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 Hidden Processes During Seasonal Isolation of a High-Altitude Watershed

2021 ◽  
Vol 9 ◽  
Author(s):  
Jessica Z. Buser-Young ◽  
Laura L. Lapham ◽  
Andrew R. Thurber ◽  
Kenneth H. Williams ◽  
Frederick S. Colwell
Keyword(s):  
Surface Water ◽  
High Altitude ◽  
Hyporheic Zone ◽  
Taxonomic Composition ◽  
Early Summer ◽  
Methane Cycling ◽  
East River ◽  
Hyporheic Zones ◽  
O Isotopes ◽  
Global Carbon

Biogeochemical processes capable of altering global carbon systems occur frequently in Earth’s Critical Zone–the area spanning from vegetation canopy to saturated bedrock–yet many of these phenomena are difficult to detect. Observation of these processes is limited by the seasonal inaccessibility of remote ecosystems, such as those in mountainous, snow- and ice-dominated areas. This isolation leads to a distinct gap in biogeochemical knowledge that ultimately affects the accuracy and confidence with which these ecosystems can be computationally modeled for the purpose of projecting change under different climate scenarios. To examine a high-altitude, headwater ecosystem’s role in methanogenesis, sulfate reduction, and groundwater-surface water exchange, water samples were continuously collected from the river and hyporheic zones (HZ) during winter isolation in the East River (ER), CO watershed. Measurements of continuously collected ER surface water revealed up to 50 μM levels of dissolved methane in July through September, while samples from 12 cm deep in the hyporheic zone at the same location showed a spring to early summer peak in methane with a strong biogenic signature (<65 μM, δ13C-CH4, −60.76‰) before declining. Continuously collected δ18O-H2O and δ2H-H2O isotopes from the water column exhibited similar patterns to discrete measurements, while samples 12 cm deep in the hyporheic zone experienced distinct fluctuations in δ18O-H2O, alluding to significant groundwater interactions. Continuously collected microbial communities in the river in the late fall and early winter revealed diverse populations that reflect the taxonomic composition of ecologically similar river systems, including taxa indicative of methane cycling in this system. These measurements captured several biogeochemical components of the high-altitude watershed in response to seasonality, strengthening our understanding of these systems during the winter months.

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.

scholarly journals A Hydrologic Landscapes Perspective on Groundwater Connectivity of Depressional Wetlands

Water ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 50 ◽  
Author(s):  
Brian P. Neff ◽  
Donald O. Rosenberry ◽  
Scott G. Leibowitz ◽  
Dave M. Mushet ◽  
Heather E. Golden ◽  
...  
Keyword(s):  
Surface Water ◽  
Water Table ◽  
Conceptual Knowledge ◽  
Groundwater Discharge ◽  
Depressional Wetlands ◽  
Hydrologic Connectivity ◽  
Site Specific ◽  
Depressional Wetland ◽  
Resource Managers ◽  
Flow Through

Research into processes governing the hydrologic connectivity of depressional wetlands has advanced rapidly in recent years. Nevertheless, a need persists for broadly applicable, non-site-specific guidance to facilitate further research. Here, we explicitly use the hydrologic landscapes theoretical framework to develop broadly applicable conceptual knowledge of depressional-wetland hydrologic connectivity. We used a numerical model to simulate the groundwater flow through five generic hydrologic landscapes. Next, we inserted depressional wetlands into the generic landscapes and repeated the modeling exercise. The results strongly characterize groundwater connectivity from uplands to lowlands as being predominantly indirect. Groundwater flowed from uplands and most of it was discharged to the surface at a concave-upward break in slope, possibly continuing as surface water to lowlands. Additionally, we found that groundwater connectivity of the depressional wetlands was primarily determined by the slope of the adjacent water table. However, we identified certain arrangements of landforms that caused the water table to fall sharply and not follow the surface contour. Finally, we synthesize our findings and provide guidance to practitioners and resource managers regarding the management significance of indirect groundwater discharge and the effect of depressional wetland groundwater connectivity on pond permanence and connectivity.

scholarly journals Insight into the influence of local streambed heterogeneity on hyporheic-zone flow characteristics

2020 ◽  
Vol 28 (8) ◽  
pp. 2697-2712
Author(s):  
Robert Earon ◽  
Joakim Riml ◽  
Liwen Wu ◽  
Bo Olofsson
Keyword(s):  
Surface Water ◽  
Hydraulic Conductivity ◽  
Penetration Depth ◽  
Hyporheic Zone ◽  
Flow Characteristics ◽  
Time Lapse ◽  
Hyporheic Exchange ◽  
Tracer Injection ◽  
Hyporheic Flow ◽  
Exchange Processes

AbstractInteraction between surface water and groundwater plays a fundamental role in influencing aquatic chemistry, where hyporheic exchange processes, distribution of flow paths and residence times within the hyporheic zone will influence the transport of mass and energy in the surface-water/groundwater system. Geomorphological conditions greatly influence hyporheic exchange, and heterogeneities such as rocks and clay lenses will be a key factor for delineating the hyporheic zone. Electrical resistivity tomography (ERT) and ground-penetrating radar (GPR) were used to investigate the streambed along a 6.3-m-long reach in order to characterise geological layering and distinct features which may influence parameters such as hydraulic conductivity. Time-lapse ERT measurements taken during a tracer injection demonstrated that geological features at the meter-scale played a determining role for the hyporheic flow field. The penetration depth of the tracer into the streambed sediment displayed a variable spatial pattern in areas where the presence of highly resistive anomalies was detected. In areas with more homogeneous sediments, the penetration depth was much more uniformly distributed than observed in more heterogeneous sections, demonstrating that ERT can play a vital role in identifying critical hydraulic features that may influence hyporheic exchange processes. Reciprocal ERT measurements linked variability and thus uncertainty in the modelled resistivity to the spatial locations, which also demonstrated larger variability in the tracer penetration depth, likely due to local heterogeneity in the hydraulic conductivity field.

scholarly journals Assessment of the effects of wastewater treatment plant effluents on receiving streams using oligochaete communities of the porous matrix

2019 ◽  
pp. 18
Author(s):  
Régis Vivien ◽  
Michel Lafont ◽  
Inge Werner ◽  
Mélanie Laluc ◽  
Benoit J.D. Ferrari
Keyword(s):  
Wastewater Treatment ◽  
Surface Water ◽  
Hyporheic Zone ◽  
Surface Sediments ◽  
Treatment Plant ◽  
Functional Trait ◽  
Porous Matrix ◽  
Biological Quality ◽  
Coarse Surface

Human activities can disturb the natural dynamics of exchanges between surface water and groundwater in rivers. Such exchanges contribute to the self-purification of the environment and an excess of infiltration can lead to contamination of groundwater. In addition, the porous matrix (coarse surface sediments and hyporheic zone), through which water exchanges occur, is a sink for pollutants. For environmental monitoring programs, it is therefore essential to take into account both the dynamics of vertical hydrological exchanges and the biological quality of this matrix. The functional trait (FTR) method, which is based on the study of oligochaete communities in coarse surface sediments and the hyporheic zone, was proposed as a tool to simultaneously assess the dynamics of vertical hydrological exchanges and the effects of pollutants present in the porous matrix. Here, we applied this method during two different periods (in March and September 2016), upstream and downstream of locations affected by discharges from wastewater treatment plants (WWTP) located in Switzerland. The biological quality of surface sediments and the hyporheic zone was shown to be better upstream of the WWTP in both campaigns. In addition, results suggested that the capacity for self-purification was lower downstream of the WWTP, and that groundwater at these locations was vulnerable to pollution by surface water. The FTR method proved valuable as a field method for detecting the effects of point source contamination on receiving streams. In the near future, this community-based approach will benefit from advances in the use of DNA barcodes for oligochaete species identification.

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.

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