Temporal variation in phytoplankton community in a freshwater coastal lake of southern Brazil

Abstract

AIM: The aim of the present study was to study the vertical variation in phytoplankton community in a subtropical coastal lake and to verify the temporal variation of this community following variation in temperature and dissolved nitrogen and phosphorus. METHODS: Sampling of phytoplankton and abiotic variables were performed monthly from June/2009 to January/2011 at four depths from the central part of Peri Lake. The data were analyzed using analysis of variance, correlation and canonical correspondence analysis. RESULTS: Vertical variation in the phytoplankton community and limnological data did not occur but temporal variation was found. The lake was limited by light and nutrients and this light limitation selected the Cyanobacteria species from Sn and S1 functional groups. Phytoplankton community was composed of five groups, with 31 freshwater taxa, in which Cyanobacteria was the most important with 87.7% of total density and Chlorophyta with 11.8%. Cylindrospermopsis raciborskii was dominant during almost the whole study period because when temperature and phosphorus increased and wind speed decreased Limnothrix sp. density was boosted. Different species of Cyanobacteria filamentous showed correlation with variables in different ways, indicating that some species can co-exist, each of them having distinct niches or can compete by the same resource. CONCLUSION: The phytoplankton presented periodicity driven by annual change in water temperature and nutrients availability. Peri Lake's features allow for the occurrence of a vertically homogeneous water column and the dominance of cyanobacterial functional groups adapted to low underwater light and nutrients deficiency

The success of the cyanobacterium Cylindrospermopsis raciborskii in freshwaters is enhanced by the combined effects of light intensity and temperature

“…Results of the three ways ANOVA for differences in growth rate of each species (C. raciborskii and P. agardhii) under different treatments (light and temperature) and culture conditions (mono-and mixed cultures). and relative biovolume of C. raciborskii in our subtropical lake (Javier Lake) was similar to those from other subtropical lakes in Brazil (Tonetta et al, 2013), China (Lei et al, 2014) and Australia (Everson et al, 2011). The three temperate lakes in the dataset (Bnińskie and Bytyńskie, Poland; Alte Donau, Austria) were all shallow, polymictic, and eutrophic to hypereutrophic (Kokociński et al, 2010), but they differed markedly in their C. raciborksii biovolumes.…”

Considerations regarding the dominance of Cylindrospermopsis raciborskii under low light availability in a low phosphorus lake

“…The lake has a surface area of 5.07 km 2 , maximum depth of 11.0 m, and showed spatial homogeneity, both horizontally and vertically, concerning chlorophyll-a and nutrients (Hennemann & Petrucio 2011). The lake has been considered polymictic and light limited, according to Tonetta et al (2013). However, recent findings from high-frequency measurements taken from the deepest part of the lake have shown that some short stratifications and de-stratifications occur on a daily basis, that the mixing zone is highly variable, and the euphotic zone is on average 4.0 m (D. Tonetta, unpubl.…”

“…In Peri Lake, this species has been recorded since 1994 (Laudares-Silva 1999; Grellmann 2006) and since 2009 has accounted for about 90% of phytoplankton total density, showing dominance throughout most of the year (Tonetta et al 2013;Silveira 2013). Although nutrient concentration has not shown significant changes since 1994, the phytoplankton density has increased considerably.…”

“…Although nutrient concentration has not shown significant changes since 1994, the phytoplankton density has increased considerably. In 1996 and 1997, C. raciborskii varied between 3 and 41 × 10 3 ind.mL (Tonetta et al 2013). In a recent review by Soares et al (2013), the authors highlighted the occurrence of Cyanobacteria in Brazil, especially the genera Cylindrospermopsis Seenayya & Subba-Raju, Dolichospermum (Ralfs ex Bornet & Flahault) P.Wacklin, L.Hoffmann & J.Komárek, and Microcystis Kützing ex Lemmermann, and the habitat preferences for these species.…”

“…It is well recognized that Cylindrospermopsis has been extending its distribution to colder regions (Vidal & Kruk 2008;Sinha et al 2012), although always in systems with high nutrients concentration. Here we focus on trying to understand the features leading to C. raciborskii dominance in an environment with low P concentration, light limitation, constantly mixed, and showing C. raciborskii dominance even at low temperatures (Hennemann & Petrucio 2011;Tonetta et al 2013).…”