Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Esta dissertação consiste de dois capítulos, cada um correspondendo a um estudo realizado de modo independente. Em um córrego de Mata Atlântica, Rio de Janeiro, Brasil, foram estudados efeitos de herbívoros e de controles ambientais no perifíton. No primeiro trabalho foram testados os efeitos do camarão Potimirim glabra, um engenheiro do ecossistema, nos parâmetros metabólicos de comunidades perifíticas (Produção, Respiração, Metabolismo Líquido da Comunidade e razão Produção:Respiração). O tratamento de inclusão de Potimirim produziu resultados inversos aos esperados, com aumento da clorofila e massa seca das comunidades perifíticas, levantando dúvida com relação à eficácia dos tratamentos. Nenhuma das variáveis metabólicas esteve relacionada aos tratamentos. Considera-se que efeitos artefato da gaiola utilizada na inclusão dos camarões podem ter prejudicado o efeito esperado de remoção de material pelos camarões. Os resultados podem indicar, entretanto, que para o efeito de herbívoros os parâmetros clorofila e massa seca sejam mais sensíveis e variáveis que os metabólicos para as comunidades estudadas. São recomendados futuros trabalhos com metodologias que reduzam os efeitos artefato, tais como exclusão de herbívoros com cercas elétricas. No segundo trabalho, foram estudados os estoques, a distribuição e os controles da biomassa perifítica para o córrego. Entre os substratos estudados, a areia apresentou os maiores estoques, com 5 vezes mais clorofila e 20 vezes mais massa seca que os substratos pedra e folha. Diferenças entre trechos com diferentes densidades do camarão herbívoro Potimirim glabra revelaram para o substrato pedra menores valores de massa seca para os locais onde o camarão é mais numeroso. Entre as variáveis ambientais, apenas a profundidade esteve relacionada aos dados de biomassa nos substratos pedra e areia. A comparação dos dados deste estudo com trabalhos anteriores pode indicar que distúrbios provocados por enchentes podem alterar os estoques e os padrões de distribuição para este córrego. / This dissertation consists of two chapters, each corresponding to an independent study. In an Atlantic Rainforest stream, Rio de Janeiro, Brazil, the effects of herbivores and of environmental controls on periphyton were studied. In the first experiment I tested the effects of the shrimp Potimirim glabra, an ecosystem engineer, on the metabolic parameters of periphytic communities (Production, Respiration, Net Daily Metabolism and Production:Respiration ratio). The Potimirim inclusion treatments produced results opposite to the expected, with higher chlorophyll and dry mass of the periphytic communities. This lead to doubt of the efficacy of the treatments. None of the metabolic variables was related to the treatments. It is considered that artificial effects of the cage used in the shrimp inclusion may have changed the expected effect of material removal by the shrimps. The results may hint, however, that the chlorophyll and dry mass parameters may be more sensitive to and variable with the effects of herbivores than the metabolic parameters in the studied communities. Future work is recommended with methods that reduce artificial effects, such as herbivore exclusion using electric fences. In the second experiment, stocks, distribution and controls of periphytic biomass were studied for the stream. Among the studied substrates, sand presented the highest stocks, with 5 times more chlorophyll and 20 times more dry mass than the rock and leaf substrates. Differences among reaches with different densities of the herbivore shrimp Potimirim glabra revealed for the stone substrate smaller dry mass values in the reaches where the shrimp is more abundant. Among environmental variables, only depth was related to biomass, in the substrates rock and sand. The comparison of data in this study with previous work may hint that disturbances caused by spates may change stocks and distribution patterns for this stream.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / The feeding rates practiced in fish cultured directly influence the economic return of activity, because excessive rates result in zootechnical, economic losses and environmental. An alternative for improving the quality of crop water and increase the production of fish is the use of artificial substrates for colonization by periphyton. This study was conducted in two consecutive phases. The first phase of research was aimed at determining, in fish farming system based substrate, the optimal rate of feeding in each track of body weight, that maximizes the weight gain and feed efficiency, and minimizes the concentrations of ammonia and nitrite in pond water. Using seven treatments and a control, with five repetitions each, totaling 40 tanks of 250 L. In the treated groups growing feeding rates were evaluated, beginning with the following values: 3, 6, 9, 12%; 15, 18 and 21% biomass per day. The second phase of the study aimed to determine the best stocking density of juvenile tilapia fed at rates optimized in the cropping system based on substrate. By regression analysis of the results of final weight, specific growth rate and yield as a function of feeding rates employed, these variables observed increase in initial feed rate of about 12% of the biomass day -Â, occurring decreased these variables with increasing feed rate. Variables of water quality for initial feed rate of 12%, as NAT (0,39 mg/L), NH3 (0,026 mg/L) and O2D (5,18 mg/L) were within the acceptable for tilapia levels. With the increase in feed rate, there was worsening in water quality, it was not possible observe the effect of biofilter periphyton. Therefore in the first phase, that the optimal rate of feeding of juvenile Nile tilapia cultured in ponds with submerged substrates for periphyton, in the growing phase (1-30 g), corresponds to the initial rate of 12% biomass day-Â. In the second experimental phase, the rate of feeding and stocking density showed higher final body weight (25 g), yield (14,77 g/ mÂ/day) and TCE (5,16) were equal to 12% biomass day- (initial) and 9 fish/tank, respectively. The variables of water quality for this treatment were within the acceptable for growing tilapia tracks. / As taxas de arraÃoamento praticadas em cultivos de peixes influenciam diretamente no retorno econÃmico da atividade, pois taxas excessivas resultam em prejuÃzos zootÃcnicos, econÃmicos e ao meio ambiente. Uma alternativa para melhorar a qualidade da Ãgua de cultivo e aumentar a produÃÃo de pescado à o emprego de substratos artificiais para colonizaÃÃo por perifÃton. O presente trabalho foi realizado em duas fases consecutivas. A primeira fase teve como objetivo geral determinar, em sistema de cultivo de peixes baseado em substrato, a taxa de arraÃoamento Ãtima, em cada faixa de peso corporal, que maximiza o ganho em peso e a eficiÃncia alimentar; e minimiza as concentraÃÃes de amÃnia e nitrito na Ãgua de cultivo. Utilizando sete tratamentos e um controle, com cinco repetiÃÃes cada, totalizando 40 tanques de 250 L. Nos grupos tratados foram avaliadas taxas crescentes de arraÃoamento, iniciando-se com os seguintes valores: 3; 6; 9; 12%; 15, 18 e 21% da biomassa ao dia. A segunda fase do trabalho teve por objetivo determinar a melhor densidade de estocagem de juvenis de tilÃpia alimentados sob taxas otimizadas, em sistema de cultivo baseado em substrato. Pela anÃlise de regressÃo dos resultados de peso final, taxa de crescimento especÃfico e produtividade em funÃÃo das taxas de arraÃoamento empregadas, observou-se aumento dessas variÃveis atà a taxa de arraÃoamento inicial de, aproximadamente, 12% biomassa dia-Â, ocorrendo queda dessas variÃveis com a elevaÃÃo da taxa de alimentaÃÃo. As variÃveis de qualidade de Ãgua para taxa alimentar inicial de 12%, como NAT (0,39 mg/L), NH3 (0,026 mg/L) e O2D (5,18 mg/L) ficaram dentro dos nÃveis aceitÃveis para o cultivo de tilÃpia. Com o aumento da taxa de alimentaÃÃo, houve piora da qualidade de Ãgua, nÃo sendo possÃvel observar o efeito de biofiltro do perifÃton. Concluiu-se, na primeira fase, que a taxa Ãtima de arraÃoamento de juvenis de tilÃpia do Nilo cultivados em tanques com substratos submersos para perifÃton, na fase de recria (1 â 30 g), corresponde à taxa inicial de 12% biomassa dia-Â. Na segunda fase experimental, a taxa de arraÃoamento e a densidade de estocagem que proporcionaram maior peso corporal final (25 g), produtividade (14,77 g/mÂ/dia) e TCE (5,16) foram iguais a 12% da biomassa dia-1 (inicial) e 9 peixes/tanque, respectivamente. As variÃveis de qualidade de Ãgua para esse tratamento se apresentaram dentro das faixas aceitÃveis para o cultivo de tilÃpia do Nilo.

Submitted by Edineia Teixeira (edineia.teixeira@unioeste.br) on 2018-11-22T18:07:16Z No. of bitstreams: 2 Cinthia_Favaretto_2018.pdf: 2179148 bytes, checksum: ecff784c58c19dda7ee6b23ade555ce2 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-11-22T18:07:16Z (GMT). No. of bitstreams: 2 Cinthia_Favaretto_2018.pdf: 2179148 bytes, checksum: ecff784c58c19dda7ee6b23ade555ce2 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-04-05 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Eunotia species from a stream located in the surrounding area of the Iguaçu National Park conservation unit was analyzed. Samples were monthly collected from September 2012 to August 2013. The periphytic material, manually obtained by squeezing an aquatic macrophyte, was oxidized and analyzed under optical and scanning electron microscopy. Twenty-one infrageneric taxa of Eunotia were identified, measured, and illustrated. Eunotia caniculoides Favaretto, Tremarin, Bueno & T. Ludwig is proposed as a new species, and eight taxa are new records for the state of Paraná: E. georgii Metzeltin & Lange-Bertalot, E. glacialifalsa Lange-Bertalot, E. guianense (Ehrenberg) de Toni, E. pileus Ehrenberg, E. pseudoimplicata Lange-Bertalot, L.F.Costa & C.E.Wetzel, E. pseudosudetica var. rotundata Cavalcante, Tremarin & T.Ludwig, E. sedina Lange-Bertalot and E. tropico-arcus Metzeltin & Lange-Bertalot. Keywords: Bacillariophyta, Diatoms, Periphyton, Southern Brazil, Taxonomy. / Espécies de Eunotia Ehrenberg de um ambiente lótico localizado em área adjacente à unidade de conservação Parque Nacional do Iguaçu foi analisada. As coletas foram realizadas mensalmente de setembro de 2012 a agosto de 2013. O material perifítico obtido do espremido manual de uma macrófita aquática foi oxidado e analisado sob microscopia óptica e eletrônica de varredura. Vinte e um táxons infragenéricos foram identificados, medidos e ilustrados. Eunotia caniculoides Favaretto, Tremarin, Bueno & T. Ludwig é proposta como uma nova espécie e oito táxons constituem novos registros para o estado do Paraná: E. georgii Metzeltin & Lange-Bertalot, E. glacialisfalsa Lange-Bertalot, E. guianense (Ehrenberg) de Toni, E. pileus Ehrenberg, E. pseudoimplicata Lange-Bertalot, L.F.Costa & C.E.Wetzel, E. pseudosudetica var. rotundata Cavalcante, Tremarin & T.Ludwig, E. sedina Lange-Bertalot e E. tropico-arcus Metzeltin & Lange-Bertalot

Grunda, näringsrika sjöar förekommer i två stadier: antingen ett med grumligt vatten och hög biomassa av växtplankton, eller ett med klart vatten och riklig undervattensvegetation. Det klara stadiet är eftersträvansvärt eftersom det skapar goda förutsättningar för en rad ekosystemtjänster, inklusive vattenkvalitet, rekreation och förutsättningar för biodiversitet. Vid eutrofiering, d v s ökat tillskott av näringsämnen, kvarstår det klara stadiet tills näringsbelastningen blir så hög att sjön övergår till ett grumligt stadium. Sjön Tåkern, i Östergötland, har under de senaste åren blivit alltmer eutrofierad och kalkning av vattnet har diskuterats som en möjlig åtgärd för att bevara det klara stadiet som sjön numera befinner sig i. Undersökningar om kalkning av eutrofierade sjöar har gjorts tidigare, men det har varit få studier av effekterna av kalkning på undervattensvegetation, substratlevande djur och påväxtalger. För att undersöka detta, gjordes ett fält- och ett laboratorieexperiment inriktade på effekter på överlevnad av vattengråsugga, Asellus aquaticus, fysiologisk status (halten klorofyll a) i kransalgen Chara globularis och tillväxt av nyetablerade påväxtalger i sjön Tåkern. Resultaten visar att A. aquaticus hade lägre överlevnad efter kalkning till pH 10 i laboratorieexperiment, men i fältförsöket hade kalkning till detta pH inte någon inverkan. C. globularis hade en högre halt klorofyll a efter kalkning till pH 10 i laboratorieexperimentet, men i fältexperimentet hade kalkning ingen effekt på halten klorofyll a. Påväxtalger hade en lägre tillväxthastighet efter kalkning i fältexperimentet. Slutsatsen är att kalkning kan vara en metod för att motverka eutrofiering av sjön Tåkern. Några inkonsekvenser mellan mesokosm- och laborationsresultaten tyder på att fler studier behövs göras för att undersöka hur kalkning till pH 10 påverkar bentiska organismer. / Shallow, nutrient-rich lakes can occur in two alternative states: either a turbid water state with high biomass of phytoplankton, or a clear water state with abundant submerged vegetation. The clear water state is worth striving for because it creates good conditions for a range of ecosystem services and biodiversity. Lake Tåkern, Östergötland, has in recent years become increasingly eutrophic and liming has been discussed as a method to reduce the phosphorus level and maintain, or trigger a shift to, the clear water state. Investigations regarding the effects of liming of eutrophic lakes on phosphorus level and plankton have been performed in the past, but few studies have examined the effects on submerged vegetation, benthic invertebrates and periphyton. To study this, a field and a laboratory experiment were performed to examine how liming to pH 10 affects survival of the benthic invertebrate Asellus aquaticus, the chlorophyll a content in the stonewort Chara globularis and growth of periphyton. Survival of A. aquaticus was not affected in a field mesocosm experiment in Lake Tåkern, but decreased after liming in a laboratory experiment. The chlorophyll a content of C. globularis was not affected in the field experiment but higher than in the controls in the laboratory experiment. Growth of periphyton was reduced in the field experiment. Based on the field experiment, effects on A. aquaticus and C. globularis were negligible, but the laboratory experiment indicate that liming to pH 10 may under certain conditions affect benthic organisms. The conclusion is, however, that liming can be a suitable method to counteract the eutrophication of Lake Tåkern. Some inconsistencies between the field and laboratory results suggest that more studies needs to be made to see how liming to pH 10 affect benthic organisms.

Human exposure to methylmercury (MeHg) through diets (e.g., fish and rice) is a global health concern. Although MeHg exposure through fish consumption has long been considered the major route of mercury health risks, studies concerning the long-term changes in MeHg exposure from fish remain lacking. In sharply contrast to the fish MeHg issue, the presence of MeHg in rice has only been reported recently and its implications on MeHg exposure, albeit probably important, are still in infancy. Focusing on the discrepancies in the studies of MeHg exposure through fish and rice consumption, this study was aimed to assess the MeHg exposure of human infants through consumption of rice cereals and to evaluate the long-term changes in fish MeHg. The presence of MeHg in rice prompted the studies on MeHg concentrations and bioaccessibility in rice cereals and potential infant dietary exposure to MeHg through cereal consumption, which is believed to be the first of its kind. The analysis of a variety of infant cereals sampled from the common markets in the United States and China showed that the concentrations of MeHg in the cereals ranged from 0.07 to 13.9 µg/kg with a mean of 1.61 µg/kg. On the basis of these MeHg concentrations, the daily intake of MeHg through rice cereal consumption for infants was estimated to be 4-122% of the reference dose (RfD). The MeHg bioaccessibility in the cereals, determined using an in vitro digestion method, ranged from 25 to 74% with a mean of 48±16%. A further examination on these results, however, revealed the occurrence of MeHg re-adsorption during extraction steps, which leads to the underestimation of MeHg bioaccessibility and warrants cautions to be exercised when using these procedures to evaluate bioaccessibility in general. The long-term changes in fish MeHg were investigated through conducting a comprehensive data analysis on datasets for the Everglades, a well-studied aquatic ecosystem for Hg contamination. The results showed a clear decline of MeHg in mosquitofish in the Everglades during the past two decades, which was probably related to changes in environmental conditions (e.g., periphyton, dissolve organic matter, and sulfate) instead of mercury deposition.

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