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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Influência da temperatura sobre plantas aquáticas em pós-tratamento de efluente da suinocultura / Influence of the temperature on aquatic crops in pos-treatment of swine sludge

Weirich, Carlos Eduardo 21 August 2009 (has links)
Made available in DSpace on 2017-07-10T17:37:36Z (GMT). No. of bitstreams: 1 Carlos_Eduardo_Weirich.pdf: 1336764 bytes, checksum: 26e875704b80ba5d54deaeedce9c2fe3 (MD5) Previous issue date: 2009-08-21 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This study aimed to evaluate the influence of temperature on production of biomass and retention of nitrogen and phosphorus in a treatment system for swine effluent, composed of two species of aquatic plants Eichhornia crassipes (water hyacinth) and Pistia stratiotes (lettuce water). The work was accomplished at the Universidade Estadual do Oeste do Paraná- Paraná State, Campus of Toledo - PR, in the periods that were on 19 February to 19 March 2008 and August 11 to 09 September 2008, referring to the summer and winter, respectively. The system was composed by 24 experimental tanks built in concrete with a length of 1,5 m, width of 0,25 m and depth of 0,16 m. A completely randomized design was used two species of macrophytes, water lettuce and water hyacinth and two periods with four replications. Water samples were collected at entry and exit system at the beginning and end of the experiment evaluating the total nitrogen (TN), total phosphorus (TP), pH, electric conductivity and dissolved oxygen. The water temperature together with the maximum and minimum temperature and air humidity were measured daily. Biomass production was analysed in the end of the experiment. The proximate analysis of biomass plants examined in the dry, were different (P <0,05) for the periods, the ash content grow in the shoot (CZPA) and root (CZR), phosphorus in the shoot (PPA ) and nitrogen in the root (NR) and shoot (NPA). As for the treatments showed meaning difference (P <0,05) for the crude protein in shoot (PBPA), gray in the root (CZR) and shoot (CZPA). The most remotion of water, as for the water hyacinth as for the track, was observed in summer with values of 85,71% and 88,69%, respectively. These values did not differ statistically from those observed for the winter. For PT a higher removal was observed on treatment with water hyacinth in the winter (43,37%) and on the runway during the summer (43,33%). The production of biomass of water hyacinth was 4,04 and 3,19 kg m-2 during the summer and winter, respectively, while the runway was 1,78 and 0,71 kg.m-2 for the same periods. The results obtained in this experiment, conclude that the plants had high biomass production and a high potential for accumulation of nitrogen and phosphorus in their plant tissue. The temperature of air and water showed variation during the periods of the experiment, indicating the summer period that favored the best performance of species evaluated / O presente trabalho teve por objetivo avaliar a influência da temperatura na produção de biomassa e retenção de nitrogênio e fósforo em um sistema de tratamento de efluente de suinocultura, composto por duas espécies de plantas aquáticas, Eichhornia crassipes (aguapé) e Pístia stratiotes (alface d'água). O trabalho foi realizado na Universidade Esta dual do Oeste do Paraná UNIOESTE, Campus de Toledo PR, durante dois períodos, que foram de 19 de fevereiro a 19 de março de 2008 e 11 de agosto a 09 de setembro de 2008, referente ao verão e inverno, espectivamente. O sistema foi composto por 24 tanques experimentais construídos em concreto com comprimento de 1,5m, largura de 0,25m e profundidade de 0,16 m. O delineamento foi inteiramente casualizado, tendo sido utilizadas duas espécies de macrófitas, pistia e aguapé e dois períodos com quatro repetições. As amostras de água foram coletadas na entrada e saída do sistema, no início e final do experimento avaliando-se o nitrogênio total (NT), fósforo total (PT), pH, condutividade elétrica e oxigênio dissolvido. A temperatura da água, juntamente com a temperatura máxima e mínima do ar e umidade relativa, foram mensuradas diariamente. A produção de biomassa foi avaliada ao final do experimento. As análises centesimal da biomassa das plantas analisadas na matéria seca, apresentaram diferença (P<0,05) para os períodos avaliados, o teor de cinzas na parte aérea (CZPA) e na raiz (CZR), o fósforo na parte aérea (PPA) e o nitrogênio na raiz (NR) e na parte aérea (NPA). Já para os tratamentos, houve diferença significativa (P<0,05) para a proteína bruta na parte aérea (PBPA), cinza na raiz (CZR) e parte aérea (CZPA). A maior remo ção de NT da água, tanto para o aguapé como para a pístia, foi observada no verão com valores de 85,71%, e 88,69%, respectivamente. Estes valores não diferiram estaticamente daqueles observados para o inverno. Para PT a maior remoção foi observada no tratamento com aguapé no período de inverno (43,37%) e para pístia no período de verão (43,33%). A produção de biomassa do aguapé foi de 4,04 e 3,19kg m-2 no período de verão e inverno, respectivamente, enquanto para a pístia foi de 1,78 e 0,71 kg.m-2 nos mesmos períodos. Diante dos resultados obtidos nesse experimento, pode-se concluir que as plantas apresentaram elevada produção de biomassa e um grande potencial de acumulação de nitrogênio e fósforo no seu tecido vegetal. A temperatura do ar e da água apresentou variação durante os períodos do experimento, indicando o período de verão o que melhor favoreceu o desempenho das espécies avaliadas
12

Remoção de metais em água utilizando Eichhornia crassipes na forma in natura, biocarvão e híbrido magnético / Removal of the metals from water using in natura, biochar, magnetic hybrid composite from Eichhornia crassipes

Lima, Jôse Raymara Alves 26 February 2018 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Water hyacinth (Eichhornia crassipes) is an invasive aquatic weed whose main characteristic is its high growth rate. The methods applied to control this plant have high cost and waste generation. Using the water hyacinth as an adsorbent for remediation of metals is a viable and eco-friendly application. In this work, a magnetic hybrid adsorbent matrix (AGMG) was synthesized utilizing water hyacinth (Eichhornia crassipes) biomass to compose an organic phase, and its adsorption efficiency was compared to the adsorption efficiency of in natura (AGIN) water hyacinth and its biochar (BIO) in the remediation of metals in water. The adsorbents were characterized by infrared spectroscopy, confirming the presence of hydroxyl groups and carboxylates, with bands that are typical of cellulose, hemicellulose and lignin, structures found in AGIN and BIO. The AGMG spectrum presented the bands previously described and new bands in the region of 513 cm-1, characteristic of the Fe-O bond of CoFeO4, confirming the formation of a magnetic hybrid. The essays on the influence of pH on the remediation of copper, zinc, nickel and cobalt presented higher percentages of removal in the range of pH 4-5 for all adsorbents, and the following crescent order of removal efficiency AGIN<AGMG<BIO for all metals. The kinetic studies showed fast kinetics for the three adsorbents and the metals under study with a removal rate of more than 50% in the first 5 minutes. The kinetic data were adjusted to the pseudo-second order model, with correlation coefficients higher than 0,99 for the three materials. The AGMG was prominent among the other adsorbents because its adsorption capacity is high and its separation from the aqueous medium is more feasible. The isotherm data for the AGMG were adjusted to the Langmuir model, showing a good linear correlation in the concentration range studied (5-250 mg g-1), with correlation coefficient r2 between 0,9973-0,9999. The values of the calculated maximum capacity of AGMG (qmax) were 18,3 mg g-1 Cu (II), 10,1 mg g-1 Zn (II) and 7,33 mg-1 Ni (II). The percentage of removal in the different mixed solutions by the adsorbent AGMG followed this order of selectivity, Cu>Zn>Ni, copper as a highlight, > 84% removal in all evaluated mixed solutions. The AGMG was reused in four cycles of adsorption in mixed solution, without using a desorption process, and the efficiency varied according to the metal. The adsorption of copper remained high in all cycles, with 77% removal in the first cycle and 72% in the fourth cycle. For zinc and nickel, the removal decreased with each cycle, and in the third cycle there was no more nickel removal. The saturated with metals AGMG residues (AGMG-sat) showed high catalytic activities in the reduction of 4- nitrophenol to 4-aminophenol. The residues were reused in ten reduction cycles and the conversion rate in the cycles ranged from 88,9 to 100%, with short periods of time (21-26 s). / Aguapé (Eichhornia crassipes) é uma planta daninha aquática invasora cuja principal característica é sua alta taxa de crescimento. Os métodos aplicados para o controle dessas plantas possuem alto custo e geração de resíduos. Uma aplicação viável e eco-amigável é utilizá-la como adsorvente para a remediação de metais. Neste trabalho foi efetuada a síntese de uma matriz adsorvente híbrida magnética (AGMG) utilizando a biomassa aguapé (Eichhornia crassipes), para compor a fase orgânica, e comparou sua eficiência adsortiva com a aguapé in natura (AGIN) e seu biocarvão (BIO), na remediação de metais em água. Os adsorventes foram caracterizados por espectroscopia de infravermelho, que confirmou a presença de grupos hidroxilas e carboxilatos, com bandas típicas da celulose, hemicelulose e lignina, estruturas essas encontradas no AGIN e BIO. O espectro do AGMG apresentou as bandas descritas anteriormente e novas bandas na região de 513 cm-1, característica da ligação Fe-O da CoFeO4, confirmando a formação do híbrido magnético. Os ensaios da influência do pH na remediação do cobre, zinco, níquel e cobalto mostraram maiores porcentagens de remoção na faixa de pH 4-5, para todos os adsorventes, podendo estabelecer a seguinte ordem crescente de eficiência de remoção AGIN<AGMG<BIO para todos os metais. O estudo cinético evidenciou uma cinética rápida para os três adsorventes e os metais em estudo com uma taxa de remoção superior a 50% nos primeiros 5 minutos. Os dados cinéticos ajustaram-se ao modelo de pseudo-segunda ordem, com coeficientes de correlação superiores a 0,99 para os três materiais. O AGMG destacou-se entre os demais adsorventes devido sua alta capacidade de adsorção e de ser mais viável sua separação do meio aquoso. Os dados das isotermas para o AGMG ajustaram-se ao modelo de Langmuir, apresentando boa correlação linear na faixa de concentração estudada (5-250 mg g-1), com coeficiente de correlação r2 entre 0,9973-0,9999. Os valores de capacidade máxima do AGMG calculada (qmax) foram de 18,3 mg g-1 Cu(II), 10,1 mg g-1 Zn(II) e 7,33 mg -1 Ni(II). A porcentagem de remoção nas diferentes soluções mistas pelo adsorvente AGMG seguiu a ordem de seletividade, Cu>Zn>Ni, com destaque para o cobre >84% de remoção em todas as soluções mistas avaliadas. O AGMG foi reutilizado em quatro ciclos de adsorção em solução mista, sem utilização de processo de dessorção, e a eficiência variou de acordo com o metal. A adsorção para o cobre permaneceu elevada em todos os ciclos, com 77% de remoção no primeiro ciclo e 72% no quarto ciclo. Para o zinco e níquel, a remoção diminuiu a cada ciclo, sendo que no terceiro ciclo não houve mais remoção de níquel. Os resíduos do AGMG saturados com metais (AGMG-sat) apresentaram altas atividades catalíticas na redução do 4-nitrofenol a 4-aminofenol. Os resíduos foram reutilizados em dez ciclos de redução e a taxa de conversão nos ciclos variou de 88,9-100%, com curtos tempos (21-26 s). / São Cristóvão, SE
13

Bioindicadores para determinação de metais pesados no Reservatório da Itaipu Binacional, Paraná, Brasil / Bioindicators for the determination of heavy metals in the reservoir of Itaipu, Paraná, Brazil

Chambo, Ana Paula Sartório 26 August 2011 (has links)
Made available in DSpace on 2017-07-10T17:48:28Z (GMT). No. of bitstreams: 1 Ana_Paula_Sartorio_Chambo.PDF: 2055310 bytes, checksum: 572f35f1e55b0455d7858396549a5810 (MD5) Previous issue date: 2011-08-26 / Fundação Araucária / This study was conducted in the reservoir of Itaipu Hydroelectric Plant, located in the western region of Paraná State, during the March/2010 to April/2009 and aimed to study the chemical composition (macronutrients, micronutrients and toxic heavy metals), the bioaccumulation of biologically essential metals, copper (Cu), iron (Fe), zinc (Zn) and manganese (Mn), and non-essential toxic heavy metals, cadmium (Cd), chromium (Cr) and lead (Pb) in tissues of the armado (P. granulosus), mollusks (L. fortunei) and aquatic plants (E. densa and E. crasssipes), beyond the study of water quality and sediment under modified atmospheres, such as reservoirs for multiple uses, during the season the year. Fifteen fish were collected monthly to determine the factor relative corporal condition (Kn), the index of viscera total (IVT), visceral fat index (IGV), the hepatosomatic index (HSI) and the metal pollution index (MPI), as well as samples the sediment, water and the biomarkers golden mussel and two species of aquatic macrophytes, E. crassipes and E. dense. It was observed that the carcass of the armado bioaccumulate in the following order Fe, Ca, Zn, Pb, Mn, K, Mg, Cr, Cu e Cd. The nitrogen was concentrated in greater proportion in the carcass (110.58 g kg-1) and fillet (109.96 g kg-1) and phosphorus in the liver (43.26 g kg-1). The Cd was present in 50% of carcass samples (1.20 mg kg-1) and skin (1.00 mg kg-1) and 100% of the samples of gills (1.00 mg kg-1). The Cr was detected in 33% of carcass samples (2.75 mg kg-1) and gills (1.00 mg kg-1) and 17% of fillet samples (2.00 mg kg-1). The presence of lead was found in 100% of samples with levels ranging from 20.17 mg kg-1 in the carcass and 7.83 mg kg-1 in the fillet. The distribution of Cu, Zn and Mn in the sediment and water did not change seasonally. The analytical method used did not detect the presence of Cu and Zn in the water sample. The physical and chemical variables of water were not oscillated along the year season. The index calculated for the E. densa responded significantly seasonal fluctuations, with the highest rates were obtained during the summer followed by spring, winter and autumn. The armado captured during the experiment were contaminated by heavy metals Cd, Cr and Pb at levels above those recommended by current legislation. The rate of metal contamination suggests that the liver is the organ most bioaccumulate heavy metals in the gun. The deposition of heavy metals in sediment and water did not change seasonally, the sampling of sediment, E. densa and root of E. crassipes may indicate the composition of environmental contamination / Este trabalho foi realizado no reservatório da Usina Hidrelétrica de Itaipu Binacional, localizada na região oeste do Estado do Paraná, durante o período de abril/2009 a março/2010 e teve como objetivo o estudo sobre a composição química (macronutrientes, micronutrientes e metais pesados tóxicos), a bioacumulação de metais pesados biologicamente essenciais, cobre (Cu), ferro (Fe), zinco (Zn) e manganês (Mn), e metais pesados tóxicos, cádmio (Cd), cromo (Cr) e chumbo (Pb), nos tecidos do armado (P. granulosus), moluscos (L. fortunei) e plantas aquáticas (E. densa e E. crasssipes), além do estudo da qualidade da água e dos sedimentos em ambientes modificados, como os reservatórios de usos múltiplos, durante as estações do ano. Foram coletados mensalmente quinze peixes para determinação do fator de condição corporal relativo, o índice de víscera total, o índice de gordura visceral, o índice hepatossomático e o índice de poluição por metais, bem como amostras de sedimento, água e dos bioindicadores mexilhão dourado e duas espécies de macrófitas aquáticas E. crassipes e E. densa. Observou-se que a carcaça do armado bioacumulou os elementos na seguinte ordem decrescente Fe, Ca, Zn, Pb, Mn, K, Mg, Cr, Cu e Cd. O nitrogênio concentrou-se em maior proporção na carcaça (110,58 g kg-1) e no filé (109,96 g kg-1) e o fósforo no fígado (43,26 g kg-1). O Cd esteve presente em 50% das amostras de carcaça (1,20 mg kg-1) e pele (1,00 mg kg-1) e em 100% das amostras de brânquias (1,00 mg kg-1). O Cr foi detectado em 33% das amostras de carcaça (2,75mg kg-1) e brânquias (1,00 mg kg-1) e em 17% das amostras de filé (2,00 mg kg-1). A presença de chumbo foi constatada em 100% das amostras com teores variando entre 20,17 mg kg-1 na carcaça e 7,83 mg kg-1 no filé. A distribuição dos metais Cu, Fe, Zn e Mn no sedimento e na água não sofreram efeito sazonal. O método analítico utilizado não detectou a presença de Cu e Zn na água do reservatório. As variáveis físicas e químicas da água não oscilaram ao longo do ano. O índice de metais pesados calculado para a E. densa respondeu significativamente as oscilações sazonais, sendo que os maiores valores obtidos durante o verão seguidos pela primavera, inverno e outono. Os armados capturados durante o período experimental estavam contaminados pelos metais pesados Cd, Cr e, Pb em níveis acima dos recomendados pela legislação vigente. O índice de contaminação por metais aponta que o fígado é o órgão que mais bioacumulou metais pesados no armado. As deposições de metais pesados no sedimento e na água não sofreram efeito sazonal. A amostragem dos sedimentos, E. densa e raiz da E. crassipes pode indicar a composição da contaminação do ambiente e a E. densa pode ser utilizado como bioindicador em áreas poluídas
14

ADSORÇÃO DE CORANTES TÊXTEIS POR CARVÃO ATIVADO PREPARADO A PARTIR DO AGUAPÉ (Eichhornia crassipes) / ADSORPTION OF TEXTILE DYES FOR ACTIVATED CARBON PREPARED FROM WATER HYACINTH (Eichhornia crassipes)

Lucena, Júlio Evangelista de 02 May 2014 (has links)
Made available in DSpace on 2016-08-19T12:56:46Z (GMT). No. of bitstreams: 1 Dissertacao JULIO EVANGELISTA DE LUCENA.pdf: 1411452 bytes, checksum: b8994e2b79faae23cab57fbe95b70fb9 (MD5) Previous issue date: 2014-05-02 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Activated carbon produced from water hyacinth (CAA) was used for the adsorption of textile dye Remazol Turquoise and Violet Remazol aqueous solutions. ZnCl₂ was used as the activating agent in the impregnation ratio (2:1) and pyrolysis was at 700 ° C under N₂ flow, resulting in a surface area with CAA 640 m² gˉ¹. The adsorbent was characterized, and analysis of the surface area by the BET method, by elemental analysis, vibrational spectroscopy in the infrared region, Boehm titration method, which quantified the phenolic, carboxylic and lactonic groups groups on the carbon surface, thermogravimetric analysis, diffraction the x rays and point of zero charge (PZC). Factors affecting adsorption, such as pH, equilibration time, concentration of adsorbate and temperature were estudied in batch system. The activated carbon showed better adsorption rate at pH's in the acidic range. The kinetic data were fitted to models Elovich, pseudo first order and pseudo-second order, which the Elovich model showed better fit. Adsorption isotherms were measured and fitted to Langmuir and Freundlich models, where the latter provided better fit to the experimental data. The thermodynamic data obtained by evaluation of the isotherms at temperatures of 10, 25, 35, 45 and 55 ° C, indicated that the adsorptive process is endothermic, spontaneous and favorable. The CAA proved ultimately to be a good alternative in the adsorption of the dyes studied, it showed a low production cost and a high rate of removal. / Carvão ativado produzido a partir do aguapé (CAA) foi utilizado para a adsorção dos corantes textêis Turquesa Remazol (TR) e Violeta Remazol (VR) em meio aquoso. Foi ultilizado o ZnCl₂ como agente ativante por impregnação na proporção (2:1) e a pirólise ocorreu em 700° C, sob fluxo de N₂, resultando em um CAA com área superficial de 640 m² gˉ¹. O adsorvente foi caracterizado, além de análise da área superficial pelo método BET, por análise elementar, espectroscopia vibracional na região do infravermelho, titulação pelo método de Boehm, que quantificou os grupos fenólicos, lactônicos e carboxílicos na superfície do carvão, análise termogravimétrica, difratometria de raios x e ponto de carga zero (pcz). Fatores que afetam a adsorção, como pH, tempo de equilíbrio, concentração do adsorvato e temperatura foram estudados em sistema de batelada. O carvão ativado apresentou uma boa taxa de adsorção em pH s na faixa ácida. Os dados cinéticos foram ajustados aos modelos de Elovich, pseudo-primeira ordem e pseudo-segunda ordem, apresentando melhor ajuste o modelo de Elovich. Isotermas de adsorção foram determinadas e ajustadas aos modelos de Langmuir e Freundlich, onde o último forneceu melhor ajuste aos dados experimentais. Os dados termodinâmicos, obtidos pela avaliação das isotermas nas temperaturas de 10, 25, 35, 45 e 55° C, indicaram que o processo adsortivo é endotérmico, espontâneo, e favorável. O CAA mostrou, por fim, ser uma boa alternativa na adsorção dos corantes estudados, pois apresentou um baixo custo de produção e um alto índice de remoção.
15

Water hyacinths (Eichornia crassipes) and their presence in Shire River, Malawi : Problems caused by them and ways of utilise them elsewhere

Mellhorn, Malin January 2013 (has links)
Malawi is one of many countries throughout the world struggling with massive amounts of water hyacinths (Eichornia crassipes) in the country’s fresh water resources.  In nutrient-rich ecosystems where the aquatic weed has no natural enemies it will reproduce very rapidly with the consequence that lakes become overgrown, water flow in rivers is reduced, and other water organisms becomes excluded. At the same time, the plants form a good breeding place for species carrying tropical diseases for example Malaria and Bilharzia. Water hyacinths are usually more of a problem for poorer countries since there are often great economic losses caused by the weed and to control their relative abundance is costly. In Malawi, 99 % of the produced electricity is based on water resources, mainly through hydropower turbines in the main river, Shire River. Water hyacinths, aggregated as islands, floating along the river and clogging the turbines cause repeated electricity black-outs and approximately 140 megawatt power is lost every day. To counter the weed interference with the electricity supply, there are great amounts of water hyacinths harvested every day and dumped along the road, with no further disposal plan. In this report, soil from one local dumping area is analysed to determine if such places are leaching nutrients or metals to the surrounding environment.  Water hyacinths contain naturally high values of nutrients and farmers use these harvested plants as a green manure to improve soil properties on agricultural land. This paper aims to examine levels of metal in water hyacinths used as green manure. This is of interest since water hyacinths have the ability to effectively absorb substances from the water body which could pose a risk for potentially toxic elements (PTEs) to accumulate in the agricultural soil and subsequently in crops. Sampling and analyses were carried out with standard methods. Metal and nutrient levels in the analysed samples were obtained through detection with atomic absorption spectrophotometry (AAS), ion chromatography (IC) and UV/VIS spectrophotometry at the Department of Chemistry of Chancellor College in Zomba, Malawi. None of the investigated metal ions (Cr, Pb, Cd) were found in the analysed water hyacinths and since soil sampling was done during the dry season this thesis cannot determine if the dumping areas are leaching nutrients. Relatively high amounts of total phosphorus were found in the plants. Overall, the conclusion is that there is no risk of using water hyacinths harvested in Shire River as a green manure on agricultural land.
16

The effect of temperature on biological control of water hyacinth, Eichhornia crassipes (Pontederiaceae) in South Africa

King, Anthony Michael 18 January 2012 (has links)
MSc., Faculty of Science, University of the Witwatersrand, 2011 / The behaviour and physiology of every insect, during all developmental stages, is largely determined by temperature. Metabolic rate, flight activity, nutrition, growth rate, oviposition and longevity can all be correlated to temperature. Consequently, insect development occurs within a definite temperature range which can be experimentally determined. This serves as a basis from which models that estimate insect growth, development and reproduction can be formulated. Such studies on temperature-dependent development are therefore important for understanding predator-prey relationships and insect population dynamics relevant in epidemiology, pest management and biological control of weeds and insect pests. The biological control of water hyacinth, Eichhornia crassipes (Pontederiaceae), in South Africa currently relies on six established agents. However, the results of this programme do not compare well with the achievements made elsewhere. This has been attributed to a number of constraining factors, chief among which is a wide variety of climatic regions, low minimum temperatures and a high incidence of frosting which slows the build-up of natural enemy populations. This research verified and augmented the thermal tolerance data available for three of South Africa’s more efficacious agents used against water hyacinth, namely Neochetina eichhorniae, N. bruchi (Curculionidae) and Eccritotarsus catarinensis (Miridae). Using these data, plant productivity and insect activity was modelled against fine-scale temperature data incorporating three distinct microclimates from 14 field sites distributed throughout South Africa’s climatic regions. Water hyacinth and its natural enemies were found to be negatively affected by low average temperatures. However, the relative consequences for each species at a population level were quite different. Similar thresholds for development, close to 10°C, meant that periods available for growth in areas where temperature is limiting were roughly the same for both plant and insects. Nevertheless, although plant growth largely ceased each winter and aerial parts were often extensively damaged from frost, low temperatures rarely led to significant plant mortality. By contrast, reduced insect recruitment coupled with a high susceptibility to cold- and frost-induced mortality of all life-history stages, pushed insect populations into winter bottlenecks and even caused local extinctions. The ability to overwinter effectively appears to the primary cause for limited control in colder regions. Surviving post-winter insect populations were therefore small, inflicted minimal damage due to reduced feeding rates, and were generally asynchronous with the recovery of water hyacinth. This asynchronous development translated into a lag period of roughly 42 days between the onset of water hyacinth growth and the time at which the plant was subjected to meaningful herbivory. Free from early season herbivory, coupled with the fact that vegetative reproduction continued through winter, water hyacinth populations were able to quickly recover and outpaced the detrimental affects caused by insect feeding well into the growth season. The implications for supplementary management strategies are also discussed in light of these outcomes.
17

Policultivo de tambaqui e camarão-da-amazônia: características limnológicas, avaliação do impacto ambiental e tratamento do efluente / Polyculture of tambaqui and amazon river prawn: limnological characteristics, environmental impact assessment and effluent treatment

Medeiros, Mateus Vitória [UNESP] 20 February 2017 (has links)
Submitted by MATEUS VITÓRIA MEDEIROS null (mateusvmedeiros@hotmail.com) on 2017-03-28T13:49:40Z No. of bitstreams: 1 Tese versao final Mateus Medeiros.pdf: 2421674 bytes, checksum: 96105d11005bdfb2ec4655cc49aa8b6a (MD5) / Rejected by Luiz Galeffi (luizgaleffi@gmail.com), reason: Solicitamos que realize uma nova submissão seguindo a orientação abaixo: O arquivo submetido não contém o certificado de aprovação. O arquivo submetido está sem a ficha catalográfica. A versão submetida por você é considerada a versão final da dissertação/tese, portanto não poderá ocorrer qualquer alteração em seu conteúdo após a aprovação. Corrija estas informações e realize uma nova submissão com o arquivo correto. Agradecemos a compreensão. on 2017-03-29T20:41:42Z (GMT) / Submitted by MATEUS VITÓRIA MEDEIROS null (mateusvmedeiros@hotmail.com) on 2017-03-30T13:49:41Z No. of bitstreams: 1 Tese versao final Mateus Medeiros 1.pdf: 2938563 bytes, checksum: 54e47db93a38593af9eb2dfe37f653e3 (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-03-30T16:44:13Z (GMT) No. of bitstreams: 1 medeiros_mv_dr_jabo.pdf: 2938563 bytes, checksum: 54e47db93a38593af9eb2dfe37f653e3 (MD5) / Made available in DSpace on 2017-03-30T16:44:13Z (GMT). No. of bitstreams: 1 medeiros_mv_dr_jabo.pdf: 2938563 bytes, checksum: 54e47db93a38593af9eb2dfe37f653e3 (MD5) Previous issue date: 2017-02-20 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O desenvolvimento sustentável da aquicultura na perspectiva ambiental inclui entre diversos tópicos, a utilização de espécies nativas, o melhor aproveitamento da ração através de sistemas mais eficientes e a redução da poluição via descarte de efluentes. Este estudo foi dividido em três etapas. Na primeira etapa foram avaliadas as características limnológicas de quatro sistemas de cultivo em viveiros escavados, dois policultivos e dois monocultivos. As espécies utilizadas são nativas da fauna brasileira, o tambaqui Colossoma macropomum e camarão-da-amazônia Macrobrachium amazonicum. Na segunda etapa, o efluente final originado dos viveiros (etapa anterior) foi tratado com duas macrófitas flutuantes Eichhornia crassipes e Lemna minor por sete dias. Na última etapa, foram determinados os impactos ambientais da primeira etapa através da metodologia da análise do ciclo de vida (ACV). A eutrofização da água, na primeira etapa, apresentou valores semelhantes nos quatros sistemas testados. Os sistemas de tratamentos de efluentes foram eficientes na redução da concentração dos nutrientes para ambas macrófitas, com resultados satisfatórios no período de 48 horas. Já os resultados da ACV mostraram diferenças entre os quatros sistemas testados (na primeira etapa), no qual um dos sistemas de policultivo apresentou melhores resultados seguido pelo monocultivo de C. macropomum. O presente estudo demonstrou que soluções simples e sem necessidade de tecnologias modernas e de alto custo, como a utilização de policultivo e de tratamento de efluente podem reduzir os impactos da aquicultura brasileira. / The sustainable development of aquaculture in the environmental viewpoint includes within many topics the use of native species, better use of the feed through more efficient rearing systems and reduction in pollution by discharged effluents. This study is divided in three stages. In the first stage, we analyzed the limnological characteristics in four rearing systems in earthen ponds, two polycultures and two monocultures. The species used are native from Brazil, the tambaqui fish Colossoma macropomum and the Amazon river prawn Macrobrachium amazonicum. In the second stage, the final portion of the pond effluent (previous stage) was treated using two floating macrophytes Eichhornia crassipes e Lemna minor for seven days. In the last stage, we evaluated the environmental impacts through the life cycle assessment (LCA) methodology. The water eutrophication, in the first stage, showed similar development in the four tested systems. The effluent treatment systems were efficient in reducing the nutrient concentration for both macrophytes, reaching satisfactory results within 48 hours. The LCA results showed differences among the four tested systems (in the first stage), in which one of the polyculture systems had the best performance followed by the monoculture of C. macropomum. This study demonstrates that simple solutions, without modern and expensive technologies, such as adding more species to monoculture system and an effluent treatment can reduce the impacts of the Brazilian aquaculture. / FAPESP: 2010/51271-6
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Effects of Anthropogenic Nutrient Enrichment on Exotic and Restored Native Aquatic Vegetation

Parnell, Allison 2011 May 1900 (has links)
Understanding how nutrient input into coastal wetlands influences aquatic vegetation and the fate of anthropogenic nutrient inputs can help improve water quality management plans. The goals of this study were to (1) compare nutrient concentrations in various storage compartments downstream from two point nutrient sources (a sewage treatment plant outfall and a residential detention basin) in Armand Bayou, a coastal brackish wetland in the Galveston Bay (Texas, USA) watershed, and (2) determine if nutrient storage in those compartments helped improve water quality downstream. Water column nutrients can be assimilated by aquatic vegetation, adsorbed to sediment, or diluted within the system as distance from source input increases. To determine the fate of nutrients to Armand Bayou, I measured nutrient concentrations in the sediment, water column, pore water, and tissue of exotic and restored native plants downstream from a sewage treatment plant and a residential detention basin. To assess nutrient removal potential of a common exotic species, I determined relative growth and nutrient uptake rates of Eichhornia crassipes. Water column total nitrogen, NH₄⁺ and NO₃ˉ concentrations decreased by 95, 96 and 99 percent downstream from the sewage outfall (~2200 m distance). Water column NH₄⁺ and NO₂ˉ concentrations decreased by 93 and 75 percent downstream from the detention basin (~2500 m distance). Exotic species Alternanthera philoxeroides, Pistia stratiotes and E. crassipes showed higher aboveground/emergent tissue nutrient content than restored, native Schoenoplectus californicus for both tributaries. Schoenoplectus californicus had the largest biomass although appeared to be limited in its ability to remove nitrogen from the water column. Nutrient uptake rates by E. crassipes were low and did not change with increasing distance from nutrient source, but high relative growth rates in both tributaries suggest the nuisance potential of this exotic species. Low sediment and pore water nutrient concentrations for both tributaries suggest these compartments are not sinks. All plant species did not respond to changes in water column nutrient concentrations with increasing distance from source input suggesting dilution to be the main factor in water column nutrient decline for both tributaries. This study will provide water quality resource managers guidance on the development of total maximum daily loads (TMDLs) for water bodies impaired by high nutrient loading and the implementation of wetland plants efficient in nutrient removal for water quality improvement.
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The impact on biodiversity, and integrated control, of water hyacinth, Eichhornia crassipes (Martius) Solms-Laubach (Pontederiaceae) on the Lake Nsezi - Nseleni River system /

Jones, Roy William. January 2008 (has links)
Thesis (M.Sc. (Zoology & Entomology)) - Rhodes University, 2009.
20

Evaluation of a plant-herbivore system in determining potential efficacy of a candidate biological control agent, cornops aquaticum for water hyacinth, eichhornia crassipes /

Bownes, Angela. January 2008 (has links)
Thesis (Ph.D. (Zoology & Entomology)) - Rhodes University, 2009.

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