Ionic regulation in an alpine peatland in the Bogong High Plains, Victoria, Australia

2009 ◽  
Vol 6 (5) ◽  
pp. 424 ◽  
Author(s):  
Ewen Silvester
Keyword(s):  
Organic Carbon ◽  
Stream Water ◽  
Critical Role ◽  
Drainage Water ◽  
Water Diversion ◽  
High Plains ◽  
Stream Discharge ◽  
Sulfate Removal ◽  
Water Composition ◽  
Alpine Peatland

Environmental context. Australian alpine peatlands are thought to have an important role in maintaining water quality in the associated headwater streams. This study has confirmed that these peatlands can significantly modify stream water through a range of mechanisms, including: nutrient uptake, salt sequestering, and the export of organic carbon. While the significance of this chemical regulation to down stream processes is yet to be fully understood, it is clear that these systems have considerable potential to modify water composition. Abstract. Heathy Spur 1 (HS-1) is an intact alpine peatland in the Bogong High Plains, Victoria, Australia, that serves as a reference system for understanding the impacts of historical land use practices (cattle grazing, water diversion) and wildfire. The major ion chemistry in the groundwater feed and drainage water at HS-1 was studied over seasonal timescales during ‘dry weather’ periods; conditions that allow a simple hydrological model to be used, where the groundwater is assumed to partition between evapotranspiration and stream discharge. With this model the acid neutralising capacity (ANC) of stream discharge can be understood in terms of evapotranspiration and proton uptake associated with nitrate and sulfate removal. Stream discharge ANC is strongly partitioned towards exported dissolved organic carbon, shifting the buffering intensity to lower pH compared to the groundwater. Given the extremely low alkalinity of the regional groundwater, these alpine peatlands likely have a critical role in increasing headwater stream buffering capacity.

scholarly journals A global hotspot for dissolved organic carbon in hypermaritime watersheds of coastal British Columbia

2017 ◽  
Vol 14 (15) ◽  
pp. 3743-3762 ◽  
Author(s):  
Allison A. Oliver ◽  
Suzanne E. Tank ◽  
Ian Giesbrecht ◽  
Maartje C. Korver ◽  
William C. Floyd ◽  
...  
Keyword(s):  
British Columbia ◽  
Organic Matter ◽  
Organic Carbon ◽  
Stream Water ◽  
Coastal Ocean ◽  
Stream Discharge ◽  
Coastal Margin ◽  
Doc Concentration ◽  
Small Catchments ◽  
Dom Composition

Abstract. The perhumid region of the coastal temperate rainforest (CTR) of Pacific North America is one of the wettest places on Earth and contains numerous small catchments that discharge freshwater and high concentrations of dissolved organic carbon (DOC) directly to the coastal ocean. However, empirical data on the flux and composition of DOC exported from these watersheds are scarce. We established monitoring stations at the outlets of seven catchments on Calvert and Hecate islands, British Columbia, which represent the rain-dominated hypermaritime region of the perhumid CTR. Over several years, we measured stream discharge, stream water DOC concentration, and stream water dissolved organic-matter (DOM) composition. Discharge and DOC concentrations were used to calculate DOC fluxes and yields, and DOM composition was characterized using absorbance and fluorescence spectroscopy with parallel factor analysis (PARAFAC). The areal estimate of annual DOC yield in water year 2015 was 33.3 Mg C km−2 yr−1, with individual watersheds ranging from an average of 24.1 to 37.7 Mg C km−2 yr−1. This represents some of the highest DOC yields to be measured at the coastal margin. We observed seasonality in the quantity and composition of exports, with the majority of DOC export occurring during the extended wet period (September–April). Stream flow from catchments reacted quickly to rain inputs, resulting in rapid export of relatively fresh, highly terrestrial-like DOM. DOC concentration and measures of DOM composition were related to stream discharge and stream temperature and correlated with watershed attributes, including the extent of lakes and wetlands, and the thickness of organic and mineral soil horizons. Our discovery of high DOC yields from these small catchments in the CTR is especially compelling as they deliver relatively fresh, highly terrestrial organic matter directly to the coastal ocean. Hypermaritime landscapes are common on the British Columbia coast, suggesting that this coastal margin may play an important role in the regional processing of carbon and in linking terrestrial carbon to marine ecosystems.

scholarly journals Changes in discharge and solute dynamics between a hillslope and a valley-bottom intermittent streams

2011 ◽  
Vol 8 (5) ◽  
pp. 9505-9536
Author(s):  
S. Bernal ◽  
F. Sabater
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Transition Period ◽  
Riparian Forest ◽  
Stream Water ◽  
Water Flux ◽  
Valley Bottom ◽  
Stream Discharge ◽  
Dry Conditions ◽  
Reactive Solutes

Abstract. We investigated differences on stream water flux as well as on chloride, carbon and nitrogen dynamics between two semiarid nested catchments, one at the hillslope and the other one at the valley-bottom. The two streams were intermittent, yet only the valley-bottom stream was embraced by a riparian forest and a well-developed alluvium with highly conductive coarse sediments. We found that stream water flux decreased by more than 40% from the hillslope to the valley-bottom during hydrological transition periods (from dry-to-wet and from wet-to-dry conditions), coinciding with periods when stream-to-aquifer fluxes prevailed. During the hydrological transition period, stream export of chloride, nitrate, and dissolved organic carbon decreased 34–97% between the hillslope and the valley-bottom catchments. There was a strong correlation between monthly differences in stream discharge and in stream Cl− export between the two catchments. In contrast, monthly differences in stream export for bio-reactive solutes were only partially explained by stream discharge. In annual terms, stream nitrate export from the valley-bottom catchment (0.32 ± 0.12 kg N ha−1 yr−1 – average ± standard deviation) was 30–50% lower than from the hillslope catchment (0.56 ± 0.32 kg N ha−1 yr−1). Although the riparian forest could be an extra source of organic matter to the valley-bottom stream, the annual export of dissolved organic carbon was similar between the two catchments (1.8 ± 1 kg C ha−1 yr−1). Our results suggested that stream hydrology was a strong driver of stream solute export during the hydrological transition period, and that hydrological retention in the alluvial zone could contribute to reduce stream water and solute export under semiarid conditions in the valley-bottom stream.

Soil and soil organic carbon effects on simulated Southern High Plains dryland Cotton production

2021 ◽  
Vol 212 ◽  
pp. 105040
Author(s):  
Steven A. Mauget ◽  
Sushil K. Himanshu ◽  
Tim S. Goebel ◽  
Srinivasalu Ale ◽  
Robert J. Lascano ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
High Plains ◽  
Cotton Production ◽  
Southern High Plains

scholarly journals Influence of Selected Coagulants of Indicator and Dioxin-Like PCB Removal from Drinking Water

2017 ◽  
Vol 24 (1) ◽  
pp. 41-51
Author(s):  
Agata Rosińska
Keyword(s):  
Surface Water ◽  
Total Concentration ◽  
Sulfate Removal ◽  
Aluminium Sulfate ◽  
Water Composition ◽  
Pcb 126 ◽  
Reduction Efficiency ◽  
Water Rate ◽  
Trade Names ◽  
Dioxin Like Pcb

Abstract The aim of the research was to compare selected coagulants efficiency in indicator and chosen dioxin-like PCB removal from surface water. As coagulants, there were used aluminium sulfate and 5 hydrolyzed polyaluminium chlorides, with trade names: PAX-XL1, PAX-XL10, PAX-XL19, PAX-XL60, PAX-XL69. For the research, surface water was used, collected from dam reservoir. The water composition was modified with standard mixtures PCB MIX24 and MIX13, in order to obtain concentration of each congener equal to 300 ng/dm3. The PCB MIX24 mixture was composed of indicator congeners solution: 28, 52, 101, 118, 138, 153, and 180, whereas the MIX13 mixture - solution of three dioxin-like PCB 77, PCB 126, and PCB 169. It was demonstrated that the application of aluminium sulfate allowed for reaching better effects for purifying water of PCB, than with the usage of pre-hydrolyzed salts, polyaluminium chlorides. Out of the studied coagulants, the best effects for indicator PCB removal were obtained with the application of aluminium sulfate, total PCB concentration was decreased by 65%. The highest efficiency for indicator congeners removal (90%) was obtained for PCB 138 and 153. After the application of hydrolyzed polyaluminium chlorides PAX-XL1, PAX-XL10 decrease in higher chlorinated PCB concentration was obtained, in the range of 23 to 74%. Selectivity of chosen PCB congener removal, depending on applied coagulant, was demonstrated; with the usage of aluminium sulfate, removal of heptachlorobiphenyl PCB 180 at the level of 34% was obtained, whereas with the application of PAX-XL1 and PAX-XL10 higher reduction efficiency for this congener was obtained, i.e. 83 and 74% respectively. For dioxin-like PCB, after application of aluminium sulfate, total concentration reduction by 74% was obtained, efficiency of this congeners removal amounted to from 54 (PCB 77) up to 72% (PCB 126), similar results were obtained after the usage of PAX-XL1. The lowest PCB removal from water rate was stated for coagulants PAX-XL60 and PAX-XL69.

Trends in hydrometeorological conditions and stream water organic carbon in boreal forested catchments

2009 ◽  
Vol 408 (1) ◽  
pp. 92-101 ◽  
Author(s):  
Sakari Sarkkola ◽  
Harri Koivusalo ◽  
Ari Laurén ◽  
Pirkko Kortelainen ◽  
Tuija Mattsson ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Stream Water ◽  
Forested Catchments ◽  
Hydrometeorological Conditions

Periodic alterations of the hydrological exchange in hyporheic sediments: colmation, hyporheic fauna and abiotic parameters in a second order stream during one year 

2021 ◽  
Author(s):  
Heide Stein ◽  
Hans Jürgen Hahn
Keyword(s):  
Hyporheic Zone ◽  
Stream Water ◽  
Anthropogenic Activities ◽  
Second Order ◽  
Critical Periods ◽  
Order Stream ◽  
Fine Sediments ◽  
Stream Discharge ◽  
One Year ◽  
Hydrological Exchange

<p>In this study, the temporal variability of the hydrological exchange between stream water (SW) and groundwater (GW), colmation, hyporheic invertebrate fauna, organic matter (OM) and physicochemical parameters were examined for the period of one year. Sampling and measuring were conducted monthly from May 2019 to April 2020 at the Guldenbach river, a second order stream in Rhineland-Palatinate, Germany. All hyporheic samples were extracted from a depth of 15 cm below stream bottom. Colmation was measured quantitatively in the same depth.</p><p>Following the biotic and abiotic patterns found, three temporal stages of different hydrological conditions can be described:</p><ul><li>1) Strong floods, in February and March 2020 caused hydromorphological alterations of the river bed, leading to a decolmation of the hyporheic zone, a wash out of OM and hyporheic fauna. Due to high GW tables the vertical hydrological gradient (VHG) was positive indicating upwelling GW.</li> <li>2) In the months of Mai to August 2019 and April 2020, precipitation and stream discharge were lowest. Predominantly exfiltrating conditions were observed, while the amount of fine sediments (clay and silt) increased as well as colmation. High densities of hyporheic fauna, dominated by fine sediment dwelling taxa, were assessed.</li> <li>3) From September 2019 to January 2020 stream discharge was low. The VHG became increasingly negative, indicating downwelling SW. In accordance, colmation increased continuously, while densities of hyporheic invertebrates decreased and sediment dwellers became more dominant.</li> </ul><p>Precipitation, discharge events and GW table were found to be the driving factors for the annual dynamics of the hydrological exchange as well as for colmation, fauna and hydrochemistry. Electric conductivity seems a suitable indicator for the origin of water with high values in months of low precipitation and lower values after extensive precipitation events, respectively. Hyporheic fauna displayed a significant seasonality and the community structure was correlated with colmation and changes in the VHG.</p><p>This pronounced seasonality seems to be typical of many streams and should be considered for the monitoring of sediments and hyporheic habitats: Seasons with lower stream discharge are probably the most critical periods for sediment conditions.</p><p>We assume that the basic patterns of the dynamics observed basically reflect the natural situation in the catchment. However, the strength of surface run-off and the amount of fine sediments are mainly the result of anthropogenic activities and land use in the catchment.</p><p>These findings underline the significance of dynamical processes for the assessment and implementation of the Water Framework Directive.</p>

scholarly journals Salinization alters fluxes of bioreactive elements from stream ecosystems across land use

2015 ◽  
Vol 12 (23) ◽  
pp. 7331-7347 ◽  
Author(s):  
S. Duan ◽  
S. S. Kaushal
Keyword(s):  
Land Use ◽  
Organic Carbon ◽  
Fresh Water ◽  
Dissolved Inorganic Carbon ◽  
Stream Water ◽  
Urban Land Use ◽  
Stream Ecosystems ◽  
Accelerated Weathering ◽  
Nutrient Mobilization ◽  
Riparian Soils

Abstract. There has been increased salinization of fresh water over decades due to the use of road salt deicers, wastewater discharges, saltwater intrusion, human-accelerated weathering, and groundwater irrigation. Salinization can mobilize bioreactive elements (carbon, nitrogen, phosphorus, sulfur) chemically via ion exchange and/or biologically via influencing of microbial activity. However, the effects of salinization on coupled biogeochemical cycles are still not well understood. We investigated potential impacts of increased salinization on fluxes of bioreactive elements from stream ecosystems (sediments and riparian soils) to overlying stream water and evaluated the implications of percent urban land use on salinization effects. Two-day incubations of sediments and soils with stream and deionized water across three salt levels were conducted at eight routine monitoring stations across a land-use gradient at the Baltimore Ecosystem Study Long-Term Ecological Research (LTER) site in the Chesapeake Bay watershed. Results indicated (1) salinization typically increased sediment releases of labile dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), total dissolved Kjeldahl nitrogen (TKN) (ammonium + ammonia + dissolved organic nitrogen), and sediment transformations of nitrate; (2) salinization generally decreased DOC aromaticity and fluxes of soluble reactive phosphorus from both sediments and soils; (3) the effects of increased salinization on sediment releases of DOC and TKN and DOC quality increased with percentage watershed urbanization. Biogeochemical responses to salinization varied between sediments and riparian soils in releases of DOC and DIC, and nitrate transformations. The differential responses of riparian soils and sediments to increased salinization were likely due to differences in organic matter sources and composition. Our results suggest that short-term increases in salinization can cause releases of significant amounts of labile organic carbon and nitrogen from stream substrates and organic transformations of nitrogen and phosphorus in urban watersheds. Given that salinization of fresh water will increase in the future due to human activities, significant impacts on carbon and nutrient mobilization and water quality should be anticipated.

scholarly journals Soil Aggregation and Organic Carbon Dynamics in Poplar Plantations

Forests ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 508 ◽  
Author(s):  
Zhiwei Ge ◽  
Shuiyuan Fang ◽  
Han Chen ◽  
Rongwei Zhu ◽  
Sili Peng ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Organic Carbon ◽  
Soil Microbial Biomass ◽  
Fine Root ◽  
Microbial Biomass Carbon ◽  
Critical Role ◽  
Stand Age ◽  
Biomass Carbon ◽  
Soil Microbial ◽  
Soil Microbial Biomass Carbon

Soil resident water-stable macroaggregates (diameter (Ø) > 0.25 mm) play a critical role in organic carbon conservation and fertility. However, limited studies have investigated the direct effects of stand development on soil aggregation and its associated mechanisms. Here, we examined the dynamics of soil organic carbon, water-stable macroaggregates, litterfall production, fine-root (Ø < 1 mm) biomass, and soil microbial biomass carbon with stand development in poplar plantations (Populus deltoides L. ‘35’) in Eastern Coastal China, using an age sequence (i.e., five, nine, and 16 years since plantation establishment). We found that the quantity of water-stable macroaggregates and organic carbon content in topsoil (0–10 cm depth) increased significantly with stand age. With increasing stand age, annual aboveground litterfall production did not differ, while fine-root biomass sampled in June, August, and October increased. Further, microbial biomass carbon in the soil increased in June but decreased when sampled in October. Ridge regression analysis revealed that the weighted percentage of small (0.25 mm ≤ Ø < 2 mm) increased with soil microbial biomass carbon, while that of large aggregates (Ø ≥ 2 mm) increased with fine-root biomass as well as microbial biomass carbon. Our results reveal that soil microbial biomass carbon plays a critical role in the formation of both small and large aggregates, while fine roots enhance the formation of large aggregates.

scholarly journals The Impact of Water Loss by Evaporation and Calcite Precipitation on the Sodium Adsorption Ratio (SAR) and an Alternative Method of Estimating the SAR of Irrigation Drainage Water

2020 ◽  
Author(s):  
Qiyu Zhou ◽  
William Bleam ◽  
Douglas Soldat
Keyword(s):  
Hazard Assessment ◽  
Water Loss ◽  
Irrigation Water ◽  
Drainage Water ◽  
Sodium Adsorption Ratio ◽  
Calcite Precipitation ◽  
Water Composition ◽  
Soluble Calcium ◽  
Irrigation Drainage ◽  
The Impact

Soil water loss by evaporation influences the sodium adsorption ratio (SAR) of irrigation drainage water. Evaporation concentrates sodium and magnesium but calcite precipitation has a more complicated effect on soluble calcium and alkalinity. Here we propose a revised sodicity hazard assessment that quantifies the impact of evaporative water loss and calcite precipitation on drainage water SAR. This paper shows sodicity hazard is determined by the initial composition of irrigation water as originally suggested by previous researchers, and provide a simple, accurate way to identify the potential sodicity hazard of any irrigation water. In particular, the initial equivalent concentration of alkalinity and calcium determine the salinization pathway followed during evaporation. If the irrigation water alkalinity exceeds soluble calcium expressed as equivalent concentrations, drainage water SAR approaches an upper limit determined by the initial relative concentration of sodium and magnesium. If irrigation water alkalinity is less than soluble calcium, drainage water SAR approaches a lower limit determined by the initial calcium, magnesium and sodium. In both cases the SAR is scaled by the square root of the concentration factor &radic;Fc quantifying soil water loss. To assess the impact of evaporation and calcite precipitation on the SAR and test the accuracy of the new sodicity hazard assessment, we evaluated data from previously published lysimeter studies. We plotted water composition boundaries for each source water, comparing these boundaries to the drainage water composition recorded in the lysimeter studies. As salinity increased by evaporation, each drainage water followed a distinct salinization path.

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