Estudo da mobilização de metais e elementos traços em ambientes aquáticos do semi-árido brasileiro aplicando análises de componentes principais

The spatial and temporal retention of metals has been studied in water and sediments of the Gavião River, Anagé and Tremedal Reservoirs, located in the semi-arid region, Bahia - Brazil, in order to identify trends in the fluxes of metals from the sediments to the water column. The determination of metals was made by ICP OES and ET AAS. The application of statistical methods showed that this aquatic system presents suitable conditions to move Cd2+ and Pb2+ from the water column to the sediment.

Degradação de polifenóis em cinco espécies vegetais em ambientes aquáticos

Estudos de degradação de polifenóis em folhas e galhos de Inga sp., Mabea caudata Pax ex Hoffn., Mezilaurus itauba (Meissn.) Taub. ex Mez., Vatairea sericea Ducke e Protium sp. foram realizados no período de 155 dias em dois lagos experimentais situados próximos a Usina Hidrelétrica de Balbina, no Estado do Amazonas. Um dos lagos ficou com vegetação intacta e o outro foi desmatado. As determinações dos compostos fenólicos ba searam-se no método de Follin-Denis e o trabalho teve por objetivo o estudo de degradação da vegetação superior no meio aquático. Os resultados mostram que, no lago 1, Inga sp. e Mezilaurus itauba apresentaram maior taxa de decomposição, enquanto que, no lago 2, a degradação foi maior para as espécies Mabea caudata e Mezilaurus itauba.

Localização de áreas de monitoramento telemétrico em ambientes aquáticos da Amazônia

O presente trabalho demonstra a aplicabilidade de imagens de sensoriamento remoto e de métodos de processamento de imagens digitais para definição de locais adequados à instalação de sistemas telemétricos de monitoramento de variáveis ambientais em sistemas aquáticos, localizados em regiões de difícil acesso. A técnica consiste essencialmente da aplicação de operações Booleanas entre mapas da pluma do Rio Amazonas e de zonas inundadas do Lago de Curuai em diferentes etapas do ciclo hidrológico. A localização exata para o sistema de monitoramento telemétrico será vital para o desenvolvimento de modelos de troca de gases traço entre a planície de inundação Amazônica e a atmosfera.

Estudo comparado da taxocenose de peixes em dois ambientes aquáticos do Parque Estadual de Itapuã, sul do Brasil

Este trabalho tem por objetivos caracterizar e comparar a taxocenose de peixes de dois ambientes aquáticos distintos dentro de uma mesma bacia hidrográfica: a praia das Pombas (lago Guaíba) e a lagoa Negra, ambos no Parque Estadual de Itapuã, Rio Grande do Sul. Foram analisados aspectos que incluem a composição quali-quantitativa da ictiofauna. Para tanto, foram utilizados índices ecológicos e de abundância, sendo avaliados espacial e temporalmente e verificando se ocorre relação entre a estrutura da taxocenose destes locais e as variáveis ambientais. Foram amostradas 61 espécies no total, sendo a riqueza a mesma nos dois ambientes (44 espécies). Os dois ambientes estudados apresentam características peculiares, refletindo na composição de espécies de cada um destes locais. Foi possível observar que o padrão de distribuição da taxocenose de peixes estudada nos dois ambientes é sazonal, uma vez que a abundância, a biomassa e a diversidade foram mais elevadas nos meses mais quentes do ano, ou seja, primavera e verão. A temperatura e o fotoperíodo foram os principais fatores que influenciaram na distribuição da fauna de peixes da praia das Pombas e na lagoa Negra.

Algas: da economia nos ambientes aquáticos à bioremediação e à química analítica

Algae constitute a large group of many different organisms, essentially aquatic and able to live in all systems giving them sufficient light and humidity. Some algae species have been used in the evaluation or in the bioremediation of aquatic systems. More recently algae have been suggested as interesting tools in the field of analytical chemistry. In this work the most important aspects related to the different uses of algae are presented with a brief discussion.

Fatores que governam a especiação do cobre em ambientes aquáticos urbanos: evidências da contribuição de sulfetos solúveis

Copper speciation and behavior in different rivers located in the city of Curitiba were evaluated in this work. Sampling locations were selected to cover different levels of urbanization regarding their anthropogenic occupation and land use. Results showed that in highly-developed areas, both organic matter and dissolved sulfides were able to control copper speciation. Dissolved sulfide species were the major complexing agent in areas where dissolved oxygen levels are low. Finally, it was demonstrated that in urban areas anthropogenic factors such as sewage inputs and occupation of the drainage basin are the key aspects controlling copper dynamics and speciation in river waters.

Estudo da mobilização de metais e elementos traços em ambientes aquáticos do semi-árido brasileiro aplicando análises de componentes principais

The spatial and temporal retention of metals has been studied in water and sediments of the Gavião River, Anagé and Tremedal Reservoirs, located in the semi-arid region, Bahia - Brazil, in order to identify trends in the fluxes of metals from the sediments to the water column. The determination of metals was made by ICP OES and ET AAS. The application of statistical methods showed that this aquatic system presents suitable conditions to move Cd2+ and Pb2+ from the water column to the sediment.

A toxicidade em ambientes aquáticos: discussão e métodos de avaliação

Aquatic toxicity tests are assays performed with different aquatic organisms of different ecological organization levels. Such tests are a source of information on the toxicity of a given substance or wastewater under controlled conditions, and they complement the physico-chemical analyses. Moreover, they allow one to evaluate the risks resulting from the presence of toxic substances in the environment. Algae, crustaceans, fishes and bacteria are frequently used in toxicity tests. In this work, we will present the main aspects related to the aquatic toxicity tests and a discussion of their applicability will also be presented.

Avaliação de risco ambiental de ambientes aquáticos afetados pelo uso de agrotóxicos

Ecological risk assessment is a process evaluating the likelihood that adverse ecological effects may occur or are occurring as a result of exposure to one or more substances. Relevant information needed to predict risks from pesticides includes their physical chemical properties, mobility in soil, persistence in the environment, and bioaccumulation and toxicity in relevant organisms. Although currently a requirement for pesticide registration in Brazil, this process is not yet fully implemented in the country. This review aims to outline the principles of environmental risk assessment for pesticides, focusing on aquatic organisms, and to discuss the studies and efforts conducted in Brazil in this area.

Discriminação de ambientes aquáticos poluídos e não poluídos através da amplificação e clivagem do rDNA 16S

O crescimento desordenado da população e a expansão mal planejada das cidades, tem levado a precariedade das condições de saneamento e abastecimento hídrico, tornando a água um importante meio de desenvolvimento e transporte de microrganismos, muitos destes patogênicos. Desta maneira, torna-se necessário além da busca de soluções, o monitoramento eficiente e constante dos níveis e focos de contaminação. O presente trabalho teve como objetivo principal diferenciar ambientes aquáticos poluídos de não poluídos por contaminação de origem fecal, através de padrões moleculares. Para tanto foram escolhidos os arroios Feijó e Carvão, localizados na região metropolitana de Porto Alegre, Rio Grande do Sul, de onde foram coletadas amostras de água no verão e no inverno de 2001, submetidas a determinação do número mais provável (NMP) de coliformes totais e fecais, através da fermentação em tubos múltiplos. No Arroio Feijó foram observados índices de coliformes fecais superiores ao arroio Carvão, portanto o primeiro foi considerado modelo de ambiente aquático poluído e o segundo, não poluído. Seguiu-se a extração do DNA total das amostras brutas, amplificação do rDNA 16S pela PCR e clivagem destes com as enzimas de restrição Rsa I, Taq I e Alu I. Os padrões de clivagens observados com Rsa I sugerem a discriminação destes ambientes, uma variação sazonal foi observada entre as amostras de verão e inverno. O método mostrou-se sensível para uma análise comparativa entre estruturas de comunidades bacterianas em ambientes aquáticos.

Análise metagenômica da microbiota de ambientes aquáticos do estado do Rio Grande do Norte - Brasil

The screening for genes in metagenomic libraries from soil creates opportunities to explore the enormous genetic and metabolic diversity of microorganisms. Rivers are ecosystems with high biological diversity, but few were examined using the metagenomic approach. With this objective, a metagenomic library was constructed from DNA soil samples collected at three different points along the Jundiaí-river (Rio Grande do Norte-Brazil). The points sampled are from open area, rough terrain and with the direct incidence of sunlight. This library was analyzed functionally and based in sequence. For functional analysis Luria-Bertani solid medium (LB) with NaCl concentration varied from 0.17M to 0.85M was used for functional analysis. Positives clones resistant to hypersaline medium were obtained. The recombinant DNAs were extracted and transformed into Escherichia coli strain DH10B and survival curves were obtained for quantification of abiotic stress resistance. The sequences of clones were obtained and submitted to the BLASTX tool. Some clones were found to hypothetical proteins of microorganisms from both Archaea and Bacteria division. One of the clones showed a complete ORF with high similarity to glucose-6-phosphate isomerase which participates in the synthesis of glycerol pathway and serves as a compatible solute to balance the osmotic pressure inside and outside of cells. Subsequently, in order to identify genes encoding osmolytes or enzymes related halotolerance, environmental DNA samples from the river soil, from the water column of the estuary and ocean were collected and pyrosequenced. Sequences of osmolytes and enzymes of different microorganisms were obtained from the UniProt and used as RefSeqs for homology identification (TBLASTN) in metagenomic databases. The sequences were submitted to HMMER for the functional domains identification. Some enzymes were identified: alpha-trehalose-phosphate synthase, L-ectoina synthase (EctC), transaminase L-2 ,4-diaminobutyric acid (EctB), L-2 ,4-diaminobutyric acetyltransferase (EctA), L-threonine 3 dehydrogenase (sorbitol pathway), glycerol-3-phosphate dehydrogenase, inositol 3-phosphate dehydrogenase, chaperones, L-proline, glycine betaine binding ABC transporter, myo-inositol-1-phosphate synthase protein of proline simportadora / PutP sodium-and trehalose-6-phosphate phosphatase These proteins are commonly related to saline environments, however the identification of them in river environment is justified by the high salt concentration in the soil during prolonged dry seasons this river. Regarding the richness of the microbiota the river substrate has an abundance of halobacteria similar to the sea and more than the estuary. These data confirm the existence of a specialized response against salt stress by microorganisms in the environment of the Jundiaí river

Protozoários de vida livre em ambientes aquáticos do RN: ocorrência, caracterização e importância para a educação básica

Water is considered an essential right to life, besides being a determinant of economic development and social welfare, represented by both the quantity available, and the quality. In semi-arid Northeast, droughts occurring on a regular basis combined with human activities, aggravate the situation regarding the conservation of water resources in this area. To alleviate this condition is common to construction of artificial reservoirs, such as reservoirs and dams. As in natural aquatic environments, these reservoirs are potential sites for the proliferation, growth and development of diverse biological communities, whether of animals, plants and microorganisms. Research on the composition and ecology of these communities, especially microbial, are still restricted. One of the least studied groups in these environments are free-living protozoa, which over time have been neglected and after discoveries about its various functions in the aquatic ecosystem are beginning to receive more attention from scholars. They are, in quantitative terms, the most important consumers of microorganisms (mainly bacteria and algae) in aquatic environments, and therefore control the abundance of these. They may therefore influence the structure of the aquatic food chain in terms of species composition, abundance, biomass and biodiversity. Despite the recognition of the importance of protozoa in the final of the trophic transfer in aquatic environments, there are few data and, in general, are still precarious knowledge of them. Given the importance of protozoa in aquatic environments and the paucity of research on this group, especially in the state of Rio Grande do Norte, the present study aimed at identifying the genus and species of free-living protozoa that are present in the Armando Ribeiro Gonçalves Dam as well as to relate the occurrence and dynamics of the trophic conditions in the environment in which they are inserted, in order to support the hypothesis that species that are in these environments can serve to indicate the water quality. We observed the presence of 65 taxa of free-living protozoa, of which 29 were identified at the species level. There was a similarity space in taxonomic composition of protozoa, suggesting a possible regulation of this type of community for limnological variables other than those studied in this work (chlorophyll a, pH, temperature). Although it was aimed to analyze the conceptions of teachers and students from nearby towns Dam Armando Ribeiro Gonçalves, on issues relating to water quality and the role of protozoa. For this, we applied questionnaires with teachers and pupils of public schools of San Rafael and Itajá. It was concluded that teachers and students recognize the multi-dam Armando Ribeiro Gonçalves, although unaware of important aspects of the dynamics and ecology of this environment. Conceptions of teachers and students are matched at various times, especially with regard to waterborne diseases. In an attempt to identify possible misconceptions about the knowledge of the protozoa, assuming that these organisms have neglected their ecological role, and are seen as only, disease, a study was done with teachers and students, following a particular methodology that allowed look so clear and precise results. It was clear that knowledge about the free-living protozoa is still quite limited. The alternative conceptions that were found show a direct relation of protozoans and diseases. From the data obtained by these studies, we planned a series of science communication activities, environmental education and health education in schools close to study environments in order to promote a didactic transposition of accumulated knowledge about these organisms, favoring continuing education of teachers and the increase of information to the local community through the knowledge of biodiversity and ecology of these organisms. Moreover, the results found in this study and reflections on it that led to propose the elaboration of a book Readers with an emphasis on the group of freeliving protozoa in the populations for use in public schools in the region where it was developed the semiarid work