RESUMO

Testate amoebae have a great potential for use in scientific researches due to their ecological characteristics such as abundance, wealth, and generation time. In this way, this study aimed to present a scientometric analysis to describe the evolution of the different advances in researches on testate amoebae and identify a temporal pattern in this evolution. The literature review was based on papers indexed by Thomson Reuters (www.isiwebofknowledge.com) and SciVerse Scopus (www.scopus.com). In total 562 papers were examined. Results showed a pattern of evolution in scientific studies, most with ecological approach with descriptive and predictive designs. At the global level, researches on testate amoebae progressed in both the number of articles published as well as in the areas studied, especially in Europe and North America. The low number of experimental studies and review articles can characterize the lack of more knowledge to be acquired, both from particular observations (descriptive studies) as well as the observations noted sufficiently predictive of work. In Brazil, studies with testate amoebae are still developing, concentrated in only some regions, but the increased number of studies in recent years allows the prediction of the same overall patterns of advance for Brazilian researches. Thus, we conclude that these organisms are being increasingly used as a tool resp

RESUMO

Testate amoebae have a great potential for use in scientific researches due to their ecological characteristics such as abundance, wealth, and generation time. In this way, this study aimed to present a scientometric analysis to describe the evolution of the different advances in researches on testate amoebae and identify a temporal pattern in this evolution. The literature review was based on papers indexed by Thomson Reuters (www.isiwebofknowledge.com) and SciVerse Scopus (www.scopus.com). In total 562 papers were examined. Results showed a pattern of evolution in scientific studies, most with ecological approach with descriptive and predictive designs. At the global level, researches on testate amoebae progressed in both the number of articles published as well as in the areas studied, especially in Europe and North America. The low number of experimental studies and review articles can characterize the lack of more knowledge to be acquired, both from particular observations (descriptive studies) as well as the observations noted sufficiently predictive of work. In Brazil, studies with testate amoebae are still developing, concentrated in only some regions, but the increased number of studies in recent years allows the prediction of the same overall patterns of advance for Brazilian researches. Thus, we conclude that these organisms are being increasingly used as a tool resp

RESUMO

Zooplankton is able to respond promptly to environmental changes, producing resting forms in order to maintain populations when the conditions become unfavorable. The hatchling of the resting eggs was assessed in environments from the upper Paraná river floodplain, during the limnophase of 2008. We predicted that a higher production of these eggs and individuals hatchling are observed at isolated lakes, during dried period. Sediment samples were obtained with a corer sampler. The resting eggs were sorted and kept in filtered water from the same environment, in the laboratory. We recorded the occurrence of 378 resting eggs, of which 122 individuals hatched (70 cladocerans and 52 rotifers). The highest number of hatchlings was verified for the isolated lakes (84 individuals), as well the shorter time for hatchling (2 days). The hatchlings occurred mainly in September, when we registered the lowest hydrologic level of Paraná river (2.40 m). Grimaldina brazzai presented the longest time for hatchling, 44 days; and Brachionus dolabratus and B. falcatus, the shortest time, 2 days. This result suggests that the longer residence time of the water, which did not allow a renewal of food resources and limnological conditions of the environment, caused a higher stress in the zooplankton.

RESUMO

Zooplankton is able to respond promptly to environmental changes, producing resting forms in order to maintain populations when the conditions become unfavorable. The hatchling of the resting eggs was assessed in environments from the upper Paraná river floodplain, during the limnophase of 2008. We predicted that a higher production of these eggs and individuals hatchling are observed at isolated lakes, during dried period. Sediment samples were obtained with a corer sampler. The resting eggs were sorted and kept in filtered water from the same environment, in the laboratory. We recorded the occurrence of 378 resting eggs, of which 122 individuals hatched (70 cladocerans and 52 rotifers). The highest number of hatchlings was verified for the isolated lakes (84 individuals), as well the shorter time for hatchling (2 days). The hatchlings occurred mainly in September, when we registered the lowest hydrologic level of Paraná river (2.40 m). Grimaldina brazzai presented the longest time for hatchling, 44 days; and Brachionus dolabratus and B. falcatus, the shortest time, 2 days. This result suggests that the longer residence time of the water, which did not allow a renewal of food resources and limnological conditions of the environment, caused a higher stress in the zooplankton.  

RESUMO

This study evaluated the spatial variations in species richness and abundance of zooplankton over a hydrological cycle, and also verified the influence of physical and chemical water variables and chlorophyll-a concentrations on the abundance of these organisms. The tested hypothesis was that the zooplankton community presents higher species richness in lotic environments and higher abundance in lentic ones. One hundred forty species were identified, distributed among rotifers (88), testate amoebae (35), cladocerans (13) and copepods (4). Higher values of species richness and abundance were observed during the dry period. During both hydrological periods, the copepods presented high abundance values, due to the contribution of young stages, followed by rotifers, cladocerans and testate amoebae. In general, testate amoebae presented high values of species richness and abundance in lotic sampling stations, whereas the other zooplankton groups (rotifers, cladocerans and copepods) presented higher abundances in lentic environments and higher species richness in lotic ones. The Pearson correlation analysis evidenced the importance of physical and chemical water variables and food resource availability influencing the variation of organisms abundance.

This study evaluated the spatial variations in species richness and abundance of zooplankton over a hydrological cycle, and also verified the influence of physical and chemical water variables and chlorophyll- concentrations on the abundance of these organisms. The tested hypothesis was that the zooplankton community presents higher species richness in lotic environments and higher abundance in lentic ones. One hundred forty species were identified, distributed among rotifers (88), testate amoebae (35), cladocerans (13) and copepods (4). Higher values of species richness and abundance were observed during the dry period. During both hydrological periods, the copepods presented high abundance values, due to the contribution of young stages, followed by rotifers, cladocerans and testate amoebae. In general, testate amoebae presented high values of species richness and abundance in lotic sampling stations, whereas the other zooplankton groups (rotifers, cladocerans and copepods) presented higher abundances in lentic environments and higher species richness in lotic ones. The Pearson correlation analysis evidenced the importance of physical and chemical water variables and food resource availability influencing the variation of organisms abundance.

RESUMO

This study evaluated the spatial variations in species richness and abundance of zooplankton over a hydrological cycle, and also verified the influence of physical and chemical water variables and chlorophyll-a concentrations on the abundance of these organisms. The tested hypothesis was that the zooplankton community presents higher species richness in lotic environments and higher abundance in lentic ones. One hundred forty species were identified, distributed among rotifers (88), testate amoebae (35), cladocerans (13) and copepods (4). Higher values of species richness and abundance were observed during the dry period. During both hydrological periods, the copepods presented high abundance values, due to the contribution of young stages, followed by rotifers, cladocerans and testate amoebae. In general, testate amoebae presented high values of species richness and abundance in lotic sampling stations, whereas the other zooplankton groups (rotifers, cladocerans and copepods) presented higher abundances in lentic environments and higher species richness in lotic ones. The Pearson correlation analysis evidenced the importance of physical and chemical water variables and food resource availability influencing the variation of organisms abundance.

This study evaluated the spatial variations in species richness and abundance of zooplankton over a hydrological cycle, and also verified the influence of physical and chemical water variables and chlorophyll- concentrations on the abundance of these organisms. The tested hypothesis was that the zooplankton community presents higher species richness in lotic environments and higher abundance in lentic ones. One hundred forty species were identified, distributed among rotifers (88), testate amoebae (35), cladocerans (13) and copepods (4). Higher values of species richness and abundance were observed during the dry period. During both hydrological periods, the copepods presented high abundance values, due to the contribution of young stages, followed by rotifers, cladocerans and testate amoebae. In general, testate amoebae presented high values of species richness and abundance in lotic sampling stations, whereas the other zooplankton groups (rotifers, cladocerans and copepods) presented higher abundances in lentic environments and higher species richness in lotic ones. The Pearson correlation analysis evidenced the importance of physical and chemical water variables and food resource availability influencing the variation of organisms abundance.

RESUMO

The upper Paraná river floodplain possesses a great diversity of rotifers, with 288 planktonic taxa recorded. Surveys performed in this ecosystem since 1992 have shown that Lecanidae is the most abundant family, with 45 registered taxa. The main goal of the present study was to investigate the occurrence of this family in environments that have not yet been studied. Seven new occurrences of Lecane were recorded in plankton samples: L. bifurca, L. rhytida, L. subtilis, L. crepida, L. bulla styrax, L. obtusa, and L. thienemanne. Although the described taxa were found in plankton, this family is characterized by being typically non-planktonic. As such, exclusively taxonomic studies must explore the great habitat heterogeneity in this floodplain, e.g., the littoral region and the extensive areas colonized by aquatic macrophytes, aiming to expand knowledge on the diversity of this family in the upper Paraná river floodplain.

planície de inundação do alto rio Paraná possui grande diversidade de rotíferos, com 288 táxons planctônicos registrados. Estudos realizados, nesse ecossistema, desde 1992, mostram que Lecanidae é a família mais especiosa, com 45 táxons registrados. Este trabalho teve como objetivo investigar a ocorrência dessa família em ambientes ainda não-estudados e consequentemente contribuir para a diversidade de rotíferos nessa planície de inundação. Foram registradas sete novas ocorrências de Lecane em amostras do plâncton: L. bifurca, L. rhytida, L. subtilis, L. crepida, L. bulla styrax, L. obtusa, e L. thienemanne. Embora os táxons descritos fossem encontrados no plâncton, essa família caracteriza-se por ser tipicamente não-planctônica. Dessa forma, visando ampliar o conhecimento sobre a diversidade dessa família na planície de inundação do alto rio Paraná, estudos exclusivamente taxonômicos devem explorar a grande heterogeneidade de hábitats presente nessa planície, como, por exemplo, a região marginal e as extensas áreas colonizadas por macrófitas aquáticas.

RESUMO

The upper Paraná river floodplain possesses a great diversity of rotifers, with 288 planktonic taxa recorded. Surveys performed in this ecosystem since 1992 have shown that Lecanidae is the most abundant family, with 45 registered taxa. The main goal of the present study was to investigate the occurrence of this family in environments that have not yet been studied. Seven new occurrences of Lecane were recorded in plankton samples: L. bifurca, L. rhytida, L. subtilis, L. crepida, L. bulla styrax, L. obtusa, and L. thienemanne. Although the described taxa were found in plankton, this family is characterized by being typically non-planktonic. As such, exclusively taxonomic studies must explore the great habitat heterogeneity in this floodplain, e.g., the littoral region and the extensive areas colonized by aquatic macrophytes, aiming to expand knowledge on the diversity of this family in the upper Paraná river floodplain.

planície de inundação do alto rio Paraná possui grande diversidade de rotíferos, com 288 táxons planctônicos registrados. Estudos realizados, nesse ecossistema, desde 1992, mostram que Lecanidae é a família mais especiosa, com 45 táxons registrados. Este trabalho teve como objetivo investigar a ocorrência dessa família em ambientes ainda não-estudados e consequentemente contribuir para a diversidade de rotíferos nessa planície de inundação. Foram registradas sete novas ocorrências de Lecane em amostras do plâncton: L. bifurca, L. rhytida, L. subtilis, L. crepida, L. bulla styrax, L. obtusa, e L. thienemanne. Embora os táxons descritos fossem encontrados no plâncton, essa família caracteriza-se por ser tipicamente não-planctônica. Dessa forma, visando ampliar o conhecimento sobre a diversidade dessa família na planície de inundação do alto rio Paraná, estudos exclusivamente taxonômicos devem explorar a grande heterogeneidade de hábitats presente nessa planície, como, por exemplo, a região marginal e as extensas áreas colonizadas por macrófitas aquáticas.

RESUMO

This study evaluated the biomass distribution of microcrustaceans in three subtropical reservoirs in Brazil and the relationship among these distributions and some limnological variables in the reservoirs. The hypothesis was that the microcrustacean biomass is distributed according to Marzolf´s third model, proposed in 1990 for zooplankton density in tropical reservoirs. The planktonic microcrustacean biomass ranged from 261.5 mg DW m-3 (Iraí reservoir, transition zone, dry season) to 0.03 mg DW m-3 (Segredo reservoir, fluvial zone, wet season). The highest biomass values were registered in the transition zone, but this longitudinal variation was not significant. The total biomass was related to the trophic state of each reservoir, and a higher difference was observed among the reservoirs than within them. The longitudinal biomass distribution was also related with the longitudinal distribution of chlorophyll-a and showed the same pattern described in Marzolf´s third model. In this way, the results suggested that this model developed for density zooplankton could be employed for the longitudinal distribution of zooplankton biomass in the studied reservoirs.

Este estudo avaliou a distribuição longitudinal da biomassa de microcrustáceos planctônicos, em três reservatórios subtropicais, no Brasil, e a relação dessa distribuição com algumas variáveis limnológicas em reservatórios. A hipótese foi que a biomassa de microcrustáceos se distribui similarmente como proposto no terceiro modelo de Marzolf (1990) para densidade zooplanctônica em reservatórios tropicais. A biomassa dos microcrustáceos variou de 261,5 mg DW m-3 (Reservatório de Iraí, zona de transição, estação seca) a 0,03 mg DW m-3 (Reservatório de Segredo, zona fluvial, estação chuvosa). Os valores mais elevados de biomassa foram registrados na zona de transição, embora esta variação não tenha sido significativa. A biomassa total esteve relacionada com o estado trófico de cada reservatório, sendo, ainda constatado uma maior diferença de biomassa entre os ambientes do que entre cada zona dos reservatórios. A distribuição longitudinal da biomassa foi relacionada também com a distribuição longitudinal de clorofila-a e apresentou padrão conforme o terceiro modelo proposto por Marzolf. Este fato sugere que esse modelo poderia ser usado para descrever a distribuição longitudinal da biomassa nos reservatórios estudados.

RESUMO

La biomasa de una comunidad acuática provee información cuantitativa de la materia orgánica disponible en los diferentes niveles tróficos. Las dificultades metodologícas en la estimación de la biomasa zooplanctónica explican los pocos estudios existentes, principalmente en Brasil. Se describen los métodos más utilizados en la estimación de la biomasa de rotíferos, se analizan sus ventajas y desventajas, se comparan los resultados obtenidos con cada técnica, y se discuten algunos factores que influyen en su biomasa. El método más utilizado es la determinación del biovolumen, obtenido a partir de las dimensiones lineales de los rotíferos. La mayor parte de los estudios sugieren que la biomasa de rotíferos varía de acuerdo con los métodos de muestreo, la conservación de los individuos, la depredación y la disponibilidad de alimentos, además de la estacionalidad. Todos estos factores evidencian la necesidad de estimar la biomasa en lugar de utilizar ecuaciones ya descritas en la literatura, as¡ como la importancia de describir el método utilizado en cada muestreo y algunas características limnológicas de los ambientes estudiados.

Assuntos

RESUMO

This study evaluated the biomass distribution of microcrustaceans in three subtropical reservoirs in Brazil and the relationship among these distributions and some limnological variables in the reservoirs. The hypothesis was that the microcrustacean biomass is distributed according to Marzolf´s third model, proposed in 1990 for zooplankton density in tropical reservoirs. The planktonic microcrustacean biomass ranged from 261.5 mg DW m-3 (Iraí reservoir, transition zone, dry season) to 0.03 mg DW m-3 (Segredo reservoir, fluvial zone, wet season). The highest biomass values were registered in the transition zone, but this longitudinal variation was not significant. The total biomass was related to the trophic state of each reservoir, and a higher difference was observed among the reservoirs than within them. The longitudinal biomass distribution was also related with the longitudinal distribution of chlorophyll-a and showed the same pattern described in Marzolf´s third model. In this way, the results suggested that this model developed for density zooplankton could be employed for the longitudinal distribution of zooplankton biomass in the studied reservoirs.

Este estudo avaliou a distribuição longitudinal da biomassa de microcrustáceos planctônicos, em três reservatórios subtropicais, no Brasil, e a relação dessa distribuição com algumas variáveis limnológicas em reservatórios. A hipótese foi que a biomassa de microcrustáceos se distribui similarmente como proposto no terceiro modelo de Marzolf (1990) para densidade zooplanctônica em reservatórios tropicais. A biomassa dos microcrustáceos variou de 261,5 mg DW m-3 (Reservatório de Iraí, zona de transição, estação seca) a 0,03 mg DW m-3 (Reservatório de Segredo, zona fluvial, estação chuvosa). Os valores mais elevados de biomassa foram registrados na zona de transição, embora esta variação não tenha sido significativa. A biomassa total esteve relacionada com o estado trófico de cada reservatório, sendo, ainda constatado uma maior diferença de biomassa entre os ambientes do que entre cada zona dos reservatórios. A distribuição longitudinal da biomassa foi relacionada também com a distribuição longitudinal de clorofila-a e apresentou padrão conforme o terceiro modelo proposto por Marzolf. Este fato sugere que esse modelo poderia ser usado para descrever a distribuição longitudinal da biomassa nos reservatórios estudados.

RESUMO

Las metodologías para estimación de biomasa son variadas. El método más difundido para el cálculo de la biomasa de microcrustáceos zooplanctónicos parte de la obtención de ecuaciones de regresión lineal, considerando la relación peso seco-longitud de los individuos. Esta metodología es de uso generalizado, siendo usada en casi 75 por ciento de las publicaciones analizadas en el presente estudio. En relación a los diferentes ambientes analizados, 52 por ciento corresponden a regiones templadas, donde también fueron realizadas la mayoría de las regresiones disponibles para diferentes especies. Es necesario, por ello, desarrollar más estudios y elaborar ecuaciones para las diferentes especies presentes en ambientes tropicales y subtropicales. La mayoría de los autores citados no especifica el uso de individuos fijados o no, ni especifican el criterio para la medición o cuántos individuos fueron utilizados en cada clase de longitud. Esto ocurre para la elaboración de las ecuaciones y para el uso de ecuaciones elaboradas en otros estudios. Estos criterios son asumidos como arbitrarios, dificultando e impidiendo el uso de estas ecuaciones, por lo que las fórmulas no deben ser aplicadas universalmente sin reservas. Las ecuaciones pueden variar, aun para una misma especie, en los valores de intersección y pendiente de la recta, dependiendo del ambiente donde fueron realizadas. Los usuarios de estas regresiones deben considerar las variaciones que las mismas pueden sufrir en función de factores que afectan la relación peso seco-longitud. Se concluye que, para calcular biomasa por ecuaciones peso seco-longitud, es necesario estandarizar los criterios de medición de la longitud de los individuos, técnicas de preservación, número de individuos por clase de longitud, así como tiempo y temperatura de secado

Assuntos

RESUMO

The present study evaluated the influence of water level fluctuations and the system type on the structure of planktonic microcrustacean assemblage, in different lagoons on the Upper Paraná River floodplain. Sampling was performed in pelagic region from 15 lagoons associated with three rivers, during flood (February 1999) and dry (October 1999) periods. Forty nine cladoceran species and sixteen copepods species were identified. Null model ANOVA results did not show significant differences in microcrustacean densities among systems. Only B. hagmanni, B. deitersi and Calanoid nauplii densities were significantly different between periods. Differences between periods in each system and among systems in each hydrological period were not significant either. Thus, spatial differences were not superior in microcrustacean structuring. However, some temporal differences were observed for bosminids and Calanoid nauplii

Este estudo avaliou a influência do nível hidrométrico e do tipo de sistema na estrutura da assembléia de microcrustáceos planctônicos, em diferentes lagoas da planície de inundação do alto rio Paraná (PR/MS). As coletas foram realizadas na região pelágica de 15 lagoas associadas a três rios, nos períodos de cheia (Fevereiro/1999) e de seca (Outubro/1999). Foram registradas 49 espécies de cladóceros e 16 de copépodos. Os resultados da ANOVA do modelo nulo não indicaram diferenças significativas das densidades dos microcrustáceos entre os sistemas. Somente as densidades de B. hagmanni, B. deitersi e náuplios de Calanoida foram significativamente diferentes entre os períodos. Diferenças entre períodos hidrológicos em cada sistema e entre sistemas em cada período hidrológico também não foram significativas. Nesse sentido, as diferenças espaciais não foram preponderantes para a estruturação da comunidade de microcrustáceos. Algumas diferenças temporais, no entanto, foram observadas para os bosminídeos e para os náuplios de Calanoida

RESUMO

The present study evaluated the influence of water level fluctuations and the system type on the structure of planktonic microcrustacean assemblage, in different lagoons on the Upper Paraná River floodplain. Sampling was performed in pelagic region from 15 lagoons associated with three rivers, during flood (February 1999) and dry (October 1999) periods. Forty nine cladoceran species and sixteen copepods species were identified. Null model ANOVA results did not show significant differences in microcrustacean densities among systems. Only B. hagmanni, B. deitersi and Calanoid nauplii densities were significantly different between periods. Differences between periods in each system and among systems in each hydrological period were not significant either. Thus, spatial differences were not superior in microcrustacean structuring. However, some temporal differences were observed for bosminids and Calanoid nauplii

Este estudo avaliou a influência do nível hidrométrico e do tipo de sistema na estrutura da assembléia de microcrustáceos planctônicos, em diferentes lagoas da planície de inundação do alto rio Paraná (PR/MS). As coletas foram realizadas na região pelágica de 15 lagoas associadas a três rios, nos períodos de cheia (Fevereiro/1999) e de seca (Outubro/1999). Foram registradas 49 espécies de cladóceros e 16 de copépodos. Os resultados da ANOVA do modelo nulo não indicaram diferenças significativas das densidades dos microcrustáceos entre os sistemas. Somente as densidades de B. hagmanni, B. deitersi e náuplios de Calanoida foram significativamente diferentes entre os períodos. Diferenças entre períodos hidrológicos em cada sistema e entre sistemas em cada período hidrológico também não foram significativas. Nesse sentido, as diferenças espaciais não foram preponderantes para a estruturação da comunidade de microcrustáceos. Algumas diferenças temporais, no entanto, foram observadas para os bosminídeos e para os náuplios de Calanoida

RESUMO

The present study aimed to carry out a compilation concerning the art status of rotifer studies in natural environments of South America, with distinction to floodplains. This compilation was carried out based on available informations in literature until now and demonstrated a single distribution of studies and research advances. The majority of studies was recorded only for three South-American countries, Brazil, Argentina, Venezuela, and mainly for the three greatest watersheds, Amazon, Paraná and Orinoco. In this way, besides the ecological importance of these organisms, it could consider that there are few studies about rotifers face to the vast and heterogeneous territorial extent, and the various floodplain environments not even explored, in which more investigations are necessary to enlarge knowledge on ecology of the group and consequently to ecology of tropical floodplains

No presente estudo objetivou-se realizar uma compilação à respeito do estado da arte dos estudos de rotíferos em ambientes naturais da América do Sul, com destaque para planícies de inundação. Esta compliação foi realizada com base nas informações disponíveis na literatura até o momento, demonstrando uma distribuição impar dos estudos e avanços nas pesquisas. A maioria dos estudos foi relatada apenas para três países sulamericanos, Brasil, Argentina, Venezuela e principalmente para as três maiores bacias hidrográficas, Amazônas, Paraná e Orinoco. No restante dos países, a existência de pesquisas sobre rotíferos é escassa ou inexistente. Dessa forma, além da importância ecológica desses organismos, pode-se considerar que há poucos estudos sobre os rotíferos, frentes à vasta extensão territorial e os diversos ambientes ainda não explorados, sendo que maiores investigações são necessárias para o conhecimento da ecologia do grupo, e consequentemente para a ecologia de planícies de inundação tropicais

RESUMO

This study aimed to investigate patterns of spatial and temporal distribution of testate amoebae (Rhizopoda) abundance in plankton of different reservoirs of Paraná State and the importance of hydrodinamical and morphometrical factors on determining these patterns. Thirty reservoirs studied are located in six different watersheds, including environments with variable area, morphometry and age. Sampling were carried out in July and November 2001, dry and rainy seasons, respectively. Samples were obtained at the surface of reservoirs, in the lacustrine region, using a motorized pump (600 liters per sample) and a plankton net with a mesh size of 68µm. Testate amoebae were registered in 23 of 30 reservoirs.Higher density were observed in JMF, Salto do Meio, Melissa, Mourão and Salto do Vau reservoirs, during dry season, and JMF, Salto Osório, Salto do Meio and Melissa reservoirs, during wet season These reservoirs present similar characteristics, as reduced depth and morphometric dimensions Besides that, most of them have hydrodynamical features similar to lotic environments, due to presenting high current velocity. On the other hand, testate amoebae were absent or presented low density, in general, in reservoirs with higher dimensions and depth. Instead of expected, seasonally, higher densities values were observed during dry season, for the most of studied reservoirs. These resu

Este trabalho teve o objetivo de investigar os padrões de distribuição espacial e temporal da abundância de tecamebas (Rhizopoda) no plâncton de diferentes reservatórios do Estado do Paraná bem como a importância de fatores hidrodinâmicos e morfométricos na determinação desses padrões. Os 30 reservatórios estudados estão localizados em seis diferentes bacias, incluindo ambientes com áreas, morfometrias e idades variáveis. As amostragens foram realizadas em julho e novembro de 2001, períodos de estiagem e chuvoso, respectivamente. As amostras foram obtidas à superfície dos reservatórios, na região lacustre, utilizando-se uma bomba (600 litros por amostra) e uma rede de plâncton com malhagem de 68 um. As tecamebas foram registradas em 23 reservatórios. Maiores densidades foram encontradas nos reservatórios JMF, Salto do Meio, Melissa, Mourão e Salto do Vau, durante o período de estiagem, e JMF, Salto Osório, Salto do Meio e Melissa, durante o período chuvoso. Esses reservatórios apresentam características similares, como reduzidas profundidades e dimensões morfométricas. Além disso, a maioria deles têm características hidrodinâmicas similares a de ambientes lóticos, por apresentarem alta velocidade de corrente. Por outro lado, as tecamebas foram ausentes ou presentes em baixas densidades, em geral, nos reservatórios com maiores dimensões e profundidade. Ao contrário do esperado,

RESUMO

This study aimed to investigate patterns of spatial and temporal distribution of testate amoebae (Rhizopoda) abundance in plankton of different reservoirs of Paraná State and the importance of hydrodinamical and morphometrical factors on determining these patterns. Thirty reservoirs studied are located in six different watersheds, including environments with variable area, morphometry and age. Sampling were carried out in July and November 2001, dry and rainy seasons, respectively. Samples were obtained at the surface of reservoirs, in the lacustrine region, using a motorized pump (600 liters per sample) and a plankton net with a mesh size of 68µm. Testate amoebae were registered in 23 of 30 reservoirs.Higher density were observed in JMF, Salto do Meio, Melissa, Mourão and Salto do Vau reservoirs, during dry season, and JMF, Salto Osório, Salto do Meio and Melissa reservoirs, during wet season These reservoirs present similar characteristics, as reduced depth and morphometric dimensions Besides that, most of them have hydrodynamical features similar to lotic environments, due to presenting high current velocity. On the other hand, testate amoebae were absent or presented low density, in general, in reservoirs with higher dimensions and depth. Instead of expected, seasonally, higher densities values were observed during dry season, for the most of studied reservoirs. These resu

Este trabalho teve o objetivo de investigar os padrões de distribuição espacial e temporal da abundância de tecamebas (Rhizopoda) no plâncton de diferentes reservatórios do Estado do Paraná bem como a importância de fatores hidrodinâmicos e morfométricos na determinação desses padrões. Os 30 reservatórios estudados estão localizados em seis diferentes bacias, incluindo ambientes com áreas, morfometrias e idades variáveis. As amostragens foram realizadas em julho e novembro de 2001, períodos de estiagem e chuvoso, respectivamente. As amostras foram obtidas à superfície dos reservatórios, na região lacustre, utilizando-se uma bomba (600 litros por amostra) e uma rede de plâncton com malhagem de 68 um. As tecamebas foram registradas em 23 reservatórios. Maiores densidades foram encontradas nos reservatórios JMF, Salto do Meio, Melissa, Mourão e Salto do Vau, durante o período de estiagem, e JMF, Salto Osório, Salto do Meio e Melissa, durante o período chuvoso. Esses reservatórios apresentam características similares, como reduzidas profundidades e dimensões morfométricas. Além disso, a maioria deles têm características hidrodinâmicas similares a de ambientes lóticos, por apresentarem alta velocidade de corrente. Por outro lado, as tecamebas foram ausentes ou presentes em baixas densidades, em geral, nos reservatórios com maiores dimensões e profundidade. Ao contrário do esperado,

RESUMO

The present study aimed to carry out a compilation concerning the art status of rotifer studies in natural environments of South America, with distinction to floodplains. This compilation was carried out based on available informations in literature until now and demonstrated a single distribution of studies and research advances. The majority of studies was recorded only for three South-American countries, Brazil, Argentina, Venezuela, and mainly for the three greatest watersheds, Amazon, Paraná and Orinoco. In this way, besides the ecological importance of these organisms, it could consider that there are few studies about rotifers face to the vast and heterogeneous territorial extent, and the various floodplain environments not even explored, in which more investigations are necessary to enlarge knowledge on ecology of the group and consequently to ecology of tropical floodplains

No presente estudo objetivou-se realizar uma compilação à respeito do estado da arte dos estudos de rotíferos em ambientes naturais da América do Sul, com destaque para planícies de inundação. Esta compliação foi realizada com base nas informações disponíveis na literatura até o momento, demonstrando uma distribuição impar dos estudos e avanços nas pesquisas. A maioria dos estudos foi relatada apenas para três países sulamericanos, Brasil, Argentina, Venezuela e principalmente para as três maiores bacias hidrográficas, Amazônas, Paraná e Orinoco. No restante dos países, a existência de pesquisas sobre rotíferos é escassa ou inexistente. Dessa forma, além da importância ecológica desses organismos, pode-se considerar que há poucos estudos sobre os rotíferos, frentes à vasta extensão territorial e os diversos ambientes ainda não explorados, sendo que maiores investigações são necessárias para o conhecimento da ecologia do grupo, e consequentemente para a ecologia de planícies de inundação tropicais

RESUMO

The aim of this study was to investigate patterns of richness, abundance and diversity of rotifers in a recently formed reservoir, Corumbá reservoir in the state of Goiás. 104 taxa were identified and seven of them were constant. Brachionidae was the most diverse, particularly in the main part of the reservoir channel. The greatest densities were found in the riverine and transitional zones and in the arms of the reservoir. The diversity was higher in the riverine zone and in one of the tributaries. Rotifer abundance shows significant correlation with Cryptophyceae, Cyanophyceae, Chlorophyceae abundances, and primary production, expressed beyond the first Component Principal Axes. Results suggested that the hydrodinamic variation, typical of the spatial heterogeneity of the area under study, plus food available are determining factors to the structure of the rotifer assemblage

Nesse estudo objetivou-se investigar os padrões de riqueza, abundância e diversidade da assembléia de rotíferos em um reservatório recém-formado do Estado de Goiás. Foram identificados 104 táxons infragenéricos, sendo sete táxons constantes, destacando-se Brachionidae, principalmente no corpo central do reservatório e em um dos braços. As maiores densidades foram registradas nos trechos superior e intermediário do reservatório e nos braços, preferencialmente à superfície, e no período de estiagem. A diversidade foi mais elevada no trecho fluvial e em um dos tributários. A abundância dos rotíferos apresentou correlações significativas com as densidades de Cryptophyceae, Cyanophyceae e Chlorophyceae, além do primeiro eixo da ACP, que resumiu a variação espaço-temporal da produção fitoplanctônica. Os resultados apresentados sugerem que as variações hidrodinâmicas, características da heterogeneidade espacial da área de estudo, e a qualidade e quantidade de alimento disponível são fatores determinantes para a estrutura da assembléia de rotíferos

RESUMO

The aim of this study was to investigate patterns of richness, abundance and diversity of rotifers in a recently formed reservoir, Corumbá reservoir in the state of Goiás. 104 taxa were identified and seven of them were constant. Brachionidae was the most diverse, particularly in the main part of the reservoir channel. The greatest densities were found in the riverine and transitional zones and in the arms of the reservoir. The diversity was higher in the riverine zone and in one of the tributaries. Rotifer abundance shows significant correlation with Cryptophyceae, Cyanophyceae, Chlorophyceae abundances, and primary production, expressed beyond the first Component Principal Axes. Results suggested that the hydrodinamic variation, typical of the spatial heterogeneity of the area under study, plus food available are determining factors to the structure of the rotifer assemblage

Nesse estudo objetivou-se investigar os padrões de riqueza, abundância e diversidade da assembléia de rotíferos em um reservatório recém-formado do Estado de Goiás. Foram identificados 104 táxons infragenéricos, sendo sete táxons constantes, destacando-se Brachionidae, principalmente no corpo central do reservatório e em um dos braços. As maiores densidades foram registradas nos trechos superior e intermediário do reservatório e nos braços, preferencialmente à superfície, e no período de estiagem. A diversidade foi mais elevada no trecho fluvial e em um dos tributários. A abundância dos rotíferos apresentou correlações significativas com as densidades de Cryptophyceae, Cyanophyceae e Chlorophyceae, além do primeiro eixo da ACP, que resumiu a variação espaço-temporal da produção fitoplanctônica. Os resultados apresentados sugerem que as variações hidrodinâmicas, características da heterogeneidade espacial da área de estudo, e a qualidade e quantidade de alimento disponível são fatores determinantes para a estrutura da assembléia de rotíferos