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Kellermann, Claudia. "Autotrophy in Groundwater Ecosystems." Diss., lmu, 2009. http://nbn-resolving.de/urn:nbn:de:bvb:19-104813.
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Giusti, Andrea. "Impact of climate changes on groundwater levels and dependent ecosystems." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018.
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Groundwater is naturally present below the ground level and is a fundamental resource which supports the activity of the surface-level ecosystems. In the semiarid region of Portugal the vegetation ecosystems have been adapted by developing root systems which enable them to access deep soil water to cope with recurring droughts. As a result of environmental changes linked to climate change, water availability in the soil is expected to decrease as consequence of temperature increment and decline in precipitation. These changes will cause a drop in the aquifer recharge and phreatic level with possible impacts on the groundwater-dependent ecosystems. Within this framework, the objective of the project is to estimate the impacts of climatic changes on the groundwater system present in the study area, which is characterized from the geotechnical, meteorological and hydrogeological points of view. To address the problem, a numerical model of the portion between ground level and the water table, referred to as the “vadose zone”, is obtained. The model acts as an investigation tool to estimate the ecosystem water balance and the water table fluctuations for different scenarios. A present scenario is modelled to understand the processes taking place in a soil vertical profile and the effects of vegetation and water table position on water dynamics. Model calibration is done using experimental data from tests performed on collected soil samples to find soil hydraulic properties, then adjusted using in-situ data. The model is used to simulate future conditions in a climate change scenario and to evaluate their impact on the overall water balance, making predictions about the evolution of the groundwater position. The results show a high dependency of the ecosystem on the soil water availability, meaning that significant impacts are expected in a climate change scenario. In this case, the model predicts a general decrease in water table level, of up to 8 m by year 2100.
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Isokangas, E. (Elina). "Quantifying the groundwater dependence of boreal ecosystems using environmental tracers." Doctoral thesis, Oulun yliopisto, 2018. http://urn.fi/urn:isbn:9789526220376.
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Abstract Groundwater-dependent ecosystems (GDEs) are aquatic or terrestrial ecosystems that rely directly or indirectly on groundwater (GW). Recent European and Finnish legislation requires better consideration of these systems in GW management. The main aim of this thesis was to develop new methods for GDE classification and management, by testing environmental tracer methods in different environments. New information about GW-surface water interactions was obtained and novel methods for GDE classification and management were developed for lakes, peatlands, streams, and springs. Stable water isotopes proved to be an efficient tool for determining the GW dependence of lakes. An iterative isotope mass balance method was applied for 67 lakes situated in the Rokua esker aquifer area. Stable water isotopes also showed potential in determining the GW dependence of a peatland surface horizon. A study conducted in peatlands adjacent to Viinivaara esker aquifer indicated that the GW dependence of peatlands can vary significantly and that GW-dependent areas can extend outside current GW protection areas. Thermal images proved useful in pinpointing clear GW seepage locations in peatlands. For streams, a novel stream tracer index method was developed to evaluate GW dependence based on GW volume in streams, thermal properties of streams, and stream water quality. The method was tested in three streams discharging from Viinivaara and Rokua aquifers and was found to efficiently capture spatial variations in GW dependence. In Oulanka region, hydrological and chemical characterization and statistical methods were used to classify springs into different types. Spring altitude and δ2H value were identified as useful proxies for spring water chemistry. The methods developed in this thesis can be helpful when classifying and studying GDEs and applying environmental tracer methods in various environments. Knowing the GW dependence of an ecosystem, the impacts of possible GW table decline caused by e.g., GW abstraction, drainage, and/or climate change can be evaluated. For large-scale applications, GDE classification methods have to be practical, effective, and low-cost. Combined use of stable water isotopes and other tracers can be especially effective for characterizing ecosystem hydrology on different temporal and spatial scalesTiivistelmä Pohjavedestä riippuvat ekosysteemit (GDE) ovat vesi- tai maaekosysteemejä, jotka ovat suoraan tai epäsuorasti riippuvaisia pohjavedestä. Euroopan Unionin ja Suomen lainsäädännön mukaan pohjavesien hallinnassa tulisi ottaa paremmin huomioon GDEt. Tämän työn tavoitteena oli kehittää uusia menetelmiä näiden ekosysteemien luokitteluun ja hallintaan. Luonnollisia merkkiainemenetelmiä soveltaen saatiin uutta tietoa pohjavesi-pintavesi vuorovaikutuksesta ja kehitettiin uusia menetelmiä GDE-luokitteluun järville, soille, puroille ja lähteille. Veden stabiilit isotoopit osoittautuivat tehokkaaksi työkaluksi järvien pohjavesiriippuvuuden määrittämisessä. Iteratiivista isotooppimassatase-menetelmää käytettiin 67 Rokuan järven pohjavesiriippuvuuden selvittämiseen. Veden stabiileilla isotoopeilla pystyttiin myös määrittämään suon pinnan pohjavesiriippuvuus. Viinivaaran harjun viereisen suoalueen tutkimus näytti, että suon pohjavesiriippuvuus voi vaihdella merkittävästi ja pohjavedestä riippuvia alueita löytyy myös nykyisten pohjavesirajojen ulkopuolelta. Lisäksi soilla havaittiin selkeitä pohjavedenpurkupaikkoja lämpökamerakuvauksen avulla. Puroille kehitettiin uusi menetelmä, jolla niiden pohjavesiriippuvuutta voidaan arvioida perustuen pohjaveden määrään puroissa, puroveden lämpötilaominaisuuksiin ja puroveden laatuun. Menetelmää testattiin Viinivaaran ja Rokuan harjuista purkautuville puroille ja sillä havaittiin pohjavesiriippuvuuden vaihtelevan purojen eri osissa. Oulangan lähteitä luokiteltiin eri tyyppeihin hydrologisen ja kemiallisen karakterisoinnin ja tilastollisten menetelmien avulla. Lähteiden altitudin ja δ2H-arvon havaittiin ennustavan lähdeveden kemiallista koostumusta. Tässä tutkimuksessa kehitetyt menetelmät voivat olla hyödyllisiä GDE-luokittelussa, eri ekosysteemien tutkimisessa ja luonnollisten merkkiainemenetelmien soveltamisessa eri ympäristöissä. Kun ekosysteemin pohjavesiriippuvuus tiedetään, voidaan arvioida pohjavedenotosta, ojituksesta ja/tai ilmaston muutoksesta mahdollisesti aiheutuvan pohjavedenpinnan laskun vaikutuksia. Suuressa mittakaavassa, GDE-luokittelumenetelmien tulee olla käytännöllisiä, tehokkaita ja halpoja. Veden stabiilien isotooppien ja muiden merkkiaineiden yhdistetty käyttö vaikuttaa olevan tähän erityisen tehokas työkalu, jolla voidaan ymmärtää ekosysteemien hydrologiaa eri temporaalisissa ja spatiaalisissa mittakaavoissa
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Rossi, P. M. (Pekka M. ). "Integrated management of groundwater and dependent ecosystems in a Finnish esker." Doctoral thesis, Oulun yliopisto, 2014. http://urn.fi/urn:isbn:9789526204789.
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Abstract Groundwater, a key part of the hydrological cycle, is under increasing pressure from different land uses and changing climate. However, less attention has been paid to integrated groundwater management than surface waters. This thesis combined hydrological and socio-economic research for the case study of the Rokua esker aquifer in order to update current concepts of groundwater management. The Rokua area contains groundwater-dependent lakes and a periodic water level decline has raised concerns about the future of these lakes. Peatland drainage in the vicinity of the aquifer has been accused of changing the aquifer conditions. Groundwater discharge from the esker aquifer to drained peatland was studied to identify relevant hydrological processes for groundwater-surface water interactions. The results revealed a connection between the aquifer and the peatland whereby groundwater can enter the ditches through seepage or preferential flow. Modeling was used to determine critical factors in the management of the esker aquifer-peatland system. The results showed that climate and land use can affect esker groundwater, while peatland drainage in the vicinity can have similar impacts to groundwater abstraction and drought. Peatland restoration by filling in drainage ditches could possibly restore the aquifer groundwater levels. However, for the Rokua aquifer, which will possibly experience less severe dry periods in the future, extensive drainage restoration is currently too major, uncertain, and expensive a measure relative to the expected benefits. Multi-criteria decision analysis was used to identify ways of facilitating stakeholder involvement and learning in groundwater management. The results obtained with this participatory process confirmed that it can foster learning on complicated groundwater issues and collaboration in a process encompassing disputes and diverse interests. The decision analysis process led to the initiation of dialogue on more integrated management, where the preferences of all stakeholders were discussed and taken into account. Overall, this thesis shows how different aspects of aquifer management, such as land use, climate, ecological and economic values, and stakeholder preferences, can all be taken into account using a combined method which reduces the mistrust between opposing interests through research and information, resulting in more robust future planningTiivistelmä Pohjaveteen, hydrologisen kierron avainosaan, kohdistuu kasvavia paineita eri maankäytön muodoista ja ilmastonmuutoksesta. Pohjaveden hallintaan ei kuitenkaan ole kiinnitetty tarvittavaa huomiota. Tässä väitöstyössä yhdistettiin hydrologista ja sosioekonomista tutkimusta Rokuan harjualueella pohjaveden hallintakonseptin päivittämiseksi. Rokuan alueella on useita pohjavedestä riippuvaisia järviä, joiden vedenpinta on kausittain laskenut voimakkaasti. Pintojen lasku on kasvattanut paikallisten huolta järvien tilasta. Harjua ympäröivät metsäojitetut turvemaat, ja ojituksia on syytetty pohjaveden tilan ja sitä kautta myös järvien tilan heikkenemisestä. Työn ensimmäisessä osassa tutkittiin pohjaveden hydrologisia purkautumisprosesseja harjun pohjavesiesiintymästä ojitetulle suoalueelle. Tulokset osoittivat hydraulisen yhteyden akviferin ja turvemaan välillä: pohjavesi pääsi purkautumaan metsäojiin joko suotautumalla tai turpeen kaksoishuokoisuusrakenteiden kautta. Seuraavassa vaiheessa työtä pohjavesimallinnusta käytettiin määrittämään kriittisiä pohjaveden tilaan vaikuttavia tekijöitä pohjavesi-turvemaa-systeemissä. Mallinnustulosten perusteella niin ilmasto kuin maankäyttökin vaikuttavat kumpikin suoraan pohjaveden pinnankorkeuden tilaan. Turvemaiden ojituksilla pohjavesialueella voi olla samoja vaikutuksia pohjaveden pinnankorkeuden tasoihin kuin pohjaveden otolla tai kuivilla kausilla. Turvemaiden ennallistaminen ojia täyttämällä voi osittain palauttaa vedenpinnan tasoja pohjavesialueella. Rokuan harjualueen tapauksessa suuren mittakaavan oja-alueiden ennallistaminen todettiin kuitenkin liian epävarmaksi ja kalliiksi toimenpiteeksi hyötyihin nähden, varsinkin jos kuivien kausien vaikutus suurilla harjualueilla heikkenee tulevaisuudessa sademäärien kasvun myötä. Työn kolmannessa osassa käytettiin monitavoitearviointia eri sidosryhmien osallistamiseen ja oppimiseen pohjavesien hallinnassa. Osallistavasta prosessista saadut tulokset vahvistivat, että menetelmää voidaan käyttää oppimisen edesauttamiseen vaikeissa pohjavesiasioissa sekä yhteistyön muodostamiseen ristiriitaisessa ja monimutkaisessa tapauksessa. Monitavoitearvioinnin prosessi johti keskustelun avaukseen yhtenäisemmän suunnittelun puolesta, joka ottaa huomioon eri sidosryhmien näkökulmat ja tuo ne osaksi keskustelua. Tämä väitöstyö osoitti miten eri pohjavesialueen hallintaan tarvittavat näkökulmat, kuten maankäyttö, ilmasto, ekologiset ja ekonomiset arvot, sekä sidosryhmien mielipiteet voidaan kaikki ottaa huomioon yhdistämällä eri metodeja. Näin tutkimuksella ja informoinnilla vähennetään epäluottamusta eri intressitahojen välillä ja luodaan pohja vakaammalle pohjavesialueiden tulevaisuuden suunnittelulle
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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.
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Hernández, del Amo Elena. "Origin and fate of nitrite in model ecosystems: case studies in groundwater and constructed wetlands." Doctoral thesis, Universitat de Girona, 2019. http://hdl.handle.net/10803/668664.
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Nitrogen pollution in water is common in our environment, especially in places affected by agriculture and livestock, industry or wastewater discharge areas. Ammonium and nitrate are the most common pollutants and can be removed primarily by microorganisms. This removal is carried out by a series of microorganisms that live in these environments as communities, the study of which is essential to evaluate the efficiency of the N removal from water. In this thesis, a variety of methods have been used to study these microorganisms accurately in two types of highly sensitive environments for pollution, wetlands and groundwater.La contaminació de l’aigua per excés de nitrogen és habitual en el nostre entorn, especialment en llocs impactats per l’agricultura i la ramaderia, zones de descàrrega d’aigües residuals, o com a resultat de l’activitat industrial. L’amoni i el nitrat són els contaminants més freqüents i poden ser eliminats principalment pels microorganismes. Aquesta eliminació la duen a terme diferents microorganismes que habiten en aquests ambients en forma de comunitats, l’estudi de les quals és cabdal per a valorar l’eficiència de l’eliminació del N de l’aigua. En aquesta tesi es desenvolupen mètodes per a fer un estudi acurat d’aquests microorganismes en dos tipus d’ambients altament sensibles a la contaminació, els aiguamolls i l’aigua freàtica.
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Sigonyela, Vuyolwethu. "Towards understanding the groundwater dependent ecosystems within the Table Mountain Group Aquifer: a conceptual approach." Thesis, University of the Western Cape, 2006. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_9454_1183462560.
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Understanding of Groundwater Dependent Ecosystems (GDEs) and their extent within the Table Mountain Group (TMG) aquifer is poor. To understand the dependence to basic ecological and hydrogeological concepts need explanation. The use of current literature aided in identification and classification. From the literature it has come clear that groundwater dependence centers around two issues, water source and water use determination. The use of Geographical Information System (GIS) showed its potential in proof of water sources. Rainfall data and a Digital Elevation Model (DEM) for the Uniondale area have been used to do watershed delineation, which is in line with locating GDEs on a landscape. Thus the conceptual approach should be a broad one that sets a basis for both investigation (scientific research) and institutional arrangements (management).
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Lehosmaa, K. (Kaisa). "Anthropogenic impacts and restoration of boreal spring ecosystems." Doctoral thesis, Oulun yliopisto, 2018. http://urn.fi/urn:isbn:9789526218533.
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Abstract Human activities have increasingly altered freshwater ecosystems. Land use is a major driver of habitat loss and land use-related input of nutrients and other pollutants from agriculture, forestry and urbanization have deteriorated water quality. Freshwater research has mainly focused on lakes and streams while the effects of anthropogenic stressors on groundwater-dependent ecosystems (GDEs) are poorly known. Likewise, the effectiveness of ecological restoration in mitigating human disturbance in GDEs remains understudied. In this thesis, I studied the effects of two main anthropogenic stressors – land drainage and groundwater contamination – on boreal spring ecosystems and evaluated the recovery of spring biodiversity and ecosystem functioning after habitat restoration. I applied several structural (macroinvertebrates, bryophytes, leaf-decomposing fungi and groundwater bacteria) and functional (organic matter decomposition and primary productivity) measures to provide a comprehensive insight into these issues. Both stressors modified spring ecosystems. Land drainage reduced the key ecosystem processes. Long-term monitoring of drainage-impacted springs showed a marked biodiversity loss and change of spring-dwelling bryophytes, and no signs of recovery were observed after about 20 years since the intial land drainage. Groundwater contamination, indicated by elevated nitrate and chloride concentrations, altered the structure of spring biota, reduced their taxonomic diversity and suppressed primary productivity in the most severely contaminated springs. Spring restoration improved habitat quality by reducing drainage-induced inflow of surface water, thus re-establishing groundwater-dominated hydrological conditions. Restoration increased abundance of habitat-specialist bryophytes and shifted macroinvertebrate composition towards natural conditions, despite the restoration actions being fairly recent. Anthropogenic activities can thus cause severe structural and functional degradation of spring ecosystems, and their self-recovery potential from these stressors seems low. Habitat restoration bears great promise as a cost-effective approach to mitigate drainage-induced impacts on spring ecosystems, but protection and co-management of groundwater resources are urgently needed to secure the role of springs as biodiversity hotspots in the boreal forest landscapeTiivistelmä Ihmistoiminta muuttaa yhä enemmän vesiekosysteemejä. Maankäyttö on johtanut elinympäristöjen häviämiseen, ja siihen liittyvä ravinne- ja haitta-ainekuormitus maa- ja metsätaloudesta sekä kaupunkiympäristöistä on merkittävästi huonontanut veden laatua johtaen maailmanlaajuiseen vesiluonnon monimuotoisuuden heikentymiseen. Vesiekosysteemien tutkimus on keskittynyt pääasiassa järvi- ja jokiympäristöihin, kun ihmistoiminnan vaikutukset pohjavesiriippuvaisiin ekosysteemeihin tunnetaan edelleen huonosti. Samoin kunnostusten merkitys pohjavesiriippuvaisten ekosysteemien tilan parantamiseksi on selvittämättä. Väitöskirjassani tarkastelin kahden keskeisen ihmistoiminnan – metsäojituksen ja pohjaveden laadun heikkenemisen – vaikutuksia lähde-ekosysteemeihin sekä arvioin elinympäristökunnostusten vaikutuksia niiden rakenteeseen ja toimintaan. Sovelsin työssäni rakenteellisia (pohjaeläimet, sammalet, lehtikariketta hajottavat sienet ja pohjavesibakteerit) ja toiminnallisia (eloperäisen aineksen hajoaminen ja perustuotanto) mittareita tuottamaan kattavan käsityksen tutkimuskysymyksiini. Sekä metsäojitukset että pohjaveden laadun heikkeneminen aiheuttavat muutoksia lähteiden rakenteessa ja toiminnassa. Metsäojitukset hidastavat keskeisiä ekosysteemitoimintoja ja johtavat lähdesammallajiston muutokseen ja monimuotoisuuden taantumiseen. Pohjaveden pilaantuminen, jota työssä ilmennettiin kohonneilla nitraatti- ja kloridipitoisuuksilla, heikentää lähdelajiston monimuotoisuutta, muuttaa lajikoostumusta ja johtaa perustuotannon laskuun voimakkaimmin kuormitetuissa lähteissä. Kunnostus parantaa lähde-elinympäristön laatua vähentämällä metsäojien aiheuttamaa pintavesivaikutusta palauttaen pohjavesivaltaisen hydrologisen tilan. Lähdekunnostusten myötä lähdesammaleet runsastuvat ja pohjaeläinyhteisön rakenne palautuu luonnontilaisten lähteiden kaltaiseksi, vaikka kunnostuksista on kulunut vasta muutamia vuosia. Väitöskirjan tulokset osoittavat, että ihmisen toiminta voi aiheuttaa muutoksia lähde-ekosysteemien rakenteessa ja toiminnassa ja lähteiden luontainen palautuminen häiriöstä on hidasta. Lähde-elinympäristöjen kunnostus vaikuttaa lupaavalta suojelutoimenpiteeltä metsäojitusten vaikutusten vähentämisessä, mutta lähteiden säilyttäminen monimuotoisena ja suojelullisesti arvokkaana luontotyyppinä edellyttää pohjavesivarojen hallinnan ja tilan suojelun tehostamista
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Mendez-Estrella, Romeo, Jose Romo-Leon, Alejandro Castellanos, Fabiola Gandarilla-Aizpuro, and Kyle Hartfield. "Analyzing Landscape Trends on Agriculture, Introduced Exotic Grasslands and Riparian Ecosystems in Arid Regions of Mexico." MDPI AG, 2016. http://hdl.handle.net/10150/621492.
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Riparian Zones are considered biodiversity and ecosystem services hotspots. In arid environments, these ecosystems represent key habitats, since water availability makes them unique in terms of fauna, flora and ecological processes. Simple yet powerful remote sensing techniques were used to assess how spatial and temporal land cover dynamics, and water depth reflect distribution of key land cover types in riparian areas. Our study area includes the San Miguel and Zanjon rivers in Northwest Mexico. We used a supervised classification and regression tree (CART) algorithm to produce thematic classifications (with accuracies higher than 78%) for 1993, 2002 and 2011 using Landsat TM scenes. Our results suggest a decline in agriculture (32.5% area decrease) and cultivated grasslands (21.1% area decrease) from 1993 to 2011 in the study area. We found constant fluctuation between adjacent land cover classes and riparian habitat. We also found that water depth restricts Riparian Vegetation distribution but not agricultural lands or induced grasslands. Using remote sensing combined with spatial analysis, we were able to reach a better understanding of how riparian habitats are being modified in arid environments and how they have changed through time.
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Maier, Nadine [Verfasser]. "A new method for spatio-temporally explicit predictions of groundwater, surface water and habitat interactions in riparian ecosystems / Nadine Maier." Gießen : Universitätsbibliothek, 2018. http://d-nb.info/1168145619/34.
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Gosselin, Marie-Pierre. "Aquatic habitat characterization and use in groundwater versus surface runoff influenced streams : brown trout (Salmo trutta) and bullhead (Cottus gobio)." Thesis, Coventry University, 2009. http://curve.coventry.ac.uk/open/items/8d69e5ee-5c54-1d43-2390-e9bea23aad35/1.
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Riverine physical habitats and habitat utilization by fish have often been studied independently. Varying flows modify habitat composition and connectivity within a stream but its influence on habitat use is not well understood. This study examined brown trout (Salmo trutta) and bullhead (Cottus gobio) utilization of physical habitats that vary with flow in terms of size and type, persistence or duration, and frequency of change from one state to another, by comparing groundwater-dominated sites on the River Tern (Shropshire) with surface runoff-dominated lowland, riffle-pool sites on the Dowles Brook (Worcestershire). Mesohabitat surveys carried out at two-month intervals on a groundwater-dominated stream and on a surface runoff-influenced stream showed differences in habitat composition and diversity between the two types of rivers. The temporal variability in mesohabitat composition was also shown to differ between the two flow regime types. In the groundwater-influenced stream, mesohabitat composition hardly varied between flows whereas in the flashy stream it varied to a great extent with discharge. Habitat suitability curves for brown trout and bullhead were constructed to predict the potential location of the fish according to flow. The resulting prediction maps were tested in the field during fish surveys using direct underwater observation (snorkelling). Under the groundwater-influenced flow regime brown trout displayed a constant pattern of mesohabitat use over flows. Mesohabitats with non-varying characteristics over flows and with permanent features such as large woody debris, macrophytes or any feature providing shelter and food were favoured. Biological processes, such as hierarchy, life cycle and life stage appeared to play a key role in determining fish habitat use and to a greater extent than physical processes in these streams. Bullhead observations in the flashy river showed that mesohabitat use varied with flow but that some mesohabitats were always favoured in the stream. Pools and glides were the most commonly used mesohabitat, due to their stability over flows and their role as shelter from harsh hydraulic conditions and as food retention zones. The presence of cobbles was also found to be determinant in bullhead choice of habitat. In this flashy environment, physical processes such as flow and depth and velocity conditions appeared to be a more decisive factor in bullhead strategy of habitat use than biological processes. This research shows that: 1. Though differences in habitat use strategies between the two flow regimes can in part be attributed to differing ecology between the species, flow variability affects fish behaviour. 2. A stable flow regime allows biological processes to be the main driving force in determining fishbehaviour and location. A highly variable environment requires fish to develop behaviour strategies in response to variations in hydraulic conditions, such as depth and velocity, which constitute the key factor in determining fish location.
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Marozava, Sviatlana [Verfasser], Rainer U. [Akademischer Betreuer] Meckenstock, and Wilfried F. M. [Akademischer Betreuer] Röling. "Insights into the microbial physiology of bacteria capable of degrading pollutants in contaminated groundwater ecosystems / Sviatlana Marozava. Gutachter: Rainer U. Meckenstock ; Wilfried F.M. Röling. Betreuer: Rainer U. Meckenstock." München : Universitätsbibliothek der TU München, 2013. http://d-nb.info/1044680474/34.
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Neufeld, David A. "Planning to protect groundwater, toward an ecosystem approach." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape15/PQDD_0011/NQ30636.pdf.
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Henderson, James D. "An ecosystem approach to groundwater management in the Gulf Islands." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0010/MQ26766.pdf.
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Muschiol, Daniel [Verfasser]. "Meiofauna in a chemosynthetic groundwater ecosystem: Movile Cave, Romania / Daniel Muschiol." Bielefeld : Universitätsbibliothek Bielefeld, 2009. http://d-nb.info/1036110915/34.
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Alaibakhsh, Masoomeh. "Digital change detection and separation of anthropogenic and natural impacts on ecohydrological conditions in the Pilbara region, WA." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2017. https://ro.ecu.edu.au/theses/1951.
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A deficiency in crucial digital data, such as vegetation cover, in remote regions is a challenging issue for sustainable water management and planning, especially for areas undergoing rapid development, such as mining in the Pilbara, Western Australia. This is particularly relevant to Inflow and Groundwater Dependent Vegetation (IGDVs) (riparian vegetation and groundwater dependent vegetation) which provide important ecological services and, as such, require regional protection. However, such invaluable assets experience changes over time due to either human activities such as land development or natural phenomena such as climate change or fire events.
The main objectives of this research was to 1) advance an approach to delineate inflow dependent ecosystems at a local scale; 2) adopt it to map the assets at regional scale using remotely sensed data (Landsat 5 TM imagery due to its appropriate temporal and spatial resolution for historical studies, 1986-2011), ground-truth data and available information such as reports, digital layer and climate data; 3) develop a method for identification and quantitative assessment of IGDVs changes and attribution of the changes to particular impacts or stressors, and 4) apply the developed change detection method to investigate and evaluate impacts of an adopted water resource management options on inflow dependent assets in the Pilbara.
Outcomes of the research exposed that the proposed delineation method allowed production of accurate inflow dependent ecosystems maps for the Pilbara bioregion. The change detection method was also effective in detecting various spatial and temporal scales of changes and separating anthropogenic and natural impacts. It was further discovered that climate has had significant impacts on the assets of the area.
The finding and information produced from this research is capable to aid government, industry and communities to consider the environmental, social, cultural and economic aspects of the sustainable use, development and management of land and water resources in arid and semiarid Pilbara, WA and areas with similar ecohydrological conditions. Four papers were prepared from the research, two are published and two are under review.
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Arufe, Jorge A. "Urbanization, water quality, and aquatic ecosystem condition in the lower Truckee River watershed." 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:1436471.
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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.
19
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.
20
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.
Full text
21
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.
22
Lee, Robert F. "Human health and coastal ecosystem risk assessment of the Massachusetts Military Reservation main base landfill groundwater plume." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/41358.
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Adjei, Cornelius Owusu. "Citizen Action, Power Relations and Wetland Management in the Tampa Bay Urban Socio-ecosystem." Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/3942.
Full textAbstract:
Wetlands are vital ecosystems that provide ecological, economic and social benefits to societies. In the Tampa Bay region in West Central Florida, a growing population has put immense pressure on wetlands. The situation has not gone unnoticed in the public domain with concerns raised about the need to formulate policies that would protect them. However, it has been difficult to ascertain the level of citizen involvement in the decision making process.
This study aimed at investigating whether the perceptions and concerns of citizens drove them to influence local water policy. Questionnaires were used to collect data from residents living in close proximity to well fields situated in wetlands in Northwestern Hillsborough County.
Results of the research showed that residents demonstrated a high degree of knowledge about water resources in the Tampa Bay region. Residents expressed concerns about groundwater pumping and development, and attributed them to changes in their environment. However, there was little engagement from residents with decision makers to address these concerns. This study therefore recommends that improved participatory mechanisms be created by local water agencies to incorporate valuable inputs from the public.
24
Franklin, Hannah Mayford. "Understanding Variation in Water Quality using a Riverscape Perspective." Thesis, University of Canterbury. Biological Sciences, 2010. http://hdl.handle.net/10092/5197.
Full textAbstract:
With the increasing degradation of rivers worldwide, an understanding of spatial and temporal patterns in freshwater quality is important. Water quality is highly variable in space and time, yet this is largely overlooked at the scale of stream catchments. I employed a landscape ecology approach to examine the spatial patterning of water quality in complex, impacted stream networks on the Canterbury Plains of the South Island of New Zealand, with the goal of understanding how land-use effects proliferate through stream systems.
In particular, I used “snapshot” sampling events in conjunction with spatial modelling and longitudinal profiles to investigate the ways in which spatial and environmental factors influence the variability of water quality in stream networks. Spatial eigenfunction analyses showed that distance measures, which took into account variable connectivity by flow and distance along the stream between sites, explained more spatial variance in water quality than traditional distance metrics. Small upstream reaches were more spatially and temporally variable than main stems (under summer base-flow conditions). The extent of spatial variation in water quality differed between stream networks, potentially depending on linkages to groundwater and the surrounding landscape. My results indicated that the water quality of headwater streams can have a disproportionate influence over water quality throughout an entire network.
I investigated spatio-temporal patterns in water quality more intensively in one stream network, the Cam River, in which I found consistent spatial pattern through time. The relative balance between nutrient inputs (pollution and groundwater) and in-stream conditions influenced the spatial pattern of water quality, as well as that of several ecosystem processes which I measured simultaneously. The spatially intensive and explicit approach has allowed identification of key factors controlling water quality and ecosystem processes throughout the Cam River. This research highlights the importance of taking a spatially explicit approach when studying stream water quality and that such an approach could be insightful and will contribute to solving current stream management problems.
25
Ben, Maamar Sarah. "Biodiversité des eaux souterraines dans un gradient de temps de résidence et d'influence anthropique : approches métagénomique et géochimique couplées." Thesis, Rennes 1, 2016. http://www.theses.fr/2016REN1S108/document.
Full textAbstract:
Les aquifères de socle fracturés très répandus en Bretagne, constituent des formations géologiques hétérogènes renfermant des ressources en eau. Ces structures sont souvent constituées d'une zone altérée et d'une zone fracturée. La zone altérée est peu épaisse et proche de la surface, elle est constituée de roches altérées envahies par l'eau souterraine qui y circule rapidement des hauts topographiques du bassin versant vers l'exutoire. L'eau y présente des temps de résidence courts (<20 ans) et est souvent polluée par les nitrates. La zone altérée située plus en profondeur et plus épaisse est constituée de roches dures traversées par des fractures. L'eau circule exclusivement au travers de fractures et lentement, le temps de résidence de l'eau y est donc long (>40 ans). Dans cette zone, l'eau est plus minéralisée et souvent riche en fer en Bretagne. Ces différentes circulations d'eau, induisent des conditions chimiques contrastées dans les zones altérée et fracturée, mais leur effet sur l'écosystème microbien des eaux souterraines n'a jamais été exploré. Cette étude montre que les circulations hydrologiques influencent à l'échelle régionale et locale la structuration des communautés microbiennes au sein des eaux souterraines d'aquifères de socle. La position d'une eau souterraine le long des voies de circulations des eaux souterraines dites « boucles hydrologiques » contrôle directement la structure des communautés microbiennes via le contrôle de la succession des donneurs et accepteurs d'électrons disponibles. Les communautés microbiennes analysées montrent une prédominance de Nitrobacter. Dans l'eau souterraine récente (<20 ans) donc principalement dans la zone altérée, les Nitrobacter. sont surtout des Comamonadaceae et Oxalobacteraceae, microorganismes versatiles et capables de dénitrifier. Dans l'eau souterraine ancienne (>40 ans) et isolée donc dans la zone fracturée, ce sont en grande majorité des Gallionellaceae, microorganismes microaérophiles spécialisés dans l'oxydation du fer(II). La prédominance des Gallionellaceae dans la zone fracturée suggère un écosystème profond basé sur l'oxydation du fer(II). Cependant, ce processus suppose une arrivée minimale d'oxygène dans la partie profonde, via par exemple un mélange avec une masse d'eau récente oxygénée. La proportion de Gallionellaceae dans les différentes eaux analysées montre une corrélation positive avec le degré de mélange des eaux anciennes avec des eaux récentes, jusqu'à une limite de 20% d'eau récente. Le suivi temporel de la dynamique des communautés d'un aquifère avant et au début de la recharge a montré dans la zone altérée des conditions chimiques très fluctuantes et une communauté microbienne très changeante mais toujours constituée de nombreux potentiels dénitrifiants. Dans la zone fracturée, la communauté dominée par les Gallionellaceae est relativement stable, malgré des changements chimiques ponctuels substantiels et un degré de mélange transitoire important (jusqu'à 60% d'eau récente) au début de la recharge. Les Gallionellaceae semblent donc capables de résister à des changements ponctuels et importants des conditions chimiques. Les eaux souterraines de la partie profonde des aquifères, bien qu'isolées, restent relativement connectées à la surface ce qui permet probablement le maintien de l'écosystème microbien profondHard-rock aquifers are heterogeneous geological structure very widespread in Britany that have the property to store groundwater. These aquifers are often made of a weathered zone and a fractured zone. The weathered zone is a rather thin layer close to the surface and is constituted of weathered rocks submerged in groundwater. In this zone, groundwater circulates rapidly from the upper parts of the watershed to the aquifer outlet, thus shows short groundwater residence time (< 20y) and is often polluted by nitrates. The fractured zone is located deeper and is thicker. It is composed of fresh rocks crossed by fractures in which groundwater exclusively flows with a very slow velocity, thus groundwater residence time in this zone is rather long (>40 y). In the fractured zone, groundwater is much more mineralized and often rich in iron, in Britany. The differences of flow velocities in the weathered and the fractured zones are responsible for contrasted chemical conditions in these two zones, but the influence of groundwater flow velocity on the microbial ecosystem in groundwater remains largely unexplored. This work shows hydrologic circulations influence the microbial community structuration in hard-rock aquifer groundwater at regional and local scales. Position of a groundwater along a hydrologic flowpath or a “hydrological loop” directly controls microbial community structure through the control of the successively available electron donors and acceptors. The analyzed microbial communities show a predominance of Betaproteobacteria. In recent groundwater (< 20y) thus particularly in the weathered zone, Betaproteobacteria are mainly Comamonadaceae and Oxalobacteraceae, which are generalists able to do denitrification. In old and isolated groundwater (> 40y) thus particularly in the fractured zone, Betaproteobacteria are mainly Gallionellaceae, which are microaerophilic iron-oxidizer. The predominance of Gallionellaceae in the fractured zone suggests a deep ecosystem based on iron oxidation. However, this process implies a minimal input of oxygen in the deeper part, for instance via mixing with recent oxygenated groundwater. Proportion of Gallionellaceae in the different analyzed groundwater shows a positive correlation with the degree of mixing between old and recent groundwater, up to a limit of 20% of recent groundwater. The temporal microbial community dynamics in a single aquifer, before and during the beginning of recharge, demonstrated in the weathered part very fluctuant chemical conditions and a shifting microbial community that remains always composed of numerous potential denitrifiers. In the fractured part, microbial community is dominated by Gallionellaceae and remains rather stable, despite the punctual but substantial changing of the chemical conditions and degree of mixing (up to 60% of recent groundwater) at the beginning of the recharge. Gallionellaceae seem thus able to resist to important and punctual chemical conditions changings. Groundwater in the deeper part of aquifers, even isolated, remains relatively connected to surface, likely allowing the deep microbial ecosystem to maintain
26
FERRARINI, ANDREA. "Furnitura multipla di servizi ecosistemici da culture energetiche poliennali." Doctoral thesis, Università Cattolica del Sacro Cuore, 2016. http://hdl.handle.net/10280/10802.
Full textAbstract:
La sfida nel 21esimo secolo è quella di fornire cibo e energia ad un mondo in continua crescita demografica e allo stesso tempo conservare l’ambiente. In questa tesi uno scenario alternativo di uso del suolo per la produzione di bioenergia è stato testato: le fasce tampone bioenergetiche. Considerate le problematiche ambientali legate al trilemma “cibo-energia-ambiente”, la struttura del Millennium Ecosystem Assessment sui servizi ecosistemici (SE) fornisce l’opportunità di esaminare l’impatto ambientale di questo nuovo scenario bioenergetico. In questa tesi ho mirato a determinare in che misura le colture bioenergetiche poliennali influenzino la fornitura multipla di SE quando coltivate come fasce tampone. Per raggiungere questo obiettivo, ho combinato una revisione sistematica della letteratura sui SE forniti da colture energetiche poliennali (CEP) con una prova sperimentale su fasce tampone bioenergetiche.
Applicando una metodologia di attribuzione di punteggi agli impatti sui SE estratti dal materiale bibliografico raccolto, ho mostrato come coltivando le CEP lungo i margini dei campi coltivati esista una grande opportunità per sostenere la fornitura multipla di SE. La coltivazione delle CEP come fasce tampone adiacenti a campi agricoli può migliorare i SE di regolazione del clima, dell’acqua e della biodiversità, sostenere la salute del suolo e fornire biomassa dedicata alla produzione di bioenergia. Al contrario, la conversione di margini di campo di prati stabili ha mostrato un impatto netto negativo sulla fornitura multipla di SE.
Tuttavia, due sono i principali svantaggi che sono stati individuati relativamente alla creazione e alla gestione delle fasce tampone bioenergetiche. Primo, diversi sono i fattori sito-specifici di tipo idro-pedologico lungo i margini dei campi che devono essere tenuti in considerazione poiché possono avere un impatto negativo sull’affrancamento delle colture e la loro produttività a medio-lungo termine. Secondo, riguardo la catena di approvvigionamento della biomassa, uno spazio di lavoro limitato per le macchine agricole è stato riconosciuto come principale inconveniente per le fasce tampone bioenergetiche rispetto alle CEP coltivate in pieno campo. Questo limite logistico di natura spaziale può inevitabilmente incrementare i tempi e le operazioni di taglio e raccolta della biomassa e quindi in ultima il consumo di combustili fossili.
Grazie ad una prova sperimentale su fasce tampone bioenergetiche condotta in un terreno sabbioso-limoso con falda acquifera poco profonda contaminata da nitrati di origine agricola, si è dimostrato come fasce tampone coltivate con miscanto e salice siano in grado di intercettare e rimuovere i nitrati in falda (>60%) tanto quanto fasce tampone con specie avventizie. CEP come miscanto e salice, grazie ai loro apparati radicali profondi, hanno mostrato essere in grado di promuovere delle relazioni pianta-suolo-microorganismi lungo l’intero profilo del suolo utili ai fini ambientali delle fasce tampone bioenergetiche. Infatti, negli strati più profondi, una maggiore biomassa radicale ha portato le CEP a superare le specie avventizie in termini di rimozione biologica dei nitrati dal suolo e mitigazione potenziale dei gas serra. Inoltre, i risultati relativi alla produzione di biomassa e le asportazioni di N legata alla fase di raccolta hanno confermato ulteriormente come la coltivazione di CEP lungo i corsi d’acqua sia una strategia win-win: produzione di biomassa e protezione dell’ambiente.
In conclusione, il potenziale rivelato dalle CEP in termini di fornitura multipla di SE suggerisce che la loro coltivazione, come elementi paesaggistici perenni in posizioni strategiche all'interno di paesaggio agricolo, è un'opzione promettente per promuovere l'intensificazione ecologicamente sostenibile degli agroecosistemi.The 21st century will challenge agriculture to feed and fuel a growing world while conserving the environment. In this thesis an alternative bioenergy land use scenario to the conversion of marginal land has been tested: the bioenergy buffers. Given the environmental issues related to “food-energy-environment” trilemma, the Millennium Ecosystem Assessment framework on ES provides an opportunity to examine the environmental impacts of this new bioenergy land use scenario. In this thesis I aimed to determine to what extent do the perennial bioenergy crops affect the delivery of multiple ES when cultivated as bioenergy buffers. To reach this aim, I combined a systematic revision of literature on ES provided by perennial bioenergy crops with a field experiment on bioenergy buffers. Applying an impact scoring methodology to the effects on ES extracted from literature, I showed that, cultivating perennial bioenergy crops along field margins of former croplands offer a great opportunity to sustain the provision of multiple ES. The cultivation of perennial bioenergy crops on field margins can improve climate, biodiversity and water regulation services, sustain soil health and provide biomass for energetic purposes. On the contrary, grassland conversion showed a net negative impact on multiple ES provision. Nevertheless, I found two main shortcomings related to bioenergy buffers establishment and management. First, several site-specific factors along field margins must be taken into account, because they can affect crop establishment and buffers long-term productivity. Second, regarding to biomass supply chain, a limited working space for the farm machinery operations has been recognized as the main disadvantages of bioenergy buffers compared to large-scale bioenergy plantations. This spatial logistics constraint may inevitably increase harvest and collection operation times and fossil fuel consumption. Conducting a field experiment with bioenergy buffers in a nitrate-enriched shallow groundwater, I showed that miscanthus and willow buffers are able to efficiently intercept and remove from groundwater the incoming NO3-N as much as buffer strips with spontaneous species. Yet, due to their deep rooting systems, bioenergy buffers promote significant plant-microbial linkages along the soil profile. At deeper soil layers, a higher fine root biomass led perennial bioenergy crops to outperform patches of adventitious vegetation in terms of biological N removal from soil and belowground GHG mitigation potential. The results on biomass production and N removal via harvesting further confirmed that the cultivation of perennial bioenergy crops along watercourses is an effective win-win strategy: biomass production and protection of the environment. In conclusion, the revealed potential of perennial bioenergy crops on multiple ES provision implies that their cultivation as perennial landscape elements in strategic locations within landscape is a promising option to promote the ecological sustainable intensification of agroecosystems.
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Kellermann, Claudia [Verfasser]. "Autotrophy in groundwater ecosystems / vorgelegt von Claudia Sabine Kellermann." 2008. http://d-nb.info/99651869X/34.
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Furlong, Michelle Ann. "Bacterial communities in natural ecosystems : groundwater, soil, earthworm casts and burrows." 2000. http://purl.galileo.usg.edu/uga%5Fetd/furlong%5Fmichelle%5Fa%5F200008%5Fphd.
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Gaskill, Teresa G. Restom. "Hydrology of forest ecosystems in the Honouliuli Preserve implications for groundwater recharge and watershed restoration /." Thesis, 2004. http://proquest.umi.com/pqdweb?index=0&did=813798261&SrchMode=1&sid=4&Fmt=2&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1235092745&clientId=23440.
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Dekker, Peter Andrew. "Evaluating the Potential for Low Impact Development to Mitigate Impacts of Urbanization on Groundwater Dependent Ecosystems using MIKE SHE." Thesis, 2012. http://hdl.handle.net/10214/5286.
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Groundwater dependent ecosystems (GDEs), including wetlands and river baseflow systems, are a topic of substantial scientific study. The degradation of GDEs due to urbanization has been well documented. An altered hydrologic regime, through increased impervious area resulting in a flashier hydrologic regime with lower troughs, higher peaks, and quicker changes, has been recognized as a main factor affecting ecological condition. Yet studies on GDEs rarely include a hydrologic modelling component.
In this study, the conjunctive hydrologic model MIKE SHE was used to simulate the Lovers Creek subwatershed near Barrie, ON. The hydrologic regime was simulated for pre-development (natural), current (urbanized), and various low-impact development (LID) land use scenarios. The results were linked to the ecological condition via the TQmean metric, which has been used in the literature to relate the hydrologic and ecological conditions of streams.
The highest percentage LID scenario restored, on average, 11% of the reduction in TQmean that occurred from pre-development to urbanized conditions, indicating that LID has the potential to protect GDEs in urbanized watersheds. It is expected that the effect of LID would be amplified if considered on a more local scale within a predominantly high density urban area. Recommendations for future modelling efforts to evaluate GDEs and represent LID are made.
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(5930639), Carolyn L. Gleason. "LIFE IN THE RAIN SHADOW: UNDERSTANDING SOURCES OF RECHARGE, GROUNDWATER FLOW, AND THEIR EFFECTS ON GROUNDWATER DEPENDENT ECOSYSTEMS IN THE PANAMINT RANGE, DEATH VALLEY, CALIFORNIA, USA." Thesis, 2019.
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Despite its location in the rain shadow of the southern Sierra Nevada, the Panamint Range within Death Valley National Park, CA hosts a complex aquifer system that supports numerous springs. These springs, in turn, support unique groundwater-dependent ecological communities. Spring emergences range in elevation from 2434 m above sea level (within the mountain block) to 77 m below sea level (in the adjacent basins). Waters were collected from representative Panamint Range springs and analyzed for environmental isotopes and geochemical tracers to address the following questions: 1) What is the primary source of recharge for the springs? How much recharge occurs on the Panamint Range? 2) What groundwater flowpaths and geologic units support springflow generation? and 3) What are the residence times of the springs? The stable isotopic composition (δ18O and δ2H) of spring water and precipitation indicate that localized high-elevation snowmelt is the dominant source of recharge to these perennial springs, though recharge from rainfall is not wholly insignificant. Geochemical evolution was evaluated using principle component analysis to compare the concentrations of all major spring cations and anions in a multidimensional space and group them according to dominant geochemical signatures. These resulting geochemical groups are controlled primarily by topography. The Noonday Dolomite and other carbonate units in the range are identified as the water-bearing units in the mountain block based on the 87Sr/86Sr of spring waters and rock samples. These units also offer higher hydraulic conductivities than other formations and are chemically similar. Radiocarbon- and 3H derived residence times of these spring waters range from modern to approximately 1840 years, with the shortest residence times at higher altitudes and Hanaupah Canyon and increasing residence times with decreasing altitude. This residence time-altitude relationship is likewise likely topography-driven though there are significant disparities in mountain block storage between the various canyons of the range resulting in variable residence times between drainages. Lower Warm Springs A and B, however, are the exceptions to this trend as they emerge at lower altitudes (750m above sea level) and are likely driven by the transport of groundwater to the surface along faults which increases both the temperature and groundwater residence times of waters from these springs. Benthic macroinvertebrates and benthic and planktonic microbes were also sampled for each spring studied. BMI and microbial community structure in the Panamint Range is likewise topography-controlled with more tolerant communities at lower elevations (within more chemically evolved waters) and less tolerant species in the unevolved waters at higher elevations.
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"Desert Playa Wetlands: Ecological Controls of their Functioning and Responses to Climate Change." Doctoral diss., 2016. http://hdl.handle.net/2286/R.I.40695.
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abstract: The Basin and Range province of southwestern USA are composed of different grassland and shrubland ecosystems. Particularly understudied ecosystems in this region are playas, which are ephemerally-flooded wetlands located in topographic low areas of hydrologically-closed dryland catchments. There is not much known about the ecological functioning of playas and the role of playas within desert basins. Even less is known about how global change drivers may affect playas in the future. The main objective of this thesis was to better understand the ecological functioning and the impact of climate change on desert playa wetlands. I collected new data, used existing long-term data, and used simulation modelling techniques to address this objective. I compared playa soils to upland soils and found that playas were hotspots of soil organic carbon and nutrient storage within a desert basin. I also used existing data to analyze the response of above-ground net primary productivity (ANPP) to annual precipitation in playas and upland ecosystems. I found that playa ANPP responded in a non-linear concave-down relationship with annual precipitation amount. Playa ANPP peaked in moderately wet years and declined in very wet years, which was most likely due to flooding; whereas, upland ANPP increased linearly with precipitation. I measured soil organic carbon and nitrogen concentrations in a representative subset of playas and measured the biophysical characteristics of the upland catchments associated with each playa. I found that both catchment geomorphology and vegetation cover were correlated to differences in soil organic carbon and nitrogen among playas. These results showed the importance external soil-inputs delivered via surface runon to playas. Finally, I empirically measured groundwater recharge beneath playas and combined these empirical data with modelling data to forecast how playa groundwater recharge may change in the future. I concluded that playas contribute to groundwater recharge in desert aquifers, playa runon is a strong predictor of playa groundwater recharge, and climate change will have a net-positive impact on groundwater recharge beneath playas. Overall, my thesis research increased the understanding of the role of desert playas on the functioning of dryland ecosystems.Dissertation/Thesis
Doctoral Dissertation Biology 2016
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Wilson, Kevin Patrick. "An in-situ temperature manipulation of a shallow groundwater ecosystem : analysing consequences of global warming /." 2008. http://proquest.umi.com/pqdlink?did=1670249881&sid=14&Fmt=2&clientId=12520&RQT=309&VName=PQD.
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Fan, Yen-Tzu, and 范晏慈. "Importance of groundwater activities in downstream urban river ecosystem: A case study in Jingmei River, Taiwan." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/3jp677.
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碩士國立臺灣大學
生物環境系統工程學研究所
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In river ecosystems, groundwater (GW) and surface water (SW) exchange is an important natural process for maintaining vertical hydrological connectivity, material fluxes and ecosystem health. The vertical GW-SW exchange could increase the habitat complexity and maintain the stability of the water physiochemistry and hydrology in the rivers. Spatial variation of GW-SW exchange pattern could represent a key factor for characterizing aquatic biodiversity and faunal community structure. Also, GW activities exhibit seasonality resulting in the dynamic patterns of river ecosystems. In the northern Taiwan, high GW level in Taipei basin during March to July and low level during September to October are influenced by the seasonal variation of precipitation and evaporation. Such temporal variation could thus be important for enhance the diversity of river habitat and aquatic biota. However, Taiwan as other countries in the world, it has been rapid population increase and urban development since the recent decades, most downstream rivers have been channelized to avoid flood and increase urban land use. River beds of some channelized rivers are commonly covered with impermeable concrete materials. This man-made structure causes the blockage of GW-SW exchange. Also, urbanization usually results in the dominance of invasive species in aquatic ecosystems and this can endanger the native communities. In this study, we first carried out small-scale field manipulative experiment on river bed of Jingmei River and compared the areas of “pit” (depression structure directly caused by GW) and “non-pit” (areas not directly affected by GW activities) to investigate the influences such as water and habitat quality, faunal composition, and the trophic basis associated with GW activities in an urban river ecosystem. Our study site located at the downstream Jingmei River in the Taipei basin where sufficient GW layer lies underground. Taipei basin is one of the densely urbanized areas and most rivers in the basin are channelized with impervious river bed to reduce flood impacts. However, sufficient GW layer widely extends underneath the Taipei basin especially at Jingmei district. The downstream Jingmei River is channelized at both river banks but the river bed remains unmodified so that GW-SW exchange could be maintained. In addition, the dominant fish in downstream Jingmei River is dominated by tilapia (Cichlidae: Oreochromis niloticus) which has a special breeding behavior that male fish make bowl-shaped craters to attract the female for spawning. As we found many bowl-shaped pits on the river bedduring our preliminary survey, we conducted the fish exclusion experiment to confirm whether the pits were formed from GW activity or fish breeding behavior in downstream Jingmei River. Then, flow visualization experiment was undertaken at pits and control locations to determine the direction of the GW activity in Jingmei River. We further compared the water chemistry between pits and non-pits to determine the differences of water quality influenced by GW activities. In addition, we investigated the invertebrate biodiversity and community structure at pits and non-pits to evaluate the biological response to GW activity. Finally, we used stable carbon and nitrogen isotope analysis in conjunction with gut content analysis to study the GW influence on the trophic basis in downstream Jingmei River. As the bowl-shaped pits were formed under both the fish exclusion and control areas, our results confirmed that GW-SW exchange did occur in downstream Jingmei River. Flow visualization experiment results revealed that the sinking rate at pits was significantly lower than at non-pits (1-way ANOVA, p < 0.05). This indicated that the GW activities at pits was via GW upwelling. In addition, conductivity, TDS, ORP, pH, and water temperature were significantly different between pits and non-pits (1-way ANOVA, p < 0.05) suggesting that GW activities strongly affected the water quality in this urban river. Moreover, our study showed that invertebrate density was higher in subsurface sediment at pits although the taxon richness and biodiversity of invertebrates were not particularly higher at pits than non-pits. This indicated that GW influenced pits by providing more suitable habitats to support high faunal density. Our findings also showed that fishes utilized high proportion (~ 40%) of pit resources in Jingmei River. Since food resources of pits were characterized by lower C/N ratio, consumers tended to use the pit resources and the dependence of pit resources was related to ontogenetic development of tilapia. Our study confirmed that GW activities could effectively enhance the habitat quality through increasing the habitat diversity in the hydromorphologically homogeneous urban river. Hence, our results could provide important information for the urban river restoration in the future.
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Peterson, Tim J. "Multiple hydrological steady states and resilience." 2009. http://repository.unimelb.edu.au/10187/8540.
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Many physically-based models of surface and groundwater hydrology are constructed without the possibility of multiple stable states. For such a conceptualisation, at the cessation of a transient hydrological disturbance of any magnitude, the model will return to the original stable state and therefore will have an infinite resilience. Ecosystem resilience science propose a very different dynamic where, if the system has a positive feedback, disturbances may shift the system over a threshold where, upon cessation of the disturbance, the system will move to a different steady state. This dissertation brings together concepts from hydrology and ecosystem resilience science to highlight this often implicit assumption within hydrology. It tests the assumption that dry land water-limited catchments always have only one steady state (henceforth referred to as 'attractor'). Following a discussion of this implicit assumption within hydrology, approaches for rigorous testing that could result in its falsification are considered and that of numerical modelling is adopted. The aims of the research were to test this assumption by proposing a biophysically plausible hydrological model; utilise it to investigate the catchment attributes likely to result in multiple attractors; and to assess the model's validity by way of implementation and calibration. (For complete abstract open document.)
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Aguilar, Perez Raquel. "Arid groundwater dependent ecosystem response to salinization processes in a coastal aquifer: deriving vegetation indicators of the aquifer condition." Master's thesis, 2013. http://hdl.handle.net/10400.1/6823.
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To maintain the groundwater quality represents a critical concern because of the increasing
levels of groundwater contamination globally. This goal is particularly important in arid
zones, where due to the scarce rainfall the groundwater is a significant source of freshwater
supply to society and ecosystems. Here we follow an ecohydrological approach to derive
effortless indicators of the aquifers condition, based on the monitoring of phreatohytic
vegetation, a particular case of Groundwater Dependent Ecosystems (GDEs). This is the
case of Z.lotus a deciduous arid shrub from North of Africa and Southeast Spain. This study
aims to relate the biological condition of Z. lotus with the groundwater condition to explore
the feasibility for using vegetation indicators to inform about the salinization levels of
groundwater in coastal aquifers. With this goal we: 1) evaluate the salinization levels of an
aquifer from the Cabo de Gata-Níjar Natural Park, by wells sampling; 2) determine the
brackish water distance gradient based on the use of Vertical Electrical Sounding (VES),the
physiological condition of Z. lotus through leaf chemical analysis and spectral vegetation
indices (NDVI and NDWI) along a salinity gradient. The results showed that the phreatic
level, distance from the sea and therefore the salinity and freshwater available to GDE, are
reflected in the leaf chemical composition of Z. lotus. However, salinity levels did not
reflected clearly in vegetation greenness (NDVI) and vegetation water content (NDWI),
probably because of Z. lotus showed salt tolerance within the range of salinity found in the
aquifer. As a conclusion, we propose leaf ion concentration as a good indicator of
groundwater salinization, while the spectral indices are good indicators of vegetation health
but not for the groundwater salinization. Z.lotus is probably the only terrestrial GDE in the
arid zones of Europe and its study is essential for the management and conservation of this
ecosystem.Manter a qualidade das águas subterrâneas constitui uma preocupação crucial devido aos crescentes níveis de contaminação dos lençois freáticos a nível mundial. Este tópico é particularmente importante nas zonas áridas, uma vez que as precipitações, que representam uma fonte importante de abastecimento de água doce subterrânea para a sociedade e para os ecosistemas, são escassas nas zonas áridas. Neste estudo utilizamos uma abordagem ecohidrológica para obter indicadores de esforço da condição dos aquíferos, com base na monitorização da vegetação freatófita, um caso particular de Ecossistemas Dependentes de Águas Subterrâneas (GDEs: Groundwater dependent ecosystems). Como exemplo de vegetação freatófita das zonas áridas analisou-se o Z.lotus que é um arbusto de folha caduca do Norte de África e Sudeste de Espanha. Este estudo teve como objetivo relacionar a estado biológico do Z. lotus com o estado das águas subterrâneas para explorar a viabilidade de utilização de indicadores de vegetação para informar sobre os níveis de salinização das águas subterrâneas dos aquíferos costeiros. Para isso: 1) avaliaram-se os níveis de salinização do aquífero do Parque do Cabo de Gata-Níjar Natural, através de amostragem de poços; 2) determinou-se o gradiente de distância de água salobra com recurso a uma sondagem elétrica vertical (SEV), a condição fisiológica do Z. lotus através da análise química foliar e os índices espectrais de vegetação (NDVI e NDWI) ao longo de um gradiente de salinidade. Os resultados mostraram que através da análise química das folhas de Z. lotus foi possivel determinar o nível freático, a distância ao mar, a salinidade e a água doce disponíveis para os GDEs. No entanto, os níveis de salinidade não se refletiram claramente no verdor da vegetação (NDVI) e no teor de água da vegetação (NDWI), provavelmente por Z. lotus apresentar tolerância ao sal dentro da gama de salinidade presente no aquífero. Em conclusão, recomendamos como bom indicador da salinização das águas subterrâneas a concentração de íons nas folhas. Em contrapartida, sugerimos que os índices espectrais de vegetação são bons indicadores da saúde da vegetação, mas não são bons para a quantificação da salinização das águas subterráneas. Z. lotus é provavelmente o único EDAS terrestre nas zonas áridas da Europa e o seu estudo é fundamental para a gestão e conservação deste ecossistema.
Universidade do Algarve, Faculdade de Ciências e Tecnologia
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Knüppe, Kathrin. "Comparative case study analysis of adaptive groundwater governance and management regimes: Exploring ecosystem services in South Africa, Spain and Germany." Doctoral thesis, 2012. https://repositorium.ub.uni-osnabrueck.de/handle/urn:nbn:de:gbv:700-2012102210424.
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Our daily lives depend on the provision of services by different ecosystems in which an important contribution is made by groundwater. To balance competing demands placed on groundwater for socioeconomic and ecological benefits constitute major challenges for water managers. At the policy-science interface the ecosystem service concept represents an appropriate approach to communicate management challenges in which researchers and politicians must take into account human and biophysical characteristics as intertwined systems. This study investigated the complexity of groundwater governance, and linkages between management and corresponding effects on ecosystem services. Empirical insights were derived from case studies in South Africa, Spain and Germany. The analytical focus includes (a) the degree of vertical (multi-level) and horizontal (cross-sectoral) integration which frame crucial characteristics of an adaptive governance regime and (b) the role of formal and informal institutions governing groundwater. In doing so, an conceptual and analytical approach was applied, especially developed to support a systematic and consistent investigation of policy and management processes. Evidence highlights that higher degrees of integration: (i) opens up the political arena for environmental perspectives, (ii) increases the quality of management plans, (iii) accelerates the implementation of measurements, (iv) mitigates conflicts between different groundwater users, and (v) increases the awareness of various ecosystem services. Further the results indicate that having well-crafted institutions in place does not automatically indicate successful groundwater management in the sense of bringing about positive results for socioeconomic or ecological sustainability. This work made a significant contribution to interdisciplinary research in the field of groundwater governance and ecosystem service management that builds the foundations for improving the policy-science interface.
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Crowell, Morgan. "An ecosystem service approach to inform reactive nitrogen management in the lower Yakima River Basin, Washington." Thesis, 2012. http://hdl.handle.net/1957/35853.
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Spatially explicit ecosystem service valuation (ESV) allows for the identification of the location and magnitude of services provided by natural ecosystems to human activities along with a measure of their significance based upon economic valuation. While ESV has been used to provide new insight into land use management, few studies have identified the connections between the values of ecosystem services and ecological sensitivity to nitrogen loading despite a growing body of ecosystem service literature. This research combines a GIS-based, value transfer approach to map ecosystem services in the Lower Yakima River Basin (LYRB), Washington, USA, along with estimates of nitrogen loading to identify how nitrogen management may affect ecosystem services in the basin. This analysis combines values of ecosystem services with estimates of nitrogen loading and identifies subwatersheds and specific parcels within a Groundwater Management Area (GWMA) most susceptible to reductions in ecosystem services due to excess nitrogen loading. Based on the benefit transfer analysis, wetlands and forested areas have disproportionately high values of ecosystem services when compared to their land area in the LYRB, while pasture and cultivated crops contribute much less to the total value of ecosystem service flows in proportion to the total area in the LYRB. Across the study area estimated nitrogen loads are strongly driven by the location of concentrated animal feeding operations (CAFOs) and cultivated crops. Areas of particularly high nitrogen loading and high ESV may highlight specific areas for achieving immediate success in increasing or maintaining ecosystem services through appropriately focused regulatory mechanisms. The land cover analysis however, completely neglects the values and importance of subsurface processes and groundwater resources in ecosystem service assessment, and therefore an econometric model is applied to estimate willingness to pay (WTP) to maintain safe nitrate levels in private wells. Through the incorporation of WTP estimates for groundwater quality, a more complete economic and ecological perspective on the effects of landscape N loading in the study site is highlighted. The results of these estimates clearly indicate that ecosystem services from groundwater should be considered to have significant value in the LYRB.
Further economic valuation data on specific land cover types and the value of groundwater quality, whether from primary studies or meta-analysis, is needed to refine relative measures of ecosystem service values and more confidently describe these values in specific dollar amounts. Additionally, limits in spatial data resolution may contribute to errors in location and magnitude of ecosystem services, and is an area in need of further development. Despite these potential limitations, this analysis highlights a promising direction for combining spatially explicit ecosystem service valuation with nutrient loading data to identify the location and potential magnitude of effects on ecosystem services from management practices.Graduation date: 2013
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"Deep Percolation in Arid Piedmont Watersheds and Its Sensitivity to Ecosystem Change." Doctoral diss., 2017. http://hdl.handle.net/2286/R.I.48444.
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abstract: Population growth within drylands is occurring faster than growth in any other ecologic zone, putting pressure on already stressed water resources. Because the availability of surface water supplies in drylands tends to be highly variable, many of these populations rely on groundwater. A critical process contributing to groundwater recharge is the interaction between ephemeral channels and groundwater aquifers. Generally, it has been found that ephemeral channels contribute to groundwater recharge when streamflow infiltrates into the sandy bottoms of channels. This process has traditionally been studied in channels that drain large areas (10s to 100s km2). In this dissertation, I study the interactions between surface water and groundwater via ephemeral channels in a first-order watershed located on an arid piedmont slope within the Jornada Experimental Range (JER) in the Chihuahuan Desert. To achieve this, I utilize a combination of high-resolution observations and computer simulations using a modified hydrologic model to quantify groundwater recharge and shed light on the geomorphic and ecologic processes that affect the rate of recharge. Observational results indicate that runoff generated within the piedmont slope contributes significantly to deep percolation. During the short-term (6 yr) study period, we estimated 385 mm of total percolation, 62 mm/year, or a ratio of percolation to rainfall of 0.25. Based on the instrument network, we identified that percolation occurs inside channel areas when these receive overland sheetflow from hillslopes. By utilizing a modified version of the hydrologic model, TIN-based Real-time Integrated Basin Simulator (tRIBS), that was calibrated and validated using the observational dataset, I quantified the effects of changing watershed properties on groundwater recharge. Distributed model simulations quantify how deep percolation is produced during the streamflow generation process, and indicate that it plays a significant role in moderating the production of streamflow. Sensitivity analyses reveal that hillslope properties control the amount of rainfall necessary to initiate percolation while channel properties control the partitioning of hillslope runoff into streamflow and deep percolation. Synthetic vegetation experiments show that woody plant encroachment leads to increases in both deep percolation and streamflow. Further woody plant encroachment may result in the unexpected enhancement of dryland aquifer sustainability.Dissertation/Thesis
Doctoral Dissertation Geological Sciences 2017
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Medina, Israel. "Characterization of a Karst Coastal Ecosystem in the Mexican Caribbean: Assessing the Influence of Coastal Hydrodynamics and Submerged Groundwater Discharges on Seagrass." Thesis, 2011. http://hdl.handle.net/1969.1/ETD-TAMU-2011-05-9060.
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Bahia de la Ascension (BA) is a pristine, shallow, karst bay located in the Mexican Caribbean, a region experiencing rapid population growth stimulated by intense tourism development. The overall objective of this study was to address the natural hydrographic variability of this inherently vulnerable ecosystem and assess its influence on a key habitat, the seagrass. The chapters follow the three-branched nature of the study which tackled the connected ecosystem issues of coastal hydrology, physical dynamics of flow and circulation, and the ecological dynamics of the seagrass species Thalassia testudinum in BA.
Freshwater input to BA is primarily by submerged groundwater discharges and surface runoff; both sources are derived from fissures in the aquifer but feature distinct water quality due to the interaction with adjacent wetlands. Hurricanes explain 36 percent of the interannual precipitation variability in the region. The water balance indicates a persistent net outflow from BA to the adjacent shelf, suggesting an intense exchange across inlets. Both diurnal and semidiurnal tidal frequencies are attenuated in the inner bay, where a meteorologically-induced subtidal water level increase may occur during four-day southeasterly winds. A clear SW-NE salinity gradient was established during dry and rainy seasons, with a strong tidally-driven marine influence throughout the central basin, and a perennial mesohaline ambient in the southwestern-most bay, where hydrodynamics are primarily controlled by wind stress. Thalassia testudinum is the dominant seagrass species in BA, occupying ~90 percent of the substrate, including the freshwater-influenced inner bay. High nutrient inputs, including phosphorus which might have limiting effects in karst environments, along with the wind-driven circulation controlling water residence times are associated with the successful development of T. testudinum (up to 1,461.23 g DW m-2) within the SW bay. Farthest into the central basin, Thalassia consistently exhibited an inverse correlation between abundance and density of shoots. This pattern was enhanced under exceptional precipitation and inputs of denuded organic matter resulting from hurricanes making landfall on this region. The relationship between nutrient distribution and the above/belowground ratio suggested that Thalassia growing in BA favors the development of the aerial component as nutrients availability increases.
This study provides a basic understanding of the most important processes molding the patterns of variability exhibited by T. testudinum in Bahia de la Ascension. The salinity gradient and external nutrient supply, along with the hydrodynamic component, define the spatial scale at which the connectivity between the adjacent wetland, the bay, and the shelf may occur.
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Kim, John H. "Trading Carbon and Water Through Vegetation Shifts." Diss., 2011. http://hdl.handle.net/10161/5703.
Full textAbstract:
In this dissertation, I explored the effects of vegetation type on ecosystem services, focusing on services with significant potential to mitigate global environmental challenges: carbon sequestration and groundwater recharge. I analyzed >600 estimates of groundwater recharge to obtain the first global combined analysis of groundwater recharge and vegetation type. Using a regression model, I found that vegetation was the second best predictor of recharge after precipitation. Recharge rates were lowest under forests, intermediate in grasslands, and highest under croplands. The differences between vegetation types were higher in more humid climates and sandy soils but proportionately, the differences between vegetation types were higher in more arid climates and clayey soils. My extensive field estimates of recharge under paired vegetation types in central Argentina and southwestern United States provided a more direct test of the relationships between vegetation and recharge. The field data confirmed the strong influences of vegetation and its interactions with abiotic factors on recharge observed in the synthesis. The results indicate that vegetation shifts have a proportionately larger potential to affect recharge in more arid climates and clayey soils.
At the same study systems, I compared my field estimates of recharge to organic carbon stocks (in biomass, litter and soil) under the different vegetation types to evaluate tradeoffs between carbon sequestration and groundwater recharge as affected by vegetation shifts. To determine net values of vegetation shifts, I combined the changes in carbon and water with reported economic values of the ecosystem services. Based on physiological tradeoffs between photosynthesis and transpiration in plants, I hypothesized that vegetation promoting carbon storage would reduce recharge and vice versa. Changes in water and carbon services were inversely proportional, with rain-fed cultivation increasing groundwater recharge but decreasing carbon storage compared to the grasslands they replaced whereas woody encroachment did the opposite. In contrast, cultivated plots irrigated with ground water decreased both ecosystem services. Higher precipitation and clay content both exacerbated changes in carbon storage with grassland conversions, whereas higher precipitation accentuated, but higher clay content diminished, those in recharge. Regardless of the nature of vegetation shift, most of the net values of grassland conversions were negative, with the shifts representing increasing costs in the following order: woody encroachment, rain-fed cultivation and irrigated cultivation. Values of changes in carbon were greater in magnitude than those of recharge, indicating that establishment of carbon markets may drive land-use changes in grasslands over water markets.
Lastly, I examined the effects of changes in subsurface hydrology resulting from grassland conversion to croplands on soil inorganic carbon stocks in the same U.S. study system. I observed significantly lower inorganic carbon stocks under both rain-fed and irrigated croplands compared to the grasslands they replaced. The losses were visible to past 6 m depth in the soil profile and were uncharacteristically rapid for the carbon pool that is considered to be relatively inert. Based on the negative relationship between the inorganic carbon stocks and recharge rates and higher estimated exports of bicarbonates in recharge under croplands, I concluded that increased recharge with cultivation resulted in dissolution and leaching of grassland soil carbonates. Ecosystem services and their relationships to biotic and abiotic factors quantified here will further our understanding of the tradeoffs and interactions between the two services through vegetation shifts.
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Ramusiya, Fhedzisani. "Hydrological Characterisation of the Shingwedzi and Mphongolo River Basins in Kruger National Park, South Africa." Diss., 2010. http://hdl.handle.net/11602/1057.
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Lamberts, Jill S. "Nutrient release and cycling in the soils of a continental lodgepole pine (Pinus contorta Doug.) ecosystem, Bootleg Mountain, B.C." Thesis, 2005. http://hdl.handle.net/1828/46.
Full textAbstract:
Nutrient dynamics in a lodgepole pine forest at Bootleg Mountain, B.C., were investigated through the sampling of soil, snow and groundwater in six one-ha blocks. Nitrogen (NO3-, NH4+, TIN, TDN, TN), phosphorus (PO43-, TDP, TP), and DOC were analyzed in addition to N mineralization and nitrification. Position and dispersion statistics were computed for each variable and correlations (Pearson and Spearman) were computed for each pair of variables. The overall heterogeneities of soil, snow, and groundwater were generally lower between 1-ha blocks than between plots. Productivity in the soil was generally N-limited with low input from snow precipitation. Very little N leached from soil to groundwater. Phosphorus contents were highly variable and were the limiting nutrient in the groundwater. Rates of net and gross N mineralization and nitrification were determined using buried bags and 15N isotope dilutions. Gross rates were greater than net rates and nitrification was low relative to high immobilization rates. The N cycle appears to be tightly regulated, thus further study will be needed to monitor the impact of harvesting on N cycling.