Resumo: Acidentes envolvendo derramamento de óleo e seus derivados no solo e em corpos hídricos são comuns e preocupantes, uma vez que comprometem a qualidade do ecossistema. Uma forma econômica e eficiente de combater derramamentos de óleo é o emprego do método de sorção utilizando materiais sorventes. Existe uma gama de materiais sorventes, no entanto, os naturais como biomassa e fibras vegetais demonstram interesse pelo baixo custo e boa capacidade sorvente. Existem trabalhos acerca da sorção de óleo cru, no entanto para diesel e biodiesel, que vem aumentado sua produção, pouco ou nada existe na literatura. O objetivo deste trabalho foi investigar a capacidade sorvente das fibras vegetais coco (Cocos nucifera) e curauá (Ananas erictifolius), paina (Ceiba speciosa) e das macrófitas aquáticas, taboa (Typha domingensis) e o aguapé (Eichhornia crassipes) frente aos combustíveis, diesel e biodiesel e compará-las com a turfa utilizada comercialmente. Os biosorventes também foram submetidos à caracterização físico-química e energética. As amostras foram moídas e classificadas com exceção da paina. Grande parte dos testes foi realizada nas faixas granulométricas de ≤180 μm; 180-425 μm; 425-850 μm e 850-3350 μm. Os testes de sorção com diesel e biodiesel foram conduzidos primeiramente em sistema seco e os biosorventes com melhor desempenho, submetidos a ensaios de sorção com água, sistema estático e dinâmico. A porcentagem de água que pode ser sorvida juntamente com óleo e a flutuabilidade também foram investigadas para avaliar a viabilidade destes biosorventes em corpos hídricos. Cada material vegetal possui características físico-químicas e anatômicas distintas, que influenciam na sorção de óleo, seja por absorção ou adsorção. Os biosorventes investigados apresentaram capacidade de sorção de diesel e biodiesel semelhante ou superior ao sorvente... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Accidents involving oil spills and its derivatives on the soil and in hidric bodies they are common and worrying once they endanger the quality of the ecosystem. An economical and efficient way of combating oil spills is the use of the sorption method using sorbents materials. There is a range of sorbents materials, however, the natural ones like biomass and vegetable fibers demonstrate interest due to the low cost and good sorbent capacity. There are works concerning the sorption of crude oil, however for diesel and biodiesel, which had their production increased, there is a little or even nothing exists in the literature. The aim of this work was investigate the sorption capacity of coir vegetable fibers (Cocos nucifera) and curauá (Ananas erictifolius), silk floss (Ceiba speciosa) and the aquatic macrophite cattail (Typha domingensis) and the water hyacinth (Eichhornia crassipes) confronting to the fuels, diesel and biodiesel and to compare them with the peat commercially used. The biosorventes were also submitted to the physiochemical and energy characterization. The samples were grinded and classified except for the paina. Most of the tests were performed on the granulometric size range of ≤180 μm; 180-425 μm; 425-850 μm e 850-3350 μm. The sorption tests with diesel and biodiesel were first conducted in dry system and the biosorbents with had shown the best performance were submitted to tests of sorption with freshwater, static and dynamic system. The percentage of water that can be sipped together with oil and the buoyancy were also investigated to evaluate the viability of these biosorbents in hidric bodies. Each vegetable materials has different physiochemical and anatomical characteristics that influence in the oil sorption, whether by absorption or adsorption. The investigated biosorventes presented capacity of diesel and biodiesel sorption similar or higher... (Complete abstract click electronic access below) / Orientador: Alcides Lopes Leão / Coorientador: José Cláudio Caraschi / Banca: Holmer Savastano Junior / Banca: Derval dos Santos Rosa / Banca: Claudio Angeli Sansígolo / Banca: Luciana Francisco Fleuri / Doutor

O aerênquima é um tecido vegetal com grandes lacunas de ar que podem ter função de circulação de gases e/ou sustentação de órgãos, estando presente nas raízes e órgãos aéreos de plantas aquáticas ou sob alagamento, podendo ainda ser formado em decorrência de algum estresse. Ceratopteris richardii é uma planta aquática, de hábito anfíbio que apresenta aerênquima em seus órgãos vegetativos. Dessa forma, esse trabalho buscou analisar a formação de aerênquima nas raízes e pecíolo desta espécie frente a uma situação de restrição hídrica e verificar sua plasticidade fenotípica. Vinte indivíduos de C. richardii foram cultivados e submetidos a um tratamento com diferentes concentrações de PEG 6000. Em todas as amostras analisadas, foi observada a formação de aerênquima. A análise qualitativa mostrou diferença entre os tratamentos, porém, a análise estatística revelou que as diferenças não são significativas para o número amostral empregado. Variações de crescimento do esporófito revelaram que a espécie de estudo modificou algumas características de desenvolvimento em resposta a restrição hídrica. Tais resultados revelam importantes características para esta espécie, que parece aclimatar-se a situação de estresse a qual foi submetida. Com base nisso, sugere-se ampliar estes estudos para elucidar questões relacionadas a formação de aerênquima e o ambiente, seja para esta espécie ou de outro grupo taxonômico. / Aerenchyma is a plant tissue with large air gaps that may have gas circulation function and / or sustain organs. This structure is present in roots and aerial organs of water plants and in plants under flooding it may also be formed during some stress. Ceratopteris richardii is an aquatic plant, with amphibious habit that has aerenchyma in their vegetative organs. Thus, the aim of this study is analyze the aerenchyma formation in roots and stem of this specie under water restriction situation and verify their phenotypic plasticity. Twenty specimen of C. richardii were cultured and subjected to treatment with different concentrations of PEG 6000. In all samples, were observed aerenchyma formation. Qualitative analysis showed differences among treatments, however, the statistical analysis revealed that the differences are not significant for the sample size. Sporophyte growth variations revealed that the specie of study modified some growth characteristics in response to water restriction. These results reveal important characteristics for C. richardii, which seems to acclimatize the stress situation which has submitted. On the base that, it is suggested further studies to become clearer the relation between aerenchyma formation and environment, even to either this species or another taxonomic group.

The need for energy is increasing rapidly directed by increased industrialization and population growth beyond environmental issues. So has focused for obtaining energy from renewable sources such as biomass. The production of 2nd generation biofuels from this feedstock, through the thermal conversion process, has been a viable alternative due to its natural availability, which can be converted into liquid, solid and gaseous biofuels. One potential source of biomass is the water hyacinth, due to its high rate of uncontrolled growth, which has affected various water bodies. Thus this paper proposes a microscale studies to evaluate the thermal conversion into liquid biofuel of Eichhornia crassipes (EC), Eichhornia azurea (EA) and Nymphaea spp. (Ny), aquatic plants present in River Poxim and Weir Macela around Aracaju-SE and Itabaiana-SE. The biomasses were characterized for moisture content, oil content, ash content, thermal gravimetric analysis (TGA), infrared (IR), elemental analysis and Fluorescence Spectrometry X-ray Energy Dispersive (EDX). The bio-oil product from micropyrolysis at 525 ± 10 °C was trapped in actived charcoal being tested as eluting solvents dichloromethane, acetonitrile, tetrahydrofuran and methanol. The solvent that showed the best extraction capacity was tetrahydrofuran. As the polar characteristic of chemical constituents, solutions of bio-oils have been subjected to derivatization with MSTFA, seeking help identify components through their silanes derivatives. The plants had high moisture content between 90-93%, oil content of 6.0% and 2.6% for EA and EC respectively. The ash content for EA, EC and Ny were 14.5, 19.2 and 13.0%, respectively. According to the TGA curve from 41% to 47% of weight loss can be attributed to the decomposition of hemicellulose and cellulose (184-390 °C) and 71% to 72.6% is attributed to lignin degradation (390-590 °C), leaving 18.5% (EA), 21.4% (EC) and 24.5% (Ny) of ash and charcoal. The IR spectra of biomasses showed absorption band in the region of 3000-3600 cm-1 which is attributed to stretching of the binding of alcohols and / or phenols, absorptions in the region 3000-2800 cm-1 typical of aliphatic and bands in C-H 1560-1575 cm-1 related to C=C vibration of aromatics. The composition of bio-oils showed predominantly the presence of oxygenates, aromatics (phenols), and aliphatic (fatty acids), being the main compounds found the 2-furanemethanol, 1,2-benzenediol, hexadecanoic acid. Preliminary studies indicate the possibility of conversion of biomass to bio-oil. Pyrolysis of EC at low temperature (300 °C) gave a yield of 14.39% bio-oil, 77.98% biochar and 7.63% of biogas. / A necessidade energética vem aumentando rapidamente, impulsionada pelo aumento da industrialização e aumento populacional, além das questões ambientais. Por isso, tem-se focado pela obtenção de energia a partir de fontes renováveis, como a biomassa. A produção de biocombustíveis de 2ª geração a partir desta fonte, através do processo de conversão térmica, tem sido uma alternativa viável devido sua disponibilidade natural, a qual pode ser produzida em grandes quantidades e ser convertida em combustíveis líquidos, sólidos e gasosos. Uma potencial fonte de biomassa é o aguapé, devido sua elevada e descontrolada taxa de crescimento, o que tem afetado diversas massas de água. Dessa forma este trabalho propõe estudos em microescala para avaliar a conversão da Eichhornia crassipes (EC), Eichhornia azurea (EA) e Nymphaea spp. (Ny), espécies presentes no Rio Poxim e Açude Macela no entorno de Aracaju-SE e Itabaiana, em bio-óleo pelo processo de pirólise. As biomassas foram caracterizadas quanto ao teor de umidade, teor de óleo, teor de cinzas, análise termogravimétrica (TGA), infravermelho (IV), analise elementar e Espectrometria de fluorescência de raios X por energia Dispersiva (EDX). O bio-óleo, produto da micropirólise realizada a 525 ± 10 °C foi aprisionado em carvão ativo sendo testados como solventes de eluição o diclorometano, a acetonitrila, o tetrahidrofurano e o metanol. O solvente que apresentou a melhor capacidade de extração foi o tetrahidrofurano. Em função da característica química polar dos constituintes, as soluções de bio-óleos foram submetidas a derivatização com MSTFA, buscando auxiliar na identificação dos componentes através dos respectivos derivados silanizados. As plantas apresentaram um alto teor de umidade, entre 90-93%, teor de óleo de 6% e 2,6% para a EA e EC respectivamente. Os teores de cinzas para EA, EC e Ny foram 14,5, 19,2 e 13,0% , respectivamente. De acordo com a curva de TGA de 41% a 47% da perda de massa pode ser atribuída a decomposição da hemicelulose e celulose (184-390 ºC), de 71% a 72,6% é atribuída a degradação da lignina (390-590 ºC), restando 18,5% (EA), 21,4% (EC) e 24,5% (Ny) de cinzas e carvão. Os espectros de IV das biomassas apresentaram banda de absorção na região de 3000-3600 cm-1 que está atribuída ao estiramento da ligação de álcoois e/ou fenóis, absorções na região de 3000-2800 cm-1 típica de C-H alifáticos e bandas em 1560-1575 cm-1 associadas a vibrações C=C de aromáticos. A composição dos bio-óleos apresentaram majoritariamente a presença de compostos oxigenados, aromáticos (fenóis), e alifáticos (ácidos graxos), sendo os principais compostos encontrados o 2-furanometanol, 1,2-benzenodiol e ácido hexadecanóico. Os estudos preliminares apontam para a possibilidade da conversão deste tipo de biomassa em bio-óleo. A pirólise da EC a baixa temperatura (300 oC) forneceu um rendimento de 14,39% de bio-óleo, 77,98% de biocarvão e 7,63% de biogás.

As lagoas de estabilização têm sido, por suas características operacionais e baixos custos de implantação, consideradas como a opção mais viável para tratamento de águas residuárias em pequenas e médias comunidades. O sistema composto por lagoa anaeróbia e facultativa em série é o mais empregado no Brasil. Com o avanço no monitoramento das lagoas de estabilização que se iniciou na década de 90, no caso do Estado de São Paulo pela SABESP, e que hoje se encontra bastante estruturado, periódico e confiável, nota-se que esses sistemas apesar de projetados seguindo as técnicas mais recentes, não possuem a eficiência esperada quando em operação. Tornam-se então prementes os estudos no sentido de melhorar o desempenho dos sistemas existentes e fornecer subsídios para novos projetos de lagoas de estabilização. Este trabalho estudou a utilização de chicaneamento nas lagoas de estabilização verificando a influência das chicanas no comportamento hidrodinâmico e desempenho desses sistemas além da utilização de macrófitas aquáticas no processo de tratamento de águas residuárias. Concluiu-se que mesmo com aumento de eficiência de remoção de DQO, 'DBO IND.5', nitrogênio Kjedahl e amoniacal, para ambos os casos: lagoa com aguapé e lagoa com lentilha d’água, os inúmeros problemas operacionais e aumento de custos que surgiram da aplicação das macrófitas aquáticas tornam desaconselhável o uso de aguapé e lentilha d’água em lagoas de tratamento de esgoto. Com relação ao chicaneamento o sistema que mais se aproximou dos valores teóricos, com relação ao tempo de detenção hidráulico e número de dispersão (d), foi a lagoa com chicaneamento longitudinal, melhorando o comportamento hidráulico do sistema, podendo ser considerado uma medida simples e de baixo custo para incrementar a eficiência de lagoas de estabilização / Due to the operational characteristics and low investment costs stabilization ponds have been considered as the most viable option for wastewater treatment in small and medium size communities. Anaerobic and facultative ponds in series are the most used in Brazil. With the progress of monitoring of the stabilization ponds, that was initiated in the decade of 1990 in the State of São Paulo by SABESP, it was observed that these systems do not possess the expected efficiency when in operation, although they were designed following the best available knowledge at that time. Thus, new studies were direct to improve the performance of the existing systems and to supply subsidies for new projects of stabilization ponds. This research examines, separately, the use of baffles and macrophytes in a pilot scale stabilization pond verifying the influence of these elements on the hydrodynamic behavior and performance of the wastewater treatment. It was concluded that although there is an increase in removal efficiency of DQO, 'DBO IND.5', nitrogen Kjedahl and ammoniacal, the several operational problems and increase of costs that had appeared with the application of water hyacinths and duckweed in the pond, it is not recommended to use these aquatic plants in sewer treatment. Concerning the use of baffles the system that came closer to the theoretical values, in relation to the hydraulic time of detention and number of dispersion (d), was the pond with longitudinal baffles. These baffles improved the hydraulic behavior of the system and are a simple measure and of low cost to develop the efficiency of stabilization ponds

Orientadores: Maria do Carmo Estanislau do Amaral, Andre Marcio Araujo Amorin / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-11T23:14:54Z (GMT). No. of bitstreams: 1 Souza_ClaraSampaioDiasde_M.pdf: 29137311 bytes, checksum: ee98cc502c433070913564d6268045d7 (MD5) Previous issue date: 2008 / Resumo: As restingas são áreas com vegetação bem estudada nas regiões sudeste e sul do Brasil, mas ainda faltam dados publicados sobre esses ambientes no norte e nordeste do país. Esses ecossistemas fazem parte do bioma da Mata Atlântica, e muito dessa vegetação já foi perdida durante todos os anos de degradação (da cobertura original restam apenas 7% da Mata Atlântica). Esse cenário é ainda pior no nordeste do país onde não há áreas de preservação que compreendam restingas em suas delimitações. Uma feição das restingas, que são as áreas palustres e lagoas, são ainda menos estudadas. As áreas palustres são caracterizadas por passarem por uma fase de alagamento durante o período chuvoso. Para facilitar o acesso ao conhecimento das plantas presentes nas restingas são necessárias publicações de listas de espécies e chaves de identificação, estas últimas tão escassas para o ambiente palustre. Durante a realização desse trabalho uma chave interativa de identificação foi elaborada para todas as espécies aquáticas e palustres encontradas na restinga da Península de Maraú, Costa do Dendê, sul do estado da Bahia. Essa chave foi elaborada com o programa de computador Lucid v.3.4, que possibilita a inserção dos caracteres e seus estados de forma hierárquica e relacionados aos taxa. Existem muitas vantagens dessas chaves sobre as dicotômicas: uso irrestrito de caracteres, modificações em tempo real, figuras e imagens disponíveis, e uma medida percentual ao lado dos táxons restantes, após a escolha dos caracteres pelo usuário, apontam a probabilidade desses serem o táxon buscado. As coletas foram realizadas durante os anos de 2006 a 2008, nos meses de maio, setembro e dezembro no ano de 2006; fevereiro, maio e julho no ano de 2007; e em janeiro de 2008. Para o material digital fotos das partes vegetativas e reprodutivas foram tiradas de todas as espécies possíveis. Baseados nos espécimes coletados foram identificados 86 espécies. A família Cyperaceae foi a mais representativa com 19 espécies, e 11 gêneros. Mas o grupo das "dicotiledôneas" apresentou 19 famílias identificadas, enquanto as monocotiledôneas tiveram 8 famílias identificadas. Entre as espécies identificadas 13 foram consideradas como novas ocorrências para o local, ou seja, não haviam sido coletadas antes. Após a comparação com floras em restingas de outros estdos observou-se algumas semelhanças. Mas houve semelhanças também com uma flora do campo rupestre do Pico das Almas, o que pode ser relacionado como disjunção. Mais coletas e outras análises com comparações mais detalhadas seriam necessárias para que esse fato fosse confirmado. A península de Maraú parece ser uma área de potencial preservação por apresentar características semelhantes a outras áreas de restinga que são unidades de conservação e de preservação permanente (Parque Nacional de Jurutiba e restinga da Marambaia, ambas no estado do Rio de Janeiro). Mais coletas são necessárias para o aumento do conhecimento da vegetação dessa área, que talvez seja uma das últimas áreas de restinga bem preservada no estado da Bahia. / Abstract: The "restinga" (costal plains on sandy soils) vegetation is well studied in the southeastern and southern regions of Brazil, but published data are still lacking for these environments in the North and Northeast of the country. These ecosystems are part of the Atlantic Forest biome, and much of the vegetation has been lost during all the years of destruction (of the original coverage only 7% of the Atlantic Forest is left). This scenario is even worse in the northeast of the country where there are no areas of preservation that have "restingas" included. One part of the "restinga", the areas with swamps and ponds, is even less studied. Those swamps are characterized by going through a period of flooding during the rainy season. To make accession to the knowledge of "restinga" plants easier publications of lists of species and identification keys are required, the latter specially for this environment. During the completion of this work an interactive identification key was prepared for all aquatic and swamp species found on the "restinga" from the Peninsula of Maraú, Coast of Dendê, in the south of Bahia state. This key was developed with the computer program Lucid v.3.4, which enables the insertion of the characters and their status in a hierarchical structure and related these to the taxa. There are many advantages of such keys over dichotomic key: unrestricted use of characters, changes in real time, figures and images can be included, and a measure of percentage of the other taxa, after the choice of characters by the user, points to the likelihood of it being searched taxon. Specimens were collected during the years from 2006 to 2008; in the months of May, September and December in the year 2006; February, May and July in the year 2007; and in January 2008. Digital photos of the vegetative and reproductive elements were taken of all species whenever possible. The specimens were identified as belonging to 83 species. The family Cyperaceae was the most represented with 19 species in 11 genera. But dicots presented 19 identified families, while the monocots had 8 identified families. Among the species identified 13 were considered as new events for the place, it means that had not been collected before. A comparison with the flora in restinga of other states some similarities where identified. But there were also similarities with a flora of the "campo rupestre" of Pico das Almas, which can be related as disjunction. More collections and other analyses would be needed to confirm the data. The peninsula of Maraú seems to be an area of potential preservation by presenting similar characteristics as other areas of restinga which are units of conservation and of permanent preservation (National Park of Jurutiba and restinga of Marambaia, both in the state of Rio de Janeiro). More colectors of non-aquatic and aquatic habitats are needed to increase the knowledge of the vegetation of that area, which is perhaps one of the last well preserved areas of restinga in the state of Bahia. / Mestrado / Mestre em Biologia Vegetal

Orientador: Luiz Lonardoni Foloni / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola / Made available in DSpace on 2018-08-22T22:50:44Z (GMT). No. of bitstreams: 1 Souza_EvandroLuizCorreade_D.pdf: 1935989 bytes, checksum: 8ed1c5f0a8eca62f3c6607c8f4bdf0b6 (MD5) Previous issue date: 2013 / Resumo: Visando avaliar o impacto ambiental do herbicida glifosato em ambiente aquático, escolheu-se estudar, em campo experimental controlado e fechado, o manejo do aguapé (Eichhornia crassipes), analisando parâmetros de qualidade de água e de resíduos de glifosato. Os experimentos foram conduzidos na área experimental do Núcleo de Pesquisas Avançadas em Matologia (NUPAM), pertencente à Faculdade de Ciências Agronômicas da UNESP, campus de Botucatu (SP). No experimento utilizaram-se 20 reservatórios de fibra de cimento, sendo quatro para cada tratamento, com capacidade de armazenamento de 250 L, sem reposição da água evapotranspirada. Os tratamentos utilizados foram: T1 - Reservatórios sem a presença de plantas de aguapé e sem aplicação de glifosato; T2 - Reservatórios sem a presença de plantas de aguapé e com aplicação de glifosato (Dose 7,0 L ha-1); T3 - Reservatórios com a presença de plantas de aguapé e com aplicação de glifosato (Dose 7,0 L ha-1); T4 - Reservatórios com a presença de plantas de aguapé e sem aplicação de glifosato e T5 - Reservatórios com a presença de plantas de aguapé e com controle por congelamento (nitrogênio líquido). Para aplicação nos reservatórios, empregou-se equipamento de precisão a gás carbônico (CO2), proporcionando vazão a 200 L ha-1. As coletas das amostras de água e de plantas foram realizadas antes da aplicação, logo após a aplicação e nos 2º, 4º, 8º, 16º, 32º e 64º dias após a aplicação. As amostras de água foram submetidas às análises de qualidade (pH, turbidez, condutividade elétrica e oxigênio dissolvido) e de resíduos (glifosato, AMPA e ácido chiquímico). Os resultados mostraram que o glifosato foi eficiente no controle do aguapé; que o uso do glifosato, aplicado diretamente na superfície da água ou sobre as plantas ou no controle do aguapé, não alterou significativamente os parâmetros de qualidade da água analisados; que os teores de resíduos de glifosato encontrados nas análises de água, nos reservatórios com ou sem a presença do aguapé, foram rapidamente degradadas ao longo do tempo. O modelo matemático de decaimento foi aplicado para descrever o decréscimo das concentrações e das cargas do glifosato. Esse modelo permitiu a estimativa da meia-vida do glifosato nos reservatórios entre 6 a 16 dias. Os resultados finais confirmam a hipótese de que o uso do herbicida glifosato no controle do aguapé (Eichhornia crassipes) em ambientes aquáticos fechados não apresenta impacto negativo na qualidade da água e/ou resíduos que impossibilitem o seu uso / Abstract: Seeking to evaluate the environmental impact of glyphosate in the aquatic environment, it was chosen to study in controlled and closed experimental field, the management of water hyacinth (Eichhornia crassipes), and analyzing parameters of water quality and residues of glyphosate. The experiments were conducted in the testing area of NUPAM at the UNESP Faculty of Agronomic Sciences, Botucatu (SP). In the experiment, 20 fiber cement tanks were used, four for each treatment, with storage capacity of 250 L, without replacement of the evapotranspirated water. The procedures for the experiment were: T1 - Tanks without water hyacinth and without glifosato application; T2 - Tanks without water hyacinth and with glyphosate application (dose - 7,0 L ha-1); T3 - Tanks with water hyacinth and with glyphosate application (dose - 7,0 L ha-1); T4 - Tanks with water hyacinth and without glyphosate application; T5 - Tanks with water hyacinth controlled by a freezing process. For application in the tanks, it was used carbon dioxide (CO2) precision equipment, providing an output of 200 L ha-1. Sample collections of water and plants were performed before the application, soon after application and on the 2nd, 4th, 8th, 16th, 32nd and 64th days after application. The samples were subjected to analyses of quality (pH, turbidity, electrical conductivity and dissolved oxygen) and residues (glyphosate, AMPA and shikimic acid). The results have shown the following: glyphosate was efficient to control the water hyacinth; the use of glyphosate, applied directly to the surface of the water or on plants or on water hyacinth control, did not significantly alter water quality parameters analyzed; the residues of glyphosate, AMPA and shikimic acid found in the analysis of water in the tanks, with or without the presence of water hyacinth, quickly degraded over time. The mathematical model of decay was applied to describe the decrease of the concentrations and loads of glyphosate. This model allowed the estimated half-life of glyphosate in the tanks between 6 to 16 days. The final results confirm the hypothesis that the use of glyphosate in the control of water hyacinth (Eichhornia crassipes) in closed aquatic environments has no negative impact on the quality of water and/or residues that prevent its use / Doutorado / Agua e Solo / Doutor em Engenharia Agrícola

M.Sc. (Zoology) / Ari investigation was made into the biological control of the submerged aquatic weeds Potamogeton pectinatus, Lagarosiphon major and L. muscoides in the Florida Lake, Transvaal using the Chinese grass carp Ctenopharyngodon idella (Val.) as biological control agent. The physical, chemical (including selected heavy metals), faunal and bacteriological conditions were also investigated over a period of one year. The total standing crop of P.pectinatusand Lagarosiphon spp, were reduced from an initial 0,193 kg m" 2 (wet mass) in March 1990 to 0,0338kg m-2 (wet mass) in March 1991. Reductions in the densities of the macrophytes coincided with a corresponding increase in chIorophyll-a values in the water columm of the lake. Abnormally high concentrations of the heavy metals copper, manganese, iron, nickel chromium, zinc and lead were found to occur in the lake sediments, aquatic macrophytes, ftlamentous algae, macroinvertebrate fauna as well as in organs and tissues of the perch Perea fluviatilis. These metals could be related to gold mining activities which occurred in the vicinity of the lake some years ago. Faecal bacterial counts of the water in the lake point towards the possible contamination of the lake water with domestic sewage. Ari analysis of the faeces of the numerically dominant birds which occur at the lake i.e. the coot Fulica aistata and the egyptian goose Alopochen aegyptiacus suggest that the main cause of faecal contamination of the lake's water possibly originates from these and other water birds frequenting the lake. By using the results on the physical-chemical conditions in the lake, conditions which presently prevail can be summarized as being largely that of a mesotrophic impoundment with strong tendencies towards eutrophic conditions. Secondary effects of the grass carp on the lake ecosystem was the progressive decline of weed eating birds and a slight increase in the numbers of piscivorous birds, both of which could be linked to the drastic reduction in the standing crop of the submerged weeds in the Lake. The present survey confirms the value of the Chinese grass carp as biological control agent in the management of excessive growths of submerged aquatic weeds in lakes and reservoirs in South Africa...

In 1985 the Diama Dam was built near the mouth of the Senegal River to regulate flows during the rainy season and prevent the intrusion of seawater during the dry season. This created ideal conditions upstream of the dam wall for invasion by two highly invasive aquatic weeds, first by water lettuce Pistia stratiotes Linnaeus (Araceae) in 1993, and then by salvinia Salvinia molesta D.S. Mitchell (Salviniaceae) in 1999. This study was focused on the management of P. stratiotes and S. molesta. Following successes that were achieved elsewhere in the world, biological control programmes involving two weevil species were inaugurated against both weeds and research was focused on several aspects. These included pre-release studies to determine the weevils' host-specificity and impact on the plants in the laboratory, their subsequent mass-rearing and releases at selected sites and post-release evaluations on their impact on the weed populations in the field. Both programmes, which reprepresented the first biocontrol efforts against aquatic weeds in Senegal, proved highly successful with severe damage inflicted on the weed populations and complete control achieved within a relatively short time span. A laboratory exclusion experiment with N. affinis on P. stratiotes showed that in treated tubs, the weevil strongly depressed plant performance as measured by the plant growth parameters: mass, rosette diameter, root length, number of leaves and daughter plants whereas control plants were healthy. Field releases started in September 1994 and water coverage by P. stratiotes at Lake Guiers was reduced by 25% in January 1995 and 50% in April 1995. A general decline of 65% in water coverage by P. stratiotes was observed in June 1995 and by August 1995, eight months after releases P. stratiotes mats were destroyed. Further, although no releases were made there, good results were obtained within 18 months at Djoudj Park water bodies, located 150 km NW from Lake Guiers indicating the potential of the weevil to disperse long distances. In 2005, P. stratiotes reappeared and the weevil N. affinis has located and controlled all of these P. stratiotes recurrences after new releases. In 1999, S. molesta covered an estimated area of 18 000 ha on the Senegal River Left Bank and tributaries (Senegal) and 7 840 ha on the Senegal River Right Bank (Mauritania). Military and Civil Development Committee (CCMAD) and community volunteers made an effort to control S. molesta using physical removal, but this costly and labour-intensive approach was unsustainable. Hence, biological control was adopted by Senegal and Mauritania to manage the weed. Host range tests to assess feeding by C. salviniae on S. molesta and non-target plants and carried out on 13 crop species showed that no feeding damage was observed on the latter and weevils only fed on S. molesta. Field releases of some 48 953 weevils at 270 sites were made from early January 2002 to August 2002. Within one year, weevils were established and were being recovered up to 50 km from the release sites. In a case study conducted at one of the release sites, the S. molesta infestation was reduced from 100% to less than 3% 24 months after release. These results are discussed in the context of the weeds’ negative impact on aquatic systems and riverside communities, and in the involvement of these communities in the programmes.

The St. Lucia Estuary, the largest estuary in South Africa, has been subject to many natural (a decade long drought) and anthropogenic impacts. A particular mouth manipulation activity, the artificial separation of the Mfolozi River and the St Lucia Estuary in 1952, was done to stop the perceived “silting up” of the estuary, but resulted in a decrease in freshwater supply. The changes in inflows (both fresh and marine) are controlled by management decisions and affect other system parameters such as salinity, water level and turbidity, which influence the distribution of biota. Therefore knowledge on the physico-chemical environment and eco-physiological tolerances of macrophytes will lead to informed future management decisions. The first of the three objectives carried out for this study determined the present state and distribution of the macrophytes of the St. Lucia and Mfolozi estuaries. The macrophyte habitats mapped in 2008 and 2013 were the submerged macrophytes, reeds and sedges, mangroves, grass and shrubs, salt marsh (succulent) and swamp forest. Results indicated that low salinity in the lakes and high water level in 2013 caused die-back or expansion of particular habitats. Submerged macrophytes, in particular Stuckenia pectinata, grows well in water with salinity <15 ppt, therefore this habitat increased by 412 ha (96%) in cover since 2008. Salt marsh decreased by 553 ha (57%) due to inundation. Since 2008 the reeds and sedges increased by 390 ha (in North Lake and the Narrows) due to the salinity decrease. In the Narrows the mangroves decreased by 28 ha (9%) in area cover. This was due to the drought that persisted for so many years, which caused low water levels and non-tidal conditions. The second objective was to determine the present state / health of the mangroves at four sites along the Narrows by assessing sediment condition and population structure of the trees. These results were compared to those obtained in 2010. The total density of Avicennia marina increased since 2010, however this was due to the large increase in seedlings at Site 1, the back channel site. The highest sediment salinity (26 ppt) and porewater salinity (29 ppt) was recorded for this site and these results show that this back channel site was strongly influenced by the open Mfolozi Estuary (increase in marine waters) and tidal conditions at the time of sampling in 2013. The total density of Bruguiera gymnorrhiza decreased, but an increase in adults was recorded at Site 2, the freshwater site. The soil collected from the Bruguiera quadrats was fresher and drier than that of the Avicennia quadrats of Site 2. Lack of seedlings (of both species) was due to the dense stands of Acrostichum aureum (mangrove fern) and Phragmites australis (common reed) and a thick, impenetrable mat of Avicennia pneumatophores. At Sites 3 and 4, the drier sites (where sediment moisture contents were the lowest for all sites at 43 and 42% respectively), seedling and sapling density was low, but adults increased in density since 2010. Recruitment and survival were impacted by the harsh environmental conditions that prevailed prior to 2013 (low water level and non-tidal influence), but adults survived. The results of the test that determined the percentage of aerenchyma of the pneumatophores indicated that waterlogging stress did not affect the aerenchyma of the pneumatophores. However the period of inundation was probably not significant enough to have affected the production of aerenchyma. The third objective formed part of an ongoing study by the Global Environmental Facility (GEF) on the feasibility of linking the Mfolozi River back to the St Lucia Estuary and the responses of these systems to different management scenarios: 1) the “do nothing” scenario; 2) maintain separate Mfolozi and St Lucia mouths representing an open mouth condition; and 3) actively facilitate a single mouth (therefore linking the Mfolozi and St Lucia mouths). Data gathered on the eco-physiological tolerances of the dominant macrophyte species was used to predict the response of the different habitats to these various management scenarios and the results indicated that the best management scenario would be to actively facilitate a single mouth (Scenario 3) as the estuary habitats would increase significantly because of preferred tidal and saline conditions, as this would represent more natural conditions. The results of the study will provide input to recommendations for future “adaptive management” strategies for the Global Environmental Facility (GEF) Project.

Estuaries require sufficient quantity, quality and appropriate timing of freshwater inflow, referred to as environmental flow requirements, to ensure adequate health and functioning. In South Africa the environmental flow requirements of estuaries is determined using Resource Directed Measures (RDM). The present health and importance of an estuary must be considered when determining the ecological flow required to maintain an estuary in its desired state. An Estuarine Health Index that quantifies changes in abiotic and biotic components from natural conditions to present day is used. Health of biotic components is assessed according to changes in species richness, abundance and community composition. There has, however, been debate regarding the calculation of these attributes. In particular, for macrophytes, the inclusion of all habitat within the Estuarine Functional Zone (i.e. 5 m topographical contour) would affect the health and changes over time determined in past assessments. This is due to different areas being included as different areas would be included The aim of this study was to test the validity and suggest improvements to South Africa’s RDM macrophyte health score determination. The health of macrophytes were assessed at varying levels of intensity from desktop studies to thorough field studies. Rapid field studies provided a visual estimate of macrophyte health; while the intermediate and comprehensive assessments quantified change by mapping the distribution of macrophyte habitats from aerial photographs. These approaches were applied to the 64 estuaries within the Mvoti-Mzimkulu Water Management Area (WMA 11), situated in KwaZulu-Natal (KZN) on the subtropical east coast. Historically, these estuaries have supported restricted macrophyte habitats. Consequently, estuaries that presently or historically supported range limited habitats such as mangroves and swamp forest are considered important. Submerged macrophytes are scarce in KZN estuaries due to siltation and low turbidity and thus estuaries supporting this macrophyte habitat are also important. Based on available literature important estuaries were highlighted and selected for field studies. Transects spanning from the estuary water channel to the boundary of the EFZ provided a generalised distribution of KZN vegetation along an elevation gradient. The transition from estuarine to terrestrial vegetation can be used to improve the current EFZ boundaries, as estuarine area has been found to occur outside of the 5 m contour in some estuaries. Results from the desktop assessment indicated that most of the estuaries are moderately modified. There was a 50 % similarity in the macrophyte health scores determined by the desktop assessment to the 2011 National Biodiversity Assessment (NBA). Field studies mostly confirmed the desktop assessment aside from seven estuaries that had different scores. There has been a significant loss of macrophyte habitat with 100% loss of certain habitats from 9 of the 22 estuaries for which there were field assessments. Submerged macrophytes were not found at any of the estuaries that were assessed in the field. Black mangroves, Bruguiera gymnorrhiza (L.) Lam., were rediscovered at Ngane Estuary, however the few individuals could not be considered a ‘mappable’ community (i.e. <0.5 ha). Mtamvuna and Mkomazi estuaries both supported small stands of mangroves that, compared to data from 2006, appeared healthy. Macrophyte habitats and surrounding coastal forest matched the species composition described in the Vegetation Map of South Africa. The freshwater mangrove or Powder puff tree, Barringtonia racemosa (L.) Roxb, was not abundant in the estuaries. It was only found at four (Damba, Fafa, Little Amanzimtoti and Mvoti) of the estuaries that were assessed in the field. Important estuaries, from a botanical perspective, included some of the larger estuaries such as Mgeni, Durban Bay and Sipingo. Smaller, healthier estuaries that presently support mangrove and swamp forest habitat were also identified as important from a botanical perspective. Macrophyte habitats have mainly been lost due to non-flow related pressures. Sugarcane cultivation occurred within the floodplain of 25% of the estuaries. Nutrient enrichment was evident for 12.5% of the estuaries and reed encroachment was evident for 27% of estuaries for which there were field assessments. Development, aside from the N2 road bridges, was evident for 40% of the estuaries assessed in the field. Invasive plant species, including aquatic invasive plants, were present in all estuaries assessed in the field. The extent of invasive plant species was related to the degree of disturbance and surrounding land use pressures. The Mkomazi and Mvoti estuaries that were assessed at a comprehensive level, as they have earmarked for further water abstraction, had the poorest macrophyte health scores. The macrophyte health of these estuaries was much lower than previously determined by the NBA. The decline in health was attributed to the removal of macrophyte habitat for sugarcane cultivation and development as well as displacement by invasive plant species. The areas covered by the macrophyte habitats also differed from the NBA highlighting the importance of updated mapping and ground truthing. Largely differing macrophyte health scores were produced when attributes were calculated using different combinations of macrophyte habitats. Results indicate that only macrophyte habitats and no other floodplain vegetation should be included when calculating abundance. All macrophyte habitats, physical habitats and floodplain should be incorporated when calculating community composition. The minimum of these attributes is used as the overall macrophyte health score as a precautionary approach is followed. Scoring of health is subjective and the only benchmark for determining the most appropriate method is comparion with previous RDM studies. This study illustrates the need for a standardised RDM scoring method that is presented in a manner that ensures the same results irregardless of the speciliast conducting the study. The updated estuary health and importance scores for WMA 11 are necessary to inform management, particularly as few of the estuaries receive formal protection. In conclusion, this study contributed to the limited knowledge of the estuaries of WMA 11 and assisted in determining appropriate methods for assessing the health and importance of estuary macrophytes.