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Dissertations / Theses on the topic 'Groundwater ecology'
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1
Chu, Wai-yan Cherry. "Effect of submarine groundwater discharge on coastal ecology /." View the Table of Contents & Abstract, 2006. http://sunzi.lib.hku.hk/hkuto/record/B36616734.
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2
Chu, Wai-yan Cherry, and 朱慧欣. "Effect of submarine groundwater discharge on coastal ecology." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B45014346.
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3
Grant, Jane D. "The significance of groundwater-surface water interactions on hyporheic physico-chemistry and stream ecology in two Scottish mountain rivers." Thesis, Available from the University of Aberdeen Library and Historic Collections Digital Resources. Online version available for University members only until Apr. 7, 2010, 2008. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?application=DIGITOOL-3&owner=resourcediscovery&custom_att_2=simple_viewer&pid=26046.
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4
Cooke, Caro Anne. "Hyporheic controls on salmonid embryo survival." Available from the University of Aberdeen Library and Historic Collections Digital Resources, 2009. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?application=DIGITOOL-3&owner=resourcediscovery&custom_att_2=simple_viewer&pid=53349.
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5
Misiti, Teresa Marie. "Groundwater nitrate reduction in a simulated free water surface wetland system." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/31847.
Full textAbstract:
Thesis (M. S.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2010.Committee Member: Pavlostathis, Spyros; Committee Member: Spain, Jim; Committee Member: Tezel, Ulas. Part of the SMARTech Electronic Thesis and Dissertation Collection.
6
Tse, Kiu-chung. "Estimation of submarine groundwater discharge into Tolo Harbour." Click to view the E-thesis via HKUTO, 2006. http://sunzi.lib.hku.hk/hkuto/record/B38230926.
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7
Rich, J. F. "Integrated mass, solute, isotopic and thermal balances of a coastal wetland /." Access via Murdoch University Digital Theses Project, 2004. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20040520.130717.
Full textAbstract:
Thesis (Ph.D.) --Murdoch University, 2004.Thesis submitted to the Division of Science and Engineering. Includes bibliographical references (leaves R-1 - R-24). Also available via the World Wide Web at.
8
Burkett, Danny, and danny burkett@deakin edu au. "Nutrient contribution to hyper-eutrophic wetlands in Perth, Western Australia." Deakin University. School of Life and Environmental Sciences, 2005. http://tux.lib.deakin.edu.au./adt-VDU/public/adt-VDU20071115.082506.
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This thesis investigates nutrient contribution to six hyper-eutrophic lakes located within close proximity of each other on the Swan Coastal Plain and 20 kilometres south of the Perth Central Business District, Western Australia. The lakes are located within a mixed land use setting and are under the management of a number of state and local government departments and organisations. These are a number of other lakes on the Swan Coastal Plain for which the majority are less than 3 metres in depth and considered as an expression of the groundwater as their base is below the regional groundwater table throughout most of the year. The limited amount of water quality data available for these six lakes and the surface water and groundwater flowing into them has restricted a thorough understanding of the processes influencing the water quality of the lakes. Various private and public companies and organisations have undertaken studies on some of the individual wetlands and there is a wide difference in scientific opinion as to the major source of the nutrients to those wetlands. These previous studies failed to consider regional surface water and groundwater effects on the nutrient fluxes and they predominantly only investigated single wetland systems. This study attempts for the first time to investigate the regional contribution of nutrients to this system of wetlands existing on the Swan Coastal plain. As such, it also includes new research on the nutrient contribution to some of the remaining wetlands. The research findings indicate that the lake sediments represent a considerable store of nutrients (nitrogen and phosphorus). These sediments in turn control the nutrient status of the lake's water column. Surface water is found to contribute on an event-basis load of nutrients to the lakes whilst the groundwater surprisingly appears to contribute a comparatively low input of nutrients but governs the water depth. Analysis of the regional groundwater shows efficient denitrifying abilities as a result of denitrifying bacteria and the transport is localised. Management recommendations for the remediation of the social and environmental value of the lakes include treatment of the lakes sediments via chemical bonding or atmospheric oxidation; utilising the regional groundwaters denitrifying abilities to treat the surface water via infiltration basins; and investigating the merits of managed or artificial aquifer recharge (MAR).
9
Olson, Patricia L. "Shallow subsurface flow systems in a montane terrace-floodplain landscape : Sauk River, North Cascades, Washington /." Thesis, Connect to this title online; UW restricted, 1995. http://hdl.handle.net/1773/5605.
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10
Golovina, A. V. "Regional ecology Kursk region." Thesis, Sumy State University, 2014. http://essuir.sumdu.edu.ua/handle/123456789/36069.
Full textAbstract:
Ecology implies the relationship of organisms, communities among themselves and with the environment. Russia has enough difficult situation with ecology, because Russia is one of the most polluted countries in the world. Economic situation exacerbates ecological one, and the severity of the prevailing negative trends is growing every day. Major rivers shallows, large amount of small rivers vanish; superficial water pollution, depletion and pollution of the groundwater, drinking water quality degradation, seas pollution, deforestation are big problems in the Russian Federation. Plowing up of turf-covered slopes, low quality agricultural methods cause accelerated soil erosion. Also there was a large degradation of the land resources in the recent years.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/36069
11
Rhymes, Jennifer. "The fate and impact of groundwater nitrogen contamination on dune slack ecology." Thesis, Bangor University, 2015. https://research.bangor.ac.uk/portal/en/theses/the-fate-and-impact-of-groundwater-nitrogen-contamination-on-dune-slack-ecology(d164cdbb-96c4-4ae0-a5fd-9cfd86b7b4b4).html.
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12
Eberhard, Stefan M. "Ecology and hydrology of a threatened groundwater-dependent ecosystem: the Jewel Cave karst system in Western Australia." Thesis, Eberhard, Stefan M. (2004) Ecology and hydrology of a threatened groundwater-dependent ecosystem: the Jewel Cave karst system in Western Australia. PhD thesis, Murdoch University, 2004. https://researchrepository.murdoch.edu.au/id/eprint/61/.
Full textAbstract:
Groundwater is a significant component of the world's water balance and accounts for >90 % of usable freshwater. Around the world groundwater is an important source of water for major cities, towns, industries, agriculture and forestry. Groundwater plays a role in the ecological processes and 'health' of many surface ecosystems, and is the critical habitat for subterranean aquatic animals (stygofauna). Over-abstraction or contamination of groundwater resources may imperil the survival of stygofauna and other groundwater-dependent ecosystems (GDEs). In two karst areas in Western Australia (Yanchep and Leeuwin-Naturaliste Ridge), rich stygofauna communities occur in cave waters containing submerged tree roots. These aquatic root mat communities were listed as critically endangered because of declining groundwater levels, presumably caused by lower rainfall, groundwater abstraction, and/or forest plantations. Investigation of the hydrology and ecology of the cave systems was considered essential for the conservation and recovery of these threatened ecological communities (TECs). This thesis investigated the hydrology and ecology of one of the TECs, located in the Jewel Cave karst system in the Leeuwin-Naturaliste Ridge. A multi-disciplinary approach was used to explore aspects pertinent to the hydrology and ecology of the groundwater system.
Thermoluminescence dating of the limestone suggested that development of the karst system dates from the Early Pleistocene and that caves have been available for colonisation by groundwater fauna since that time. Speleogenesis of the watertable maze caves occurred in a flank margin setting during earlier periods of wetter climate and/or elevated base levels. Field mapping and leveling were used to determine hydrologic relationships between caves and the boundaries of the karst aquifer. Monitoring of groundwater levels was undertaken to characterise the conditions of recharge, storage, flow and discharge. A hydrogeologic model of the karst system was developed.
The groundwater hydrograph for the last 50 years was reconstructed from old photographs and records whilst radiometric dating and leveling of stratigraphic horizons enabled reconstruction of a history of watertable fluctuations spanning the Holocene to Late Pleistocene. The watertable fluctuations over the previous 50 years did not exceed the range of fluctuations experienced in the Quaternary history, including a period 11,000 to 13,000 years ago when the watertable was lower than the present level.
The recent groundwater decline in Jewel Cave was not reflected in the annual rainfall trend, which was above average during the period (1976 to 1988) when the major drop in water levels occurred. Groundwater abstraction and tree plantations in nearby catchments have not contributed to the groundwater decline as previously suggested. The period of major watertable decline coincided with a substantial reduction in fire frequency within the karst catchment. The resultant increase in understorey vegetation and ground litter may have contributed to a reduction in groundwater recharge, through increased evapotranspiration and interception of rainfall. To better understand the relationships between rainfall, vegetation and fire and their effects on groundwater recharge, an experiment is proposed that involves a prescribed burn of the cave catchment with before-after monitoring of rainfall, leaf-area, ground litter, soil moisture, vadose infiltration and groundwater levels.
Molecular genetic techniques (allozyrne electrophoresis and mitochondria1 DNA) were used to assess the species and population boundaries of two genera and species of cave dwelling Amphipoda. Populations of both species were largely panrnictic which was consistent with the hydrogeologic model. The molecular data supported the conclusion that both species of amphipod have survived lower watertable levels experienced in the caves during the Late Pleistocene. A mechanism for the colonization and isolation of populations in caves is proposed.
Multi Dimensional Scaling was used to investigate patterns in groundwater biodiversity including species diversity, species assemblages, habitat associations and biogeography. Faunal patterns were related to abiotic environmental parameters. Investigation of hydrochemistry and water quality characterized the ecological water requirements (EWR) of the TEC and established a baseline against which to evaluate potential impacts such as groundwater pollution.
The conservation status of the listed TEC was significantly improved by increasing the number of known occurrences and distribution range of the community (from 10 m2 to > 2 x lo6 m2), and by showing that earlier perceived threatening processes (rainfall decline, groundwater pumping, tree plantations) were either ameliorated or inoperative within this catchment. The GDE in the Jewel Cave karst system may not have been endangered by the major phase of watertable decline experienced 1975-1987, or by the relatively stable level experienced up until 2000. However, if the present trend of declining rainfall in southwest Wester,,Australia continues, and the cave watertable declines > 0.5 m below the present level, then the GDE may become more vulnerable to extinction.
The occurrence and distribution of aquatic root mat communities and related groundwater fauna in other karst catchments in the Leeuwin-Naturaliste Ridge is substantially greater than previously thought, however some of these are predicted to be threatened by groundwater pumping and pollution associated with increasing urban and rural developments. The taxonomy of most stygofauna taxa and the distribution of root mat communities is too poorly known to enable proper assessment of their conservation requirements. A regional-scale survey of stygofauna in southwest Western Australia is required to address this problem. In the interim, conservation actions for the listed TECs need to be focused at the most appropriate spatial scale, which is the karst drainage system and catchment area. Conservation of GDEs in Western Australia will benefit fi-om understanding and integration with abiotic groundwater system processes, especially hydrogeologic and geomorphic processes.
13
Eberhard, Stefan M. "Ecology and hydrology of a threatened groundwater-dependent ecosystem : the Jewel Cave karst system in Western Australia /." Access via Murdoch University Digital Theses Project, 2004. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20051010.141551.
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14
Loveless, Alicia Maree. "The spatial, temporal and biogeochemical dynamics of submarine groundwater discharge in a semi-enclosed embayment /." Connect to this title, 2006. http://theses.library.uwa.edu.au/adt-WU2007.0113.
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15
Tse, Kiu-chung, and 謝喬中. "Estimation of submarine groundwater discharge into Tolo Harbour." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B38230926.
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16
Carpenter, Kathryn Elizabeth. "Nutrient, fluvial and groundwater fluxes between a North Norfolk, U.K. saltmarsh and the North Sea." Thesis, University of East Anglia, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357211.
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17
Birkenholtz, Trevor L. "The politics of groundwater scarcity technology, institutions, and governance in Rajasthani irrigation /." Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1167686351.
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18
Karlinski, Melissa. "Seedling xylem anatomy of two Banksia species relative to availability of groundwater." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2019. https://ro.ecu.edu.au/theses/2217.
Full textAbstract:
Fluctuating environmental conditions place plants at risk of mortality if they cannot adapt, particularly to warmer temperatures and drier environments. Plants are known to modify their morphology, physiology and anatomy to thrive under these conditions, and xylem anatomy and hydraulic architecture are common traits studied to understand plant adaptations and responses to changeable water availability. However, little is known about the changes to the hydraulic architecture of groundwater dependent plants during their early establishment in water-limited environments. By exposing young seedlings of two Banksia species to contrasting groundwater availability treatments in a glasshouse experiment, it was possible to analyse the xylem vessel traits (vessel diameter (Vd), maximum vessel diameter (Dmax), vessel density (Dv) and vessel length (VL)) in root and stem tissue samples using ImageJ software. Analysis of vessel traits identified significant vascular tapering in both Banksia attenuata and B. littoralis, i.e. a low density of large diameter vessels found in roots, and a higher density of small diameter vessels found in the stem. Vessel traits of B. attenuata and B. littoralis seedlings with access to an artificial water table did not differ significantly to those with access to only unsaturated soil. This lack of significant difference was surprising as studies have shown variation in xylem anatomy of plants exposed to contrasting water availabilities, commonly referred to as the hydraulic efficiency and safety trade-off theory. However, the traits did vary between the two species, with significantly larger mean Vd and Dv in B. attenuata seedling roots, and significantly higher mean Dv in B. littoralis seedling roots. VL also differed, with B. attenuata having significantly longer vessels than B. littoralis. These differences may relate to the contrasting habitat requirements of the chosen species. B. attenuata occurs across varying gradients in depth to groundwater, while B. littoralis is found in low-lying swampy areas. This could suggest that B. attenuata may be more ‘flexible’ in its xylem development, whereas B. littoralis develops a more rigid anatomy, affording protection in case of disconnection from groundwater. The findings from this study provide a better insight into how the xylem anatomy of groundwater-dependent species varies in relation to groundwater availability, and how and why species of the same genus may develop significantly different vessel traits.
19
Malcolm, Iain A. "Groundwater-surface water interactions in the hyporheic zone of salmon spawning streams : hydrology, hydrochemistry and ecological response." Thesis, University of Aberdeen, 2002. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU161207.
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The links between hydrology, hydrochemistry and salmonid ecology were examined in an interdisciplinary study of the effects of hyporheic water quality on the survival and the development of salmonid ova. Three catchments located in the northeast of Scotland were examined. Work focussed on the Newmills Burn, a degraded agricultural catchment. Complementary studies were also undertaken on the Pow Burn, a comparative agricultural catchment, and the Girnock Burn, a contrasting semi-pristine upland catchment. The relative importance of sediment transport, groundwater-surface water (GW-SW) interactions and hydrochemistry, for the survival and development of salmonid ova, was assessed between spawning in autumn, and hatch in spring. Hydrochemical, hydrometric, isotopic and modelling techniques were applied to the problem in an evolving, serial approach to investigation. The infiltration of fine sediment to the streambed was not sufficient to explain observed fine scale spatial variability (<1m), nor complex spatial patterns of sub-surface hydrochemical change. Hydrochemical and piezometric data indicated that the observed spatial and temporal patterns could be explained by variable contributions of chemically reduced groundwater to the hyporheic zone. At the catchment scale, gross differences in land-use and channel characteristics substantially affected GW-SW interactions and consequently in-redd water quality. At the reach scale, local GW-SW interactions were controlled by geomorphology and riparian sedimentary stratigraphy. At the scale of individual redds, the influence of groundwater generally increased with depth into the hyporheic zone. Dissolved oxygen (DO) levels were implicated as the dominant control on in-redd mortality. Embryo survival and development correlated with mean DO concentrations. Mortality rates from samplers located within artificial redds ranged from 0-100% and showed a significant inverse relationship with mean DO concentrations (r2 = 0.85, P < 0.01). Where embryos survived, low DO affected rates of development. Embryos exposed to low DO concentrations retained a higher portion of the yolk sac mass near to hatch than those developing in more favourable conditions.
20
Bailey, Jennifer Diane. "Vertical Distribution of Wetland Plant Roots and Their Associated Bacteria in Groundwater-fed Wetlands." Wright State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=wright1452708738.
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21
au, Stefan@calm wa gov, and Stefan Eberhard. "Ecology and Hydrology of a Threatened Groundwater-Dependent Ecosystem:The Jewel Cave Karst System in Western Australia." Murdoch University, 2004. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20051010.141551.
Full textAbstract:
Groundwater is a significant component of the world's water balance and accounts for
>90 % of usable freshwater. Around the world groundwater is an important source of
water for major cities, towns, industries, agriculture and forestry. Groundwater plays a
role in the ecological processes and 'health' of many surface ecosystems, and is the
critical habitat for subterranean aquatic animals (stygofauna). Over-abstraction or
contamination of groundwater resources may imperil the survival of stygofauna and
other groundwater-dependent ecosystems (GDEs). In two karst areas in Western
Australia (Yanchep and Leeuwin-Naturaliste Ridge), rich stygofauna communities
occur in cave waters containing submerged tree roots. These aquatic root mat
communities were listed as critically endangered because of declining groundwater
levels, presumably caused by lower rainfall, groundwater abstraction, and/or forest
plantations. Investigation of the hydrology and ecology of the cave systems was
considered essential for the conservation and recovery of these threatened ecological
communities (TECs). This thesis investigated the hydrology and ecology of one of the
TECs, located in the Jewel Cave karst system in the Leeuwin-Naturaliste Ridge. A
multi-disciplinary approach was used to explore aspects pertinent to the hydrology and
ecology of the groundwater system.
Thermoluminescence dating of the limestone suggested that development of the karst
system dates from the Early Pleistocene and that caves have been available for
colonisation by groundwater fauna since that time. Speleogenesis of the watertable
maze caves occurred in a flank margin setting during earlier periods of wetter climate
and/or elevated base levels. Field mapping and leveling were used to determine
hydrologic relationships between caves and the boundaries of the karst aquifer.
Monitoring of groundwater levels was undertaken to characterise the conditions of
recharge, storage, flow and discharge. A hydrogeologic model of the karst system was
developed.
The groundwater hydrograph for the last 50 years was reconstructed from old
photographs and records whilst radiometric dating and leveling of stratigraphic horizons
enabled reconstruction of a history of watertable fluctuations spanning the Holocene to
Late Pleistocene. The watertable fluctuations over the previous 50 years did not exceed the range of fluctuations experienced in the Quaternary history, including a period
11,000 to 13,000 years ago when the watertable was lower than the present level.
The recent groundwater decline in Jewel Cave was not reflected in the annual rainfall
trend, which was above average during the period (1 976 to 1988) when the major drop
in water levels occurred. Groundwater abstraction and tree plantations in nearby
catchments have not contributed to the groundwater decline as previously suggested.
The period of major watertable decline coincided with a substantial reduction in fire
frequency within the karst catchment. The resultant increase in understorey vegetation
and ground litter may have contributed to a reduction in groundwater recharge, through
increased evapotranspiration and interception of rainfall. To better understand the
relationships between rainfall, vegetation and fire and their effects on groundwater
recharge, an experiment is proposed that involves a prescribed burn of the cave
catchment with before-after monitoring of rainfall, leaf-area, ground litter, soil moisture,
vadose infiltration and groundwater levels.
Molecular genetic techniques (allozyrne electrophoresis and mitochondria1 DNA) were
used to assess the species and population boundaries of two genera and species of cave
dwelling Amphipoda. Populations of both species were largely panrnictic which was
consistent with the hydrogeologic model. The molecular data supported the conclusion
that both species of amphipod have survived lower watertable levels experienced in the
caves during the Late Pleistocene. A mechanism for the colonization and isolation of
populations in caves is proposed.
Multi Dimensional Scaling was used to investigate patterns in groundwater biodiversity
including species diversity, species assemblages, habitat associations and biogeography.
Faunal patterns were related to abiotic environmental parameters. Investigation of
hydrochemistry and water quality characterized the ecological water requirements
(EWR) of the TEC and established a baseline against which to evaluate potential
impacts such as groundwater pollution.
The conservation status of the listed TEC was significantly improved by increasing the
number of known occurrences and distribution range of the community (from 10 m2 to >
2 x lo6 m2), and by showing that earlier perceived threatening processes (rainfall
decline, groundwater pumping, tree plantations) were either ameliorated or inoperative
within this catchment. The GDE in the Jewel Cave karst system may not have been
endangered by the major phase of watertable decline experienced 1975-1987, or by the
relatively stable level experienced up until 2000. However, if the present trend of
declining rainfall in southwest Wester,,Australia continues, and the cave watertable
declines > 0.5 m below the present level, then the GDE may become more vulnerable to
extinction.
The occurrence and distribution of aquatic root mat communities and related
groundwater fauna in other karst catchments in the Leeuwin-Naturaliste Ridge is
substantially greater than previously thought, however some of these are predicted to be
threatened by groundwater pumping and pollution associated with increasing urban and
rural developments. The taxonomy of most stygofauna taxa and the distribution of root
mat communities is too poorly known to enable proper assessment of their conservation
requirements. A regional-scale survey of stygofauna in southwest Western Australia is
required to address this problem. In the interim, conservation actions for the listed TECs
need to be focused at the most appropriate spatial scale, which is the karst drainage
system and catchment area. Conservation of GDEs in Western Australia will benefit
fi-om understanding and integration with abiotic groundwater system processes,
especially hydrogeologic and geomorphic processes.
22
Roets, Wietsche. "Groundwater Dependence of Aquatic Ecosystems associated with the Table Mountain Group Aquifer." Thesis, University of the Western Cape, 2008. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_3210_1263507816.
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Results from this study enables a better understanding of groundwater surface water interactions in the TMG, particularly regarding aquatic ecosystems. It has also highlighted the necessity to do proper impact assessments before proceeding with bulk abstraction from this important aquifer. The results also demonstrated the importance of differentiating between real groundwater and non-groundwater discharge contributions to surface hydrology and where these interface areas are located.
23
Birkenholtz, Trevor L. "The politics of groundwater scarcity: technology, institutions, and governance in Rajasthani irrigation." The Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=osu1167686351.
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24
Harper-Smith, Sarah. "Modeling relative effects of riparian cover and groundwater inflow on stream temperature in lowland Whatcom County, Washington /." Online version, 2008. http://content.wwu.edu/cdm4/item_viewer.php?CISOROOT=/theses&CISOPTR=288&CISOBOX=1&REC=6.
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25
Sjöholm, Pia. "Groundwater Recharge in Jakkur Lake : Possibilities and Risks of Sewage Water Reuse." Thesis, Uppsala universitet, Luft-, vatten och landskapslära, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-208989.
Full textAbstract:
The aim of this project is to study the nitrate levels of the treated water flowing into Jakkur Lake in Bangalore, from the treatment plant situated at the inlet to the lake, and thereby evaluate the function of the lake as for secondary and tertiary wastewater treatment as well as an infiltration basin. Obtained nitrate levels are used as indicators to study the wastewater flow in the lake, and to find other possible inflows of sewage which can affect the lakes’ total treatment efficiency. A literature study is done on wetlands and on groundwater recharge through infiltration basins, and the possibility of recharging groundwater below Jakkur Lake is evaluated. Water samples are collected around and in the lake and the samples are tested for nitrate, pH and total dissolved solids. Extra focus is put on research on nitrates in water.The risks of groundwater recharge in Jakkur Lake include pollution of wells by bacteria, viruses, parasites and traces of medicine. Further geotechnical investigations need to be pursued mainly on the soil structure under and around the lake, and studies need to be performed on the retention time of the water in the lake. The technical limitations such as fluctuations in efficiency and pollutant migration must be minimized, which initially could be done by building a constructed wetland and controlling the inflow to the lake.
26
White, James C. "Quantifying riverine macroinvertebrate community responses to water resource management operations." Thesis, Loughborough University, 2018. https://dspace.lboro.ac.uk/2134/33559.
Full textAbstract:
Water resource management operations have significantly modified river flow regimes globally, prompting widespread lotic ecosystem responses. There is a growing need to better understand how increasingly prevalent hydrological alterations to riverine systems will affect biota dependent on specific elements of river flow regimes. This thesis examines macroinvertebrate community responses to river flow regimes modified by various water resource management operations across southwest England though four detailed investigations. The first study examines the influence of river impoundments and how macroinvertebrate communities differ between regulated and non-regulated sections of river. Findings from this investigation highlight that flow regulation alters the structure and function of faunal assemblages due to significant changes to the flow regime, rather than stream temperature modifications associated with the reservoirs. The second study focusses on groundwater dominated headwater streams transitioning from temporary (i.e. reaches periodically drying positioned furthest upstream) to perennial flow conditions which are subjected to variable groundwater abstraction intensities. The results indicate that macroinvertebrate communities respond significantly to the duration of antecedent flowing conditions and the spatial proximity of sampling sites to perennial sources; but faunal assemblages are not sensitive to groundwater abstraction. The third study examines how communities inhabiting different organic and mineralogical lotic habitats responded to multiple river flow properties (hydrological indices, anthropogenic flow alteration measures and hydraulic variables) in perennial, groundwater dominated systems. The findings highlight that faunal assemblages are most responsive to local hydraulic conditions measured at the point of sampling, rather than antecedent hydrological conditions. The influence of hydraulic properties on communities differs between lotic habitats, highlighting that mineralogical and organic characteristics of riverbeds strongly mediate how biota respond to flow. The final study presents the results of a long-term (1995-2016), region-wide (spanning Dorset, Hampshire and Wiltshire) examination of macroinvertebrate communities inhabiting groundwater dominated rivers and their responses to hydrological variability (including extreme low- and high-flow events) and anthropogenic flow alterations. The results indicate that indices characterising the proportion of discharge added to (through effluent water returns and low-flow alleviation strategies) or removed from the river (via groundwater abstraction) exert profound effects on faunal assemblages over long-term periods. These results provide empirical evidence that reductions in river discharges via groundwater abstraction of approximately 15% have no perceptible negative ecological effects on macroinvertebrate communities. The results from the four detailed investigations are used to develop conceptual models to illustrate how research undertaken within this thesis can be applied more widely. The findings and study designs presented within this thesis could inform surface and groundwater water resource management operations and underpin the development of environmental flow methodologies required to conserve riverine ecosystems globally.
27
Spence, Victora. "Estimating groundwater discharge in the oligohaline ecotone of the Everglades using temperature as a tracer and variable-density groundwater models." Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3361.
Full textAbstract:
Recent research suggests that brackish, marine-derived groundwater up-wells in the oligohaline ecotone of the coastal Everglades, bringing with it phosphorus to an otherwise phosphorus-poor environment. The purpose of this study is to estimate the rates and timing of the groundwater discharge by using variable-density groundwater models constructed, calibrated, and validated with field measurements of hydraulic head and surface and subsurface temperature. Modeled groundwater discharge rates ranged from 5.4E-04 mm/day in August to -1.3E-03 mm/day in June for Shark Slough and 4.8E-01 mm/day in June to -1.4E-01 mm/day in January for Taylor Slough, where positive values imply groundwater discharge and negative values imply groundwater recharge. These results indicate that groundwater discharge rates during the period of study were low and perhaps a negligible source of marine-derived phosphorous in the oligohaline ecotone of Shark Slough but much higher and perhaps significant source of marine-derived phosphorous in the oligohaline ecotone of Taylor Slough.
28
Eberhard, Stefan. "Ecology and hydrology of a threatened groundwater-dependent ecosystem: the Jewel Cave karst system in Western Australia." Eberhard, Stefan (2004) Ecology and hydrology of a threatened groundwater-dependent ecosystem: the Jewel Cave karst system in Western Australia. PhD thesis, Murdoch University, 2004. http://researchrepository.murdoch.edu.au/61/.
Full textAbstract:
Groundwater is a significant component of the world's water balance and accounts for >90 % of usable freshwater. Around the world groundwater is an important source of water for major cities, towns, industries, agriculture and forestry. Groundwater plays a role in the ecological processes and 'health' of many surface ecosystems, and is the critical habitat for subterranean aquatic animals (stygofauna). Over-abstraction or contamination of groundwater resources may imperil the survival of stygofauna and other groundwater-dependent ecosystems (GDEs). In two karst areas in Western Australia (Yanchep and Leeuwin-Naturaliste Ridge), rich stygofauna communities occur in cave waters containing submerged tree roots. These aquatic root mat communities were listed as critically endangered because of declining groundwater levels, presumably caused by lower rainfall, groundwater abstraction, and/or forest plantations. Investigation of the hydrology and ecology of the cave systems was considered essential for the conservation and recovery of these threatened ecological communities (TECs). This thesis investigated the hydrology and ecology of one of the TECs, located in the Jewel Cave karst system in the Leeuwin-Naturaliste Ridge. A multi-disciplinary approach was used to explore aspects pertinent to the hydrology and ecology of the groundwater system.
Thermoluminescence dating of the limestone suggested that development of the karst system dates from the Early Pleistocene and that caves have been available for colonisation by groundwater fauna since that time. Speleogenesis of the watertable maze caves occurred in a flank margin setting during earlier periods of wetter climate and/or elevated base levels. Field mapping and leveling were used to determine hydrologic relationships between caves and the boundaries of the karst aquifer. Monitoring of groundwater levels was undertaken to characterise the conditions of recharge, storage, flow and discharge. A hydrogeologic model of the karst system was developed.
The groundwater hydrograph for the last 50 years was reconstructed from old photographs and records whilst radiometric dating and leveling of stratigraphic horizons enabled reconstruction of a history of watertable fluctuations spanning the Holocene to Late Pleistocene. The watertable fluctuations over the previous 50 years did not exceed the range of fluctuations experienced in the Quaternary history, including a period 11,000 to 13,000 years ago when the watertable was lower than the present level.
The recent groundwater decline in Jewel Cave was not reflected in the annual rainfall trend, which was above average during the period (1976 to 1988) when the major drop in water levels occurred. Groundwater abstraction and tree plantations in nearby catchments have not contributed to the groundwater decline as previously suggested. The period of major watertable decline coincided with a substantial reduction in fire frequency within the karst catchment. The resultant increase in understorey vegetation and ground litter may have contributed to a reduction in groundwater recharge, through increased evapotranspiration and interception of rainfall. To better understand the relationships between rainfall, vegetation and fire and their effects on groundwater recharge, an experiment is proposed that involves a prescribed burn of the cave catchment with before-after monitoring of rainfall, leaf-area, ground litter, soil moisture, vadose infiltration and groundwater levels.
Molecular genetic techniques (allozyrne electrophoresis and mitochondria1 DNA) were used to assess the species and population boundaries of two genera and species of cave dwelling Amphipoda. Populations of both species were largely panrnictic which was consistent with the hydrogeologic model. The molecular data supported the conclusion that both species of amphipod have survived lower watertable levels experienced in the caves during the Late Pleistocene. A mechanism for the colonization and isolation of populations in caves is proposed.
Multi Dimensional Scaling was used to investigate patterns in groundwater biodiversity including species diversity, species assemblages, habitat associations and biogeography. Faunal patterns were related to abiotic environmental parameters. Investigation of hydrochemistry and water quality characterized the ecological water requirements (EWR) of the TEC and established a baseline against which to evaluate potential impacts such as groundwater pollution.
The conservation status of the listed TEC was significantly improved by increasing the number of known occurrences and distribution range of the community (from 10 m2 to > 2 x lo6 m2), and by showing that earlier perceived threatening processes (rainfall decline, groundwater pumping, tree plantations) were either ameliorated or inoperative within this catchment. The GDE in the Jewel Cave karst system may not have been endangered by the major phase of watertable decline experienced 1975-1987, or by the relatively stable level experienced up until 2000. However, if the present trend of declining rainfall in southwest Wester,,Australia continues, and the cave watertable declines > 0.5 m below the present level, then the GDE may become more vulnerable to extinction.
The occurrence and distribution of aquatic root mat communities and related groundwater fauna in other karst catchments in the Leeuwin-Naturaliste Ridge is substantially greater than previously thought, however some of these are predicted to be threatened by groundwater pumping and pollution associated with increasing urban and rural developments. The taxonomy of most stygofauna taxa and the distribution of root mat communities is too poorly known to enable proper assessment of their conservation requirements. A regional-scale survey of stygofauna in southwest Western Australia is required to address this problem. In the interim, conservation actions for the listed TECs need to be focused at the most appropriate spatial scale, which is the karst drainage system and catchment area. Conservation of GDEs in Western Australia will benefit fi-om understanding and integration with abiotic groundwater system processes, especially hydrogeologic and geomorphic processes.
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Lee, Chun-ming, and 李進銘. "Estimation of submarine groundwater discharge and nutrient loading of Tolo Harbour." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B48330206.
Full textAbstract:
Tolo Harbour is naturally eutrophic with frequent algal blooms in the past. Water quality of the Harbour has been improved in past 20 years but the phytoplankton density is still high compared to other waters in Hong Kong. This study aimed to quantify submarine groundwater discharge (SGD) to Tolo Harbour and to show the important role of SGD in terms of nutrient loading with ecological effect.
SGD was determined by one of the natural geochemical tracers, 226Ra. Mass balance of 226Ra was applied to quantify SGD and SGD was estimated to be 8.28 × 106 m3 d-1. A large portion of the SGD was recirculated seawater while the freshwater component of SGD, or submarine fresh groundwater discharge (SFGD), was only a small portion of that. SFGD was estimated to be 2.31 ×105 m3 d-1 using water balance. The flushing time of Tolo Harbour was estimated to be 77.9 d by using SFGD as one of the fresh water input components.
Different nutrients including NH3—N, NO2—N, NO3—N, PO43-—P, SiO2—Si and dissolved inorganic nitrogen (DIN) were applied to nutrient mass balance analyses. The mass balance is based on non-point sources which include aerosol deposition (dry deposition), rainfall (wet deposition), diffusion from sediment, river, SGD and tidal exchange. Removal of nutrients was determined once all the non-point sources were estimated. SGD is the major source which contributes more than 88 % for different nutrients. Other sources contribute less than 10 % individually. The total nutrient loads of DIN, PO43-–P and SiO2—Si are 8.33 ×105, 1.03 ×104 and 1.28 ×106 mol d-1 respectively. The removals of DIN, PO43-–P and SiO2—Si are 6.87 ×105, 5.10 × 103 and 1.28 ×106 mol d-1 respectively. Assume the removal of nutrients was only due to consumption of phytoplankton, primary productivity was estimated to be 1.16g C m-2 d-1.
Limitations of this study were about the determination of atmospheric depositions and diffusion from sediment. However, the contribution of nutrient loading from these sources was insignificant compared with SGD. Even if SGD is replaced by SFGD for the nutrient loading estimation, it is still the major contributor among all other non-point sources.
In spite of the limitations, the important role of SGD in terms of nutrient loading is evident. Groundwater quality should be monitored and controlled as it has significant ecological impact to the Harbour.published_or_final_version
Earth Sciences
Master
Master of Philosophy
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Hartenstine, Sandra A. "Nutrient Standing Stocks and Partitioning in a Forested Coastal Plain Watershed: Groundwater, Stream and Marsh Creek." W&M ScholarWorks, 1991. https://scholarworks.wm.edu/etd/1539617639.
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Taylor, Robert. "An investigation into using stable water isotopes to determine the dependency of vegetation on groundwater at Cape Point Nature Reserve." Bachelor's thesis, University of Cape Town, 2003. http://hdl.handle.net/11427/25993.
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We hypothesized that rainwater had a different and distinct isotopic signal to groundwater, and thus plants growing on groundwater-fed areas would have a unique and distinct isotopic composition compared to plants growing on freely-drained soils. We studied two groundwater-fed areas and adjacent freely-drained areas in the Cape Point Nature Reserve, Cape Peninsula. We sampled groundwater and analyzed the isotopic composition and compared this to the isotope composition of rainfall. We found that δ¹⁸O and oD values of rainwater (δ¹⁸O = O%o to -5.6%o and oD = +11 %o to -22%o) overlapped the isotopic composition of groundwater (δ¹⁸O = -4.2%o to -4.5%o and oD = -11.9%o to -13.2%o). Thus isotopic analysis could not determine which areas were groundwater-fed and which were rain-fed. We also sampled xylem water from five species, namely Leucadendron laureolum and Metalasia muricata (both of which grew on both dry and wetland areas), Mimetes hirtus (wetland only), Erica labialis (dry area only), and Erica multumbellifera (wet area orily). Our results suggest that both of L. laureolum and Metalasia muricata had access to groundwater on both groundwater-fed sites and the free-drained site. E. multumbellifera at a groundwater-fed marsh was likely also using groundwater, however on the adjacent freely drained site E. labialis was likely using rainwater. M. hirtus had a much more positive isotopic composition (δ¹⁸O = -1.5 ±1.2%o and δD = 5.1 ± 18.0%o) than either groundwater or rainwater, indicating that it was using evaporated water, which suggests the species were very shallow rooted. Thus M. hirtus would be very sensitive to drying out of the soil. This study has demonstrated that stable water isotopes cannot clearly distinguish rainwater and groundwater and we may have use other methods such as thermal imagery, chemical analysis, and xylem pressure potentials to determine the degree of dependency of vegetation on groundwater.
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Burk, Rosemary A. "Ecology and Recolonization of Benthic Macroinvertebrates in a Groundwater-dependent Stream in North Central Texas During a Supra-seasonal Drought." Thesis, University of North Texas, 2012. https://digital.library.unt.edu/ark:/67531/metadc115054/.
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Extreme climatic events such as droughts are known to eliminate aquatic biota and alter community structure and function. Perennial headwater springs provide important drought refugia to benthic macroinvertebrates and an important source of colonists via drift or aerial adults to intermittent streams post-drought. During a supra-seasonal drought in North-central Texas summer and fall 2006, benthic macroinvertebrates from persistent groundwater-dependent macrohabitats of varying hydrological connectivity and riparian shading were studied: perennial riffles, connected pools, shaded disconnected pools, and full sun disconnected pools. Riffles were a distinct habitat with significantly higher taxa richness, proportion of lotic taxa, diversity and evenness than other macrohabitats. Macrohabitats were found to be important refugia for 106 benthic macroinvertebrates and 4 microcrustacean taxa. Throughout the extreme drought, perennially flowing habitats were refugia to 19 taxa (17.9% total taxa) not collected in disconnected pools. Shaded disconnected pools contained lotic taxa not previously known to be able to complete their lifecycles in lentic habitats, emphasizing the importance of groundwater effluent and shading. With the resumption of flow at a downstream intermittent site of Ash Creek in mid-October 2006, an annual recolonization study was conducted comparing the perennial headwaters’ benthic macroinvertebrate taxa richness, densities and community ecology with the downstream intermittent site. The headwaters supported higher mean taxa richness than the intermittent site over the duration of the study (ANOVA P < 0.001). However, the unexpected result of overall decreasing taxa richness at the perennial headwater site from August 2006 to April 2008 appears to reflect lag effects of the supra-seasonal drought combined with effects of multiple spates of 2007, which are factors confounding the point of recovery for taxa richness. Recovery of taxa richness at the intermittent site took 9 months compared to 1 to 2 months reported in other arid and semi-arid streams in the United States recovering from seasonal drying and floods. Sustainable use of groundwater resources and conservation of riparian corridors is vital to protecting groundwater-dependent ecosystems that play a vital role in maintaining regional biodiversity by serving as biotic refugia during catastrophic disturbance.
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Knust, Andrew E. "Uncertainties associated with using an anthropogenic fluctuating signal to estimate hyporheic exchange." abstract and full text PDF (free order & download UNR users only), 2006. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1438921.
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Hwang, Chiachi. "Assessment of bacterial communities and an iron-reducing bacterium in relation to an engineered bioremediation system designed for the treatment of uranium-nitric acid contaminated groundwater." Oxford, Ohio : Miami University, 2009. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=miami1241117969.
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Ali, Ayesha. "Water Politics in a Water-Scarce Landscape : Examining the Groundwater Debate in California’s Central Valley." Thesis, Uppsala universitet, Institutionen för arkeologi och antik historia, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-414194.
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The history of California is in many ways a story about water, and the outsized effect that droughts, floods, and seasonal precipitation rates have had on the political and economic development of the state over the past 170 years. This thesis uses discourse analysis of historical and ongoing negotiations that have been presented in federal and state reports, narratives, case laws and legislation to explore how the discourse around water politics has been shaped in the state. From this, an antiessentialist environmental history develops around the relationship between overdrafted groundwater basins in the Central Valley and the agriculture industry located there. Finally, this thesis explores what the future of a waterscape built during the capitalization of modern society may look like as we move towards a new regime of nature.
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Durkota, Jessica M. "Groundwater ecology : invertebrate community distribution across the benthic, hyporheic and phreatic habitats of a chalk aquifer in southeast England." Thesis, University College London (University of London), 2018. http://discovery.ucl.ac.uk/10040830/.
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Groundwater is an important resource for drinking water, agriculture, and industry, but it also plays an essential role in supporting the functioning of freshwater ecosystems and providing habitat for a number of rare species. However, despite its importance, groundwater ecology often receives little attention in environmental legislation or research. This study aims to improve our understanding of the organisms living in groundwater-dependent habitats and the influence of environmental conditions on their distribution. Invertebrate communities occurring in the benthic, hyporheic and phreatic habitats were surveyed at twelve sites over four years across the Stour Chalk Block, a lowland catchment in southern England. A diverse range of stygoxenes, stygophiles and stygobionts, including the first record of Gammarus fossarum in the British Isles, were identified using morphological and molecular techniques. The results indicate that under normal conditions, each habitat provided differing environmental conditions which supported a distinctive invertebrate community. While the community recorded in the benthic habitat was characterised by a diverse assemblage of surface water species typical of Chalk streams, the phreatic community comprised a small number of exclusively crustacean stygofauna (such as Niphargus kochianus and Crangonyx subterraneus) and the hyporheic habitat supported a mixture of surface and groundwater species. Surprisingly, the results indicate that some species, such as Agapetus fuscipes (normally considered a surface water taxon), move into the hyporheic habitat in a predictable, seasonal pattern, potentially in response to grazing opportunities. However, the results collected during the high and low flow events which occurred during this study also show the widespread movement of multiple species (such as Gammarus pulex and Niphargus fontanus) between habitats in response to environmental disturbance. Collectively, these results reflect the movement of fauna longitudinally, laterally and vertically over time throughout the catchment, as though along a continuum rather than between three separate habitats. This suggests that our conceptualisation of lotic functioning should be expanded to better integrate the contribution from groundwater. The approach taken by this study provides a greater understanding of the full diversity of aquatic invertebrates within this catchment and the way in which their distribution fluctuates across habitats. This study is one of the first to concurrently assess invertebrate distribution across the benthic, hyporheic and phreatic habitats; in addition, the relatively frequent and long-term sampling approach also facilitated a more detailed temporal assessment of these communities. A greater understanding of the distribution and requirements of the fauna inhabiting groundwater-dependent habitats, and their response to environmental change is essential for the conservation of these species and management of lotic ecosystems.
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Vionnet, Leticia Beatriz, and Leticia Beatriz Vionnet. "Investigation of stream-aquifer interactions using a coupled surface water and groundwater flow model." Diss., The University of Arizona, 1995. http://hdl.handle.net/10150/187414.
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A finite element numerical model is developed for the modeling of coupled surface-water flow and ground-water flow. The mathematical treatment of subsurface flows follows the confined aquifer theory or the classical Dupuit approximation for unconfined aquifers whereas surface-water flows are treated with the kinematic wave approximation for open channel flow. A detailed discussion of the standard approaches to represent the coupling term is provided. In this work, a mathematical expression similar to Ohm's law is used to simulate the interacting term between the two major hydrological components. Contrary to the standard approach, the coupling term is incorporated through a boundary flux integral that arises naturally in the weak form of the governing equations rather than through a source term. It is found that in some cases, a branch cut needs to be introduced along the internal boundary representing the stream in order to define a simply connected domain, which is an essential requirement in the derivation of the weak form of the ground-water flow equation. The fast time scale characteristic of surface-water flows and the slow time scale characteristic of ground-water flows are clearly established, leading to the definition of three dimensionless parameters, namely, a Peclet number that inherits the disparity between both time scales, a flow number that relates the pumping rate and the streamflow, and a Biot number that relates the conductance at the river-aquifer interface to the aquifer conductance. The model, implemented in the Bill Williams River Basin, reproduces the observed streamflow patterns and the ground-water flow patterns. Fairly good results are obtained using multiple time steps in the simulation process.
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Jenkins, Michael Edward 1961. "Ground and surface water assessments supporting instream flow protection at the Hassayampa River Preserve, Wickenburg, Arizona." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/277236.
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The Arizona Nature Conservancy's Hassayampa River Preserve is 50 miles northwest of Phoenix near the town of Wickenburg. Four miles of the largely ephemeral Hassayampa River are perennial within the preserve, supporting one of the finest remaining cottonwood-willow forests in the state. Stream flows are affected by wells pumping ground water directly from the alluvial aquifer and may be influenced by wells which intercept lateral inflow from the regional basin-fill aquifer. Developing effective management strategies to protect base flow conditions (∼4 cfs) depends on a clear understanding of the surface and ground-water systems in the preserve. Provided that ground water developers near Wickenburg recognize and incorporate the interconnected nature of each hydrologic system, perennial flow within the preserve is not believed to be immediately threatened. (Abstract shortened with permission of author.)
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Gramling, Carolyn M. "A radiocarbon method and multi-tracer approach to quantifying groundwater discharge to coastal waters." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/69769.
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Thesis (Ph. D.)--Joint Program in Marine Geology and Geophysics (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), September 2003.Includes bibliographical references.
Groundwater discharge into estuaries and the coastal ocean is an important mechanism for the transport of dissolved chemical species to coastal waters. Because many dissolved species are present in groundwater in concentrations that are orders of magnitude higher than typical river concentrations, groundwater-borne nutrients and pollutants can have a substantial impact on the chemistry and biology of estuaries and the coastal ocean. However, direct fluxes of groundwater into the coastal ocean (submarine groundwater discharge, or SGD) can be difficult to quantify. Geochemical tracers of groundwater discharge can reflect the cumulative SGD flux from numerous small, widely dispersed, and perhaps ephemeral sources such as springs, seeps, and diffuse discharge. The natural radiocarbon content (A14C) of dissolved inorganic carbon (DIC) was developed as a tracer of fresh, terrestrially driven fluxes from confined aquifers. This A14C method was tested during five sampling periods from November 1999 to April 2002 in two small estuaries in southeastern North Carolina. In coastal North Carolina, fresh water artesian discharge is characterized by a low A14C signature acquired from the carbonate aquifer rock. Mixing models were used to evaluate the inputs from potential sources of DIC-A'4C to each estuary, including seawater, springs, fresh water stream inputs, and salt marsh respiration DIC additions. These calculations showed that artesian discharge dominated the total fresh water input to these estuaries during nearly all sampling periods.
(cont.) These new A14C-based SGD estimates were compared with groundwater flux estimates derived from radium isotopes and from radon-222. It is clear that these tracers reflect different components of the total SGD. The fluxes of low-A14C and of 222Rn were dominated by artesian discharge. Estuarine 226Ra showed strong artesian influence, but also reflected the salt water SGD processes that controlled the other three radium isotopes. The flux of 228Ra seemed to reflect seepage from the terrestrial surficial aquifer as well as salt water recirculation through estuarine sediments. The fluxes of 224Ra and 223Ra were dominated by salt water recirculation through salt marsh sediments. This multi-tracer approach provides a comprehensive assessment of the various components contributing to the total SGD.
by Carolyn M. Gramling.
Ph.D.
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Sibley, Samuel D. Jr. "The Impact of Salt Marsh Hydrogeology on Dissolved Uranium." Thesis, Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/7262.
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We quantified U removal and investigated the efficacy of uranium as a quantitative tracer of groundwater discharge in a headwater salt marsh of the Okatee River, Bluffton, SC. Determining the magnitude of U removal is important for advancing U as a tracer of paleo-oceanic conditions. Since salt marsh groundwater is typically enriched in nutrients and other biologically and chemically reactive species, quantifying groundwater discharge from marshes is critical for understanding the ability of salt marshes to modify the chemistry of important species in surface waters.
We hypothesized that water-column U(VI) was removed by tidally-induced advection of surface water into permeable, anoxic salt marsh sediments, a process resulting in bacterially-mediated precipitation of insoluble U(IV)O2 and/or sorption of uranium to iron-oxides at the oxic/anoxic sediment interface. Furthermore, we suggested that hydraulic pressure gradients established by marsh-surface tidal inundation and seasonally-variable rainfall promote the discharge of salt-marsh-processed, uranium-depleted groundwater to tidal creeks, producing the surface-water U-removal signal.
Groundwater and surface water data revealed non-conservative uranium behavior. We documented extensive uranium removal from shallow marsh groundwater and seasonally variable uranium removal from surface waters. These observations allowed for the calculation of seasonally-dependent salt marsh uranium removal rates. On a yearly basis, our removal rate (58 to 104 mol m-2 year-1) reemphasized the importance of anoxic coastal environments for U removal.
High uranium removal, high barium concentration water observed seeping from creek banks at low tide supported our hypothesis that groundwater discharge must contribute to uranium removal documented in tidal surface waters. Average site groundwater provided an analytically reasonable endmember for explaining uranium depletion in surface water. Therefore, we used three endmember mixing models for estimating the fraction of surface water with presumed a groundwater signature. Our discharge estimates of 8 to 37 L m-2 day-1 agreed closely with previously published salt marsh values. Seasonality in discharge rates can be rationalized with appeal to seasonal patterns in observed rainfall, tidal forcing, and marsh surface bioturbation. Although more work is needed, the results of this portion of the study suggest that U may be an effective quantitative tracer of groundwater discharge from salt marshes.
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Chan, Yi-kei, and 陳伊祺. "Nutrient input of Tolo Harbour by river, atmospheric deposition and submarine groundwater discharge." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B46732718.
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Piontkowski, S., Phillip R. Scheuerman, and L. R. Curtis. "Concentration of Bacteria in Groundwater and Two Streams in a Rural Community of East Tennessee." Digital Commons @ East Tennessee State University, 1998. https://dc.etsu.edu/etsu-works/2918.
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Canham, Caroline. "The response of Banksia roots to change in water table level in a Mediterranean-type environment." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2011. https://ro.ecu.edu.au/theses/389.
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For phreatophytic plants to persist in a given habitat they need to maintain a functional connection to the water table, and the capacity for roots to respond to changes in the water table is a key aspect of this. If root growth is limited by season, plants may not be able to grow roots to adjust to changes in the water table at a particular time of the year. The redistribution of roots, particularly the capacity for roots to follow the water table down in summer and autumn months, is vital for phreatophytic plants to maintain a functional connection with the water table. Root activity by phreatophytic Banksia in south-west Western Australia was assessed using root in-growth bags, with above-ground plant phenological processes observed simultaneously. The root in-growth bag technique that was used showed that Banksia roots are able to grow, provided soil conditions are conducive and there are no endogenous limitations to root growth at different times of the year, such as a dormancy period. The ability to grow at any time in response to soil conditions might be an essential prerequisite for phreatophytes if they are to survive fluctuating water table conditions in seasonally water-limited environments.
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Chivell, Eleanor Heather. "Investigation into the plant ecology of the Karstland area in Namibia : with particular reference to the proposed large-scale abstraction of groundwater." Master's thesis, University of Cape Town, 1992. http://hdl.handle.net/11427/17366.
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Includes bibliographical references.The planned large-scale abstraction of groundwater from the Karst area in northern Namibia prompted concern with respect to possible negative effects on the plant ecology of that area. Although it was thought improbable that the lowering of the groundwater table would result in the deterioration of the vegetation, it was considered necessary to examine the existing vegetation status in order to establish a pre-abstraction baseline datum. It was thus important to establish a broad overview of the current vegetation, any changes in its condition within a two years period, and also the prevailing environmental factors in the Karst area. This was achieved through both manual and photographic monitoring of selected representative transects within the proposed abstraction area during 1986 and 1987. The manual monitoring exercise included the usual measures of density cover and frequency of all species, whereby a full inventory of the transects was established. The environmental conditions were assessed through the collection and evaluation of data on rainfall, groundwater levels and soil conditions, both within the transects and for the area as a whole. Below average rainfall during and prior to the baseline study years, resulting in poor recharge to the groundwater table, was recorded for most of the karst area. Both the vegetation and environmental data were utilized in two ways. Firstly, the 1986 and 1987 vegetation data were analysed, and those aspects indirectly related to the vegetation's vitality status, were then evaluated. A comparison of the parameters such as the quantity of dead material, and the number of standing dead trees, reflected a general decline in vitality over the two year period. In view of the poor rainfall conditions, this decline was interpreted as that which can be expected under natural adverse climatic conditions. Secondly, in order to establish and critically examine the possible relationships between the vegetation data and components of the environmental data, a Canonical Correspondence Analysis was performed. Despite a large amount of "noise" caused by the broad nature of the environmental data, it was possible to identify a number of species which occur within precisely defined environmental conditions. A change in abundance or distribution of these species can in the future first be investigated in terms of their defined vegetation-habitat relationships, and thereafter in terms of any other introduced factors which may be suspected of having an influence. Infra-red aerial photography was another monitoring technique used to obtain a pre-abstraction record of the vitality status of the vegetation. Two surveys were carried out during the baseline period and counts made of stressed and dead trees. A comparison of the counts reflected an increase in stress within the vegetation over this period, thus supporting the findings of the manual surveys. Selected sections of vegetation at various points of interest within the transects, were monitored using fixed point photography on a bi-annual basis. Although these photographic records ret1ected small changes, these were not considered significant. The main purpose of this method is to provide a pre-abstraction record of vegetation at potentially "sensitive" points with which future surveys .could be compared. The usefulness and cost-effectiveness of the three central monitoring methods were evaluated, and an indication provided of how monitoring may continue in the long term as large-scale abstraction goes ahead.
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Loveless, Alicia Maree. "The spatial, temporal and biogeochemical dynamics of submarine groundwater discharge in a semi-enclosed embayment." University of Western Australia. School of Environmental Systems Engineering, 2007. http://theses.library.uwa.edu.au/adt-WU2007.0113.
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[Truncated abstract] It has become widely apparent throughout the world that the discharge of nitrogen contaminated groundwater is reducing surface water quality of marine coastal waters, and is subsequently contributing to the decline of benthic habitats such as seagrasses. A process-based understanding of submarine groundwater discharge (SGD) has lagged behind these impacts, and this lack of understanding is addressed by this thesis. This thesis, of the spatial and temporal complexity of SGD, has uncovered and answered questions regarding the sources, fate and transport of SGD in a complex coastal discharge environment. Radium isotope techniques, groundwater biogeochemical investigations and HAMSOM surface water modelling have identified the magnitude, transport and fate of SGD in Cockburn Sound, a semienclosed embayment in Western Australia. A temporal periodicity that encompassed end-of-winter, early-summer, late-summer and mid-winter regimes of hydrology and oceanography, was employed in field studies that spanned the years 2003, 2004 and 2005. ... The fate of the groundwater in the semi-enclosed embayment was investigated using knowledge of surface water currents. Localised regions of high groundwater influence were identified in the surface waters of the embayment, and through the application of a 3-dimensional hydrodynamic model (HAMSOM) it was discovered that, despite similar total volume residence times, variation in the surface flow regime resulted in very different fates for groundwater discharged to the embayment. For three of the four investigated seasonal regimes, groundwater discharged at the shoreline was shown to be rapidly exported out of the embayment (within approximately 1-3 days). During mid-winter very different wind and current regimes existed, resulting in the lateral transport of shoreline groundwater across the embayment, presenting potential for nutrient recirculation within the system for longer time periods (10+ days). Lateral transport of groundwater during mid-winter from the limestone region of the coastline, may contribute to peaks in phytoplankton biomass that have been reported to occur at this time. The investigations into spatial, temporal and biogeochemical dynamics of SGD provided for further dissertation of the processes that affect these dynamics, at a scale that was relevant to marine embayments, coastal aquifers and the coastal ecosystem. It is hoped that this thesis will contribute to a better understanding of the inputs, dynamics and impacts of SGD on coastal ecosystems and lead to improved management strategies for coastal zones.
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Goddard, Nathaniel Lee. "Emergent Insect and Neotropical Migratory Bird Interactions and Responses to Habitat, Hydrology, and Progressive Urbanization in the Tampa Bay Region." Scholar Commons, 2015. http://scholarcommons.usf.edu/etd/5954.
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The growing human population threatens the many of the earth’s biological systems. In the last 600 years extinction rates risen from 1 extinction per million species per year (E/MSY) in the 1400’s to 50 E/MSY today. During this time period 1.5% of all known birds have gone extinct, because they could not adapt quickly enough to human mediated changes. The goal of this dissertation was to determine how urbanization and anthropogenic services needed to support urban areas impact cypress dome wetland aquatic insect and migratory bird populations that depend on them. In Central Florida cypress dome hydroperiods are driven by seasonal rainfall conditions and fill June and July with the onset of the Florida rainy season then begin drying beginning in October with the onset of the dry season. Some wetlands were strongly influenced by groundwater pumping and dried out quicker than others, a characteristic that reduced annual insect emergence. Decreased adult insect populations were associated with lower emergence rates early in the dry season led to lower utilization by insectivorous birds. Winter migratory birds significantly related with adult insect abundance during winter months (r = 0.578, p=0.049), and utilized this region at the peak in adult insect populations. Conversely, Neotropical migrants travel through the region during spring when insects are scarce, and adult insects began sharp decline suggesting that Neotropical migrants depleted populations possibly leading to interspecies competition. Neotropical migrants strongly avoided urban areas and declined by 70% in urban areas, which may contribute to declining Neotropical migratory bird populations as a lack in adequate stopover sites may limit entire species. If they are not able to adapt foraging patterns that utilize urban areas in Central Florida where urban development is increasing rabidly populations may continue to decline.
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Bauermeister, Jan [Verfasser], Sharmishtha [Akademischer Betreuer] Dattagupta, and Volker [Akademischer Betreuer] Thiel. "Diversity and ecology of ectosymbioses between sulfur-oxidizing Thiothrix bacteria and groundwater niphargid amphipods / Jan Bauermeister. Gutachter: Sharmishtha Dattagupta ; Volker Thiel. Betreuer: Sharmishtha Dattagupta." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2013. http://d-nb.info/1044173114/34.
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Vionnet, Leticia Beatriz, Thomas III Maddock, and David C. Goodrich. "Investigations of stream-aquifer interactions using a coupled surface-water and ground-water flow model." Department of Hydrology and Water Resources, University of Arizona (Tucson, AZ), 1997. http://hdl.handle.net/10150/615700.
Full textAbstract:
A finite element numerical model is developed for the modeling of coupled
surface-water flow and ground-water flow. The mathematical treatment of subsurface
flows follows the confined aquifer theory or the classical Dupuit approximation for
unconfined aquifers whereas surface-water flows are treated with the kinematic wave
approximation for open channel flow. A detailed discussion of the standard approaches to
represent the coupling term is provided. In this work, a mathematical expression similar
to Ohm's law is used to simulate the interacting term between the two major hydrological
components. Contrary to the standard approach, the coupling term is incorporated
through a boundary flux integral that arises naturally in the weak form of the governing
equations rather than through a source term. It is found that in some cases, a branch cut
needs to be introduced along the internal boundary representing the stream in order to
define a simply connected domain, which is an essential requirement in the derivation of
the weak form of the ground-water flow equation. The fast time scale characteristic of
surface-water flows and the slow time scale characteristic of ground-water flows are
clearly established, leading to the definition of three dimensionless parameters, namely, a
Peclet number that inherits the disparity between both time scales, a flow number that
relates the pumping rate and the streamflow, and a Biot number that relates the
conductance at the river-aquifer interface to the aquifer conductance.
The model, implemented in the Bill Williams River Basin, reproduces the observed
streamflow patterns and the ground-water flow patterns. Fairly good results are obtained
using multiple time steps in the simulation process.
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Amey, Katherine Springer. "Hydrology And Predictive Model Of Headwater Streams And The Groundwater/Surface Water Interactions Supporting Brook Trout Habitat In Northeast Ohio." Kent State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=kent1301618586.
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Armas, Rafael Dutra de. "Caracterização da comunidade bacteriana em água subterrânea contaminada com tetracloroeteno." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/11/11138/tde-26022008-163013/.
Full textAbstract:
Dentre os contaminantes de água subterrânea de maior importância está o tetracloroeteno (PCE), o qual é altamente tóxico e potencialmente carcinógeno. As comunidades bacterianas de águas subterrâneas contaminadas com PCE e a diversidade de bactérias capazes de degradar esses organoclorados são pouco conhecidas. O objetivo deste trabalho é comparar a estrutura das comunidades de bactérias de amostras de água subterrânea em uma área contaminada com PCE e selecionar um consórcio microbiano capaz de degradar eficientemente o PCE em reator horizontal de leito fixo (RHLF). Amostras de água subterrânea de oito poços de monitoramento, instalados em uma área contaminada com PCE foram coletadas e analisadas para determinação de oxigênio dissolvido, potencial redox, condutividade elétrica, pH e concentração de tetracloroeteno, tricloroeteno, cis-dicloroeteno e cloreto de vinila (COVs). As amostras foram analisadas também para a determinação da estrutura das comunidades de bactéria por PCRDGGE e seqüenciamento de clones do gene rRNA 16S. Os parâmetros físico-químicos oscilaram consideravelmente ao longo do tempo em todos os poços de monitoramento (PM). Tetracloroeteno e tricloroeteno foram detectados apenas no PM6. As estruturas das comunidades bacterianas dos PMs analisados mostraram tanto variação temporal quanto espacial. As análises das comunidades bacterianas nos PM6 e PM8, contaminado e não-contaminado com PCE, revelaram resultados semelhantes aos obtidos por DGGE. Uma maior riqueza estimada de espécies bacterianas foi observada nas amostras do PM8, pelo menos em duas épocas de amostragem, sugerindo que a contaminação com PCE está associada com a redução da diversidade bacteriana em água subterrânea. Cultivos de enriquecimento e ensaios de degradação do PCE foram realizados utilizando-se um RHLF, o qual foi preenchido com sedimento do PM6 imobilizado em espuma de poliuretano e enriquecido com meio mineral básico suplementado com PCE. A análise das alterações nas comunidades de bactérias nos reatores foi feita por PCRDGGE e seqüenciamento parcial do gene rRNA 16S. No ensaio de degradação do PCE no RHLF foi utilizado meio com PCE suplementado ou não com lactato e acetato. Tanto pelo DGGE quanto pelo seqüenciamento, foi observada a seleção de bactérias específicas no reator. A partir das análises de seqüenciamento, essas bactérias foram identificadas como Alphaproteobacteria e Sphingobacteria. No ensaio de degradação do PCE, os parâmetros físico-químicos do meio não mostraram variações ao longo do comprimento dos reatores. As análises de COVs mostraram uma grande eficiência na degradação do PCE (98%), com um tempo de retenção de 12 horas, não havendo diferença significativa na percentagem de degradação em meio com lactato ou acetato, com relação ao controle sem fonte de carbono. No processo de degradação nenhum dos produtos da via de degradação do PCE foi detectado, o que sugere uma via alternativa de degradação do PCE, a qual ocorre em aerobiose.Tetrachloroethene (PCE) is one of the most important contaminants of groundwater, since it is highly toxic and potentially carcinogenic. The bacterial communities of PCE contaminated groundwater and the diversity of bacteria capable of degrading this contaminant are barely known. The objective of this work is to compare the structure of bacterial communities from groundwater samples from a PCE contaminated site and select a microbial consortium capable to degrading efficiently PCE in a horizontal fixed bed reactor (HFBR). Groundwater samples from eight monitoring wells, installed in a PCE contaminated site were collected and analyzed for determination of dissolved oxygen, redox potential, electrical conductivity, pH, and concentrations of tetrachloroethene, trichloroethene (TCE), cis- and trans-dichloroethene, vinyl chloride (VOCs). The structure of the bacterial communities was determined by PCR-DGGE and 16S rRNA gene clone sequencing. The physical-chemical parameters oscillated considerately throughout time in all the monitoring wells (MW). PCE and TCE were detected only in MW6. The bacterial community structures in the groundwater from the MWs analyzed showed temporal and spatial variation. The analysis of the bacterial communities in MW6 and MW8, contaminated and non-contaminated with PCE, respectively, based on sequencing of 16S rRNA gene clones revealed results to the ones observed by DGGE. Estimated richness of bacterial species was higher in samples from MW8, at least in two sampling times, suggesting that the contamination with PCE is associated with reduction of bacterial diversity in groundwater. Enrichment cultures and PCE biodegradation assays were performed in a HFBR, which was filled with sediment from MW6 immobilized onto polyurethane foam and enriched with basic mineral medium supplemented with PCE. Shifts in bacterial community structure were analyzed using PCRDGGE and partial sequencing of 16S rRNA gene clones. In the PCE biodegradation assays in the HFBR, were performed in medium containing lactate or acetate. DGGE and 16S rRNA gene clone sequencing data suggest selection of specific bacteria in the reactor. Sequencing data showed that these bacteria belong to Alphaproteobacteria and Sphingobacteria. In the PCE biodegradation assays, media physical-chemical parameters did not show variation along the reactor length. VOC analyses showed a great efficiency in the degradation of PCE (98%) with a residence time of 12 hours in the reactor, and no significant differences were observed in the presence of lactate or acetate, as compared to the medium without a carbon source. During the biodegradation process, none of the products from the anaerobic pathway of PCE reductive dechlorination was detected, suggesting that an alternative PCE biodegradation pathway is occurring in aerobiosis.