Thesis (MSc)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: Understanding the responses of individual plant communities to variations in near-surface water levels and to water quality is a step towards determining the critical or important factors applicable to a Rapid Wetland Assessment System. This thesis describes and discusses factors associated with wetland plant communities, with an attempt to predict changes in a wetland system. This study was initiated with a primary aim of establishing the relationship between plant communities and the variation in near-surface water levels in areas occupied by various plant communities in the Middelvlei wetland system at Stellenbosch. A second aim was to assess whether water quality had an influence on the plant communities. Seven plant communities are identified and described from this particular wetland system using standard Braun-Blanquet techniques (Typha capensis Reedswamp; Cyperus textilis Sedgeland; Pennisetum macrourum Grassland; Juncus effusus Sedgeland; Cyperus longus Sedgeland; Cliffortia strobilifera Shrubland and Populus canescens Forest). The Typha capensis Reedswamp community is found in the wettest parts of the wetlands, with a fluctuation in water table from 0.10 m above surface during the wet season to 0.43 m below surface during the dry season. The Populus canescens Forest is actively invading the wetland replacing the wetland species by modifying the wetland hydrological condition. Water samples from 35 wells, collected on a monthly basis over 11 months, are used to assess sodium, magnesium, potassium, calcium, nitrate and phosphate, pH, redoxs potencial and dissolved oxygen levels in each community, over four seasons. Both multivariate analysis (ANOVA) and regression tree analysis (CART) are applied to evaluate differences between communities or groups of plant communities on a seasonal basis. Direct gradient analysis (CCA) is used to determine the relationship between plant communities and environmental variable gradients. A wide variation in water quality condition between plant communities is present. The Typha capensis Reedswamp community is associated with low nutrient levels (phosphates and nitrates) in all seasons. The Cyperus textilis Sedgeland is associated with low levels of nitrates and high phosphate levels. The Juncus effusus Sedgeland displays the highest phosphate concentration, occurring in summer, while low nitrate levels occur in this community during all the seasons. Dissolved oxygen in the near-surface water in this wetland is at very low concentrations, and has no significant difference between communities. It plays no major role in determining the occurrence and distribution of the plant communities. Most of the water chemical constituents measured in this study are the result of multiple complex relationships, with constituent variations occurring differently between communities. A remarkable seasonal distinction in the chemical constituents in different communities is present. Despite the complex nature of the relationships between plant communities and environmental factors, the low species diversity levels through the tendency for single species dominance and the strong association of these communities with particular environmental variables, the combination of these factors all add value to the use of wetland vegetation as a good tool to indicate wetland condition. An effort to understand wetland plant communities in relation to determining environmental factors would promote the use of plant communities as user-friendly tools for wetland monitoring and assessment. / AFRIKAANSE OPSOMMING: Om die reaksies van plantgemeenskappe teenoor variasies in naby-oppervlakte watervlakke te verstaan, is die eerste krities-belangrike faktor die ontwikkeling van ‘n sisteem om vleilande vinnig te assesseer. Hierdie studie se basiese mikpunt is om verwantskappe te soek tussen plantgemeenskappe in die Middelvlei Vleilandsisteem en wisseling in naby-oppervlak watervlakke. ‘n Sekondêre doel is om te bepaal of daar enige korrelasie is tussen waterkwaliteit en die plantgemeenskappe teenwoordig in die vleiland. Sewe plantgemeenskappe is in hierdie vleilandsisteem geïdentifiseer en beskryf deur gebruik te maak van standaard Braun-Blanquet tegnieke, naamlik die Typha capensis Rietmoeras; Cyperus textilis Biesieveld; Pennisetum macrourum Grasveld; Juncus effusus Biesieveld; Cyperus longus Biesieveld; Cliffortia strobilifera Struikveld en ‘n Populus canescens Woud. Die Typha capensis Rietmoeras kom in die natste dele van die vleilande voor, met vrywater wisselling vanaf 0.10 m bo grondoppervlakte, tydens die nat-seisoen, tot 0.43 m onder grondoppervlakte tydens die droë seisoen. Die Populus canescens Woud het die grootste wisseling in watervlak vanaf die grondoppervlakte tot ten minste ‘n diepte van 1.0 m gehad. Dit blyk dat die Populus canescens Woud besig is om die vleigemeenskappe aktief binne te dring deur die vleiland uit te droog. Water is maandeliks, oor 11 maande, uit 35 geperforeerde plastiek pype, sogenaamde ‘putte’ onttrek, om natrium, magnesium, kalium, kalsium, nitrate en fosfate, pH, redokspotensiaal en opgeloste suurstof vlakke se seisoenale wisseling te bepaal. Beide veelvuldige analise (ANOVA) en regressie-analises (CART) is bereken om enige betekenisvolle verskille tussen plantgemeenskappe te bepaal. Direkte Gradiëntanalise (CCA) is gebruik om die verwantskap tussen plantgemeenskappe en gradiënte van omgewingsveranderlikes te bepaal. Groot variasies in waterkwaliteit tussen plantgemeenskappe is waargeneem. Die Typha capensis Rietmoeras-gemeenskap is geassosieer met lae voedingstofvlakke (veral van fosfate en nitrate) in alle seisoene. Die Cyperus textilis Biesieveld-gemeenskap is geassosieer met lae nitraat- en hoë fosfaatvlakke. Die Juncus effusus Biesieveldgemeenskap vertoon die hoogste fosfaatvlakke, tydens die die somermaande, terwyl die nitraatvlakke deur al die seisoene ook laag bly. Opgeloste suurstof in die naby-oppervlakte water in die vleilandsisteem het deurgaans ‘n lae konsentrasie vertoon met geen betekenisvolle verskille tussen gemeenskappe nie. Dit speel dus geen belangrike rol in die voorkoms of verspreiding van die plantgemeenskappe nie Die meeste van hierdie faktore, gemeet om die waterkwaliteit te bepaal, het veelvoudige, komplekse verhoudingsverskille, gebaseer veral op konsentrasieverskille, tussen die gemeenskappe. Ten spyte van die komplekse verwantskap tussen die plantgemeenskappe en omgewingsfaktore, is die spesierykheid laag en kom die neiging tot eensoortigedominansie algemeen in die vleiland-plantgemeenskappe voor. Die sterk assosiasie tussen die plantgemeenskappe en bepaalde omgewingsveranderlikes voeg aansienlike waarde daaraan toe om vleilandplantegroei te gebruik as indikator van vleilandtoestand. ‘n Poging om die verwantskappe tussen vleiland-plantgemeenskappe en omgewingsveranderlikes algemeen te bepaal, sal die gebruikersvriendelike nut van vleiland-plantgemeenskappe vir vleilandmonitering en assessering duidelik uitwys.

<p>The main objectives of this study were to investigate (i) anovel wetland treatment technology and (ii) selected bed filtermedia for the removal of contaminants from landfill leachate. Areview of the literature concerning experiences of the use ofconstructed wetlands (CW) for the removal of nitrogen fromlandfill leachate, showed that at least three groups oftreatment systems are in practice: sub-surface flow wetlands,hybrid systems (a combination of vertical and horizontal flowwetlands) and, compact constructed wetland (CCW). Most of thesetypeswere generally effective in reducing nitrogen (N,<i>e.g.</i>NH₄-N, dominant N species in leachate) down toeffluent concentrations of about 10 mg L^-1. Unfortunately, very little evidence ofresponsible mechanisms for the removal of N was presented,although some data indicated denitrification. The treatmentperformance of a compact constructed wetland (CCW) applied atthe Tveta Landfill, Södertälje, Sweden, wasevaluated. Chemically purified leachate and untreated leachatewere applied in periods of 7 day submergence and 7 day drainageto different sections of the CCW. The removal efficiency variedbetween 40 and 82%, and a mass removal rate of up to 5.1 g m²d^-1was achieved. The chemical pre-treatment had adecisive role for the highest removal efficiencies obtained andit was unclear whether that treatment enhanced the efficiencybecause of lower toxicity and/or content of fewer competingcations. The possible combination of bed filter media and CCWas an ecotechnological treatment method for landfill leachatewas investigated by bench-scale laboratory column experiments.Reactive filter media (sorbents) was selected from their knownor suggested capacities for removal of heavy metals, nitrogenand phosphorus. Quartz sand or natural sand from an esker wasused as reference medium. Peat was used as an additionalcomponent in mixtures with the reactive media Polonite^®(product from the bedrock opoka) and blastfurnace slag (BFS). A small column study also involved zeolite.Phosphorus was efficiently removed by Polonite^®and NH₄-N to some extent. Concerning metal removal, thebest performance was found as well for Polonite^®, especially for Mn, Fe, Zn and Cu. The BFSshowed good removal efficiency for Cu, Ni and Mo. The removalof different elements was suggested to be a combination ofseveral factors,<i>e.g.</i>precipitation, ion exchange and adsorption. Priorto full-scale application of reactive filters at a landfillsite, matrix selection, filter design and operationalprocedures must be developed.</p><p><b>Keywords:</b>Blast furnace slag; Compact constructedwetland; Metals; Nitrogen; Polonite; Sorbents</p>

The United States Corps of Engineers is a federal agency responsible for regulating impacts to wetlands. Permit applications requesting authorization to impact wetlands are reviewed using a three step sequence: avoidance, minimization and compensatory mitigation. A national goal of no net loss of wetland acreage and function in compensatory mitigation has been recommended since 1987.Thirty Norfolk District projects requiring compensatory wetland mitigation in the permit years 1996-1998 were randomly selected for field review. The results showed that 10% of the project were never initiated or completed. Another 19% of the projects showed a net loss of acreage. However, many projects exceeded their required mitigation acreage. The mitigation types included creation/restoration (18 permits), commercial mitigation bank (3 permits), and an in-lieu fee trust fund (9 permits). Overall 1.76 acres were mitigated for every acre of wetland impacted. Creation/restoration projects had the highest ratio (2 acres mitigated for every acre impacted and the mitigation bank realized 1.82 acres for every acre impacted. Therefore, this study indicated that the Norfolk District is gaining more than 1 acre of wetland mitigation for every acre impacted, thus meeting the goal of no net loss of wetland acreage.

Ces travaux contribuent à caractériser des compartiments environnementaux (i.e. eau, sol et solution du sol, substrat, macrophytes à l’échelle individuelle et des communautés) et leur fonctionnement pour in fine améliorer l’efficacité de zones humides construites (CW) à décontaminer une masse d’eau contaminée en cuivre. Les connaissances sur le maintien de l’homéostasie de Cu chez les végétaux ainsi que sa phytotoxicité aux expositions élevées sont résumées. Les principaux mécanismes physico-chimiques et biologiques intervenant en phytoremédiation d’eaux contaminées en Cu en CW sont également discutés. Plusieurs solutions de phytoremédiation de type phytostabilisation aidée ont été évaluées en lysimètres in situ sur un site de traitement du bois contaminé au Cu, afin d’établir le potentiel de certains amendements à sorber Cu dans le substrat des CW. Les concentrations en éléments traces potentiellement toxiques (PTTE, dont Cu) et macroéléments des lixiviats migrants vers les horizons aquifères ont été quantifiées. Un laitier sidérurgique de type Linz-Donawitz enrichi en P (LDS, 1%) a permis le meilleur développement de Lemna minor L., utilisé ici comme bioindicateur, exposée aux lixiviats. En parallèle, les communautés de macrophytes ont été suivies le long du parcours de la Jalle d’Eysines, une rivière urbaine contaminée en Cu et autres PTTE. Les concentrations en PTTE ont été déterminées dans le sol, l’eau, l’eau interstitielle et les feuilles de 7 espèces de macrophytes. Un modèle statistique multivarié (analyse discriminante linéaire, LDA) a ensuite été élaboré sur la base des concentrations foliaires en PTTE pour biosurveiller l’exposition des macrophytes. Des populations de macrophytes ont aussi été prélevées sur des zones humides de contamination croissante en Cu en Europe (France, Espagne, Portugal et Italie), Biélorussie et Australie. La production de racines chez les macrophytes exposées pendant 3 semaines à des concentrations croissantes en Cu (0,08 ; 2,5 ; 5 ; 15 et 25 µM Cu) montre une variabilité intra-spécifique de la tolérance au Cu pour des populations de Juncus effusus, Schoenoplectus lacustris et Phalaris arundinacea. A l’inverse, une réponse similaire à une tolérance constitutive a été obtenue chez Typha latifolia et Iris pseudacorus, deux espèces à forte production de rhizomes. L’importance des rhizomes est discutée. Phragmites australis produit également des rhizomes, mais a présenté une variabilité intra-spécifique dans sa production racinaire en réponse à une exposition au Cu. En CW, à l’échelle du mésocosme (110 dm3), jusqu’à 99% du Cu de la masse d’eau (concentration initiale: 2.5µM Cu) ont été éliminés dans les trois modalités plantées de Juncus articulatus, P. arundinacea et P. australis, ainsi que dans le contrôle non planté. Les rôles du biofilm microbien, du substrat et des macrophytes en CW ainsi que leurs interactions sont discutés. La sélection d’écotypes de macrophytes tolérants aux PTTE pour leur utilisation en zone humide construite ainsi que les mécanismes moléculaires impliqués dans la variabilité intra-spécifique de cette tolérance, notamment chez P. australis, sont deux thèmes de recherche à promouvoir. / This work aims at characterizing environmental compartments (i.e. water, soil and soil pore water, substrate, macrophytes at the individual and community scale) and their functioning to in fine improve the effectiveness of constructed wetlands (CW) for cleaning Cu-contaminated waters. Knowledge on the homeostasis of Cu in plants and its phytotoxicity at medium and high exposures are summarized. The main physico-chemical and biological mechanisms involved in the phytoremediation of Cu-contaminated water in CW are discussed. Several aided-phytostabilisation options were in situ evaluated in lysimeters at a Cu-contaminated wood preservation site to assess the potential of four amendments to sorb Cu in a CW substrate. Concentrations of potentially toxic trace elements (PTTE, including Cu) and macronutrients of leachates migrating from the root zone to the aquifers were quantified. Based on the responses of Lemna minor L. used as a bioindicator, exposed to the leachates,.Linz-Donawitz slag spiked with P (LDS, 1%) best performed to sorb labile Cu in the root zone. In parallel, macrophyte communities were monitored along the Jalle Eysines River, an urban river slightly contaminated by Cu and other PTTE. The PTTE concentrations were determined in the soil, water, soil pore water, and in the leaves of seven macrophyte species. A multivariate statistical model was developed based on the foliar PTTE concentrations for biomonitoring macrophyte exposures. Populations of macrophytes were also collected in wetlands displaying an increasing Cu contamination in Europe (France, Spain, Portugal, and Italy), Belarus and Australia. Root production of macrophytes exposed for 3 weeks at increasing Cu concentrations (0.08, 2.5, 5, 15 and 25 µM Cu) shows an intra-specific variability of Cu tolerance in populations of Juncus effusus, Schoenoplectus lacustris and Phalaris arundinacea. In contrast, a similar response to constitutive tolerance occurred for Typha latifolia and Iris pseudacorus, two species with high production of rhizomes. The rhizome influence is discussed. Phragmites australis also produces rhizomes but showed intra-specific variability in response to Cu exposure. In a CW at mesocosm scale (110 dm3), up to 99% of Cu in water (initial concentration: 2.5μM Cu) was removed after 2 weeks in the three modalities planted with Juncus articulatus, P. arundinacea and P. australis, and in the unplanted control. The influences of microbial biofilms, the substrate, and the macrophyte species and their interactions in CW are discussed. The selection of PTTE-tolerant macrophytes for their used in CW and the understanding of molecular mechanisms underlying the intra-specific variability in PTTE- tolerance, i.e for P. australis, require further investigations.

Southern Louisiana is experiencing a dramatic loss of freshwater wetlands as a result of natural and man-made changes in the landscape. Multitempral remotely sensed data were used to examine the impact of the Caernarvon Freshwater Diversion Structure, built in 1991 to divert water to Breton Sound. Satellite imagery data covering the period from 1974 to 2006 were analyzed by computing several spectral indices including NDVI, VI, IR/R, Sqrt IR/R, T-NDVI, and NDWI, as well as principle component analysis. The resulting enhanced images were classified into two classes, vegetation or open water. The ratios of vegetation to open water were then calculated and the changes graphed over the 1974-2006 timeframe. The results indicated that despite the infusion of freshwater, the open water portion of the Breton Sound area continued to expand, indeed the expansion rate increased from approximately 0.25% per year before construction of Caernarvon to 0.45% per year after construction.

Orientador: Daniel Marcos Bonotto / Resumo: As áreas úmidas são caracterizadas como ecossistemas da interface entre o ambiente terrestre e aquático, influenciada por inundações permanentes ou periódicas, possuindo floras e faunas típicas adaptadas a sua dinâmica hídrica distinta. Configuram como um dos ecossistemas mais frágeis e ameaçados do mundo, que devido a sua heterogeneidade e a falta de padrões específicos dificulta a criação e adoção de políticas públicas efetivas para a manutenção e conservação dessas áreas. A chapada sedimentar no Oeste de Minas Gerais abriga um importante sistema de áreas úmidas, que são essenciais na manutenção e no equilíbrio hídrico da região, atuando como área de recarga para os córregos, rios e aquíferos existentes. A ocorrência dessas áreas está associada a presença de dois níveis freáticos, sendo um superficial e outro profundo, alimentado pelo primeiro nos períodos de estiagem, relacionados com a arquitetura pedológica da região. O substrato consiste em um sistema latossolo-gleissolo, onde as áreas hidromorfizadas deprimidas topograficamente exibem um importante indicativo para a presença de argilas altamente aluminosas, explorada economicamente na região. Análises hidroquímicas foram realizadas a fim de determinar a composição das águas nessas áreas úmidas, além da observação de possíveis impactos relacionados às intensivas atividades agrícolas na área, a partir das concentrações de elementos traços presentes. A região apresentou um pH neutro, com grande variação nos valores de con... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The wetlands are characterized as ecosystems of the interface between terrestrial and aquatic environment, affected by permanent or periodic waterlogging, presenting typical flora and fauna, adapted to its distinct hydric dynamics. They represent one of the most fragile and endangered ecosystems of the world, which due its heterogeneity and absence of specific standards hinders the creation and implementation of effective public policies for preservation and conservation of these areas. The sedimentary plateau in Western Minas Gerais holds an important wetland system that is essential in the maintenance and hydric equilibrium of the region, acting as a recharge zone for present creeks, rivers and aquifers. The existence of these areas is associated to the presence of two groundwater levels, one superficial and the other deep, supplied by the first during drought season, related to the site pedological architecture. The substratum consists in a latosol-gleysol system, where the hidromorphized areas, topographically depressed, exhibit a leading indicator for the existence of highly aluminous clays, economically exploited in the area. Hydrochemical analysis were conducted to determine water composition in these wetlands, as well as monitoring the possible impacts related to the intensive agricultural activities in the area, from the trace element concentration. The studied region showed neutral pH, with great variation in the values of electrical conductivity, relative to the di... (Complete abstract click electronic access below) / Mestre

Magister Artium - MA / This thesis investigates the influence of climate change and climatic variability on wetland ecosystems (coastal and inland wetlands) on the Agulhas coastal plain. Firstly, this research examines coastal wetland ecosystem resilience to sea level rise by modelling sea level rise trajectories for the Droё River wetland. The rate of sediment accretion was modelled relative to IPCC sea level rise estimates for multiple RCP scenarios. For each scenario, inundation by neap and spring tide and the 2-, 4- and 8-year recurrence interval water level was modelled over a period of 200 years. When tidal variation is considered, the rate of sediment accretion exceeds rising sea levels associated with climate change, resulting in no major changes in terms of inundation. When sea level rise scenarios were modelled in conjunction with the recurrence interval water levels, flooding of the coastal wetland was much greater than current levels for the 1 in 4 and 1 in 8 year events. The study suggests that for this wetland, variability of flows may be a key factor contributing to wetland resilience. Secondly, the thesis examines the variability of open wetland water surface areas and their relation to rainfall to determine wetland hydrological inputs for the Nuwejaars wetland system and respective wetlands. A remote sensing approach was adopted, Landsat 5 TM and 8 OLI multispectral imagery were used to detect changes of water surfaces for the period 1989 to 2017. Water surfaces were enhanced and extracted using the Modified Normalized Difference Water Index of Xu (2006). The coefficient of variation of wetland water surface area was determined. The variability ranges from low to high for respective wetlands. A correlation analysis of wetland water surfaces and local and catchment rainfall for the preceding 1, 3, 6, 9, 12 and 24 months was undertaken. The preceding month and associated inputs explains the annual variability of surface waters. The study suggests that, the variability of wetland water surface area are related to variations to water inputs and groundwater, as well as variations in water outputs such as evapotranspiration and an outlet channel.

Environmental degradation is a serious problem in Lesotho, Africa. The majority of studies dealing with soil loss and gully erosion have mainly focused on the mechanics of the erosion. However, mountain watersheds are sensitive and vulnerable to degradation and in so being, have large inherent environmental implications. Gully erosion diversifies the micro-topographical and hydrological environment. The severe changes and eventual system degradation incurred as a result of gullying has rarely been quantified. This paper specifically highlights mire phytogeographic responses to valley head degradation at selected sites in eastern Lesotho by comparing patterns observed in gullied mires to those seen in other non-gullied mires. Soil and vegetation belt transects are set up across five mires (2 gullied) in the highlands of eastern Lesotho. The response of many of the plant species to the overall environmental gradient was asymmetrical and unimodal in pattern. The spatial distribution of the soil’s physical properties, topography and vegetation community patterns were found to reflect the spatial mosaic of the soil moisture gradient. The negative impact that gullying has on the ecohydrological regime of the valley heads is evident and is allowing for shrub encroachment. Both the wetland and dryland vegetation communities correlate strongly with the changes in the surface soil moisture gradient. Gully erosion is clearly a threshold phenomenon. Continued grassland degradation, accelerated soil erosion and subsequent gullying of the wetlands will lead to plant and animal diversity loss, decreased livestock productivity, sediment-laden water and shortened dam life-span.

A research report submitted to the Faculty of Science, in partial fulfilment of the requirements for the degree of Master of Science, University of the Witwatersrand. Johannesburg, 2016. / Mining and associated anthropogenic activities have improved the livelihoods and economy of many countries but negatively impacted the environment and caused detrimental effects on fresh and ground water systems through the generation of acid mine drainage (AMD). The study evaluated three macrophyte species of P. communis, S.corymbosus and T. capensis for uptake of Mg, P, S, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, and Pb in acid mine drainage polluted water. The concentration of elements was also determined in sediments and water so as to calculate the bioconcentration and translocation factors in various parts of the macrophtes. The homogenised plant samples were milled using a Fritsch Pulverisette 6 Mill into pulverized powder and element analysis was done using Spectroscout Geo+ XRF Analyzer Pro. Sediment samples were digested with microwave assisted extraction and analysed by inductively coupled plasma optical emission spectrometry (ICP-OES). Water samples were analysed directly using ICP-OES after filteration with ICP-OES. The concentration levels of these elements in water were compared in all the sites to determine which section of the site (inflow, midflow and outflow) have high amount of the selected elements. The results indicated that elements distribution varied in all the points where the water samples were collected. The concentration level of sediment was compared to the concentration levels of elements in the roots, rhizomes and leaves to determine the translocation and bio concentration factor (TC and BCF). Drinking water quality standards by international organisations were also used as a guideline to compare the concentration levels of elements found in water. Iron (Fe), Nickel (Ni), Manganese (Mn) and Copper (Cu) to determine whether their concentrations in the water were above or below the acceptable levels. the concentrations of Fe, Ni, Mn and Cu were found to be above the international water quality standards for drinking water and their average concentrations was 2230, 282, 5950 and 14080 μg/l respectively. The study found out that in autumn, Mg, S, P, and Mo were highly accumulated by leaves of T. capensis, S. Corymbosus leaves and rhizomes as well as the P. communis leaves and the highest concentrations were 6.61, 72900, 2.00 μg/g respectively. In autumn, Co was the only element highly accumulated by the roots of T. capensis with the highest concentration of 342.80 μg/g. On the other hand, Cr and Fe, was highly accumulated by S. corymbosus roots with the highest concentration of 279.20 and 10.03 μg/g in summer. In summer, Cr, Mn, Ni, Cu, Zn and Pb were highly accumulated by the roots of P. communis and the concentrations were 279.20, 39390, 204.10, 299.50, 813.80 and 47.5 μg/g respectively. The results show that although the plant species accumulated the elements in various concentrations, there was no plant species that accumulated all the selected elements in higher concentrations than the other plant species. They all accumulated a variety of elements in varying amounts and stored them in their different parts. Finally, in all the three plant species analysed, the leaves were the best accumulator of Mg, S, and Mo, whilst the roots were the best accumulators of Cr, Fe, Co, Ni, Cu, Zn and Pb. Since the translocation and bioconcentration factors showed that the macrophyte species accumulated higher concentrations of elements than water and sediments, they can be regarded as hyperaccumulators. Macrophytes species can uptake and accumulate in their different parts various elements and they have the potential to clean the heavy metal polluted sites due to their phytostabilisation and phytoextraction abilities. / LG2017

Shortened periods of inundation due to water management have led to the encroachment and expansion of Carolina willow (Salix caroliniana) in sawgrass (Cladium jamaicense) marsh communities. Morphologic and physiologic differences between sawgrass and willow have potential consequences for microhabitat conditions and ecosystem function such as a reduction in temperatures and light availability and changes in primary productivity. Since it is a woody shrub, willow is often assumed to exhibit higher rates of transpiration than non woody plants, which in turn can affect photosynthesis and carbon exchange and ultimately wetland water management. In this study willow was found to have higher rates of stomatal conductance (gs) and photosynthesis (Anet) than sawgrass. However, sawgrass had greater intrinsic water use efficiency (WUE) than willow. This suggests that willow is capable of greater gas exchange and carbon assimilation than sawgrass but requires more water. Understanding the implications of willow expansion will improve landscape models of wetland water and carbon exchange and inform water management decisions. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2015. / FAU Electronic Theses and Dissertations Collection