Made available in DSpace on 2015-04-17T14:55:36Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2483351 bytes, checksum: 279c66c6699042d45f2f5b1724dd02da (MD5) Previous issue date: 2010-08-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Ontogenetic studies constitute an important step to increase the knowledgebase about shifts in food preference and micro-habitats, as well as for improving taxonomy, production for aquaculture, and fisheries management; they may also shed new light on the implications of the extraction of a high volume of animals for trade. This study aimed to estimate the initial growth of the seahorse Hippocampus reidi, and to morphologically describe its ontogeny, from the embryonic period to the reproductive phase. Both aspects are relevant in face of (1) the morphological and biological singularities of the genus, including the ability to bend the body and the body covering formed by bony rings, a prehensile tail and the development of a pouch in males and (2) the need to increase our understanding of the biology and ecology of seahorses, a group globally threatened by overfishing and habitat loss. Growth was estimated using ex-situ data obtained from two different broods of H. reidi, while description of the ontogeny was done using data collected both in-situ and ex situ. Data were grouped into two distinct phases: planktonic and postplanktonic (when juveniles are able to use holdfasts). The main results obtained in the study are: H. reidi exhibited an initial daily growth rate of 0.017 cm; juveniles showed a decrease in the percentage of the head, and in the depth of the snout and trunk in relation to standard length with age. During the planktonic phase, juveniles exhibited a a positive growth in the tail region, weak pigmentation and had the pectoral fins positioned near the base of the head. After that period, the body acquired a more solid structure, and various base became evident (at 2.59 cm); the snout became more elongated, and the pectoral fins were positioned near the level of the orbits. / Estudos acerca da ontogenia constituem uma etapa importante para ampliar o entendimento sobre mudanças na preferência alimentar e por micro-habitats, bem como para o aprimoramento da taxonomia, otimização da produção em s e l e ; a r i e u q s e p o ã t s e g a a r a p e a r u t l u c i u q a a m u r a i c i p o r p m e d o p m é b m a t maior compreensão acerca das implicações da extração de um alto volume de animais para o comércio. O presente trabalho buscou estimar o crescimento inicial da espécie de cavalo-marinho Hippocampus reidi e descrever morfologicamente sua ontogenia, do período embrionário à fase reprodutiva. Ambos aspectos são relevantes face às (1) singularidades morfológicas e biológicas do gênero, que incluem a capacidade de dobrar o corpo dorsoventralmente e a presença de placas ósseas dispostas em forma de anel ao longo do corpo, a cauda preênsil e o desenvolvimento de uma bolsa incubadora nos machos e (2) à necessidade de ampliar o conhecimento acerca da biologia e ecologia dos cavalos-marinhos, um grupo globalmente ameaçado pela sobrepesca e pela perda de habitat. Para a análise de crescimento, foram obtidos dados ex-situ de duas diferentes proles de H. reidi. A descrição ontogenética foi realizada utilizando-se dados obtidos in-situ e ex-situ . Foram consideradas duas fases distintas: planctônica e pós-planctônica (quando os jovens são capazes de se prender a estruturas de apoio). Principais resultados obtidos no estudo: H. reidi apresentou uma taxa de crescimento inicial de 0,017 cm ao dia; indivíduos jovens apresentaram decréscimo no percentual da cabeça, da altura do focinho e do tronco em relação ao comprimento padrão, com a idade. Durante a fase planctônica, os jovens exibiram cauda em processo de crescimento, pigmentação discreta e nadadeiras peitorais implantadas próximas à base da cabeça. Após este período, a estrutura corporal tornou-se mais sólida e cores de base variadas tornaram-se evidenciadas (aos 2,59 cm); o focinho tornou-se mais alongado e as nadadeiras peitorais passaram a se posicionar próximo à linha das órbitas.

Neste trabalho, investigou-se o crescimento e as interações de microorganismos, anaeróbios, em batelada com células planctônicas e em reatores diferenciais com biofilme, sob condições termofílicas (55ºC). Foram utilizadas técnicas clássicas para caracterizar os microorganismos anaeróbios estritos e biologia molecular (FISH), com sondas fluorescentes específicas, para caraterizar e quantificar os microrganismos pertencentes ao domínios Archea e Bacteria. Foram realizadas experimentos com meios de cultivo contendo acetato de sódio e propionato de sódio, na presença de sulfato de sódio. Os resultados do FISH mostraram, para os ensaios em batelada com acetato e sulfato, o predomínio de organismos pertencentes ao Domínio Archea (ARC915+MB1174) representados pelo gênero Methanosarcina sp. e bacilos fluorescentes. No biofilme, para a mesma condição, houve predomínio de células do Domínio Bacteria (EUB338) e relacionadas com a oxidação do acetato. Para a condição de cultivo com lactato e sulfato, as células bacterianas semelhantes a Desulfotomaculum sp. predominaram nos reatores em batelada e diferenciais, justificando a elevada porcentagem de células do Domínio Bacteria. Os resultados do NMP mostraram uma maior concentração de anaeróbios totais na condição lactato e sulfato (\'10 POT.11\' - \'10 POT.12\'). Para as arqueas metanogênicas essa concentração foi eveidenciada para a condição de cultivo com acetato e sulfato (\'10 POT.4\'). Os resultados desse trabalho sugeriram que em reatores em batelada, na condição de cultivo com acetato e sulfato, ocorreu equilíbrio entre metanogênese, oxidação de acetato e sulfatogênese, enquanto no biofilme, foram favorecidos os dois primeiros tipos de metabolismo. A condição lactato mais sulfato favoreceu a sulfetogênese em ambos os reatores. No reator diferencial, alimentado com proprionato e sulfato ocorreu fermentação com crescimento sintrófico entre oxidadoras de proprionato, metanogênicas e redutoras de sulfato hidrogenotróficas. / In this work, were investigated the growth and interactions of anaerobic microorganisms, in batch and differential reactors with planktonic cells and biofilm, respectively, in thermophilic conditions (55°C). Classic and molecular biology methods (FISH) were utilized to characterize strict anaerobes, with specific fluorescence probes, to characterize the Archaea and Bacteria Domain cells. Experiments with sodium acetate, s01ium lactate and sodium propionate plus sodium sulfate were realized. To the acetate and sulfate batch assays the results of FISH showed the predominance of Archaea Domain cells (ARC915+MB1174), represented by genera Methanosarcina sp. and fluorescents rods. Under the same conditions the biofilm results showed predominance of Bacteria Domain cells (EUB338) and those related to the acetate oxidation. In lactate plus sulfate condition the bacteria cells, as Desulfotomaculum sp., predominated in batch and differential reactors, justifying the high percentage of Bacteria Domain cells. The MPN results showed a high concentration of total anaerobes under lactate plus sulfate condition (\'10 POT.11\' - \'10 POT.12\'). For methanogenic arquea this concentration was obtained in the acetate plus sulfate condition (\'10 POT.4\'). These results suggest a process equilibrium may have occurred among methanogenesis, acetate oxidation and sulfidogenesis in batch reactors under acetate plus sulfate conditions. However, methanogenesis and acetate oxidation metabolisms predominated in the biofilm. Sulfidogenesis was easier in both reactors, under lactate plus sulfate conditions. In the differential reactors with propionate plus sulfate, the fermentation was in syntrophic co-culture among propionate oxidizing bacteria, methanogenic and hydrogenotrophic sulfate reducing bacteria.

The fishery for octopus in Northwest Mexico has increased to over 2,000 tons annually, but to date the specific composition of the catch has been ignored. With at least three main species targeted by artisanal fisheries in the region with distinct life histories, the lack of basic biological information about the distribution, metapopulation size and structure of each species could impede effective fisheries management to avoid overexploitation. We tested if different life histories of three species of octopus could help predict observed patterns of genetic diversity, population dynamics, structure and connectivity and how this information could be relevant to the sustainable management of the fishery. We sequenced two mitochondrial genes and genotyped seven nuclear microsatellite loci to identify the distribution of each species in 20 locations from the Gulf of California and the west coast of the Baja California peninsula. We tested five hypotheses derived from population genetic theory based on differences in the fecundity and dispersal potential for each species. We discovered that Octopus bimaculoides with low fecundity and direct development (without a planktonic phase) had lower average effective population size and genetic diversity, but higher levels of kinship, population structure, and richness of private alleles, than the other two species. These features indicated limited dispersal and high local recruitment. In contrast, O. bimaculatus and O. hubbsorum with higher fecundity and planktonic phase as paralarvae had higher effective population size and genetic diversity, and overall lower kinship and population structure than O. bimaculoides. These observations supported higher levels of gene flow over a larger geographical scale. O. bimaculatus with the longest planktonic paralarval duration and therefore larger dispersal potential had differences in the calculated parameters possibly associated with increased connectivity. We propose O. bimaculoides is more susceptible to over exploitation of small, isolated populations and could have longer recovery times than the other two species. This species may benefit from distinct fishery management within each local population. O. bimaculatus and O. hubbsorum may benefit from fishery management that takes into account metapopulation structure over larger geographic scales and the directionality and magnitude of larval dispersal driven by ocean currents and population connectivity among individuals of each locality. The distribution of each species and variations in their reproductive phenology is also important to consider when establishing marine reserves or seasonal fishing closures.

Chemotherapy of tuberculosis (TB), a disease caused by Mycobacterium tuberculosis (M. tuberculosis), is successful against actively-growing bacilli but ineffective against dormant/persistent organisms, found mainly in a protective lipid-laden granuloma, possibly necessitating the use of lipophilic antibiotics. In vitro, these bacilli are encased in lipid-rich biofilms. In this study, the antimycobacterial activity of one such agent, clofazimine, and its nanoparticle formulation, have been investigated against Mycobacterium smegmatis (M. smegmatis), as a surrogate for M. tuberculosis, by determining the bacteriostatic and bactericidal activities of the native (NC) and spray-dried (SDC) preparations of this agent on planktonic and biofilm populations, as well as their effects on biofilm formation and its lipid compositions, specifically free mycolic acid (FM) content. Both preparations were comparable, being bacteriostatic for rapidly-proliferating bacilli, bactericidal for slow-growing, biofilm-producing sessile bacteria, but ineffective against non-replicating, biofilm-encased M. smegmatis organisms. However, similar studies in M. tuberculosis are required. / Dissertation (MSc)--University of Pretoria, 2013. / Immunology / Unrestricted

Masters of Science / Located on the western offshore on the Atlantic Ocean margin of Southern Africa, the Orange Basin is the youngest and largest of the South Africa’s seven sedimentary basins. This passive margin basin in known for its hydrocarbon potential and therefore is the focus of attraction of several oil exploration companies. The study area lies near the continental margin in which four exploratory wells were drilled. An attempt has been made in this work to understand the depositional settings of these reservoirs and their biostratigraphy. Distribution of important planktonic index foraminifera helps in dating the reservoir sections. Paleoecological studies of benthic foraminifera were used for understanding the prevailing environment during the Cretaceous period. The study indicates that most of the reservoirs are distributed in the Albian (Early Cretaceous) and a few in the Cenomanian age sediments. Relatively shallow shelf sedimentation prevailed in the Late Aptian to middle part of Albian with deposition of arenaceous units. There were periodic localised deepening as well as very shallow depositional condition leading to exposure (diastem) as indicated by lithology and faunal composition. Gradual rise in sea level started in Late Albian and the entire area was under bathyal environment till the end of Cenomanian stage. This is indicated by deposition of claystone rich units and the associated fossil benthics indicates deposition in slope area. The few relatively minor argillaceous sandstone and siltstone units are with poor reservoir quality.

Thesis (PhD(Microbiology))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: Pathogenic Flavobacterium spp. cause serious disease outbreaks in a variety of farmed fish, which lead to large economic losses in the aquaculture industry on an annual basis. The ability of Flavobacterium johnsoniae-like isolates to grow as surface-associated communities (biofilms) in aquaculture systems poses a threat to fish health over extended periods of time. The biofilmforming ability of 28 F. johnsoniae-like isolates obtained from diseased fish were correlated with their chitin-degrading abilities and extracellular carbohydrate complexes (ECC) and their pulsed-field gel electrophoresis (PFGE) genotypes. Physiological changes in the proteome of 5 day planktonic, biofilm and agar surface-associated cultures of F. johnsoniae-like isolates YO12 and YO64 were analyzed by two-dimensional (2-D) gel electrophoresis and 17 differentially expressed and 14 uniquely expressed proteins were identified using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Thirty-two differentially expressed genes in 5 day biofilm and agar surface-associated cultures of F. johnsoniae-like isolates YO12 and YO64 were identified using suppression subtractive hybridization (SSH). Significant negative correlations were observed between the chitin-degrading abilities and ECC and the biofilmforming capacity of 24 h biofilm cultures of F. johnsoniae-like isolates. Genetic heterogeneity was displayed by the F. johnsoniae-like isolates following PFGE. A significant positive correlation was observed between PFGE types and fish host species. Differentially and uniquely expressed proteins identified in planktonic, biofilm and agar surface-associated phases by 2-D/MS as well as differentially expressed genes identified in the biofilm and agar surface-associated phases by SSH were categorized as being involved in adaptation/protection, metabolic processes, membrane/transport/ motility and transcription/ translation. As far as we know, this is the first report on the characterization of differentially expressed genes and gene products of F. johnsoniae-like isolates obtained from diseased fish in South Africa. / AFRIKAANSE OPSOMMING: Patogene Flavobacterium spp. veroorsaak ernstige infeksie uitbrake in ’n verskeidenheid gekweekte vissoorte, wat jaarliks tot groot ekonomiese verliese in die akwakultuur bedryf lei. Die vermoë van Flavobacterium johnsoniae-tipe isolate om as oppervlak-gehegde gemeenskappe (biofilms) in akwakultuur sisteme te groei bedreig visgesondheid oor verlengde periodes. Die vermoë van 28 F. johnsoniae-tipe isolate om biofilms te vorm is vergelyk met hul vermoë om chitien te degradeer, die profiel van hul ekstrasellulêre koolhidraat komplekse (EKK) en bandpatrone verkry met puls-veld jel elektroforese (PVJE). Fisiologiese veranderinge in die proteoom van 5-dagoue planktoniese-, biofilm- en agar oppervlak-geassosieerde kulture van F. johnsoniae-tipe isolate YO12 en YO64 is met twee-dimensionele (2-D) jel elektroforese geanaliseer. Sewentien differensieël uitgedrukte en 14 uniek uitgedrukte proteïene is deur middel van matriks-geassisteerde laser desorpsie ioniserings-tyd van vlug-massa spektrometrie (MGLDI-TVV MS) geïdentifiseer. Twee-en-dertig differensieël uitgedrukte gene in 5-dag-oue biofilm- en agar oppervlak-geassosieerde kulture van F. johnsoniae-tipe isolate YO12 en YO64 was deur middel van suppressie afgetrokke hibridisasie (SAH) geïdentifiseer. Beduidende negatiewe korrelasies is tussen die chitin-degraderings vermoë en EKK en die biofilm-vormings kapasiteit van 24-uur-oue biofilm kulture van F. johnsoniae-tipe isolate waargeneem. Resultate verkry met PVJE het die heterogene samestelling van F. johnsoniae-tipe isolate uitgewys. ‘n Beduidende positiewe korrelasie is tussen PVJE groeperings en vis gasheer spesie waargeneem. Differensieël en uniek uitgedrukte gene geidentifiseer in die planktoniese-, biofilm- en agar oppervlak-geassosieerde fases is deur middel van 2-D/MS asook differensieël uitgedrukte gene geïdentifiseer in die biofilm en agar oppervlakgeassosieerde fases deur middel van SAH was as betrokke by aanpassing/beskerming, metaboliese prosesse, membraan/vervoer/ beweeglikheid en transkripsie/translasie gekategoriseer. Sover bekend is hierdie die eerste beskrywing van differensieël uitgedrukte gene en geenprodukte van F. johnsoniae-tipe isolate afkomstig van geinfekteerde vis in Suid Afrika.

Cinq carottes de la Méditerranée occidentale ont fait l’objet des approches multidisciplinaires basées essentiellement sur l'analyse des dinokystes, des foraminifères planctoniques et des isotopes afin d'identifier et préciser l'évolution climatique de ce bassin. L'ensemble de l'Holocène correspond au maximum de développement des dinokystes S. mirabilis et I. aculeatum et des foraminifères planctoniques G. inflata et G. ruber tandis que les épisodes froids sont caractérisés par la présence de Nematosphaeropsis labyrinthus et a un degré moindre de Spiniferites elongatus. Si dans la proximité du détroit de Gibraltar il est possible de distinguer les évènements de Heinrich du Maximum Glaciaire (LGM) cette distinction est moins évidente en se dirigeant vers l’Est. Au contraire le Younger Dryas s’exprime de façon identique sur l'ensemble du bassin occidental et se caractérise par le développement optimal de N. labyrinthus s’accompagnant d’après les fonctions de transfert dinos d’une baisse importante de la salinité. Cet épisode est marqué aussi par des concentrations maximales de dinokystes remarquablement corrélées à une augmentation du ?13C de G. bulloides. Cette augmentation de la productivité primaire au Dryas Récent est à relier à l’intensification des échanges Méditerranée-Atlantique. Par opposition, l'Holocène inférieur montre une baisse de la productivité primaire en Méditerranée occidentale contemporaine de la mise en place du sapropéle S1 dans le bassin oriental. Comme dans l'océan Atlantique, le refroidissement du "8.2 event" est clairement observée en Méditerranée occidentale ainsi que trois autres épisodes correspondant à ~9,3 ka; ~7 ka et ~2,7 ka cal. BP. / A multidisciplinary approach is occurred on five western Mediterranean cores based on dinocysts, planktonic foraminifera and isotopes to identify the climatic evolution of this region. The Holocene correspond to the maximal development of dinocysts S. mirabis and I. aculeatum and planktonic foraminifera G. inflata and G. ruber but the cold periods are characterised by the presence of N. labyrinthus and Spiniferites elongatus. The microfaunistic assemblages show that it's less easier to distinguish the LGM to Heinrich events (HE) when the study sites are far to strait of Gibraltar. The Younger Dryas is marked by the optimal development of N. labyrinthus on the entire basin in association to an important decrease of Sea Surface Salinity reconstructed on the basis of dinocyst transfer function. During this period, an intensification of Mediterranean-Atlantic water masses exchange is recorded by the increase of the ?13C of G. bulloides associated to the maximal dinocysts concentration. By contrast, the lower Holocene shows a decrease of primary productivity in western Mediterranean contemporaneous to the deposition of S1 sapropel in eastern basin. As in Atlantic Ocean, the 8.2 event is clearly observed in western Med with three other cold events at 9.3 ka, 7 ka and 2.7 ka cal. BP.

Para o desenvolvimento deste estudo, foi utilizado um testemunho de alta resolução coletado no talude da Bacia de Santos, em que foram realizadas análises de foraminíferos planctônicos e isótopos de oxigênio. Os resultados foram complementados por dados de razões de Fe/Ca e Ti/Ca e permitiram a compreensão do cenário paleoceanográfico no setor oeste do Atlântico Sul nos últimos 15 mil anos. Condições mais frias foram encontradas no início do registro até aproximadamente 8 mil anos A.P., com predomínio da fauna fria (G. truncatulinoides, N. dutertrei, e G. inflata) e valores mais altos de ? 18O. Maior produtividade também é sugerida pela componente principal 2 (CP2), relacionada à camada de mistura e caracterizada pela assembléia G. ruber (white) e G. sacculifer. As razões de Fe/Ca e Ti/Ca indicam maior aporte de terrígenos pela pluma do Rio da Prata para o ambiente oceânico, provavelmente contribuindo para fertilização das águas superficiais. A partir de 8 mil anos A.P. observa-se aumento dos valores da curva paleoclimática e diminuição progressiva dos valores de ? 18O. A CP2 apresenta valores máximos entre 10 e 5 mil anos A.P., indicando uma coluna de água mais quente e altamente estratificada. Neste período, apresentam-se os mínimos de razões de Fe/Ca e Ti/Ca, indicando um período mais seco, relacionado ao mínimo de insolação de verão no hemisfério sul e posicionamento da ZCIT mais ao norte. A partir de 5 mil anos A.P. até o final do registro, observa-se novamente menores valores da CP2 e razões crescentes Fe/Ca e Ti/Ca, indicando condições mais úmidas e de maior produtividade no Holoceno superior. / For this study, faunal changes in foraminifer\'s assemblages and oxygen stable isotopes were carried out on a high- resolution core retrieved from the slope of Santos Basin. The results, complemented with Fe/Ca and Ti/Ca ratios enabled the understanding of paleoceanografic changes occurred in the last 15 Kyr. Cold conditions were recognized in the late deglaciation until 8 mil Kyr B.P., characterized by the cold assemblage (G. truncatulinoides, N. dutertrei, and G. inflata) and higher values of ? 18O. The low values of principal component 2 (PC 2), related to the mixed layer and dominated by the species G. ruber (white) and G. sacculifer suggest enhanced surface productivity. The Fe/Ca and Ti/Ca ratios on the sedimentary record indicate a high terrigenous input from the Plata Plume outflow in the oceanic environment, which probably contributed to the fertilization of superficial waters. From 8 Kyr B.P., an increase in the paleoclimatic curve values and gradual reduction in the ? 18O were observed in the data. The PC 2 yields maximum values between 10 and 5 Kyr B.P., indicating warm and highly stratified water-column conditions. In this period, low Fe/Ca and Ti/Ca ratios point out dryer conditions, related to the low peak austral summer insolation and the ITCZ located farther north. From 5 mil Kyr B.P. decreasing PC 2 values and increasing Fe/Ca and Ti/Ca ratios may be a sign of more productivity and humid conditions in the late Holocene.

O conhecimento das preferências ecológicas de espécies de foraminíferos planctônicos tem sido muito utilizada em investigações paleoceanográficas obtendo bons resultados. O presente estudo realizou inferências sobre as condições oceanográficas das águas superficiais da porção sudoeste do Atlântico Sul nos últimos 450.000 anos através da variação da abundância de foraminíferos planctônicos em dois testemunhos da Bacia de Campos. A partir da Análise de Correspondência foram identificados os três principais fatores responsáveis pela variação dos foraminíferos planctônicos encontrados em cada um dos testemunhos. No testemunho KF-13 os três fatores principais foram interpretados como temperatura, espessura da camada de mistura e sazonalidade; enquanto para o testemunho KF-14 os fatores foram definidos como espessura da camada de mistura, produtividade e sazonalidade. Com esses fatores foram identificados os intervalos de maior intensidade de ventos e produtividade na região. As principais mudanças climáticas do Atlântico Sul encontram-se relacionadas às mudanças de intensidade de ventos e dos sistemas dependentes deles como o Giro Subtropical do Atlântico e a Zona de Convergência Subtropical. / Paleoceanographic investigations based on planktonic foraminifera ecologic preferences are widely and succesfully applied. The present study infered surface waters oceanographic conditions from the South Atlantic southwest margin in the past 450.000 years through the planktonic foramifera abundance variation in two cores from Campos Basin. Correspondence Analysis defined three principal factors responsible for the planktonic foraminifera abundance variation in each core. The three KF-13 main factors were interpreted as temperature, mixed layer thickness and sazonality; KF-14 principal factors were defined as mixed layer thickness, productivity and sazonality. These factors made it possible to identify higher wind stress and higher productivity intervals in this region. The main climatic variations in South Atlantic are due to changes in wind stress and the systems which depend on it such as the Atlantic Subtropical Gyre and the Subtropical Convergence Zone.

A diversidade de organismos aquáticos de águas doces é ainda incompletamente conhecida no Brasil e atualmente graves problemas de alterações na qualidade das águas superficiais e destruição de habitats, têm levado a perdas de diversidade. O estudo da diversidade das comunidades planctônicas, incluindo uma análise ecológica dos fatores que alteram a riqueza e a abundância das espécies, é essencial para o entendimento dos processos controladores da diversidade. O presente trabalho visa analisar a diversidade da comunidade zooplanctônica em um reservatório e em um lago natural. As comunidades zooplantônicas da represa de Barra Bonita, SP e da lagoa Baixa Verde, MG, foram amostradas em diferentes periódicos, comparando-se a região limnética e a região litorânea. As principais variáveis físicas e químicas da água foram determinadas. As coletas de água foram feitas com garrafa de Van Dom e para as comunidades planctônicas com bomba de sucção, realizando-se coletas integradas na coluna d\'água e filtrando-se volumes de 100 a 200 litros, em redes de 20 e 68 micrômetros de abertura de malha para zooplâncton, respectivamente. As amostras foram fixadas com formol 4% e analisadas qualitativa e quantitativamente, utilizando-se bibliografias especializadas e recorrendo-se a especialistas para a identificação de algumas espécies. Com base em diferentes parâmetros físicos, químicos e biológicos, a represa de Barra Bonita pode ser considerada como um ambiente eutrófico e a lagoa Baixa Verde como um ambiente oligo-mesotrófico, corroborando classificações anteriormente realizadas por diversos autores. A comunidade zooplanctônica da represa de Barra Bonita foi bastante diversificada, sendo composta por 68 taxa, dos quais 31 taxa pertencentes aos Rotifera, 9 aos Cladocera e 8 aos Copepoda. Na lagoa Baixa Verde a riqueza de espécies foi baixa, tendo sido registrados 19 taxa, sendo 9 de Rotifera, 8 de Cladocera e 2 de Copepoda. A ocorrência das espécies Eurialona orientalis e Daphnia laevis na represa Barra Bonita constituem novos registros para aquele reservatório. Para a lagoa Baixa Verde, foram consideradas novas ocorrências de 8 espécies de Rotifera e 7 de Cladocera. A análise comparativa da diversidade e abundância do zooplâncton nas regiões limnéticas, revelou que no reservatório as maiores diversidades e densidades são encontradas na região limnética, ao passo que na lagoa a maior riqueza de espécies é encontrada na região litorânea, e a maior densidade na região limnética. As causas para estas diferenças são discutidas, em relação às características morfométricas, grau de trofia e a hipótese do distúrbio intermediário em reservatórios. / The biodiversity of most Brazilian waters is not completely known. Nowadays there are great problems related to the changes in water quality and habitat destruction, leading to biodiversity losses. Studies focusing the diversity of planktonic communities including analyses on main ecological factors determining the richness of species and population numbers are very important to the understanding of biodiversity controlling processes. The present work aimed to analyze the diversity of zooplankton communities of an artificial system, a reservoir and of a natural one, a lake. Zooplankton sampling was carried out in Barra Bonita reservoir, SP, and in Baixa Verde lake MG, in contrasting hydrological periods, comparing stations located in tlile limnetic and in the littoral region of the lakes. Main physical and chemical variables were determined. Water was collected by a Van Dorn bottle and plankton communities were sampled from the whole water column by a suction pump under low pressure. One hundred liters of water were filtered through nets of 20 um and 68 um mesh sizes for phytoplankton and zooplankton respectively. Samples were preserved on 4% formol solution for posterior qualitative and quantitative analyses using specialized literature. Based on physical, chemical and biological characteristics Barra Bonita was considered an eutrophic environment and Baixa Verde an oligo-mesotrófico one, corroborating the findings of previous studies. The analysis of zooplankton composition at Barra Bonita revealed a diversified and rich community represented by 68 taxa, 31 taxa belonging to Rotifera, 9 to Cladocera and 8 Copepoda. On the other hand, in lake Baixa Verde species richness was low, comprising 19 taxa, from which 9 of Rotifera, 8 of Cladocera and 2 of Copepoda. The occurrence of the species Eurialona orientalis and Daphnia laevis in Barra Bonita reservoir constitutes new records of species for that environment and also for Baixa Verde Lake 8 species of Rotifera and 7 of Cladocera are new occurrences. The comparative analysis of the diversity and abundance of zooplankton in the limnetic and in the littoral region revealed that in Barra Bonita reservoir the highest species richness is found in the limnetic zone whereas in Lagoa Verde the highest richness is found in the littoral zone. The reasons for these difterences are discussed in relation to morphometry, trophic state and intermediate disturbance hypothesis.