Species richness of the genera Trachelomonas and Strombomonas (pigmented Euglenophyceae) in a subtropical urban lake in the Porto Alegre Botanical Garden, RS, Brazil

Abstract

The objective of this study was to evaluate the taxonomic composition and richness of the genera Trachelomonas and Strombomonas (pigmented Euglenophyceae) in a subtropical urban lake (30°03'05"S; 51°10'34"W) within the Botanical Garden, in the city of Porto Alegre, located in the state of Rio Grande do Sul, Brazil, in order to contribute to the floristic knowledge of Euglenophyta in artificial urban lakes. From July 2007 to June 2008, we collected samples monthly from two sampling stations, using a 25-μm mesh plankton net. The samples were preserved in 4% formaldehyde. We evaluated the following environmental variables related to the water in the lake: ammonia content, silica content, organic matter content, dissolved oxygen concentration, temperature, pH, depth, transparency, electrical conductivity and rainfall. To study the species composition in relation to environmental factors, we used cluster analysis, principal components analysis, canonical correspondence analysis and indicator species analysis. At the specific and infraspecific level, 22 taxa were identified, Trachelomonas elliptica (Playf.) Defl. and T. gracillima Bal. & Dast. representing new records for the state of Rio Grande do Sul. The cluster analysis indicated seasonal variation, species richness being highest in the spring of 2007. Seven indicator species were characterized as acid-tolerant.

Relationship between phytoplankton structure and environmental variables in tropical reservoirs with different trophic states

“…Additionally, the Zygnematophyceae Mougeotia sp. prefers higher temperatures and favors oligo-mesotrophic conditions (Kálmán et al 2015), similar to the Euglenophyceae Trachelomonas volvocinopsis, a typical species found in shallow and mesotrophic environments (Alves-da-Silva et al 2013). In the guild associated with eutrophic and hypertrophic reservoirs, Microcystis aeruginosa was found to be dominant in the hypertrophic reservoir, and Oscillatoria tenuis was abundant in the eutrophic sites.…”

Phytoplankton, Trophic State and Ecological Potential in reservoirs in the State of São Paulo, Brazil

“…Regarding the qualitative analysis, the samples were collected with a 20μm mesh net by horizontal trawls at the surface. The material was identified following specialized bibliography: (Ramos et al, 2015a;2015b;Alves-Da-Silva et al, 2013;Tucci et al, 2006;Sant'anna and Azevedo, 2000). The organisms were counted using the method described by Utermöhl (1958).…”

Determination of Trophic State Changes with Diel Dissolved Oxygen: A Case Study in a Shallow Lake

“…In the recent decades, there have been a number of studies looking into the causes of and solutions to DO depletion for lake systems, including establishment of real-time monitoring (Markogianni et al, 2014), phytoplankton activities (Alves-da- Silva et al, 2013;Oliva Martinez et al, 2008), nutrients transformations (Guo et al, 2012), and aquatic vegetation management (Morris et al, 2003(Morris et al, , 2004. Although DO is widely measured as a water quality parameter for natural waters, wastewaters, and treatment waters, many DO studies have only limited point-by-time measurements, whereas field data are usually collected at insufficient time intervals.…”