Seasonal variation of the protozooplanktonic community in a tropical oligotrophic environment (Ilha Solteira reservoir, Brazil)

Abstract

The seasonal variation of the protozooplanktonic community (ciliates and testate amoebae) was studied in a tropical oligotrophic reservoir in Brazil, which was under the influence of two contrasting climatic seasons (rainy/warm and dry/cold). The aim of this study was to evaluate the effect of these climatic changes on physical, chemical and biological variables in the dynamic of this community. The highest mean density of total protozoans occurred in the rainy/warm season (5683.2 ind L -1 ), while the lowest was in the dry/cold (2016.0 ind L -1 ). Considering the seasonal variations, the protozoan groups that are truly planktonic, such as the oligotrichs (Spirotrichea), predominated in the dry season, whereas during the rainy season, due to the material input and resuspension of sediment, sessile protozoans of the Peritrichia group were the most important ones. The dominant protozoans were Urotricha globosa, Cothurnia annulata, Pseudodifflugia sp. and Halteria grandinella. The highest densities of H. grandinella were associated with more oxygenated and transparent water conditions, while the highest densities of C. annulata occurred in sites with high turbidity, pH and trophic state index (TSI). The study demonstrated that density and composition of protozooplanktonic species and groups of the reservoir suffered seasonal variation due to the environmental variables (mainly temperature, turbidity, water transparency, dissolved oxygen and TSI) and the biological variables (e.g. morphological characteristics, eating habits and escape strategies from predation of the species).Keywords: protozoans, freshwater, ciliates, testate amoebae.Variação sazonal da comunidade protozooplanctônica em um ambiente oligotrófico tropical (reservatório de Ilha Solteira, Brasil) ResumoA variação sazonal da comunidade protozooplanctônica (ciliados e amebas testáceas) foi estudada em um reservatório oligotrófico tropical no Brasil, que estava sob a influência de dois períodos climáticos contrastantes (chuvoso/quente e seco/frio). O objetivo deste estudo foi avaliar os efeitos destas mudanças climáticas sobre as variáveis físicas, químicas e biológicas na dinâmica desta comunidade. A maior densidade média de protozoários total ocorreu no período chuvoso e quente (5683,2 ind L -1), enquanto a menor foi no período seco e frio (2016,0 ind L -1 ). Considerando-se as variações sazonais, os grupos de protozoários que são verdadeiramente planctônicos, como os oligotrichs (Spirotrichea), predominaram no período seco, enquanto que, no período chuvoso, em razão da entrada de material e da ressuspensão do sedimento, os protozoários sésseis do grupo Peritrichia foram os mais importantes. Os protozoários dominantes foram Urotricha globosa, Cothurnia annulata, Pseudodifflugia sp. e Halteria grandinella. As maiores densidades de H. grandinella foram associadas com condições de águas mais oxigenadas e transparentes, enquanto que as maiores densidades de C. annulata ocorreram em locais com alta turbidez, pH e índice de estado trófico (IET). O es...

Protozooplankton and its relationship with environmental conditions in 13 water bodies of the Mogi-Guaçu basin - SP, Brazil

“…This correlation could be indicative of higher photosynthetic rates in the environments, since the release of oxygen by phytoplankton is associated with the consumption of carbon dioxide during photosynthesis, what may increase the pH of the environment. Mansano et al (2013) reported positive correlation among H. grandinella density and DO, but no correlation with pH.…”

“…Researches about the protozoa composition in Brazilian water bodies -Lobo Reservoir (São Carlos, SP), Rio Grande Reservoir (São Paulo, SP), Ilha Solteira Reservoir (Ilha Solteira, SP), reservoirs in the basin of Piranhas-Assu River (Rio Grande do Norte state), Lake Monte Alegre (Ribeirão Preto, SP) and Monjolinho Reservoir (São Carlos, SP) -found that H. grandinella was among the most frequent and abundant species in these environments (Araújo & Costa 2007, Barbieri & GodinhoOrlandi 1989, Gomes & Godinho 2003, Mansano et al 2013, RegaliSeleghim 1992, 2001). …”

“…(e.g. Barbieri & Godinho-Orlandi 1989, Buosi et al 2011, Dias et al 2008, Gomes & Godinho 2003, Mansano et al 2013, Pauleto et al 2009, Regali-Seleghim et al 2011, and have widespread geographic distribution in Brazil (Foissner et al 1999(Foissner et al , Šimek et al 2000.…”

Inter-annual ciliate distribution variation within the late stratification oxycline in a monomictic lake, Lake Alchichica (Mexico)

“…The information on ciliate stratification in tropical monomictic water bodies is limited to a few such bodies (Hecky and Kling, 1981;Pirlot et al, 2005;Yasindi et al, 2007;Peštová et al, 2008;Tarbe et al, 2011;BautistaReyes and Macek, 2012;Mansano et al, 2013). Among them, Lake Alchichica investigations have included both general limnology and all trophic levels (cf., Macek et al, 2009;Oliva et al, 2001;Ciros-Pérez et al, 2015, for bacteria, phytoplankton and zooplankton / fish interactions, respectively).…”

Richness of protists in El Cajón dam, Querétaro, Mexico: temporal and spatial approximation

“…La entrada de agua a la presa conlleva, entre otras cosas, una suspensión de sedimentos y el acarreo de algunos protistas bentónicos a la capa superficial de la presa (Mansano et al 2013), como fue el caso Figura 7. Riqueza mensual de especies de agosto 2015 a julio 2016 en los sitios de muestreo.…”