Periphytic algae dynamics in lentic ecosystems in the Brazilian semiarid

Abstract

The hydrological periods drive the structure and organization of aquatic communities in semiarid regions. We hypothesize that a decrease of the precipitation during the dry period will favor the development of the periphytic algal community, leading to higher richness and density in this period. To test this hypothesis, we investigated the changes in the periphytic algal community structure in three shallow and eutrophic ecosystems of the Brazilian semiarid. The sampling was performed between 2007 and 2010 at two-mensal intervals. The sampling of periphytic algal was performed in aquatic macrophytes and rocks. The abiotic variables were analyzed simultaneously. Dominance in diatoms, cyanobacteria and chlorophytes, respectively, was observed in two periods. In the dry period, waters were alkaline and had high concentrations of nitrate and total phosphorus associated with the highest densities of Bacillariophyceae. In the rainy period the water was warmer, oxygenated and high concentrations of ammonia and soluble reactive phosphorus with diatoms remained dominant but with reduced density, while cyanobacteria and chlorophytes increased. Overall, periphytic algal community composition no responded to changes in the hydrological periods. However, the hydrological periods altered the dynamics of periphytic algal community, supported by the alternation of the most representative classes (diatoms and cyanobacteria) between the hydrologic periods. Our data suggest that the morphometric and chemical and physical characteristics of lentic aquatic ecosystems studied were more important in the dynamics of periphytic algal community than the hydrological periods and types of substrates.Keywords: seasonality, reservoirs, lentic aquatic ecosystems, periphyton. Estrutura da comunidade de algas perifíticas do semiárido brasileiro ResumoOs períodos hidrológicos impulsionam a estrutura e organização das comunidades aquáticas em regiões semiáridas. Nós hipotetizamos que uma diminuição da precipitação durante o período seco irá favorecer o desenvolvimento da comunidade de algas perifíticas, levando a uma maior riqueza e densidade nesse período. Para testar esta hipótese, nós investigamos as mudanças na estrutura da comunidade de algas perifíticas em três ecossistemas rasos e eutróficos do semiárido brasileiro. As amostragens foram realizadas entre 2007 e 2010 em intervalos de bimensais. A amostragem das algas perifíticas foi realizada em macrófitas aquáticas e rochas. As variáveis abióticas foram analisadas simultaneamente. A dominância de diatomáceas, cianobactérias e clorófitas, respectivamente, foi observada em todos os períodos. No período seco, as águas foram alcalinas com altas concentrações de nitrato e fósforo total associado às maiores densidades de Bacillariophyceae. Durante o período chuvoso as águas apresentaram-se mais quentes, oxigenadas e com altas concentrações de amônia e fósforo reativo solúvel. As diatomáceas permaneceram dominantes, mas com densidade reduzida, enquanto as cianobactérias e clorofíceas aumen...

Community structure of periphytic Zygnematophyceae (Streptophyta) in urban eutrophic ponds from central Brazil (Goiânia, GO)

“…Total periphyton density in the urban ponds from Goiânia was relatively high as well. The results reported here were similar to the ones described for other Brazilian eutrophic urban lentic systems, with the predominance of Cyanobacteria, B a c i l l a r i o p h y c e a e a n d C h l o r o p h y c e a e (Borduqui et al, 2008;Cordeiro et al, 2017), and Zygnematophyceae contribution around 1%. In oligo-mesotrophic systems, such contribution has reached around 25% (França et al, 2011;Pellegrini & Ferragut, 2012;Souza & Ferragut, 2012;Santos & Ferragut, 2013;Camargo & Ferragut, 2014).…”

“…Zygnematophyceae algae are exclusively freshwater organisms in general associated to oligo-mesotrophic environments, with pH ranging between 4 and 7 (Brook, 1981;Coesel, 1975Coesel, , 1983Coesel, , 1996Gerrath, 2003). Pristine environments from central Brazil at the Cerrado biome (Brazilian savanna), with acidic waters, provide suitable habitats for this algal group (Estrela et al, 2011;Dunck et al, 2013;Fonseca & Estrela, 2015;Silva & Felisberto, 2015;Fonseca et al, 2018), differently from eutrophic systems, which are frequently dominated by other groups such as cyanobacteria, diatoms and coccoid green algae (Borduqui et al, 2008;Cordeiro et al, 2017). Some Zygnematophyceae taxa can also be reported with relatively high abundance in eutrophic ecosystems (Coesel, 1982) and alkaline waters (Brook, 1981).…”

Perifíton e Estado Trófico em dois Mananciais de Abastecimento em Araraquara (SP)

“…Quanto à diversidade de microalgas encontrada nos dois ambientes, não foram observadas diferenças significativas, pois ambos apresentaram características limnológicas semelhantes, como águas levemente ácidas e altos valores de nutrientes no período de chuva. Estas características podem ter influenciado a composição das algas perifíticas encontradas nestes ambientes, com a maior disponibilidade de nitrogênio e fósforo (Ferragut & Bicudo, 2012;Cordeiro et al, 2017). Assim, pode-se inferir que a maior influência na qualidade da água e na composição da comunidade perifítica foi exercida pela hidrologia e pela ação antrópica, pois alterações na química da água, associadas ao processo de urbanização, podem provocar mudanças na estrutura das comunidades de algas perifíticas (Baker et al, 2009;Wu et al, 2009).…”

Evaluation of the operational conditions in the production and morphology of Chlorella sp.

“…Algae, like most marine organisms, need to develop and survive in a highly competitive environment, which, together with the fact that they do not have an immune system, leads the development of biochemical and physiological mechanisms from an evolutionary point of view to guarantee its survival (Hay, 2009), (López, 2008), (Cordeiro et al, 2017).…”