Protozoans bacterivory in a subtropical environment during a dry/cold and a rainy/warm season

Autor(es)

Hisatugo, Karina F. ^[1] ; Mansano, Adrislaine S. ^[1] ; Seleghim, Mirna H. R. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed Sao Carlos, Ecol & Evolutionary Biol Dept, BR-13565905 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Brazilian Journal of Microbiology; v. 45, n. 1, p. 143-151, 2014.
• Citações Web of Science: 1

Resumo

In aquatic ecosystems, bacteria are controlled by several organisms in the food chain, such as protozoa, that use them as food source. This study aimed to quantify the ingestion and clearance rates of bacteria by ciliates and heterotrophic nanoflagellates (HNF) in a subtropical freshwater reservoir (Monjolinho reservoir -São Carlos -Brazil) during one year period, in order to verify their importance as consumers and controllers of bacteria in two seasons, a dry/cold and a rainy/warm one. For this purpose, in situ bacterivory experiments were carried out bimonthly using fluorescently labeled bacteria with 5-(4,6 diclorotriazin-2yl) aminofluorescein (DTAF). Although ciliates have shown the highest individual ingestion and clearance rates, bacterivory was dominated by HNF, who showed higher population ingestion rates (mean of 9,140 bacteria h-1mL-1) when compared to ciliates (mean of 492 bacteria h-1mL-1). The greater predation impact on bacterial communities was caused mainly by the small HNF (< 5 µm) population, especially in the rainy season, probably due to the abundances of these organisms, the precipitation, trophic index state and water temperature that were higher in this period. Thus, the protozoan densities together with environmental variables were extremely relevant in determining the seasonal pattern of bacterivory in Monjolinho reservoir. (AU)

• Processo FAPESP: 08/03545-0 - Avaliação do consumo de bactérias por protozoários em um Reservatório Eutrófico Raso (Reservatório do Monjolinho-São Carlos-SP).
• Beneficiário: Karina Ferreira Hisatugo
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica