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1
Iepure, Sanda, David Gomez-Ortiz, Javier Lillo, Rubén Rasines-Ladero, and Tiziana Di Lorenzo. "Applying Electrical Resistivity Tomography and Biological Methods to Assess the Hyporheic Zone Water Exchanges in Two Mediterranean Stream Reaches." Water 14, no. 21 (October 26, 2022): 3396. http://dx.doi.org/10.3390/w14213396.
Повний текст джерелаАнотація:
The hyporheic zone (HZ) is a critical area of all river ecosystems. It is the area beneath the stream and adjacent to the stream, where the surface water and groundwater are mixed. The HZ extends both vertically and laterally depending on the sediment configuration, namely their porosity and permeability. This influences the hyporheic communities’ structural pattern and their active dispersal among distinct rivers compartments and alluvial aquifers. It is still difficult to assess the spatial extent of the HZ and the distribution of the mixing zones. This study applies time-lapse images obtained using electrical resistivity tomography (ERT) of 20 m wide and 5 m deep alluvial streams, with regards to the structural pattern of hyporheic communities represented by cyclopoids and ostracods, in order to assess the extent of the HZ in the riverbed and the parafluvial sediment configurations. The ERT images obtained at the hyporheic Site 1 are characterized by alluvial deposits dominated by coarse and very coarse sands with resistivity values ranging from ~20 to 80 Ohm.m, indicating a permeable zone up to ~0.5 m thick and extending laterally for ca. 5 m from the channel and associated with the hyporheic zone. The sediment configurations, texture, and structure indicate an active surface–hyporheic water exchange and low water retention into the sediments. This is also indicated by the hyporheic copepods and ostracods communities’ structure formed by a mixture of non-stygobites (five species) and stygobites (two species). A low-resistivity (<70 Ohm.m) permeable zone located 2.3 m below the streambed and unconnected with the river channel was also detected and associated with the associated alluvial aquifer. In contrast, the resistivity image at Site 2 dominated by coarse, medium, and very fine sands, shows a low-permeability zone in the upper ~0.5 m of the profile, with a resistivity value ranging from ~45 to 80 Ohm.m, indicating a reduced HZ extension in both vertical and lateral dimensions. Here the sediment configurations indicate that the water retention and interaction with the sediment is higher, reflected by more diverse hyporheic communities and with highly abundant stygobite species. The two examples show that non-invasive ERT images and biological assessments provide complementary and valuable information about the characterization of the sub-channel architecture and its potential hydraulic connection to the floodplain aquifer.
2
Beasley, Gary, and Pauline Kneale. "Reviewing the impact of metals and PAHs on macroinvertebrates in urban watercourses." Progress in Physical Geography: Earth and Environment 26, no. 2 (June 2002): 236–70. http://dx.doi.org/10.1191/0309133302pp334ra.
Повний текст джерелаАнотація:
Pollution-free stream water and sediments are crucial to support healthy stream flora and fauna, but urban surface runoff impairs water quality and leaves a legacy of pollution in the sediments. Pollution in sediments influences the development of macroinvertebrates, the lowest members of the food chain, leading to modification of the whole ecological structure. This review focuses on the sources and impacts of zinc, nickel, copper and oil derivative polycyclic aromatic hydrocarbon (PAH) contaminants on macroinvertebrates in urban streams. Land use, and the connectivity of the runoff and sediment are seen to have an effect on the ecological integrity of the watercourse but case examples are sparse. The literature indicates that while reduced species diversity has been identified at a number of sites the dynamics are neither well understood nor well modelled. The literature evidence is compared with field evidence from a study of 62 source areas in headwater catchments with residential, urban, industrial and motorway land uses. From the review and field results it is evident that there is still an important need for process-based field measurements of urban water quality parameters. It is suggested that forecasting the ecological status of watercourses would benefit from data on sediment chemistry and the interaction effects of metals and PAHs.
3
Skoglund, Rannveig Øvrevik, Christos Pennos, Aurel Perşoiu, and Yorgos Sotiriadis. "Karstic Aquifers—Simple or Hybrid Systems? Thermal Stories from Maaras Cave, Greece." Water 15, no. 3 (January 26, 2023): 488. http://dx.doi.org/10.3390/w15030488.
Повний текст джерелаАнотація:
Karst systems, such as caves, provide a unique opportunity to study the groundwater from the inside in contrast to spring studies, where hydrographs, chemographs, and thermographs show an integrated signal from the entire catchment and aquifer. Studies from karst springs show that recharge and conduit characteristics significantly influence how the temperature signal is transmitted and thus could inform on the structure of underground flow paths. Here, we present monitoring temperature data from a two-year-long study of a 10 km long river cave, Maaras, in northern Greece. Our data from five measuring stations along the cave stream show how different flow paths transform the temperature signal. The catchment area consists of a polje impacting the recharge conditions that change seasonally from diffuse to concentrated. Diffuse recharge stabilizes the temperature regardless of the conduit conditions. However, temperature fluctuations occur on four different time scales: seasonal, event-based, diurnal, and hourly, indicating different passage conditions. Interaction between the cave stream and the in-cave porous aquifer in the clastic sediments strongly impacts the alteration of the thermal signal through the cave: temperature fluctuations are damped, and the temperature is raised.
4
Pagano, Stefano Giorgio, Donato Sollitto, Marco Colucci, Davide Prato, Fabio Milillo, Giovanni Francesco Ricci, and Francesco Gentile. "Setting Up of an Experimental Site for the Continuous Monitoring of Water Discharge, Suspended Sediment Transport and Groundwater Levels in a Mediterranean Basin. Results of One Year of Activity." Water 12, no. 11 (November 8, 2020): 3130. http://dx.doi.org/10.3390/w12113130.
Повний текст джерелаАнотація:
The study of suspended sediment transport requires continuous measurement of water discharge to better understand the sediment dynamics. Furthermore, a groundwater monitoring network can support the stream discharge measures, as it reveals how the interactions between surface water and groundwater may affect runoff and consequently sediment transport during flood events. An experimental site for the continuous monitoring of water discharge, suspended sediment transport and groundwater levels was set up in the Carapellotto basin (27.17 km2), which is located in Apulia, Southern Italy. Seven flood events that occurred in the operation timespan were covered with a full record of both water discharge and sediment concentration. Some monitoring problems, largely due to the clogging of the float by mud, suggested to improve the experimental set up. The results show high values of suspended sediments concentration which indicate the sub-basin’s key role in the sediment delivery to the whole river system, while counter-clockwise hysteresis loops are the most frequent due to the basin characteristics. The effects of the interaction between surface water and groundwater are related not only to the flood magnitude but also to the hydrogeological features in the hyporheic zone.
5
Kasahara, Tamao, Thibault Datry, Michael Mutz, and Andrew J. Boulton. "Treating causes not symptoms: restoration of surface - groundwater interactions in rivers." Marine and Freshwater Research 60, no. 9 (2009): 976. http://dx.doi.org/10.1071/mf09047.
Повний текст джерелаАнотація:
Many river restoration projects seek to address issues associated with impaired hydrological and ecological connectivity in longitudinal (e.g. effects of dams, weirs) or lateral (e.g. alienated floodplain) dimensions. Efforts to restore the vertical dimension of impaired stream–groundwater exchange are rare, hampered by limited understanding of the factors controlling this linkage in natural alluvial rivers. We propose a simplified two-axis model of the ‘primary drivers’ (sediment structure and vertical hydraulic gradient) of stream–groundwater exchange that acknowledges their interaction and provides a practical template to help researchers and river managers pose hypothesis-driven solutions to restoration of damaged or lost vertical connectivity. Many human activities impact on one or both of these drivers, and we review some of the tools available for treating the causes (rather than symptoms) in impacted stream reaches. For example, creating riffle-pool sequences along stream reaches will enhance vertical hydraulic gradient, whereas flushing flows can remove clogging layers and sustain sediment permeability. Our model is a first step to specifying mechanisms for recovery of lost vertical connectivity. Assessing results of river restoration using this approach at reach to catchment scales will provide scientific insights into the interplay of hydrology, fluvial geomorphology and river ecosystem function at appropriately broad scales.
6
Mojarrad, Brian Babak, Andrea Betterle, Tanu Singh, Carolina Olid, and Anders Wörman. "The Effect of Stream Discharge on Hyporheic Exchange." Water 11, no. 7 (July 12, 2019): 1436. http://dx.doi.org/10.3390/w11071436.
Повний текст джерелаАнотація:
Streambed morphology, streamflow dynamics, and the heterogeneity of streambed sediments critically controls the interaction between surface water and groundwater. The present study investigated the impact of different flow regimes on hyporheic exchange in a boreal stream in northern Sweden using experimental and numerical approaches. Low-, base-, and high-flow discharges were simulated by regulating the streamflow upstream in the study area, and temperature was used as the natural tracer to monitor the impact of the different flow discharges on hyporheic exchange fluxes in stretches of stream featuring gaining and losing conditions. A numerical model was developed using geomorphological and hydrological properties of the stream and was then used to perform a detailed analysis of the subsurface water flow. Additionally, the impact of heterogeneity in sediment permeability on hyporheic exchange fluxes was investigated. Both the experimental and modelling results show that temporally increasing flow resulted in a larger (deeper) extent of the hyporheic zone as well as longer hyporheic flow residence times. However, the result of the numerical analysis is strongly controlled by heterogeneity in sediment permeability. In particular, for homogeneous sediments, the fragmentation of upwelling length substantially varies with streamflow dynamics due to the contribution of deeper fluxes.
7
Shu, Qiang, Shunjie Zhang, and Ye Chen. "Physicochemical Property Indexes of Sediment Lixiviums in Sea–Land Interaction Zone of Subei Basin and Their Significance to Transgression." Journal of Marine Science and Engineering 9, no. 7 (June 29, 2021): 719. http://dx.doi.org/10.3390/jmse9070719.
Повний текст джерелаАнотація:
In current studies, the physicochemical properties of water, such as total dissolved solids, salinity, and electrical conductivity, are used mainly to investigate changes in the properties of surface water and groundwater. In our experimental study, we aimed to introduce the physicochemical properties of water bodies into the field of paleoenvironmental changes. We employed the physicochemical property indexes of sediment lixiviums in two research sections of the sea–land interaction zone in the eastern margin of the Subei Basin (China). Preliminary tests determined that the optimal solvent for preparing the sediment lixiviums is ultrapure water; the use of this water can prevent errors caused by soluble solids in the solvent. Using a container with a lid to prepare the sediment lixiviums could reduce errors caused by evaporation. Furthermore, we determined the appropriate process and duration for testing the physicochemical properties of sediment lixiviums. The optimal time for testing the physicochemical properties was 120 h (mixture fully stirred daily) or 168 h (no stirring). The weight of the sediment, volume of the solvent, and test time should be consistent in the same research section. Comparing the physicochemical property indexes of sediment lixiviums with geochemical elements and diatom indicators, we found that these indexes show obvious indications of transgression, and have an obvious advantage in indicating transgression.
8
Åberg, Susanne Charlotta, Annika Katarina Åberg, and Kirsti Korkka-Niemi. "Three-dimensional hydrostratigraphy and groundwater flow models in complex Quaternary deposits and weathered/fractured bedrock: evaluating increasing model complexity." Hydrogeology Journal 29, no. 3 (February 17, 2021): 1043–74. http://dx.doi.org/10.1007/s10040-020-02299-4.
Повний текст джерелаАнотація:
AbstractGreater complexity in three-dimensional (3D) model structures yields more plausible groundwater recharge/discharge patterns, especially in groundwater/surface-water interactions. The construction of a 3D hydrostratigraphic model prior to flow modelling is beneficial when the hydraulic conductivity of geological units varies considerably. A workflow for 3D hydrostratigraphic modelling with Leapfrog Geo and flow modelling with MODFLOW-NWT was developed. It was used to evaluate how the modelling results for groundwater flow and recharge/discharge patterns differ when using simple or more complex hydrostratigraphic models. The workflow was applied to a study site consisting of complex Quaternary sediments underlain by fractured and weathered crystalline bedrock. Increasing the hydrostratigraphic detail appeared to improve the fit between the observed and simulated water table, and created more plausible groundwater flow patterns. Interlayered zones of low and high conductivity disperse the recharge/discharge patterns, increasing the vertical flow component. Groundwater flow was predominantly horizontal in models in which Quaternary sediments and bedrock were simplified as one layer per unit. It appears to be important to define the interlayered low-conductivity units, which can limit groundwater infiltration and also affect groundwater discharge patterns. Explicit modelling with Leapfrog Geo was found to be effective but time-consuming in the generation of scattered and thin-layered strata.
9
N., Bustamante-Penagos, and Niño Y. "Flow–Sediment Turbulent Ejections: Interaction between Surface and Subsurface Flow in Gravel-Bed Contaminated by Fine Sediment." Water 12, no. 6 (June 3, 2020): 1589. http://dx.doi.org/10.3390/w12061589.
Повний текст джерелаАнотація:
Several researchers have studied turbulent structures, such as ejections, sweeps, and outwards and inwards interactions in flumes, where the streamwise velocity dominates over vertical and transversal velocities. However, this research presents an experimental study in which there are ejections associated with the interchange between surface and subsurface water, where the vertical velocity dominates over the streamwise component. The experiment is related to a surface alluvial stream that is polluted with fine sediment, which is percolated into the bed. The subsurface flow is modified by a lower permeability associated with the fine sediment and emerges to the surface current. Quasi-steady ejections are produced that drag fine sediment into the surface flow. Particle image velocimetry (PIV) measured the velocity field before and after the ejection. The velocity data were analyzed by scatter plots, power spectra, and wavelet analysis of turbulent fluctuations, finding changes in the distribution of turbulence interactions with and without the presence of fine deposits. The flow sediment ejection changes the patterns of turbulent structures and the distribution of the turbulence interactions that have been reported in open channels without subsurface flows.
10
Gong, Fan, Li, Li, Zhang, Gromig, Smith, et al. "Coring of Antarctic Subglacial Sediments." Journal of Marine Science and Engineering 7, no. 6 (June 22, 2019): 194. http://dx.doi.org/10.3390/jmse7060194.
Повний текст джерелаАнотація:
Coring sediments in subglacial aquatic environments offers unique opportunities for research on paleo-environments and paleo-climates because it can provide data from periods even earlier than ice cores, as well as the overlying ice histories, interactions between ice and the water system, life forms in extreme habitats, sedimentology, and stratigraphy. However, retrieving sediment cores from a subglacial environment faces more difficulties than sediment coring in oceans and lakes, resulting in low yields from the most current subglacial sediment coring methods. The coring tools should pass through a hot water-drilled access borehole, then the water column, to reach the sediment layers. The access boreholes are size-limited by the hot water drilling tools and techniques. These holes are drilled through ice up to 3000–4000 m thick, with diameters ranging from 10–60 cm, and with a refreezing closure rate of up to 6 mm/h after being drilled. Several purpose-built streamline corers have been developed to pass through access boreholes and collect the sediment core. The main coring objectives are as follows: (i) To obtain undisturbed water–sediment cores, either singly or as multi-cores and (ii) to obtain long cores with minimal stratigraphic deformation. Subglacial sediment coring methods use similar tools to those used in lake and ocean coring. These methods include the following: Gravity coring, push coring, piston coring, hammer or percussion coring, vibrocoring, and composite methods. Several core length records have been attained by different coring methods, including a 290 cm percussion core from the sub-ice-shelf seafloor, a 400 cm piston core from the sub-ice-stream, and a 170 cm gravity core from a subglacial lake. There are also several undisturbed water–sediment cores that have been obtained by gravity corers or hammer corers. Most current coring tools are deployed by winch and cable facilities on the ice surface. There are three main limitations for obtaining long sediment cores which determines coring tool development, as follows: Hot-water borehole radial size restriction, the sedimentary structure, and the coring techniques. In this paper, we provide a general view on current developments in coring tools, including the working principles, corer characteristics, operational methods, coring site locations, field conditions, coring results, and possible technical improvements. Future prospects in corer design and development are also discussed.
11
Kasahara, Tamao, and Alan R. Hill. "Effects of rifflestep restoration on hyporheic zone chemistry in N-rich lowland streams." Canadian Journal of Fisheries and Aquatic Sciences 63, no. 1 (January 1, 2006): 120–33. http://dx.doi.org/10.1139/f05-199.
Повний текст джерелаАнотація:
Stream restoration projects that aim to rehabilitate ecosystem health have not considered surfacesubsurface 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 rifflestep construction projects may only be temporary in streams that receive increased sediment and nutrient inputs from urban areas and croplands.
12
Bialik, Robert J. "Numerical Study of Near-Bed Turbulence Structures Influence on the Initiation of Saltating Grains Movement." Journal of Hydrology and Hydromechanics 61, no. 3 (September 1, 2013): 202–7. http://dx.doi.org/10.2478/johh-2013-0026.
Повний текст джерелаАнотація:
Abstract The focus of this paper is on the analysis of the influence of near-bed turbulence structures with the inclusion of existing coherent structures on the entrainment of saltating particles in a water stream from the Lagrangian perspective. The interactions between turbulence structures and initiation of particles movement is the key for better understanding of the physics of sediment transport and particles behaviour. These aims are addressed by use of a 3D relevant model of spherical saltating particles, in which a special procedure has been designed to produce coherent structures. In this method, the spectra of turbulent kinetic energy, consisting of four ranges, are used to generate the time series of turbulent velocities in the streamwise, vertical and transversal directions. Numerical results suggest that the initiation of sediment movement is strongly correlated to positive streamwise velocity fluctuations and as such, supports earlier laboratory experimental and field observations, showing that the sweeps and outward interactions play a crucial role in the initiation of saltating particles’ movement.
13
V. I. Donenko, O. M. Nazarenko, I. A. Nazarenko, M. P. Marchenko, and V. P. Sulima. "Technical advantages of the city sedimentation water reconstruction system." Ways to Improve Construction Efficiency, no. 45 (October 16, 2020): 26–36. http://dx.doi.org/10.32347/2707-501x.2020.45.26-36.
Повний текст джерелаАнотація:
The work designs a system of production components of urban infrastructure to create an energy efficient city. Hydraulic, hydrological, heat exchange processes of interaction of water structure and elements of treatment structures for centrifugal deposition of suspended matter have been investigated. Depending on the degree of contamination, devices for resource recovery are calculated. The duration of recovery operations was investigated. The technological cycle of re-water recovery and the number of cycles of cavitation generator for controlled conditioning of conditionally clean and dirty waters have been determined. Reverse osmosis devices for the recovery of conditionally pure water have been investigated. Categorized potential effluents of industrial waters as appropriate for restoration. Samples of experimental sediments for the needs of the construction industry at operating and supercritical modes of operation of the technological stream were obtained. A mathematical model of the productivity of irrigation of agro-centers in drought conditions with drip irrigation by repeated water has been developed.
14
Peralta-Maraver, Ignacio, Anne L. Robertson, and Daniel M. Perkins. "Depth and vertical hydrodynamics constrain the size structure of a lowland streambed community." Biology Letters 15, no. 7 (July 2019): 20190317. http://dx.doi.org/10.1098/rsbl.2019.0317.
Повний текст джерелаАнотація:
Abundance–body mass (N–M) relationships are prominent macroecological patterns and provide an integrated measurement of the structure and energy flow through natural communities. However, little is known about how N–M relationships are constrained by local environmental conditions. Here, we quantify how sediment depth and direction of surface–groundwater exchange (vertical hydrodynamics), two major drivers of the streambed ecology, determine N–M scaling in a sandy lowland European stream. Streambed assemblages included flagellates, ciliates, meiofauna and macroinvertebrates, and spanned five orders of magnitude in body mass. We detected a significant interaction of body mass with depth and vertical hydrodynamics with a sharp reduction in N–M slopes in the hyporheic zone and under upwelling conditions. These results revealed that streambed assemblages become more size-structured as environmental constraints increase with direct implications for the metabolic capacity and functioning of the system.
15
de la Garza Varela, Alonso, M. Leopoldina Aguirre-Macedo, and José Q. García-Maldonado. "Changes in the Rhizosphere Prokaryotic Community Structure of Halodule wrightii Monospecific Stands Associated to Submarine Groundwater Discharges in a Karstic Costal Area." Microorganisms 11, no. 2 (February 16, 2023): 494. http://dx.doi.org/10.3390/microorganisms11020494.
Повний текст джерелаАнотація:
Belowground seagrass associated microbial communities regulate biogeochemical dynamics in the surrounding sediments and influence seagrass physiology and health. However, little is known about the impact of environmental stressors upon interactions between seagrasses and their prokaryotic community in coastal ecosystems. Submerged groundwater discharges (SGD) at Dzilam de Bravo, Yucatán, Mexico, causes lower temperatures and salinities with higher nutrient loads in seawater, resulting in Halodule wrightii monospecific stands. In this study, the rhizospheric archaeal and bacterial communities were characterized by 16S rRNA Illumina sequencing along with physicochemical determinations of water, porewater and sediment in a 400 m northwise transect from SGD occurring at 300 m away from coastline. Core bacterial community included Deltaproteobacteria, Bacteroidia and Planctomycetia, possibly involved in sulfur metabolism and organic matter degradation while highly versatile Bathyarchaeia was the most abundantly represented class within the archaeal core community. Beta diversity analyses revealed two significantly different clusters as result of the environmental conditions caused by SGD. Sites near to SGD presented sediments with higher redox potentials and sand contents as well as lower organic matter contents and porewater ammonium concentrations compared with the furthest sites. Functional profiling suggested that denitrification, aerobic chemoheterotrophy and environmental adaptation processes could be better represented in these sites, while sulfur metabolism and genetic information processing related profiles could be related to SGD uninfluenced sites. This study showed that the rhizospheric prokaryotic community structure of H. wrightii and their predicted functions are shaped by environmental stressors associated with the SGD. Moreover, insights into the archaeal community composition in seagrasses rhizosphere are presented.
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Veras, Tatiane Barbosa, Jaime Joaquim da Silva Pereira Cabral, Anderson Luiz Ribeiro de Paiva, Roberto Lima Barcellos, and Laércio Leal dos Santos. "Vertical hydraulic gradient research in hyporheic zone of Beberibe river in Pernambuco State (Brazil)." RBRH 21, no. 4 (October 13, 2016): 674–84. http://dx.doi.org/10.1590/2318-0331.011615153.
Повний текст джерелаАнотація:
ABSTRACT The interaction between groundwater and surface water occurs naturally and is dependent on the dynamics in the hyporheic zone. The hyporheic zone is the interface between the surface water source and the phreatic aquifer and it’s a system that also influences the water quality. An important feature is the ability to flux in this zone. This work aimed to evaluate the vertical hydraulic gradient in the hyporheic zone at two points in Beberibe river, Olinda-PE, to understand the hyporheic environment characteristics and water flow dynamics in experimental area, in addition to identify the existence of hydraulic connection between surface water and groundwater. The experimental phase consisted of infiltration tests in riverbed with cylinder infiltrometer and vertical hydraulic gradients readings with differential piezometer, complemented with grain size information, for an assessment of the water budget between the river and the aquifer. Analyzing the behavior of the interaction over the period of 10 months, it was observed that the Beberibe river (middle course) contributes to the groundwater recharge in most of the time. The average infiltration rate was 1.02 mm/min in point 1 and 0.85 mm/min in point 2. It was concluded that there is a variability in flow direction, which often is top-down, but may undergo change in the stream showing upstream after long periods of rainfall. Another conclusion is that grain size distribution of bed sediment, that is predominantly sandy, influences hydraulic conductivity of hyporheic zone and influences consequently the vertical flow rates.
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Fischione, Piera, Davide Pasquali, Daniele Celli, Carmine Di Nucci, and Marcello Di Risio. "Beach Drainage System: A Comprehensive Review of a Controversial Soft-Engineering Method." Journal of Marine Science and Engineering 10, no. 2 (January 22, 2022): 145. http://dx.doi.org/10.3390/jmse10020145.
Повний текст джерелаАнотація:
The beach drainage can be included among the soft engineering methods aimed to counteract the shoreline retreat related to the sediment redistribution along the beach profile. The idea that the groundwater table plays a role in the mobilization of the sediment grains underlies the application of the beach drainage system (BDS) as a tool able to modify the natural dynamics of groundwater table at sandy beaches. Indeed, BDS consists of a series of alongshore buried drains aimed to lower the groundwater table. Due to the drainage, the thickening of the layer of dry sand makes the solid grains less prone to be mobilized by the action of the waves at the swash zone, where interaction phenomena between the percolating and the incoming water lens take place. This tool had a troubled history. Its first applications were encouraging. Since then, controversial performances of both experimental and prototype scale experiences have been observed around the world. This paper aims to present an up-to-date full review of the studies and experiments carried out so far, in order to provide the reader with a complete perspective on its strength and weakness as well as open challenges to be faced in the near future.
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Attanayake, M. P., and D. H. Waller. "Use of seepage meters in a groundwater – lake interaction study in a fractured rock basin — a case study." Canadian Journal of Civil Engineering 15, no. 6 (December 1, 1988): 984–89. http://dx.doi.org/10.1139/l88-130.
Повний текст джерелаАнотація:
Applications of seepage meters in lakes with slight bottom sediments in fractured rock basins have not been reported. A study of the hydrogeology of Long Lake, at Halifax, Nova Scotia, used seepage meters in this situation. Fifteen meters were installed in the 1.7 km2 lake — seven in a line extending from the shore, the remaining eight on the lake periphery. Seepage measurements were made monthly over 1 year. Groundwater levels were measured in boreholes in the fractured granite of the watershed. A positive inflow of groundwater to the lake occurred through the year, seepage flux at the shoreline meters varied from 0.15 to 0.78 mL∙m−2∙s−1, with no consistent seasonal variations. Seepage decreased exponentially with offshore distance. A linear relationship was evident between water levels in a borehole near the shore and rate of seepage at the closest meter. Chloride applied to this borehole was reflected in elevated chloride concentrations in seepage collected by the meter. Key words: seepage meter, groundwater – lake system, fractured rock tracers.
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Harvey, Mark C., Danielle K. Hare, Alex Hackman, Glorianna Davenport, Adam B. Haynes, Ashley Helton, John W. Lane, and Martin A. Briggs. "Evaluation of Stream and Wetland Restoration Using UAS-Based Thermal Infrared Mapping." Water 11, no. 8 (July 29, 2019): 1568. http://dx.doi.org/10.3390/w11081568.
Повний текст джерелаАнотація:
Large-scale wetland restoration often focuses on repairing the hydrologic connections degraded by anthropogenic modifications. Of these hydrologic connections, groundwater discharge is an important target, as these surface water ecosystem control points are important for thermal stability, among other ecosystem services. However, evaluating the effectiveness of the restoration activities on establishing groundwater discharge connection is often difficult over large areas and inaccessible terrain. Unoccupied aircraft systems (UAS) are now routinely used for collecting aerial imagery and creating digital surface models (DSM). Lightweight thermal infrared (TIR) sensors provide another payload option for generation of sub-meter-resolution aerial TIR orthophotos. This technology allows for the rapid and safe survey of groundwater discharge areas. Aerial TIR water-surface data were collected in March 2019 at Tidmarsh Farms, a former commercial cranberry peatland located in coastal Massachusetts, USA (41°54′17″ N 70°34′17″ W), where stream and wetland restoration actions were completed in 2016. Here, we present a 0.4 km2 georeferenced, temperature-calibrated TIR orthophoto of the area. The image represents a mosaic of nearly 900 TIR images captured by UAS in a single morning with a total flight time of 36 min and is supported by a DSM derived from UAS-visible imagery. The survey was conducted in winter to maximize temperature contrast between relatively warm groundwater and colder ambient surface environment; lower-density groundwater rises above cool surface waters and thus can be imaged by a UAS. The resulting TIR orthomosaic shows fine detail of seepage distribution and downstream influence along the several restored channel forms, which was an objective of the ecological restoration design. The restored stream channel has increased connectivity to peatland groundwater discharge, reducing the ecosystem thermal stressors. Such aerial techniques can be used to guide ecological restoration design and assess post-restoration outcomes, especially in settings where ecosystem structure and function is governed by groundwater and surface water interaction.
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KEY, KERRY, and MATTHEW R. SIEGFRIED. "The feasibility of imaging subglacial hydrology beneath ice streams with ground-based electromagnetics." Journal of Glaciology 63, no. 241 (July 27, 2017): 755–71. http://dx.doi.org/10.1017/jog.2017.36.
Повний текст джерелаАнотація:
ABSTRACTSubglacial hydrologic systems in Antarctica and Greenland play a fundamental role in ice-sheet dynamics, yet critical aspects of these systems remain poorly understood due to a lack of observations. Ground-based electromagnetic (EM) geophysical methods are established for mapping groundwater in many environments, but have never been applied to imaging lakes beneath ice sheets. Here, we study the feasibility of passive- and active-source EM imaging for quantifying the nature of subglacial water systems beneath ice streams, with an emphasis on the interfaces between ice and basal meltwater, as well as deeper groundwater in the underlying sediments. We describe a suite of model studies that exam the data sensitivity as a function of ice thickness, water conductivity and hydrologic system geometry for models representative of a subglacial lake and a grounding zone estuary. We show that EM data are directly sensitive to groundwater and can image its lateral and depth extent. By combining the conductivity obtained from EM data with ice thickness and geological structure from conventional geophysical techniques, such as ground-penetrating radar and active seismic surveying, EM data have the potential to provide new insights on the interaction between ice, rock and water at critical ice-sheet boundaries.
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Jorgenson, M. Torre, Vladimir Romanovsky, Jennifer Harden, Yuri Shur, Jonathan O’Donnell, Edward A. G. Schuur, Mikhail Kanevskiy, and Sergei Marchenko. "Resilience and vulnerability of permafrost to climate changeThis article is one of a selection of papers from The Dynamics of Change in Alaska’s Boreal Forests: Resilience and Vulnerability in Response to Climate Warming." Canadian Journal of Forest Research 40, no. 7 (July 2010): 1219–36. http://dx.doi.org/10.1139/x10-060.
Повний текст джерелаАнотація:
The resilience and vulnerability of permafrost to climate change depends on complex interactions among topography, water, soil, vegetation, and snow, which allow permafrost to persist at mean annual air temperatures (MAATs) as high as +2 °C and degrade at MAATs as low as –20 °C. To assess these interactions, we compiled existing data and tested effects of varying conditions on mean annual surface temperatures (MASTs) and 2 m deep temperatures (MADTs) through modeling. Surface water had the largest effect, with water sediment temperatures being ~10 °C above MAAT. A 50% reduction in snow depth reduces MADT by 2 °C. Elevation changes between 200 and 800 m increases MAAT by up to 2.3 °C and snow depths by ~40%. Aspect caused only a ~1 °C difference in MAST. Covarying vegetation structure, organic matter thickness, soil moisture, and snow depth of terrestrial ecosystems, ranging from barren silt to white spruce ( Picea glauca (Moench) Voss) forest to tussock shrub, affect MASTs by ~6 °C and MADTs by ~7 °C. Groundwater at 2–7 °C greatly affects lateral and internal permafrost thawing. Analyses show that vegetation succession provides strong negative feedbacks that make permafrost resilient to even large increases in air temperatures. Surface water, which is affected by topography and ground ice, provides even stronger negative feedbacks that make permafrost vulnerable to thawing even under cold temperatures.
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Stamatis, G. "GROUNDWATER QUALITY OF THE AG. PARASKEVI/TEMPI VALLEY KARSTIC SPRINGS - APPLICATION OF A TRACING TEST FOR RESEARCH OF THE MICROBIAL POLLUTIO (KATO OLYMPOS/NE THESSALY)." Bulletin of the Geological Society of Greece 43, no. 4 (January 25, 2017): 1868. http://dx.doi.org/10.12681/bgsg.11378.
Повний текст джерелаАнотація:
The study of the Kato Olympos karst system, based on the implementation of tracer tests and hydrochemical analyses, is aimed at the investigation of surface-groundwater interaction, the delineation of the catchment area and the detection of the surface microbial source contamination of the Tempi karst springs. The study area is formed by intensively karstified carbonate rocks, metamorphic formations, Neogene sediments and Quaternary deposits. The significant karst aquifer discharges through karst springs in Tempi valley and in Pinios riverbed. The karst springs present important seasonal fluctuations in discharge rate, moderate mineralization with TDS between 562 to 630 mg/l and they belong to Ca-HCO3 water type. The inorganic pollution indicators, such as Na+, K+, Cl- , NO3 - , NH4 +, PO4 3 , show low concentrations and do not reveal any surface influences. On the other hand, the presence of microbial parameters in karst springs proclaims the high rate of microbial contamination of karst aquifer. Tracer tests reveal hydraulic connection between the surface waters of Xirorema – Rapsani basin and the karst aquifer. The high values of groundwater flow velocity upwards of 200 m/h, show the good karstification rate of the carbonate formations and the cavy structure dominated in the study area, as well as the low self purification capability of the karst aquifer.
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Hauer, F. Richard, Harvey Locke, Victoria J. Dreitz, Mark Hebblewhite, Winsor H. Lowe, Clint C. Muhlfeld, Cara R. Nelson, Michael F. Proctor, and Stewart B. Rood. "Gravel-bed river floodplains are the ecological nexus of glaciated mountain landscapes." Science Advances 2, no. 6 (June 2016): e1600026. http://dx.doi.org/10.1126/sciadv.1600026.
Повний текст джерелаАнотація:
Gravel-bed river floodplains in mountain landscapes disproportionately concentrate diverse habitats, nutrient cycling, productivity of biota, and species interactions. Although stream ecologists know that river channel and floodplain habitats used by aquatic organisms are maintained by hydrologic regimes that mobilize gravel-bed sediments, terrestrial ecologists have largely been unaware of the importance of floodplain structures and processes to the life requirements of a wide variety of species. We provide insight into gravel-bed rivers as the ecological nexus of glaciated mountain landscapes. We show why gravel-bed river floodplains are the primary arena where interactions take place among aquatic, avian, and terrestrial species from microbes to grizzly bears and provide essential connectivity as corridors for movement for both aquatic and terrestrial species. Paradoxically, gravel-bed river floodplains are also disproportionately unprotected where human developments are concentrated. Structural modifications to floodplains such as roads, railways, and housing and hydrologic-altering hydroelectric or water storage dams have severe impacts to floodplain habitat diversity and productivity, restrict local and regional connectivity, and reduce the resilience of both aquatic and terrestrial species, including adaptation to climate change. To be effective, conservation efforts in glaciated mountain landscapes intended to benefit the widest variety of organisms need a paradigm shift that has gravel-bed rivers and their floodplains as the central focus and that prioritizes the maintenance or restoration of the intact structure and processes of these critically important systems throughout their length and breadth.
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Taft, Linda, and Mariele Evers. "A review of current and possible future human–water dynamics in Myanmar's river basins." Hydrology and Earth System Sciences 20, no. 12 (December 15, 2016): 4913–28. http://dx.doi.org/10.5194/hess-20-4913-2016.
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Abstract. Rivers provide a large number of ecosystem services and riparian people depend directly and indirectly on water availability and quality and quantity of the river waters. The country's economy and the people's well-being and income, particularly in agriculturally dominated countries, are strongly determined by the availability of sufficient water. This is particularly true for the country of Myanmar in South-east Asia, where more than 65 % of the population live in rural areas, working in the agricultural sector. Only a few studies exist on river basins in Myanmar at all and detailed knowledge providing the basis for human–water research is very limited. A deeper understanding of human–water system dynamics in the country is required because Myanmar's society, economy, ecosystems and water resources are facing major challenges due to political and economic reforms and massive and rapid investments from neighbouring countries. However, not only policy and economy modify the need for water. Climate variability and change are other essential drivers within human–water systems. Myanmar's climate is influenced by the Indian Monsoon circulation which is subject to interannual and also regional variability. Particularly the central dry zone and the Ayeyarwady delta are prone to extreme events such as serious drought periods and extreme floods. On the one hand, the farmers depend on the natural fertiliser brought by regular river inundations and high groundwater levels for irrigation; on the other hand, they suffer from these water-related extreme events. It is expected that theses climatic extreme events will likely increase in frequency and magnitude in the future as a result of global climate change. Different national and international interests in the abundant water resources may provide opportunities and risks at the same time for Myanmar. Several dam projects along the main courses of the rivers are currently in the planning phase. Dams will most likely modify the river flows, the sediment loads and also the still rich biodiversity in the river basins, to an unknown extent. Probably, these natural and anthropogenically induced developments will also impact a special type of farming; we call it alluvial farming in the river floodplains and on sandbars in the Ayeyarwady River basin in Myanmar, which is called Kaing and Kyun, respectively. Relevant aspects for future development of Myanmar's river basins combine environment-water-related factors, climate, economic and social development, water management and land use changes. Research on these interplays needs to capture the spatial and temporal dynamics of these drivers. However, it is only possible to gain a full understanding of all these complex interrelationships if multi-scale spatiotemporal information is analysed in an inter- and trans-disciplinary approach. This paper gives a structured overview of the current scientific knowledge available and reveals the relevance of this information with regard to human–environment and particularly to human–water interactions in Myanmar's river basins. By applying the eDPSIR framework, it identifies key indicators in the Myanmar human–water system, which has been shown to be exemplary by giving an example of use related to alluvial farming in the central dry zone.
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Жолобов, Владимир Васильевич, Валерий Юрьевич Морецкий, and Рустям Фаатович Талипов. "Distribution of volume of water accumulations in profile oil pipeline." SCIENCE & TECHNOLOGIES OIL AND OIL PRODUCTS PIPELINE TRANSPORTATION, no. 5 (October 31, 2022): 438–51. http://dx.doi.org/10.28999/2541-9595-2022-12-5-438-451.
Повний текст джерелаАнотація:
Введение. Имеющиеся математические модели поведения воды в эксплуатируемых нефтепроводах не учитывают возможность одновременного существования неподвижной и подвижной форм водных образований. Это ограничивает область применимости таких расчетных моделей и делает актуальной разработку обобщенных гидравлических моделей. Методы. Применение положений многоскоростного континуума позволяет сформулировать общую математическую модель многофазной среды, которая при адаптации допускает высокую степень детализации гидравлического описания накопления и миграции воды. При этом будут сформулированы незамкнутые уравнения (балансовые законы сохранения), которые применимы к описанию формирования условно неподвижного водного скопления и миграции коалесцированной воды как в непрерывной (ручейковой), так и в дисперсно-капельной форме на технологическом участке магистрального нефтепровода. Постановка задачи сводится к конкретизации межфазного взаимодействия на основе пограничного слоя и аналогии с движением влекомых наносов в теории русловых течений. Результаты. На основе соотношений пограничного слоя на поверхности контакта фаз и аналогового предположения о профиле продольной скорости получены расчетные зависимости для скорости среды на границе контакта, а также формулы для расчета силового взаимодействия и дисперсно-капельного массообмена. В отличие от имеющихся в научно-технической литературе вариантов замыкания здесь применен профиль скорости в циркуляционном течении воды. Обсуждение. Полученные зависимости в общем случае содержат дополнительные параметры, подлежащие идентификации и ранжированию по степени влияния на основные гидродинамические характеристики стратифицированных течений с поправкой на разницу в диаметрах срываемых и оседающих капель. Для этого требуются данные специально поставленных стендовых и численных экспериментов. Выводы. Представленная модель поведения воды в профильном трубопроводе сформулирована с учетом возможного волнового срыва капель с поверхности неподвижного водного скопления, полного дисперсно-капельного выноса или переноса капель на последующие участки. При практических расчетах, помимо обычной процедуры предварительной идентификации параметров однофазных моделей, дополнительно необходима идентификация параметров пограничного слоя на границе контакта фаз. Ключевые слова: стратифицированное течение, ручейковое течение, водные скопления в трубопроводах, двухфазное течение, математическая модель течения, дисперсная фаза, гидравлическая модель Introduction. The available mathematical models of water behavior in operated oil pipelines do not take into account the possibility of simultaneous existence of fixed and mobile forms of water formations. This limits the applicability of such design models and makes the development of generalized hydraulic models relevant. Methods. In the mechanics of multiphase media, on the basis of a multi-speed continuum, a mathematical apparatus is built, which, when adapted, allows any degree of detail in the hydraulic description of the process of accumulation and migration of water. At the same time, unclosed equations (balance conservation laws) are formulated, which are also applicable to the description of the formation of a conditionally stationary water accumulation and migration of coalesced water both in continuous (stream) and dispersed-droplet form in the technological section of the main oil pipeline. The formulation of the problem is reduced to the concretization of interphase interaction on the basis of the boundary layer and analogy with the movement of attracted sediments in the theory of channel currents. Results. Based on the ratios of the boundary layer on the phase contact surface and the assumption of the longitudinal velocity profile, calculated dependencies for the velocity of the medium at the contact boundary, as well as formulas for calculating the force interaction and disperse-droplet mass transfer, are obtained. In contrast to the options available in the literature, the velocity profile in the circulation flow of water is applied here. Discussion. The obtained dependencies in the general case contain additional parameters to be identified and ranked according to the degree of influence on the main hydrodynamic characteristics of the stratified currents, adjusted for the difference in the diameters of the torn and settling droplets. This requires data from specially staged bench and numerical experiments. Conclusion. The presented model of water behavior in the profile pipeline is formulated taking into account the possible wave breakage of droplets from the surface of a stationary water accumulation, complete dispersion-droplet removal or transfer of droplets to subsequent areas. In practical calculations, in addition to the usual procedure for preliminary identification of the parameters of single-phase models, it is additionally necessary to identify the parameters of the boundary layer at the phase contact boundary.
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Singer, David M., Anne J. Jefferson, Eric L. Traub, and Nicolas Perdrial. "Mineralogical and geochemical variation in stream sediments impacted by acid mine drainage is related to hydro-geomorphic setting." Elementa: Science of the Anthropocene 6 (January 1, 2018). http://dx.doi.org/10.1525/elementa.286.
Повний текст джерелаАнотація:
Acid mine drainage (AMD) discharge has severe, long lasting impacts on water quality and stream ecology in affected watersheds due in part to the dynamic relationship between toxic metals (e.g. Al, Mn, and Cu) and Fe(III) oxy-hydroxides. Localized areas of biogeochemical activity that can mediate mineralogical transformation changes and cause metal release are potentially linked to stream geomorphology. This relationship has not been previously considered with respect to potential longitudinal variation within an impacted stream. The current work aims to determine how Fe(III) (oxy)-hydroxide speciation and distribution, and pore water chemistry in an AMD-impacted streambed, are affected by the presence of two geomorphic structures (a debris dam and step-pool sequence) in an Ohio watershed impacted by historical coal mining. In terms of solid phase mineralogy and geochemistry, in both the tributary and main stem, goethite was the dominant Fe-bearing phase throughout the AMD deposit depth in cores taken upstream of the geomorphic structures, whereas poorly-crystalline phases dominated downstream of the structures, despite the presence of Fe in the reducible fraction. The concentrations and distribution of extractable Al, Mn, and Cu were also different upstream versus downstream of each structure. Pore water Fe and Mn concentrations were higher downstream of the structures than upstream. Strong downward hydraulic gradients were present above the debris dam and in step-pool 1, whereas weaker upward hydraulic gradients were present below the debris dam and in step-pool 2. This work highlights that AMD deposit speciation and distribution, and pore water chemistry, are not spatially uniform within stream reaches, potentially as a result of groundwater-stream exchange-facilitated interactions in the presence of AMD-derived materials.
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Vanikar, Jyoti Chetan, Rajeev Kumar Bansal, and Vineeta Basotia. "Mathematical Modelling of Surface-Groundwater Interactions under Varying Hydrological Conditions: Review of Past Works." Journal of Engineering Research and Reports, March 24, 2021, 89–97. http://dx.doi.org/10.9734/jerr/2021/v20i417298.
Повний текст джерелаАнотація:
Surface-groundwater interaction is a research area of significant importance for its central role in wastewater treatment, irrigation, drainage, flood control, erosion and sediment control. Mathematical models are often used for the estimation of surface-groundwater interactions under the variety of hydrological conditions. Due to cost effectiveness and ability to accommodate variations in aquifer parameters, mathematical models have gained immense importance in the past few decades. The objective of this review paper is to portray the contribution of the hydrologist towards the growing area of surface-ground water interaction from all over the world who proposed, analyzed, executed and validated the developed Mathematical models. To begin with, we briefly introduce the main mathematical equations that govern the flow of groundwater in unconfined and confined aquifer systems. The development of stream-aquifer models is presented in a chronological order to provide a clear understanding of the contributions of past works. The methodology used in the past work is adequately discussed without going into mathematical details. Furthermore, we also summarize recent developments concerning groundwater flow in presence of vertical streambed, partial penetration, stream-stage variations and multiple recharge/discharge basins.
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Protano, Giuseppe, Stefano Bianchi, Matteo De Santis, Luigi Antonello Di Lella, Francesco Nannoni, and Massimo Salleolini. "New geochemical data for defining origin and distribution of mercury in groundwater of a coastal area in southern Tuscany (Italy)." Environmental Science and Pollution Research, February 18, 2023. http://dx.doi.org/10.1007/s11356-023-25897-7.
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Abstract A geochemical study was conducted in a coastal plain in the Orbetello Lagoon area in southern Tuscany (Italy), acquiring new data on groundwater, lagoon water, and stream sediment for insights into the origin, distribution, and behaviour of mercury in a Hg-enriched carbonate aquifer. The main hydrochemical features of the groundwater are ruled by the mixing of Ca–SO4 and Ca–Cl continental fresh waters of the carbonate aquifer and Na–Cl saline waters of the Tyrrhenian Sea and Lagoon of Orbetello. Groundwater had highly variable Hg concentrations (< 0.1–11 μg/L) that were not correlated with the percentage of saline water, depth in the aquifer, or distance from the lagoon. This excluded the possibility that saline water could be the direct source of Hg in groundwater and responsible for release of the element through interaction with the carbonate lithologies of the aquifer. The origin of Hg in groundwater could be ascribed to the Quaternary continental sediments overlying the carbonate aquifer because i) high Hg concentrations were found in the continental sediments of the coastal plain and in the contiguous lagoon sediments; ii) waters from the upper part of aquifer had the highest Hg concentrations; iii) Hg levels in groundwater increased with increasing thickness of the continental deposits. The high Hg content in the continental and lagoon sediments is geogenic due to regional and local Hg anomalies and to sedimentary and pedogenetic processes. It can be assumed that i) water circulating in these sediments dissolves the solid Hg-bearing constituents and mobilises this element mainly as chloride complexes; ii) Hg-enriched water moves from the upper part of the carbonate aquifer due to the cone of depression generated by intense pumping of groundwater by fish farms in the study area.
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Canora, Carolina, Jaime Cuevas Rodríguez, José Jesús Martínez Díaz, and Antonio Garralón. "Analysis of a travertine system controlled by the transpressional activity of the Alhama de Murcia fault: The Carraclaca site, eastern Betic Cordillera, Spain." Frontiers in Earth Science 11 (February 9, 2023). http://dx.doi.org/10.3389/feart.2023.1060363.
Повний текст джерелаАнотація:
Continental carbonates, such as travertines and tufas, formed from CO2-rich groundwater degassing as it emerges at the Earth’s surface, are often associated with major crustal-scale faults. The Carraclaca site, in the Lorca-Totana section of the Alhama de Murcia Fault, Spain, presents a complex geomorphological landscape controlled by active tectonics. The geology here records the interaction between Quaternary alluvial fans, travertines, and a pop-up structure developed in a transpressional section of the fault. The Alhama de Murcia Fault is an 80 km long left-lateral strike-slip fault that is one of the main seismogenic structures in the Iberian Peninsula. In this work, we examined the relation between travertine precipitation in the Carraclaca site and the tectonic activity of this fault zone through morphological and geochemical studies. The δ13C and δ18O isotopic signals indicate that the carbonate deposits are hydrothermal. In addition, the 87Sr/86Sr ratios in the samples suggest subsurface fluid interaction with the Miocene sediments and the Alpujárride basement, located below the alluvial deposits. Tectonic activity in the Alhama de Murcia Fault might generate the opening of deep water circulation in the crust every time a seismic event occurs, giving rise to hydrothermally derived carbonates precipitation. Deep waters rise and reach the surface interacting with meteoric waters, resulting in travertine formation. Therefore, the Carraclaca carbonate deposits study can inform us about the seismogenic cycle of the fault in the Lorca-Totana section.
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Romero, Ferran, Vicenç Acuña, and Sergi Sabater. "Multiple Stressors Determine Community Structure and Estimated Function of River Biofilm Bacteria." Applied and Environmental Microbiology 86, no. 12 (April 3, 2020). http://dx.doi.org/10.1128/aem.00291-20.
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ABSTRACT Freshwater ecosystems are exposed to multiple stressors, but their individual and combined effects remain largely unexplored. Here, we investigated the response of stream biofilm bacterial communities to warming, hydrological stress, and pesticide exposure. We used 24 artificial streams on which epilithic (growing on coarse sediments) and epipsammic (growing on fine sediments) stream biofilms were maintained. Bacterial community composition and estimated function of biofilms exposed during 30 days to individual and combined stressors were assessed using 16S rRNA gene metabarcoding. Among the individual effects by stressors, hydrological stress (i.e., a simulated low-flow situation) was the most relevant, since it significantly altered 57% of the most abundant bacterial taxa (n = 28), followed by warming (21%) and pesticide exposure (11%). Regarding the combined effects, 16% of all stressor combinations resulted in significant interactions on bacterial community composition and estimated function. Antagonistic responses prevailed (57 to 89% of all significant interactions), followed by synergisms (11 to 43%), on specific bacterial taxa, indicating that multiple-stressor scenarios could lead to unexpected shifts in the community composition and associated functions of riverine bacterial communities. IMPORTANCE Freshwater ecosystems such as rivers are of crucial importance for human well-being. However, human activities result in many stressors (e.g., toxic chemicals, increased water temperatures, and hydrological alterations) cooccurring in rivers and streams worldwide. Among the many organisms inhabiting rivers and streams, bacteria are ecologically crucial; they are placed at the base of virtually all food webs and they recycle the organic matter needed for bigger organisms. Most of these bacteria are in close contact with river substratum, where they form the biofilms. There is an urgent need to evaluate the effects of these stressors on river biofilms, so we can anticipate future environmental problems. In this study, we experimentally exposed river biofilms to a pesticide mixture, an increase in water temperature and a simulated low-flow condition, in order to evaluate the individual and joint effects of these stressors on the bacterial community composition and estimated function.
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Griebler, Christian, Clemens Karwautz, Moritz Grabner, Ayac Jimenez Salvador, Felix Puff, Rajiv-Raphael Kumar, Mona Lauritz, et al. "Decipher groundwater food web interactions by means of stable isotope and gut microbiome analyses." ARPHA Conference Abstracts 5 (July 14, 2022). http://dx.doi.org/10.3897/aca.5.e89712.
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The traditional perception of groundwater food webs is that of short and poorly structured food chains extending to only few trophic levels. This is mainly attributed to the lack of light and the shortfall of substantial primary production as well as the shortage of dissolved organic carbon and nutrients. It is frequently argued that microbes form the basis of groundwater food webs. In reality, the obvious lack of comprehensive biofilms may point to detritus as the main common food source and an opportunistic and omnivorous feeding strategy with most groups and species. Also, the relative stability of groundwater environments may have led to low trait variability. However, recent research also contrasts the paradigm of poorly structured food chains against emerging convoluted mechanisms sustaining a great range of biotic diversity and functional complexity. In summary, understanding of the ecological and functional linkages among stygofaunal groups, and their interaction with the microbial community, is still in its infancy. Stygofauna sampled from three spots of a shallow alluvial aquifer in the vicinity of the Danube River in the city of Vienna, Austria, has been analyzed by means of bulk stable carbon and nitrogen isotope and gut microbiome analysis to disentangle food web interactions. Our preliminary data revealed the following pattern: plant material, terrestrial insects, and detritus show a narrow range in carbon (-32 to -25δ13C) and a wide range in nitrogen (-1.5 to 6.5 δ15N) isotope signatures. In terms of nitrogen isotope values, the next tropic level is represented by isopods and gastropods, followed by ostracods, oligochaetes and amphipods. The broader range of stygofauna in carbon isotope signatures indicate an additional food source; most probably microbes; gut microbiome analyses indicate differences with oligochaetes, gastropods, ostracodes, isopods and amphipodes, however, with a few individuals from the later three groups sharing a very similar gut microbiome; within the amphipods, there is obviously a difference in gut microbiome composition with species and sampling sites; carbon and nitrogen isotope signatures underline amphipod-species differences; microbiome diversity in all cases was less divers in the animal guts when compared to environmental water, sediment and detritus samples. plant material, terrestrial insects, and detritus show a narrow range in carbon (-32 to -25δ13C) and a wide range in nitrogen (-1.5 to 6.5 δ15N) isotope signatures. In terms of nitrogen isotope values, the next tropic level is represented by isopods and gastropods, followed by ostracods, oligochaetes and amphipods. The broader range of stygofauna in carbon isotope signatures indicate an additional food source; most probably microbes; gut microbiome analyses indicate differences with oligochaetes, gastropods, ostracodes, isopods and amphipodes, however, with a few individuals from the later three groups sharing a very similar gut microbiome; within the amphipods, there is obviously a difference in gut microbiome composition with species and sampling sites; carbon and nitrogen isotope signatures underline amphipod-species differences; microbiome diversity in all cases was less divers in the animal guts when compared to environmental water, sediment and detritus samples. Finally, we first collected evidence for anaerobic processes taking place in animal guts living in an oxic groundwater environment. In light of our data, putative groundwater food web interactions in the shallow alluvial aquifer are discussed.
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Akob, Denise M., Adam C. Mumford, Andrea Fraser, Cassandra R. Harris, William H. Orem, Matthew S. Varonka, and Isabelle M. Cozzarelli. "Oil and Gas Wastewater Components Alter Streambed Microbial Community Structure and Function." Frontiers in Microbiology 12 (November 29, 2021). http://dx.doi.org/10.3389/fmicb.2021.752947.
Повний текст джерелаАнотація:
The widespread application of directional drilling and hydraulic fracturing technologies expanded oil and gas (OG) development to previously inaccessible resources. A single OG well can generate millions of liters of wastewater, which is a mixture of brine produced from the fractured formations and injected hydraulic fracturing fluids (HFFs). With thousands of wells completed each year, safe management of OG wastewaters has become a major challenge to the industry and regulators. OG wastewaters are commonly disposed of by underground injection, and previous research showed that surface activities at an Underground Injection Control (UIC) facility in West Virginia affected stream biogeochemistry and sediment microbial communities immediately downstream from the facility. Because microbially driven processes can control the fate and transport of organic and inorganic components of OG wastewater, we designed a series of aerobic microcosm experiments to assess the influence of high total dissolved solids (TDS) and two common HFF additives—the biocide 2,2-dibromo-3-nitrilopropionamide (DBNPA) and ethylene glycol (an anti-scaling additive)—on microbial community structure and function. Microcosms were constructed with sediment collected upstream (background) or downstream (impacted) from the UIC facility in West Virginia. Exposure to elevated TDS resulted in a significant decrease in aerobic respiration, and microbial community analysis following incubation indicated that elevated TDS could be linked to the majority of change in community structure. Over the course of the incubation, the sediment layer in the microcosms became anoxic, and addition of DBNPA was observed to inhibit iron reduction. In general, disruptions to microbial community structure and function were more pronounced in upstream and background sediment microcosms than in impacted sediment microcosms. These results suggest that the microbial community in impacted sediments had adapted following exposure to OG wastewater releases from the site. Our findings demonstrate the potential for releases from an OG wastewater disposal facility to alter microbial communities and biogeochemical processes. We anticipate that these studies will aid in the development of useful models for the potential impact of UIC disposal facilities on adjoining surface water and shallow groundwater.
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Simioni, João Paulo Delapasse, Laurindo Antonio Guasselli, and Cecilia Balsamo Etchelar. "Connectivity among Wetlands of EPA of Banhado Grande, RS." RBRH 22 (2017). http://dx.doi.org/10.1590/2318-0331.011716096.
Повний текст джерелаАнотація:
ABSTRACT The Environmental Protection Area (EPA) of Banhado Grande, located in the Metropolitan Region of Porto Alegre, comprises three areas of marshes, the Banhado Chico Lomã, the Banhado Grande and Banhado dos Pachecos. In periods of large flood pulses extensive flooded areas are formed between these wetlands and the river Gravataí floodplain, establishing a connectivity between the Wetlands of EPABG. This connectivity indicates that there is an interaction between these wetlands, such as exchange of nutrients, sediments and living organisms. Thus, this study aims to map extensive floodable areas associated with large flood pulses and to analyze the connectivity areas in EPABG. For this, the work is structured in three steps: i) choice of satellite images between the years 2000 to 2015 to identify largest flood pulses; ii) mapping of floodable areas in large flood pulses using images Normalized Difference Index Water (NDWI); and iii) analysis of the connectivity among wetlands. As the results, in large flood pulses, with precipitation greater than 247 mm, in the 30 days prior to the date of the image, establishing a large area of connectivity between the wetlands, forming on the polygon defined by elevation of 11 metres, two types of connectivity: wetlands-wetlands connectivity, allowing interactions among environments with turf and lagoon deposits; and wetlands-stream connectivity, linking the alluvial and floodplain of the Gravataí River deposits with the background lagoon and paludals deposits. Already, in flood pulses of flooding with rainfall less than or equal to 200 mm, in the last 30 days, the flooded area appears fragmented inside the polygon associated at an elevation of 11 metres, mainly in the corridor between the marshes Grande and the Pachecos, that does not connect by flood, forming just wetlands-stream connectivity. Thus, the characterization of the flood pulses and connectivity become fundamental to the understanding of the dynamic of wetlands, because, make aware of for the need to preserve these areas of importance for flood control, microclimate regulation and maintenance of biodiversity.