35 research outputs found
Distribuição espacial da comunidade de rotĂferos em tanques de piscicultura em Cruzeiro do Sul – AcreSpatial distribution of the rotifers community in fishponds in Cruzeiro do Sul - Acre State
Os rotĂferos sĂŁo organismos microscĂłpicos e representam um dos mais importantes grupos da comunidade zooplanctĂ´nica, nĂŁo apenas pela riqueza de espĂ©cies, mas tambĂ©m pela abundância dos organismos. A situação hipotĂ©tica para a realização desta pesquisa consiste em verificar se a distribuição espacial da comunidade de rotĂferos Ă© heterogĂŞnea e se há diversidade de organismos em tanques de piscicultura em Cruzeiro do Sul. Os tanques selecionados foram agrupados, considerando o zooplâncton, atravĂ©s da análise de cluster utilizando dissimilaridade, e ainda sobre a comunidade foram aplicados tambĂ©m os Ăndices de diversidade e riqueza. Os resultados nĂŁo revelaram agrupamento significativo para os tanques; cada sistema apresentou sua peculiaridade.AbstractRotifers are microscopic organisms that present themselves as one of most significant groups of the zooplankton community, not only by species richness, but also by the numerical abundance. A hypothetical situation for this research is whether the spatial distribution of the rotifer community in fishponds is heterogeneous and has organism’s diversity in Cruzeiro do Sul is heterogeneous. The selected tanks were grouped, considering the zooplankton by cluster analysis using dissimilarity multivariate analysis, as well as on the community has been applied also the diversity and richness indexes. The results revealed no significant clustering for tanks, with each system its peculiarity
Correlation among water quality parameters of grow-out ponds of Macrobrachium amazonicum
Pond water quality is basic for the success of aquaculture, especially in ponds containing freshwater prawns. The variables considered most important are the dissolved oxygen and the ammonia-nitrogen. Twelve 0.01ha earthen ponds were stocked with 20 juveniles.m-2. Prawns were fed on commercial diet at a rate of 7 to 9% of biomass until the 14th week. After 145 days of stocking, all ponds were drained and harvested. The following water parameters were determined weekly: temperature, dissolved oxygen, oxygen biochemical demand, pH, total alkalinity, electrical conductivity, nitrate-N, nitrite-N, ammonia-N, total nitrogen, soluble orthophosphate, total phosphate, chlorophyll a, chlorophyll b, chlorophyll c, pheophytin, total suspended solids and turbidity. Water exchange and daily feeding affected water quality slightly. Correlations among water quality parameters were either weak or absent. The limnological variables analyzed showed that the highest correlations were between the dissolved oxygen and ammonia-nitrogen and between nitrite and turbidity
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http://dx.doi.org/10.5007/2175-7925.2008v21n4p65A qualidade da água dos viveiros Ă© fundamental para o sucesso da aqĂĽicultura. Entre as variáveis as maisimportantes estĂŁo o oxigĂŞnio dissolvido e o nitrogĂŞnio amoniacal. Neste trabalho, foi realizado um estudo limnolĂłgico de viveiros de cultivo de Macrobrachium amazonicum.. Doze viveiros com cerca de 0,01ha foram povoados com 20 juvenis de M. amazonicum.m-2. Os animais foram alimentados com ração extrusada na proporção de 6 a 9% da biomassa atĂ© a 14a semana. Depois de 145 dias de estocagem dos camarões, todos os viveiros foram drenados e despescados. Semanalmente, foram determinadas as seguintes variáveis da água: temperatura,oxigĂŞnio dissolvido, demanda bioquĂmica de oxigĂŞnio, pH, alcalinidade total, condutividade elĂ©trica, nitrato, nitrito, nitrogĂŞnio amoniacal, nitrogĂŞnio total, ortofosfato solĂşvel, fĂłsforo total, clorofila a, clorofila b, clorofila c, feofitina, turbidez e sĂłlidos totais suspensos. Este trabalho analisou, em viveiros de Macrobrachium amazonicum, a correlação entre diversas variáveis limnolĂłgicas. Semanalmente, os dados foram obtidos de doze viveiros com cerca de 0,01ha e profundidade de 1,0m, povoados com 20 juvenis de M. amazonicum.m-2, alimentados comração extrusada, na taxa de 6 a 9% da biomassa atĂ© a 14a semana. Depois de 145 dias de cultivo, os viveiros foram drenados e despescados. A ração diária teve pouco efeito sobre a qualidade da água dos viveiros do que da água de renovação. Das variáveis limnolĂłgicas analisadas, as que apresentaram as maiores correlações signifi cativas foram entre o oxigĂŞnio dissolvido e nitrogĂŞnio amoniacal e entre o nitrito e a turbidez.Correlation among water quality parameters of grow-out ponds of Macrobrachium amazonicum. Pond water quality is basic for the success of aquaculture, especially in ponds containing freshwater prawns. The variables considered most important are the dissolved oxygen and the ammonia-nitrogen. Twelve 0.01ha earthen ponds were stocked with 20 juveniles.m-2. Prawns were fed on commercial diet at a rate of 7 to 9% of biomass until the 14th week. After 145 days of stocking, all ponds were drained and harvested. The followingwater parameters were determined weekly: temperature, dissolved oxygen, oxygen biochemical demand, pH, total alkalinity, electrical conductivity, nitrate-N, nitrite-N, ammonia-N, total nitrogen, soluble orthophosphate, total phosphate, chlorophyll a, chlorophyll b, chlorophyll c, pheophytin, total suspended solids and turbidity.Water exchange and daily feeding affected water quality slightly. Correlations among water quality parameters were either weak or absent. The limnological variables analyzed showed that the highest correlations were between the dissolved oxygen and ammonia-nitrogen and between nitrite and turbidity
Estudo comparativo da composição do zooplâncton de dois ecossistemas lacustres da Amazônia Sul-Ocidental
<b>Abundância do zooplâncton em diferentes zonas (pelágica e litorânea) e horários (manhã e noite) em dois lagos meândricos amazônicos</b> - DOI: 10.4025/actascibiolsci.v25i2.2011 <b>Abundance of zooplankton from different zones (pelagic and littoral) and time periods (morning and night) in two Amazonian meandering lakes</b> - DOI: 10.4025/actascibiolsci.v25i2.2011
Durante 10 meses foi estudada a abundância do zooplâncton em dois lagos da AmazĂ´nia Sul-Ocidental, situados respectivamente nas coordenadas 10°02'36''S; 67°50'24''W (Lago Amapá) e 9°27'21"S; 67°31'39"W (Lago Pirapora). Ambos os lagos caracterizam-se como de meandro abandonado. O objetivo desse estudo foi comparar as regiões pelágica e litorânea, com base na abundäncia da comunidade zooplanctönica, bem como observar diferenças da distribuição dessa comunidade na coluna da água no perĂodo da manhĂŁ e noite. As coletas foram realizadas com filtragem em rede de zooplâncton (55µm) e posterior passagem em garrafa de Van Dorn de 5L. Coletou-se 4L na superfĂcie e 5L nas camadas do meio e fundo, totalizando 14L de água para cada estação de coleta. Adicionalmente, foram medidos parâmetros fĂsicos e quĂmicos como transparĂŞncia, temperatura, pH, oxigĂŞnio dissolvido, condutividade elĂ©trica e turbidez. Anova (análise de variância) e teste de Tukey foram usados. NĂŁo houve diferença estatĂstica significativa nem para as regiões estudadas como tambĂ©m para os diferentes horários observados. Os resultados dos coeficientes de correlação de Pearson (p < 0.05) demonstraram que as caracterĂsticas fĂsicas e quĂmicas foram correlacionadas com os cladĂłceros <em>Moina</em> spp. (representados por <em>Moina minuta</em> e <em>Moina reticulata</em>) e <em>Ceriodaphnia reticulata. Daphnia gessneri</em> tambĂ©m apresentou correlação com Chaoboridae<br>The abundance of zooplankton in two lakes of Southwest Amazonia was studied for 10 months in different regions and at different periods of the day. The lakes were <em>Lago Amapá</em>, located at 10°02'36''S, 67°50'24''W, and <em>Lago Pirapora</em>, at 9°27'21"S, 67°31'39". Both lakes are characterized as oxbow lakes. The aim of this study was to compare the pelagic and littoral regions, as well as to determine differences in the distribution of zooplankton in the water column in the morning and at night. Collections were made by filtering water through a 55µm zooplankton net into a 5L Van Dorn bottle, collecting 4L from the top and 5L from the middle and bottom layers, totaling 14L of water for each sampling location. In addition, physical and chemical parameters were measured, including transparency, temperature, pH, dissolved oxygen, electrical conductivity and turbidity. Anova (analysis of variance) and Tukey’s test were used. There was no statistically significant difference between the regions studied, nor between the two time periods examined. The results of the Pearson correlation (p < 0.05) demonstrated that the physical and chemical characteristics of the water correlated with the cladocerans <em>Moina</em> spp. (represented by <em>M. minuta</em> and <em>M. reticulate</em>) and <em>Ceriodaphnia cornuta</em>, and that <em>Daphnia gessneri</em> was associated with Chaoborida
Estudo comparativo da composição do zooplâncton de dois ecossistemas lacustres da Amazônia Sul-Ocidental - DOI: 10.4025/actascibiolsci.v25i2.2042
The zooplankton communities of two lacustrine ecosystems in southwestern Amazonia (Lago Amapá and Lago Pirapora) were studied based on samples collected over an 11-month period. The general aim of the present work was to contribute to the knowledge of the zooplankton fauna in southwestern Amazonia, by studying the occurrence of certain species; and to improve the knowledge of the Rio Acre tributaries. The total number of taxa included 38 species of rotifers, 6 cladocerans and 7 copepods. Most of the species were from the rotifer family Brachionidae. Jaccard´s similarity index was similar for the two lakes at 0.6964 The constancy index defined the species Keratella cochlearis, Filinia cf. terminalis, Filinia opoliensis, Hexarthra intermedia braziliensis, Ceriodaphnia cornuta, Moina minuta, Diaphanosoma spinulosum, and immature forms (nauplii and copepodites) as the constant in these lakes. The presence of zooplankton with higher number of species occupying the middle depths, during morning and night periodsA comunidade zooplanctĂ´nica de dois ecossistemas lacustres localizados na AmazĂ´nia Sul-Ocidental (Lago Amapá e Lago Pirapora) foi estudada, com base em amostras coletadas, durante 11 meses. O objetivo geral do presente trabalho foi contribuir com o conhecimento da fauna do zooplâncton na AmazĂ´nia Sul-Ocidental, estudando particularmente a ocorrĂŞncia de certas espĂ©cies nos tributários do Rio Acre. Foi registrado o total de taxas: 38 rotĂferos, 6 cladĂłceros e 7 copĂ©podos. O Ăndice de Jaccard, para comparar a similaridade entre os dois lagos, foi 0,6964. Brachionidae foi a famĂlia com o maior nĂşmero de espĂ©cies. O Ăndice de constância definiu as espĂ©cies Keratella cochlearis, Filinia cf. terminalis, Filinia opoliensis, Hexarthra intermedia braziliensis, Ceriodaphnia cornuta, Moina minuta, Diaphanosoma spinulosum, e ainda as formas imaturas (náuplios e copepoditos) como constantes nos lagos estudados. Observou-se o maior nĂşmero de espĂ©cies ocupando o meio da coluna da água, durante o perĂodo da manhĂŁ e noit
Toxicity of sodium chloride and methyl parathion on the macrophyte Lemna minor (Linnaeus, 1753) with respect to frond number and chlorophyll
Duckweed, Lemna minor L., is a suitable plant model for toxicity evaluation of many contaminants due to its small size and rapid growth. Methyl parathion is a toxic compound which is utilized to eliminate aquatic insect larvae, among other purposes. Its toxicity was evaluated with the use of L. minor in this study. Methyl parathion was added to Hoagland’s nutrient medium at concentrations of 0, 8, 16, 22, 28 and 32mg.L–1. Lemna minor is used as a tool in evaluating chemical test products for toxic effects. The sensitivity of Lemna to sodium chloride, the reference substance, at concentrations of 0, 2, 4, 6, 7 and 8 g.L–1, was determined for comparison and resulted in an IC50 of 6.87g.L–1. Methyl parathion in L. minor showed an IC50 of 49.48mg.L–1