scholarly journals Is the Hyporheic Zone Relevant beyond the Scientific Community?

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2230 ◽  
Author(s):  
Jörg Lewandowski ◽  
Shai Arnon ◽  
Eddie Banks ◽  
Okke Batelaan ◽  
Andrea Betterle ◽  
...  
Keyword(s):  
Hyporheic Zone ◽  
Aquatic Organisms ◽  
Ecosystem Functions ◽  
Major Research ◽  
Research Gaps ◽  
Diverse Range ◽  
Scientific Disciplines ◽  
Hyporheic Zones ◽  
Reactive Interface ◽  
River Corridors

Rivers are important ecosystems under continuous anthropogenic stresses. The hyporheic zone is a ubiquitous, reactive interface between the main channel and its surrounding sediments along the river network. We elaborate on the main physical, biological, and biogeochemical drivers and processes within the hyporheic zone that have been studied by multiple scientific disciplines for almost half a century. These previous efforts have shown that the hyporheic zone is a modulator for most metabolic stream processes and serves as a refuge and habitat for a diverse range of aquatic organisms. It also exerts a major control on river water quality by increasing the contact time with reactive environments, which in turn results in retention and transformation of nutrients, trace organic compounds, fine suspended particles, and microplastics, among others. The paper showcases the critical importance of hyporheic zones, both from a scientific and an applied perspective, and their role in ecosystem services to answer the question of the manuscript title. It identifies major research gaps in our understanding of hyporheic processes. In conclusion, we highlight the potential of hyporheic restoration to efficiently manage and reactivate ecosystem functions and services in river corridors.

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 Assessment of Hydrologic Transient Storage of Three Streams

2003 ◽  
Vol 27 ◽  
pp. 79-80
Author(s):  
Michael Gooseff
Keyword(s):  
Porous Media ◽  
Hyporheic Zone ◽  
Stream Water ◽  
Stream Sediments ◽  
Hyporheic Exchange ◽  
Ecosystem Functions ◽  
Main Stream ◽  
Stream Channel ◽  
Ample Opportunity ◽  
Biogeochemical Transformations

Stream sediments are important locations of biogeochemical transformations upon which many stream ecosystem functions depend. Stream water is often exchanged between the stream channel and surrounding subsurface locations - this process is known as hyporheic exchange. While stream water is moving through the hyporheic zone, solutes and nutrients may undergo important chemical reactions that are not possible in the main stream channel. Further, because the hyporheic zone is composed of porous media (sand, sediment, alluvium, etc.), flow inherently slows down and the exchanging water has ample opportunity to interact with mineral grain surfaces and biofilms.

scholarly journals Eye movements in vocabulary research

2021 ◽  
Author(s):  
Ana Pellicer-Sánchez ◽  
Anna Siyanova
Keyword(s):  
Eye Movements ◽  
Eye Tracking ◽  
Future Research ◽  
Auditory Input ◽  
Major Research ◽  
Research Gaps ◽  
Comprehensive Overview ◽  
Formulaic Sequences ◽  
Online Processing ◽  
Research Findings

Abstract The field of vocabulary research is witnessing a growing interest in the use of eye-tracking to investigate topics that have traditionally been examined using offline measures, providing new insights into the processing and learning of vocabulary. During an eye-tracking experiment, participants’ eye movements are recorded while they attend to written or auditory input, resulting in a rich record of online processing behaviour. Because of its many benefits, eye-tracking is becoming a major research technique in vocabulary research. However, before this emerging trend of eye-tracking based vocabulary research continues to proliferate, it is important to step back and reflect on what current studies have shown about the processing and learning of vocabulary, and the ways in which we can use the technique in future research. To this aim, the present paper provides a comprehensive overview of current eye-tracking research findings, both in terms of the processing and learning of single words and formulaic sequences. Current research gaps and potential avenues for future research are also discussed.

Migrant Domestic Workers: Disadvantaged Work, Social Support, and Collective Strategies in East Asia

2020 ◽  
Vol 64 (6) ◽  
pp. 703-708
Author(s):  
Eric Fong ◽  
Brenda S. A. Yeoh
Keyword(s):  
Domestic Workers ◽  
Working Environment ◽  
Special Issue ◽  
Major Research ◽  
Research Gaps ◽  
Migration Research ◽  
Sources Of Support ◽  
Work Social Support ◽  
Migration Flows ◽  
Migrant Domestic Workers

The movement of migrant domestic workers constitutes an important aspect of migration flows in Asia. We identify and outline three major research gaps in this area: (1) their unique working environment and the consequences of working under these conditions, (2) formal and informal sources of support, and (3) policies implemented by local government in response to the working environment of migrant domestic workers. We discuss how the articles in this special issue address these major gaps in migration research.

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 Characterizing the Variation of Dissolvable PAHs in Receiving Water in a Reclaimed Water Irrigation Region

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2766
Author(s):  
Yajun Wang ◽  
Binghua Li ◽  
Ying Ma ◽  
Lihu Yang ◽  
Xianfang Song
Keyword(s):  
Environmental Protection Agency ◽  
Environmental Pollutants ◽  
Reclaimed Water ◽  
Aquatic Organisms ◽  
Temporal Variations ◽  
Ecosystem Functions ◽  
Factors Affecting ◽  
Polycyclic Aromatic ◽  
Potential Factors ◽  
Reclaimed Water Irrigation

Long-term wastewater and reclaimed water irrigation systems constitute the major processes in local water circulation, which concomitantly introduce plenty of undesirable substances that can threaten water quality, ecosystem functions and human health. At the Southeast Reclaimed Water Irrigation Region (SRWIR) of Beijing, wastewater irrigation was adopted from 1969 to 2002, and second-treated effluents (reclaimed water) has been used thereafter. Polycyclic aromatic hydrocarbons (PAHs) were the most ubiquitously detected contaminant in wastewater and reclaimed water and are reported to be carcinogenic. Hence, we measured the concentrations of dissolved sixteen United States Environmental Protection Agency (USEPA) priority PAHs in surface water and groundwater at the SRWIR to characterize their spatial and temporal variations, and to clarify the role of reclaimed water to natural water. The concentration of 16 individual PAHs in reclaimed water, rivers and groundwater varied from 339.4 to 636.2 ng/L, 359.1 to 3,435.0 ng/L and 216.5 to 488,205.2 ng/L, respectively. The lower aromatic rings of PAHs prevailed in aquatic environments rather than the higher ones. Thereinto, naphthalene was the predominant isomer within the highest concentration reached to 486,600 µg/L. The groundwater samples had higher PAHs concentrations at Tongzhou district which attributed to the higher vulnerability of aquifer. Additionally, strong correlations between PAHs and total nitrogen, nitrate, dissolved oxygen and electrical conductivity suggested those potential factors affecting the photo degradation and/or biodegradation of PAHs. The relationship identified between PAHs concentrations and physical and chemical indices would help us to enhance the understanding migration and transformation of PAHs spatially and temporally, enable us to assess the potential risks of the environmental pollutants to aquatic organisms and human water supplies.

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 It Depends…Different Direct Democratic Instruments and Equality in Europe from 1990 to 2015

2019 ◽  
Vol 7 (2) ◽  
pp. 365-379 ◽  
Author(s):  
Brigitte Geißel ◽  
Anna Krämling ◽  
Lars Paulus
Keyword(s):  
Decision Making ◽  
Direct Democracy ◽  
Current Debate ◽  
Major Research ◽  
Political Equality ◽  
Top Down ◽  
Research Gaps ◽  
Bottom Up ◽  
Actual Output ◽  
Cross National

Despite the popularity of direct democracy in recent decades, research on the actual output effects of popular decision-making is rare. This is especially true with regard to equality, where there are at least three major research gaps: 1) a lack of cross-national analyses; 2) insufficient investigation of the differential effects of different direct democratic instruments on equality; and 3) a failure to distinguish between different aspects of equality, i.e., socioeconomic, legal and political equality. This article takes a first step to tackle these shortcomings by looking at all national referenda in European democracies between 1990 and 2015, differentiating between mandatory, bottom-up and top-down referenda. We find that a large majority of successful direct democratic bills—regardless of which instrument is employed—are not related to equality issues. Of the remaining ones, there are generally more successful pro-equality bills than contra-equality ones, but the differences are rather marginal. Mandatory referenda tend to produce pro-equality outputs, but no clear patterns emerge for bottom-up and top-down referenda. Our results offer interesting, preliminary insights to the current debate on direct democracy, pointing to the conclusion that popular decision-making via any type of direct democratic instrument is neither curse nor blessing with regard to equality. Instead, it is necessary to look at other factors such as context conditions or possible indirect effects in order to get a clearer picture of the impacts of direct democracy on equality.

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.

Strategic entrepreneurship: mapping a research field

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Katharina Schröder ◽  
Victor Tiberius ◽  
Ricarda B. Bouncken ◽  
Sascha Kraus
Keyword(s):  
Design Methodology ◽  
Research Field ◽  
Bibliographic Coupling ◽  
Future Research ◽  
Major Research ◽  
Research Gaps ◽  
Content Type ◽  
Strategic Entrepreneurship ◽  
Integrated Research ◽  
Seeking Behavior

PurposeStrategic entrepreneurship (SE) depicts the nexus of strategic management and entrepreneurship, suggesting that firms can create superior wealth when simultaneously pursuing advantage-seeking and opportunity-seeking behavior. As the rapid growth in SE research led to a multidisciplinary, scattered and fragmented literature landscape, the authors aim to structure this research field.Design/methodology/approachThe authors employ a bibliographic coupling and literature review of the strategic entrepreneurship research field.FindingsThe authors identify and describe five major research streams with 15 sub-themes in recent SE research. Based on our findings, the authors propose an integrated research framework and research gaps for future research.Originality/valueTo the authors’ knowledge, this is the first review on SE based on a bibliographic coupling.

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