ABSTRACT
Abstract The objective of this work was to investigate the patterns of diversity and abundance of ciliates protozoa community in three tropical urban streams and verify which species can be considered bioindicators of water quality. In each stream, three regions (headwater, middle and mouth) were sampled in two years, in the rainy and dry seasons. The abiotic factors (dissolved oxygen, pH, temperature, turbidity, width, depth, flow and conductivity) and biotic factors (total coliforms, bacterioplankton, chlorophyll and flagellates) were analyzed using appropriate methods and ciliates were identified and counted through specialized literature. We identified 84 species distributed into 24 orders. Peniculida was the most representative order followed by Prorodontida. The RDA scores showed a spatial difference between streams. On the other hand, regarding the temporal variation, there was no separation of the sampled data. The Indval analysis showed ten species indicators, such as Coleps hirtus, Euplotes moebiusi and Tintinidium pusillum. The Cluster analysis per stream versus period showed a greater distinction of the streams in the dry season. On the other hand, a low similarity was observed between sections within the same stream. In summary, the results indicated that the ciliates can be used as important tools as bioindicators in lotic environments affected by different degrees of pollution, due to the fact that they have short life cycle, allowing the detection of impacts on a small time scale, as well as by having direct answers to environmental changes and high sensitivity to contaminants.
Resumo O objetivo deste trabalho foi investigar os padrões de diversidade e abundância da comunidade de protozoários ciliados em três córregos urbanos tropicais, bem como verificar quais espécies podem ser consideradas bioindicadoras da qualidade da água. Em cada córrego foram amostradas três regiões (cabeceira, intermediária e foz) em dois anos, nas estações chuvosa e seca. Os fatores abióticos (oxigênio dissolvido, pH, temperatura, turbidez, largura, profundidade, fluxo e condutividade) e fatores bióticos (coliformes totais, bacterioplâncton, clorofila e flagelados) foram analisados por metodologia específica e os ciliados foram contados e identificados por meio de literatura especializada. Foram identificadas 84 espécies distribuídas em 24 ordens. Peniculida foi a ordem mais representativa, seguida por Prorodontida. Os escores da RDA mostraram uma diferença espacial entre os córregos. Por outro lado, em relação à variação temporal, não houve separação entre os dados amostrados. A análise Indval mostrou dez espécies indicadoras, como Coleps hirtus, Euplotes moebiusi e Tintinidium pusillum. A análise de Cluster realizada por riacho versus período evidenciou uma maior distinção dos córregos no período seco. Por outro lado, foi observada uma baixa similaridade entre os locais dentro do mesmo córrego. Em síntese, os resultados indicaram que os ciliados podem ser utilizados como ferramentas importantes como bioindicadores em ambientes lóticos afetados por diferentes graus de poluição, devido ao fato de apresentarem um curto ciclo de vida, permitindo a detecção de impactos em uma pequena escala de tempo, bem como por apresentarem respostas diretas às mudanças ambientais e alta sensibilidade a contaminantes.
Subject(s)
Water Microbiology , Water Quality , Ciliophora/isolation & purification , Rivers/microbiology , Seasons , Brazil , Ciliophora/growth & developmentABSTRACT
The objective of this work was to investigate the patterns of diversity and abundance of ciliates protozoa community in three tropical urban streams and verify which species can be considered bioindicators of water quality. In each stream, three regions (headwater, middle and mouth) were sampled in two years, in the rainy and dry seasons. The abiotic factors (dissolved oxygen, pH, temperature, turbidity, width, depth, flow and conductivity) and biotic factors (total coliforms, bacterioplankton, chlorophyll and flagellates) were analyzed using appropriate methods and ciliates were identified and counted through specialized literature. We identified 84 species distributed into 24 orders. Peniculida was the most representative order followed by Prorodontida. The RDA scores showed a spatial difference between streams. On the other hand, regarding the temporal variation, there was no separation of the sampled data. The Indval analysis showed ten species indicators, such as Coleps hirtus, Euplotes moebiusi and Tintinidium pusillum. The Cluster analysis per stream versus period showed a greater distinction of the streams in the dry season. On the other hand, a low similarity was observed between sections within the same stream. In summary, the results indicated that the ciliates can be used as important tools as bioindicators in lotic environments affected by different degrees of pollution, due to the fact that they have short life cycle, allowing the detection of impacts on a small time scale, as well as by having direct answers to environmental changes and high sensitivity to contaminants.
Subject(s)
Ciliophora/isolation & purification , Rivers/microbiology , Water Microbiology , Water Quality , Brazil , Ciliophora/growth & development , SeasonsABSTRACT
Resistance to acetolactate synthase (ALS)-inhibiting herbicides in Brazil has been documented for six species. The probability to select biotypes of Euphorbia heterophylla (EPPHL) with multiple resistance increases in the same order of magnitude as the use of other herbicides belonging to only one mechanism of action. The objectives of this work were to evaluate the distribution of resistant populations (R) in the states of the Parana and Santa Catarina; to determine the existence of populations of EPHHL with multiple resistance to ALS and PROTOX inhibitors, and to confirm the occurrence of cross resistance to compounds of these mechanisms of action. Seeds of EPHHL of areas with suspected resistance had been sampled in 97 places during 2003. In the greenhouse experiment samples of each population were sprayed with imazethapyr or fomesafen, at only one rate. To identify the resistant ones they were sprayed with different levels of the herbicides imazethapyr and fomesafen. Later they were sprayed with diverse herbicides of the same mechanisms of action to confirm the multiple/cross resistance. There is widespread distribution in the region of populations with resistance to ALS inhibitors. Some biotypes demonstrated resistance to herbicides from the two mechanisms of action. The resistance factor (FR), or the relation of resistance between R and susceptible biotypes, confirms the existence of two biotypes of EPHHL with cross resistance to several herbicides inhibitors of ALS and PROTOX.
