Spatial and temporal distribution of free-living protozoa in aquatic environments of a Brazilian semi-arid region

Abstract

Free-living protozoa organisms are distributed in aquatic environments and vary widely in both qualitative and quantitative terms. The unique ecological functions they exhibit in their habitats help to maintain the dynamic balance of these environments. Despite their wide range and abundance, studies on geographical distribution and ecology, when compared to other groups, are still scarce. This study aimed to identify and record the occurrence of freeliving protozoa at three points in Piancó-Piranhas-Açu basin, in a semi-arid area of Rio Grande do Norte (RN) state, and to relate the occurrence of taxa with variations in chlorophyll a, pH and temperature in the environments. Samples were collected in the Armando Ribeiro Gonçalves Dam, from two lentic environments upstream and a lotic ecosystem downstream. Sixty-five taxa of free-living protozoa were found. The Student's t-test showed significant inter-variable differences (p <0.05). Similar protozoan species were recorded under different degrees of trophic status according to chlorophyll a concentrations, suggesting the organisms identified are not ideal for indicating trophic level. We hypothesize that food availability, the influence of lentic and lotic systems and the presence of aquatic macrophytes influenced protozoan dynamics during the study period.Keywords: Planktonic microorganisms, reservoirs; biodiversity.Distribuição espacial e temporal de protozoários de vida livre em ambientes aquáticos de uma região semiárida brasileira RESUMO Os protozoários de vida livre são organismos amplamente distribuídos em ambientes aquáticos tanto em termos qualitativos como quantitativos. Eles possuem funções ecológicas únicas em seus habitats e ajudam a manter, através delas, o equilíbrio na dinâmica desses ambientes. Apesar do seu variado leque funcional e sua abundância, os estudos que abordam sua ecologia e distribuição geográfica, quando comparados a outros grupos, ainda são escassos. Diante disso o presente trabalho teve por objetivo registrar a ocorrência e identificar os protozoários de vida livre de três pontos da Bacia Hidrográfica Piancó-Piranhas-Açu, localizada no semiárido potiguar, bem como relacionar a ocorrência dos táxons catalogados com as variações de clorofila a, pH e temperatura dos ambientes em questão. As amostras foram coletadas em dois ambientes lênticos à montante e um ambiente lótico à jusante da MEDEIROS, M. L. Q.; ARAÚJO, M. F. F.; SODRÉ-NETO, L.; AMORIM, A. S. Spatial and temporal distribution of free-living protozoa in aquatic environments of a Brazilian semi-arid region. Ambi-Agua, Taubaté, v. 8, n. 2, p. 46-56, 2013

Free-living protozoa (ciliophora, excavata and amoebozoa) in two water sources for human supply in the municipality of Blumenau, SC

“…Of these, it was possible to identify 20 new taxain P1 and 10 taxa in P2 (Table 2). These values corroborate with those observed in other studies (PAULETO et al, 2009;VELHO et al, 2013, COLZANI, ALVES, 2013, KÜPPERS, CLAPS, 2012, MEDEIROS et al, 2013, which registered values between 22 and 65 species in cultivations. The difference found between the numbers of taxa identified in the readings taken on the day of collection concerning the cultures can be explained by the fact that the protozoa are encysted at the time of collection.…”

“…and Arcella sp. in Brazilian water sources (LANSAC-TÔHA et al, 2000;VELHO et al, 2000;MEDEIROS et al, 2013). Godinho (2008) and Godinho (2003), in studies carried out in tropical environments, reported the association relationships between Thecamoebae and aquatic macrophytes, which could justify the presence of these organisms in P1 and P2 since in both places there is the presence of vegetation in the water sources margins.…”