High Flow ◽  
Low Flow ◽  
River Continuum ◽  
Fluorescence Measurements ◽  
Tropical Areas ◽  
Stream Transport

Abstract. Large rivers transport considerable amounts of terrestrial dissolved organic matter (DOM) to the ocean. Yet, downstream gradients and temporal variability in DOM fluxes and characteristics are poorly studied at the scale of large river basins, especially in tropical areas. Here, we report longitudinal patterns in DOM content and composition based on absorbanc e and fluorescence measurements along the Zambezi River and its main tributary, the Kafue River, during two hydrological seasons. During high flow periods, a greater proportion of aromatic and humic DOM was mobilized along rivers due to the hydrological connectivity with wetlands and high flow velocities, while low flow periods were characterized by lower DOM content of less aromaticity resulting from loss of connectivity with wetlands, more efficient degradation of terrestrial DOM and enhanced autochthonous productivity. Changes in water residence time due to contrasting water discharge were found to modulate the fate of DOM along the river continuum. Thus, terrestrial DOM dynamics shifted from transport-dominated during the wet seasons towards degradation during the dry season, with substantial consequences on longitudinal DOM content and composition. The longitudinal evolution of DOM was also strongly impacted by a hydrological buffering effect in large reservoirs in which the seasonal variability of DOM fluxes and composition was strongly reduced.

scholarly journals Land Use and Season Influence Event‐Scale Nitrate and Soluble Reactive Phosphorus Exports and Export Stoichiometry from Headwater Catchments

2020 ◽  
Vol 56 (10) ◽  
Author(s):  
Dustin W. Kincaid ◽  
Erin C. Seybold ◽  
E. Carol Adair ◽  
William B. Bowden ◽  
Julia N. Perdrial ◽  
...  
Keyword(s):  
Land Use ◽  
Soluble Reactive Phosphorus ◽  
Event Scale ◽  
Headwater Catchments ◽  
Reactive Phosphorus

Biogeochemical Asynchrony: Ecosystem Drivers of Seasonal Concentration Regimes across the Great Lakes Basin

2020 ◽  
Author(s):  
Kimberly Van Meter ◽  
Nandita Basu ◽  
Danyka Byrnes
Keyword(s):  
Land Use ◽  
Phase Behavior ◽  
Nutrient Dynamics ◽  
Soluble Reactive Phosphorus ◽  
Low Flow ◽  
Nutrient Concentrations ◽  
Stream Metabolism ◽  
Great Lakes Basin ◽  
Discharge Data ◽  
Reactive Phosphorus

&lt;p&gt;Changes in seasonal climate regimes, and related changes in seasonal nutrient dynamics, are occurring across a range of climates and land use types. Although it is known that seasonal patterns in nutrient availability are key drivers of both stream metabolism and eutrophication, there has been little success in developing a comprehensive understanding of seasonal variations in nutrient export across watersheds or of the relationship between nutrient seasonality and watershed characteristics. In the present study, we have used concentration and discharge data from more than 200 stations across US and Canadian watersheds to identify (1) archetypal seasonal concentration regimes for nitrate, soluble reactive phosphorus, and total phosphorus, and (2) dominant watershed controls on these regimes across a gradient of climate, land use, and topography. Our analysis shows that less impacted watersheds, with more forested and wetland area, most commonly exhibit concentration regimes that are in phase with discharge, with concentration lows occurring during summer low-flow periods. Agricultural watersheds also commonly exhibit in-phase behavior, though the seasonality is usually muted compared to that seen in less impacted areas. With increasing urban area, however, nutrient concentrations frequently become essentially aseasonal or even exhibit clearly out-of-phase behavior. In addition, our data indicate that seasonal SRP concentration patterns may be strongly influenced by proximal controls such as the presence of dams and reservoirs. In all, these results suggest that human activity is significantly altering nutrient concentration regimes, with large potential consequences for both in-stream metabolism and eutrophication risk in downstream water bodies.&lt;/p&gt;

scholarly journals Effects of Lanthanum Modified Bentonite and Polyaluminium Chloride on the Environmental Variables in the Water and Sediment Phosphorus Form in Lake Yanglan, China

Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1947
Author(s):  
Ling Su ◽  
Chen Zhong ◽  
Lei Gan ◽  
Xiaolin He ◽  
Jinlei Yu ◽  
...  
Keyword(s):  
Suspended Solids ◽  
Soluble Reactive Phosphorus ◽  
Particulate Phosphorus ◽  
Modified Bentonite ◽  
Combined Application ◽  
Water And Sediment ◽  
Phosphorus Form ◽  
Labile P ◽  
Reactive Phosphorus ◽  
Polyaluminium Chloride

The application of lanthanum modified bentonite (Phoslock®) and polyaluminium chloride (PAC) is popular in the restoration of European temperate lakes; however, the effects of the application on the concentrations of phosphorus (P) in both the water and the sediments have been poorly evaluated to date. We studied the effects of the application of Phoslock® + PAC on the concentrations of total phosphorus (TP), particulate phosphorus (PP), soluble reactive phosphorus (SRP), total suspended solids (TSS) and chlorophyll a (Chla) in the water, and different P forms in the sediments, in an isolated part of Lake Yanglan. The results showed that the concentrations of TP, PP, SRP, TSS and Chla decreased significantly after the addition of Phoslock® + PAC. Moreover, the concentrations of labile-P, reductant-soluble-P and organic-P in the sediments were also significantly decreased after the Phoslock® + PAC application. However, the concentrations of both the stable apatite-P and residual-P in the sediments after application of Phoslock® + PAC were much higher than the pre-addition values, while the concentrations of metal-oxide-P did not differ significantly between the pre- and post- application conditions. Our findings imply that the combined application of Phoslock® and PAC can be used in the restoration of subtropical shallow lakes, to reduce the concentrations of P in the water and suppress the release of P from the sediments.

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