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 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.

Effects of riffle–step restoration on hyporheic zone chemistry in N-rich lowland streams

2006 ◽  
Vol 63 (1) ◽  
pp. 120-133 ◽  
Author(s):  
Tamao Kasahara ◽  
Alan R Hill
Keyword(s):  
Urban Areas ◽  
Hyporheic Zone ◽  
Stream Water ◽  
Ion Concentration ◽  
Hyporheic Exchange ◽  
Ecosystem Functions ◽  
Exchange Flow ◽  
Nutrient Inputs ◽  
Lowland Streams ◽  
Hyporheic Zones

Stream restoration projects that aim to rehabilitate ecosystem health have not considered surface–subsurface linkages, although stream water and groundwater interaction has an important role in sustaining stream ecosystem functions. The present study examined the effect of constructed riffles and a step on hyporheic exchange flow and chemistry in restored reaches of several N-rich agricultural and urban streams in southern Ontario. Hydrometric data collected from a network of piezometers and conservative tracer releases indicated that the constructed riffles and steps were effective in inducing hyporheic exchange. However, despite the use of cobbles and boulders in the riffle construction, high stream dissolved oxygen (DO) concentrations were depleted rapidly with depth into the hyporheic zones. Differences between observed and predicted nitrate concentrations based on conservative ion concentration patterns indicated that these hyporheic zones were also nitrate sinks. Zones of low hydraulic conductivity and the occurrence of interstitial fines in the restored cobble-boulder layers suggest that siltation and clogging of the streambed may reduce the downwelling of oxygen- and nitrate-rich stream water. Increases in streambed DO levels and enhancement of habitat for hyporheic fauna that result from riffle–step construction projects may only be temporary in streams that receive increased sediment and nutrient inputs from urban areas and croplands.

Oak contribution to litter nutrient dynamics in an Appalachian forest receiving elevated nitrogen and dolomite

2009 ◽  
Vol 39 (5) ◽  
pp. 936-944 ◽  
Author(s):  
K.B. Piatek ◽  
P. Munasinghe ◽  
W.T. Peterjohn ◽  
M.B. Adams ◽  
J.R. Cumming
Keyword(s):  
Atmospheric Deposition ◽  
Nutrient Dynamics ◽  
Lignin Content ◽  
Nutrient Fluxes ◽  
Mixed Species ◽  
N Dynamics ◽  
P Flux ◽  
P Immobilization ◽  
High Lignin Content ◽  
N Flux

Ecosystem nitrogen (N), phosphorus (P), and calcium (Ca) fluxes are affected by inputs of atmospheric N. Oak litter may additionally affect these fluxes because of its high-lignin content. We analyzed nutrient dynamics in ambient mixed-species litter in an aggrading hardwood stand at the Fernow Experimental Forest in West Virginia. We separated oak from the mix for analysis (oak) and compared it with total litter (all species) to understand how oak affects nutrient fluxes in the litter layer. The study was conducted under ambient atmospheric deposition, under elevated atmospheric deposition, and under elevated deposition plus mitigation with dolomite. N flux between litterfall and 12 months later indicated a net loss in all-species litter of up to 7.3 kg N·ha–1 and a retention of up to 0.6 kg N·ha–1 in oak. P flux included losses in all species in ambient and in dolomite treatments of up to 0.19 kg P·ha–1 and gains of up to 0.12 kg P·ha–1 in oak in all treatments. Oak mineralized Ca at an average across treatments of 4.6 kg Ca·ha–1 compared with 16 kg Ca·ha–1 in all species, with half of that when trees were dormant. Percent immobilization and release over initial litter were greater in oak than in all species, but nutrient fluxes were lower in oak than in all species because of low oak litter mass. Elevated deposition lowered N and increased P immobilization. Dolomite appeared to affect early N dynamics only. With an increase in litterfall mass when forests mature, these effects are also likely to increase.

Sediment metabolism in a transitional continental - marine area: The Albufera of Majorca (Balearic Islands, Spain)

1995 ◽  
Vol 46 (1) ◽  
pp. 45 ◽  
Author(s):  
P Lopez ◽  
M Vidal ◽  
X Lluch ◽  
JA Morgui
Keyword(s):  
Oxygen Consumption ◽  
Pore Water ◽  
Respiratory Quotient ◽  
Nutrient Dynamics ◽  
Anaerobic Respiration ◽  
Ammonium Phosphate ◽  
Nutrient Concentrations ◽  
Co2 Efflux ◽  
Marine Areas ◽  
Diffusive Fluxes

The concentrations of nutrients in sediment pore water and the fluxes of nutrients at the water-sediment interface were measured in a channel that joins continental and marine areas in the Albufera of Majorca in order to evaluate the role of sediments in the nutrient dynamics in this system. Upstream, surficial pore water presented lower values of Eh, which became negative in summer, whereas downstream Eh remained positive. Nutrient concentrations were especially high upstream, reaching 1000 mol L-1 of NH4 and 75 μmol L-1 of PO4 during summer. In summer, measured fluxes showed intense respiration upstream, with an oxygen consumption of 130 mg m-2 h-1 and a respiratory quotient near 4, which indicates dominance of anaerobic respiration. Total CO2 efflux and nutrient fluxes were also high, reaching 30.50 mmol m-2 h-1 for CO2, >2000 μmol m-2 h-1 for NH4 and 58 μmol m-2 h-1 for PO4. A substantial amount of the total CO2 efflux (14 mmol m-2 h-1) was due to calcium carbonate redissolution. Downstream, oxygen consumption, respiratory quotient and ammonium fluxes were lower (around 70 mg m-2 h-1, between 2 and 3, and <20 μmol m-2 h-1, respectively), which indicates a moderate rate of decomposition activity and suggests denitrification as the main respiratoy process. Differences between fluxes measured 'in situ' and those calculated from pore-water concentrations indicated non-diffusive fluxes upstream and suggest substantial denitrifying activity downstream. Extra keywords: benthic chambers, sediment fluxes, pore water, ammonium, phosphate.

scholarly journals Impact of Bed Form Celerity on Oxygen Dynamics in the Hyporheic Zone

Water ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 62 ◽  
Author(s):  
Philipp Wolke ◽  
Yoni Teitelbaum ◽  
Chao Deng ◽  
Jörg Lewandowski ◽  
Shai Arnon
Keyword(s):  
Hyporheic Zone ◽  
Time Lapse ◽  
Oxygen Distribution ◽  
Anoxic Zone ◽  
Fine Grain ◽  
Uptake Rates ◽  
Hyporheic Zones ◽  
Bed Form ◽  
Gradual Disappearance ◽  
Oxygen Dynamics

Oxygen distribution and uptake in the hyporheic zone regulate various redox-sensitive reactions and influence habitat conditions. Despite the fact that fine-grain sediments in streams and rivers are commonly in motion, most studies on biogeochemistry have focused on stagnant sediments. In order to evaluate the effect of bed form celerity on oxygen dynamics and uptake in sandy beds, we conducted experiments in a recirculating indoor flume. Oxygen distribution in the bed was measured under various celerities using 2D planar optodes. Bed morphodynamics were measured by a surface elevation sensor and time-lapse photography. Oxygenated zones in stationary beds had a conchoidal shape due to influx through the stoss side of the bed form, and upwelling anoxic water at the lee side. Increasing bed celerity resulted in the gradual disappearance of the upwelling anoxic zone and flattening of the interface between the oxic (moving fraction of the bed) and the anoxic zone (stationary fraction of the bed), as well as in a reduction of the volumetric oxygen uptake rates due shortened residence times in the hyporheic zone. These results suggest that including processes related to bed form migration are important for understanding the biogeochemistry of hyporheic zones.

scholarly journals Deterministic influences exceed dispersal effects on hydrologically-connected microbiomes

2016 ◽  
Author(s):  
Emily B. Graham ◽  
Alex R. Crump ◽  
Charles T. Resch ◽  
Sarah Fansler ◽  
Evan Arntzen ◽  
...  
Keyword(s):  
Surface Water ◽  
Ecosystem Function ◽  
Hyporheic Zone ◽  
Groundwater Discharge ◽  
Ecosystem Models ◽  
Organic C ◽  
Water Mixing ◽  
Riverine Ecosystem ◽  
Water Intrusion ◽  
Hyporheic Zones

SummarySubsurface groundwater-surface water mixing zones (hyporheic zones) have enhanced biogeochemical activity, but assembly processes governing subsurface microbiomes remain a critical uncertainty in understanding hyporheic biogeochemistry. To address this obstacle, we investigated (a) biogeographical patterns in attached and waterborne microbiomes across three hydrologically-connected, physicochemically-distinct zones (inland hyporheic, nearshore hyporheic, and river); (b) assembly processes that generated these patterns; (c) groups of organisms that corresponded to deterministic changes in the environment; and (d) correlations between these groups and hyporheic metabolism. All microbiomes remained dissimilar through time, but consistent presence of similar taxa suggested dispersal and/or common selective pressures among zones. Further, we demonstrated a pronounced impact of deterministic assembly in all microbiomes as well as seasonal shifts from heterotrophic to autotrophic microorganisms associated with increases in groundwater discharge. The abundance of one statistical cluster of organisms increased with active biomass and respiration, revealing organisms that may strongly influence hyporheic biogeochemistry. Based on our results, we propose a conceptualization of hyporheic zone metabolism in which increased organic carbon concentrations during surface water intrusion support heterotrophy, which succumbs to autotrophy under groundwater discharge. These results provide new opportunities to enhance microbially-explicit ecosystem models describing hyporheic zone biogeochemistry and its influence over riverine ecosystem function.Originality-Significance StatementSubsurface zones of groundwater and surface water mixing (hyporheic zones) are hotspots of biogeochemical activity and strongly influence carbon, nutrient and contaminant dynamics within riverine ecosystems. Hyporheic zone microbiomes are responsible for up to 95% of riverine ecosystem respiration, yet the ecology of these microbiomes remains poorly understood. While significant progress is being made in the development of microbially-explicit ecosystem models, poor understanding of hyporheic zone microbial ecology impedes development of such models in this critical zone. To fill the knowledge gap, we present a comprehensive analysis of biogeographical patterns in hyporheic microbiomes as well as the ecological processes that govern their composition and function through space and time. Despite pronounced hydrologic connectivity throughout the hyporheic zone—and thus a strong potential for dispersal—we find that ecological selection deterministically governs microbiome composition within local environments, and we identify specific groups of organisms that correspond to seasonal changes in hydrology. Based on our results, we propose a conceptual model for hyporheic zone metabolism in which comparatively high-organic C conditions during surface water intrusion into the hyporheic zone support heterotrophic metabolisms that succumb to autotrophy during time periods of groundwater discharge. These results provide new opportunities to develop microbially-explicit ecosystem models that incorporate the hyporheic zone and its influence over riverine ecosystem function.

scholarly journals Hyporheic hydraulic geometry: Conceptualizing relationships among hyporheic exchange, storage, and water age

PLoS ONE ◽  
2022 ◽  
Vol 17 (1) ◽  
pp. e0262080
Author(s):  
Geoffrey C. Poole ◽  
S. Kathleen Fogg ◽  
Scott J. O’Daniel ◽  
Byron E. Amerson ◽  
Ann Marie Reinhold ◽  
...  
Keyword(s):  
Hyporheic Zone ◽  
Quantitative Description ◽  
Hyporheic Exchange ◽  
Water Volume ◽  
Mathematical Framework ◽  
Hydraulic Geometry ◽  
Water Age ◽  
Mathematical Basis ◽  
Hyporheic Zones ◽  
Improved Accuracy

Hyporheic exchange is now widely acknowledged as a key driver of ecosystem processes in many streams. Yet stream ecologists have been slow to adopt nuanced hydrologic frameworks developed and applied by engineers and hydrologists to describe the relationship between water storage, water age, and water balance in finite hydrosystems such as hyporheic zones. Here, in the context of hyporheic hydrology, we summarize a well-established mathematical framework useful for describing hyporheic hydrology, while also applying the framework heuristically to visualize the relationships between water age, rates of hyporheic exchange, and water volume within hyporheic zones. Building on this heuristic application, we discuss how improved accuracy in the conceptualization of hyporheic exchange can yield a deeper understanding of the role of the hyporheic zone in stream ecosystems. Although the equations presented here have been well-described for decades, our aim is to make the mathematical basis as accessible as possible and to encourage broader understanding among aquatic ecologists of the implications of tailed age distributions commonly observed in water discharged from and stored within hyporheic zones. Our quantitative description of “hyporheic hydraulic geometry,” associated visualizations, and discussion offer a nuanced and realistic understanding of hyporheic hydrology to aid in considering hyporheic exchange in the context of river and stream ecosystem science and management.

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