scholarly journals Quantifying nutrient fluxes in Hyporheic Zones with a new Passive Flux Meter (HPFM)

2016 ◽  
Author(s):  
Julia Vanessa Kunz ◽  
Michael Annable ◽  
Jaehyun Cho ◽  
Wolf von Tümpling ◽  
Kirk Hatfield ◽  
...  
Keyword(s):  
Pore Water ◽  
Hyporheic Zone ◽  
River Sediments ◽  
Nutrient Fluxes ◽  
Heterogeneous Environments ◽  
Running Waters ◽  
Grab Sampling ◽  
Solute Fluxes ◽  
Passive Flux Meter ◽  
Deployment Time

Abstract. The hyporheic zone is a hotspot of biogeochemical turnover and nutrient removal in running waters. However, due to methodological constraints, our quantitative knowledge on nutrient fluxes to those reactive zones is still limited. In groundwater systems passive flux meters, devices which simultaneously detect water and nutrient flows through a screen well in the subsurface, proofed to be valuable tools for load estimates. Here we present adaptations to this methodology and a smart deployment procedure which allow its use for investigating water and solute fluxes in river sediments. The new hyporheic passive flux meter (HPFM) delivers time integrating values of horizontal hyporheic nutrient fluxes for periods of several days up to weeks. Especially in highly heterogeneous environments like the hyporheic zone, measuring flow and nutrient concentration in a single device is preferable when compared to methods that derive flux estimates from separate measurements of water flows and chemical compounds. We constructed HPFMs of 50 cm length, separated in 5–7 segments which allowed for vertical resolution of horizontal nutrient and water transport in the range of 10 cm. The results of a seven day long field test, which included simultaneous measurements of oxygen and temperature profiles and manual sampling of pore water, revealed further advantages of the method: While grab sampling of pore water could not account for the high temporal variability of nitrate fluxes in our study reach, HPFMs accumulatively captured reliable values for the complete deployment time. Mass balances showed that more than 50 % of the nitrate entering the hyporheic zone was removed in the assessed area. Being low in costs and labor effective, many flux meters can be installed in order to capture larger areas of river beds. The extended application of passive flux meters in hyporheic studies has therefore the potential to deliver the urgently needed quantitative data which is required to feed into realistic models and lead to a better understanding of nutrient cycling in the hyporheic zone.

scholarly journals Quantifying nutrient fluxes with a new hyporheic passive flux meter (HPFM)

2017 ◽  
Vol 14 (3) ◽  
pp. 631-649 ◽  
Author(s):  
Julia Vanessa Kunz ◽  
Michael D. Annable ◽  
Jaehyun Cho ◽  
Wolf von Tümpling ◽  
Kirk Hatfield ◽  
...  
Keyword(s):  
Pore Water ◽  
Nutrient Dynamics ◽  
Hyporheic Zone ◽  
Sampling Site ◽  
Nutrient Fluxes ◽  
Running Waters ◽  
Grab Sampling ◽  
Biofilm Growth ◽  
Hyporheic Zones ◽  
Passive Flux Meter

Abstract. The hyporheic zone is a hotspot of biogeochemical turnover and nutrient removal in running waters. However, nutrient fluxes through the hyporheic zone are highly variable in time and locally heterogeneous. Resulting from the lack of adequate methodologies to obtain representative long-term measurements, our quantitative knowledge on transport and turnover in this important transition zone is still limited.In groundwater systems passive flux meters, devices which simultaneously detect horizontal water and solute flow through a screen well in the subsurface, are valuable tools for measuring fluxes of target solutes and water through those ecosystems. Their functioning is based on accumulation of target substances on a sorbent and concurrent displacement of a resident tracer which is previously loaded on the sorbent.Here we evaluate the applicability of this methodology for investigating water and nutrient fluxes in hyporheic zones. Based on laboratory experiments we developed hyporheic passive flux meters (HPFMs) with a length of 50 cm which were separated in 5–7 segments allowing for vertical resolution of horizontal nutrient and water transport. The HPFMs were tested in a 7 day field campaign including simultaneous measurements of oxygen and temperature profiles and manual sampling of pore water. The results highlighted the advantages of the novel method: with HPFMs, cumulative values for the average N and P flux during the complete deployment time could be captured. Thereby the two major deficits of existing methods are overcome: first, flux rates are measured within one device instead of being calculated from separate measurements of water flow and pore-water concentrations; second, time-integrated measurements are insensitive to short-term fluctuations and therefore deliver more representable values for overall hyporheic nutrient fluxes at the sampling site than snapshots from grab sampling. A remaining limitation to the HPFM is the potential susceptibility to biofilm growth on the resin, an issue which was not considered in previous passive flux meter applications. Potential techniques to inhibit biofouling are discussed based on the results of the presented work. Finally, we exemplarily demonstrate how HPFM measurements can be used to explore hyporheic nutrient dynamics, specifically nitrate uptake rates, based on the measurements from our field test. Being low in costs and labour effective, many flux meters can be installed in order to capture larger areas of river beds. This novel technique has therefore the potential to deliver quantitative data which are required to answer unsolved questions about transport and turnover of nutrients in hyporheic zones.

scholarly journals Occurence of microplastics in the hyporheic zone of rivers

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
S. Frei ◽  
S. Piehl ◽  
B. S. Gilfedder ◽  
M. G. J. Löder ◽  
J. Krutzke ◽  
...  
Keyword(s):  
Drinking Water ◽  
Food Webs ◽  
Hyporheic Zone ◽  
River Sediments ◽  
Size Fraction ◽  
Dry Weight ◽  
Surface Flow ◽  
Hyporheic Exchange ◽  
Pore Scale ◽  
River Bank

Abstract Although recent studies indicate that fluvial systems can be accumulation areas for microplastics (MPs), the common perception still treats rivers and streams primarily as pure transport vectors for MPs. In this study we investigate the occurrence of MPs in a yet unnoticed but essential compartment of fluvial ecosystems - the hyporheic zone (HZ). Larger MP particles (500–5,000 µm) were detected using attenuated total reflectance (ATR) - Fourier-transform infrared (FTIR) spectroscopy. Our analysis of MPs (500–5,000 µm) in five freeze cores extracted for the Roter Main River sediments (Germany) showed that MPs were detectable down to a depth of 0.6 m below the streambed in low abundances (≪1 particle per kg dry weight). Additionally, one core was analyzed as an example for smaller MPs (20–500 µm) with focal plane array (FPA)- based µFTIR spectroscopy. Highest MP abundances (~30,000 particles per kg dry weight) were measured for pore scale particles (20–50 µm). The detected high abundances indicate that the HZ can be a significant accumulation area for pore scale MPs (20–50 µm), a size fraction that yet is not considered in literature. As the HZ is known as an important habitat for invertebrates representing the base of riverine food webs, aquatic food webs can potentially be threatened by the presence of MPs in the HZ. Hyporheic exchange is discussed as a potential mechanism leading to a transfer of pore scale MPs from surface flow into streambed sediments and as a potential vector for small MPs to enter the local aquifer. MPs in the HZ therefore may be a potential risk for drinking water supplies, particularly during drinking water production via river bank filtration.

TRENDS IN VERTICAL PORE WATER FLUX IN THE HYPORHEIC ZONE OF A LOW GRADIENT THIRD ORDER STREAM

2017 ◽  
Author(s):  
F. Claire Harris ◽  
◽  
Eric W. Peterson
Keyword(s):  
Pore Water ◽  
Hyporheic Zone ◽  
Water Flux ◽  
Third Order ◽  
Order Stream

scholarly journals Lateral inflow into the hyporheic zone tested by a laboratory model

2008 ◽  
Vol 5 (3) ◽  
pp. 1567-1601 ◽  
Author(s):  
P. Y. Chou ◽  
G. Wyseure
Keyword(s):  
Pore Water ◽  
Hyporheic Zone ◽  
Column Experiment ◽  
Breakthrough Curves ◽  
Water Velocity ◽  
Hyporheic Exchange ◽  
Laboratory Model ◽  
Transport Parameters ◽  
Pore Water Velocity ◽  
River Bed

Abstract. Groundwater and river water with a different composition interact and exchange in the hyporheic zone. The study of hyporheic zone and its impact on water quality has recently received growing interest because of its role in nutrients and pollutants interactions between rivers and the aquifer. In this research our main purpose is to identify the physical processes and characteristics needed for a numerical model, which include the unsaturated recharge zone, the aquifer and the river bed. In order to investigate such lateral groundwater inflow process, a laboratory J-shaped column experiment was designed. This study determined the transport parameters of the J-shaped column by fitting an analytical solution of the convective-dispersion equation on individual segments to the observed resident breakthrough curves, and by inverse modelling on the entire flow domain for every flux. The obtained transport parameters relation was tested by numerical simulation using HYDRUS 2D/3D. Four steady-state flux conditions (i.e. 0.5 cm hr−1, 1 cm hr−1, 1.5 cm hr−1 and 2 cm hr−1) were applied, transport parameters including pore water velocity and dispersivity were determined for both unsaturated and saturated sections along the column. Results showed that under saturated conditions the dispersivity was fairly constant and independent of the flux. In contrast, dispersivity under unsaturated conditions was flux dependent and increased at lower flux. For our porous medium the dispersion coefficient related best to the quotient of the pore water velocity divided by the water content. A simulation model of the hyporheic exchange of the water and dissolved materials should take this into account.

scholarly journals Characterization of potential mercury contamination in the ASGM area of Mandailing Natal, North Sumatera

2021 ◽  
Vol 882 (1) ◽  
pp. 012062
Author(s):  
H Astika ◽  
S Handayani ◽  
R Damayanti ◽  
W Surono ◽  
Maryono ◽  
...  
Keyword(s):  
River Sediments ◽  
Ecological Impacts ◽  
Mercury Contamination ◽  
Small Scale ◽  
Gold Extraction ◽  
Grab Sampling ◽  
The North ◽  
Soils And Sediments ◽  
Area Sampling

Abstract A large amount of Hg is used for gold extraction through the amalgamation process in the Mandailing Natal derived from artisanal and small-scale gold mining (ASGM) area located in the North Sumatera Province, Indonesia. The objective of this work was to characterize the potential contamination of total Hg in water, sediments, and soil in this ASGM area. Sampling was done in two locations in West Panyabungan and Huta Bargot Districts using grab sampling method. Results showed that accumulation of Hg in the studied soils and sediments was the highest, but Hg in aquatic solution was below the detection limit of the analytical method of the studied community wells and rivers. The highest concentration of Hg was found in the river sediments of the Saba Padang irrigation (1,63 mg/kg), and in the soil of the plantation area of Huta Bargot (1,62 mg/kg) respectively. These concentrations may pose a serious problem for aquatic and land life, related ecosystems, and human health. For further study, there is a need to study Hg availability in riverine biota to better understand the cycling of Hg in this ASGM area. Understanding the ecological impacts can assist in the prioritizing of impact mitigation efforts.

Short term changes in pore water chemistry in river sediments during the early colonization by Vallisneria spiralis

Hydrobiologia ◽  
2010 ◽  
Vol 652 (1) ◽  
pp. 127-137 ◽  
Author(s):  
Erica Racchetti ◽  
Marco Bartoli ◽  
Cristina Ribaudo ◽  
Daniele Longhi ◽  
Luciana E. Q. Brito ◽  
...  
Keyword(s):  
Water Chemistry ◽  
Pore Water ◽  
River Sediments ◽  
Short Term ◽  
Vallisneria Spiralis ◽  
Pore Water Chemistry

Field study of geochemistry and solute fluxes in flooded uranium mine tailings

2002 ◽  
Vol 39 (2) ◽  
pp. 357-376 ◽  
Author(s):  
Vicky Peacey ◽  
Ernest K Yanful ◽  
Roger Payne
Keyword(s):  
Pore Water ◽  
Mine Tailings ◽  
Diffusion Flux ◽  
Metal Mobility ◽  
Oxidation Products ◽  
Uranium Mine ◽  
Dissolved Metals ◽  
Dissolved Solids ◽  
Solute Fluxes ◽  
Water Cover

A geochemical investigation was conducted at the Quirke cell 14 mine waste management area near Elliot Lake, Ontario, Canada, to assess the evolution of water quality of submerged preoxidized uranium mine tailings. Dissolved solids, sulphate, and radium fluxes towards the water cover were calculated using measured solute concentrations, water-cover volumes, and seepage rates for 1993 and 1999. Results indicate that flooding of preoxidized tailings can lead to the initial release of dissolved solids, acidity, and sulphate from the tailings to the overlying water cover. However, the overall impact of this release on the water cover can be minimal in the long term because of dilution from precipitation and fresh water inflows and flushing of the oxidation products down into the pore water. Profiles of dissolved metals and sulphate across the tailings–water interface at the study site indicated a high degree of chemical stability. Solute concentrations in the water cover were homogeneous and generally low at all stations. Pore-water profiles revealed minor remobilization of some trace metals and radionuclides in the shallow pore water (~0.15 m).Key words: mine tailings, water cover, pore-water geochemistry, radium, metal mobility, diffusion, flux.

Diagenetic processes and nutrient fluxes at the sediment-water interface, northern Adriatic Sea, Italy

1995 ◽  
Vol 46 (1) ◽  
pp. 55 ◽  
Author(s):  
A Barbanti ◽  
MC Bergamini ◽  
F Frascari ◽  
S Miserocchi ◽  
M Ratta ◽  
...  
Keyword(s):  
Organic Matter ◽  
Pore Water ◽  
The Other ◽  
Nutrient Concentrations ◽  
Nutrient Fluxes ◽  
Water Interface ◽  
Po River ◽  
Northern Adriatic ◽  
Diagenetic Processes ◽  
Decomposition Of Organic Matter

Early diagenetic processes that control pore-water chemistry and nutrient fluxes at the sediment-water interface were studied in late summer 1989 and spring 1990 at four sites influenced by fine sediments of the Po River. Parameters on the solid fraction (grain size and C, N and P) and pore- water profiles of SO42-, NO3-, NH3, alkalinity, PO43-, Fe, Mn, Ca and Mg were determined. Data interpretation was supported by application of kinetic and stoichiometric modelling. Nutrient fluxes were calculated by Fick's first law. In the prodelta station the pore-water profiles showed large depletion in SO42- ions, jointly with the increase with depth of alkalinity, NH3 and PO43- concentrations, thus indicating anaerobic decomposition of organic matter, mainly due to bacterial sulfate reduction. At the other three sites the results were completely different. Nutrient concentrations in pore water were one order of magnitude lower. The peaks of alkalinity, NH3 and PO43- values near the interface and the constant presence of SO42- ions indicate aerobic decomposition of organic matter in the uppermost sediment. Nutrient fluxes showed much higher values in the prodelta station, whereas fluxes in the remaining stations decreased southward. In addition, seasonal variations produced higher summertime fluxes. The clear-cut difference in diagenetic processes as a function of the distance from the main Po River mouth can be explained by the rapid burial of sediments rich in organic matter and inorganic compounds in the prodelta station. At the other stations, the lower sedimentation rate and more efficient bioturbation and resuspension processes cause a prolonged exposure of sediments to aerobic metabolization reactions before burial.

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