Longitudinal variation of attributes from flagellate protozoan community in tropical streams

Abstract

This study verified the existence of longitudinal patterns in species composition, richness, density and biomass of flagellate protozoan in tropical streams and investigated whether the possible zonation patterns are different between two periods of the year. For this, samplings were carried out in three regions from 10 streams, during the summer and winter. The flagellate community may be considered species-rich, because it was represented by 106 taxa, belonging to 8 orders and 1 residual group. The values of density and biomass are greater than those commonly found in other lotic environments, with mean values close to 2.3x10 4 cels. mL -1 and 150.8 μgC L -1 . We did not observe any conspicuous and significant longitudinal pattern of the attributes from flagellates community. Only temporal variations of these attributes were verified. The Pearson Correlation evidenced that this temporal patterns was mainly driven by the nutrients availability, temperature and dissolved oxygen, since, the higher values of species richness, density and biomass were recorded during the winter, when the higher concentrations of nutrients and dissolved oxygen and lower temperatures were registered. In summary, the absence of patterns may be ascribed to the unidirectional and continuous flow from lotic environments.

The role of limnological variables and habitat complexity in impacted tropical streams as regulatory factors on the flagellate protozoa community

“…These differences can be related to the climate, latitude and especially to methodological procedures, once these authors have considered only heterotrophic flagellates and the present study considered this community as a whole, evaluating the heterotrophic, mixotrophic and autotrophic fractions. The studies that have considered all fractions (Carlough and Meyer, 1989;Araújo and Godinho, 2008;Camargo and Velho, 2011) presented composition patterns more similar to the observed in this study, with an expressive qualitative contribution of euglenids.…”

“…In general, this community can be controlled by both biotic and abiotic factors, such as food resource availability, predation pressure, pH, electrical conductivity, dissolved oxygen, trophic state, and climatic seasonality (Pace and Funke, 1991;Arndt, 1993;Samuelsson et al, 2006;Araújo and Godinho, 2008;Camargo and Velho, 2011). Nevertheless, evidences have suggested that in tropical lotic environments flagellates are primarily controlled by seasonal variation of the rainfall regime (Araújo and Godinho, 2008;Camargo and Velho, 2011), which modifies the structure and metabolism of the environment and aquatic communities as well (Cushing and Allan, 2001). On the other hand, the water quality can also influence the distribution of these organisms, as reported by some authors (Jiang and Shen, 2005;Araújo and Godinho, 2008).…”

“…This is because most studies has no taxonomical detail (Arndt et al, 2000), which makes difficult to know the patterns of composition and richness of this community. Among the few studies in lotic environments with some taxonomic detail on flagellate protozoa community, stand out the studies developed by Carlough and Meyer (1989), Arndt and Mathes (1991), Weitere and Arndt (2003), Tikhonenkov and Mazei (2006), Kosolapova (2007), Araújo and Godinho (2008), Tikhonenkov and Mazei (2008), Kiss et al (2009) and Camargo and Velho (2011).…”

Protozoa ciliates community structure in urban streams and their environmental use as indicators

“…According to Camargo and Velho (2011), the success of flagellate protozoa in streams can be attributed to human activities in the region, as some groups are considered indicators of impacted environments because of their preference for environments rich in organic matter (Reynolds and Descy, 1996).…”

“…Such studies have focused on the diverse effects of human activities on these environments (Kühl et al, 2010;Camargo and Velho, 2011;Cunico et al, 2012).…”