Fluctuations of Testate Amoebae Populations (Rhizopoda) in Plankton from Different Environments on the Upper Paraná River Floodplain, Brazil

Abstract

Fluctuations in temporal and spatial abundance are remarkable features of all animal populations. Regional synchrony of local population dynamics has been verified in several studies. This study investigated the existence of coherent patterns in temporal fluctuations of the principal testate amoebae population abundance in plankton from the upper Paraná river floodplain in Brazil. Testate amoebae sampling was carried out every three months, from February 2000 to November 2002, and twice in 2003. Sampling occurred in 12 environments associated with three different rivers. Samples were obtained at the subsurface of the pelagic region, using a motorized pump and a 68 µm mesh plankton net. Ninety-three testate amoebae species from eight families were identified. The families Difflugiidae, Arcellidae, and Centropyxidae had the greatest number of species. Arcella conica, A. discoides, A. vulgaris, Centropyxis aculeata, C. ecornis, Difflugia gramen, D. pseudogramen and Cucurbitella dentata were the most abundant species, and they were chosen for spatial synchrony analysis. No coherent pattern of abundance fluctuation was found, in any of the floodplain environments studied. Nevertheless, when analyzing only the channels, spatial synchrony was observed to Centropyxis ecornis. Mantel tests showed that the synchrony level, as identified by Spearman and Pearson correlations, was not correlated to geographic distance between environments. We conclude that regional factors in the Upper Paraná River floodplain are not the main determinants of the population dynamics of testate amoebae. The high floodplain heterogeneity seems determine a great relevance of local factors.

Testate amoebae (Arcellinida and Euglyphida) from Pantanal dos Marimbús, Chapada Diamantina, Bahia state, Brazil, including new occurrences

“…The most taxon-rich families in our study, Arcellidae, Centropyxidae, and Difflugiidae, were also identified as the most representative in other studies of testate amoebae in both plankton and periphyton (Velho et al 1999;Fulone et al 2005;Lansac-tôha et al 2008;Alves et al 2008Alves et al , 2010Alves et al , 2012Oliveira and Hardoim 2010). Alves et al (2010) observed a greater richness of testate amoebae in the periphyton than in plankton in a lagoon in the upper Paraná River floodplain, as aquatic macrophytes increase habitat heterogeneity and allow greater testate amoebae diversity, stability (Agostinho et al 2007), and productivity (Souza 2005;Chambers et al 2008).…”

“…Additionally, those taxa have hyaline carapaces, and exposure to light in planktonic habitats can be prejudicial to their protoplasm -thus reducing their occurrence in that habitat. Nebela has been most frequently reported in plankton in Brazil (Alves et al 2007(Alves et al , 2008Oliveira and Hardoim 2010;Schwind et al 2016;Picapedra et al 2017;Souza 2018;Gomes 2020), with few reports of their presence in the periphyton (Souza 2005;López 2009) or in sphagnum (Wailes 1913;Rhoden and Pitoni 1999), although studies of testate amoebae in periphyton or peat moss are even more scarce than studies in plankton.…”

“…The species distributions were determined using available references for each state: Acre State (Araújo 2019), Amapá State ( Vieira 2017), Amazonas (Arrieira et al 2016;Arrieira et al 2017;Reczuga et al 2015), Bahia (Cunha 1916;Neumann-Leitão and Nogueira-Paranhos 1987;Silva et al 2009;Cruz 2012;Araújo and Nogueira 2016;Silva 2016;Silva et al 2020), Ceará (Cunha 1913), Goiás (Lansac-Tôha et al 2000bArrieira et al 2017), Maranhão (Picapedra et al 2017), Mato Grosso (Hardoim andHeckman 1996;Missawa 2000;Oliveira and Hardoim 2010;Arrieira et al 2017), Mato Grosso do Sul (Torres 1996;Velho et al , 1999Alves et al 2007Alves et al , 2008, Minas Gerais (Dabés 1995;Dabés and Velho 2001;Souza 2005;López 2009), Pará Matsumura-Tundisi et al 2015;Vieira 2017;Gomes 2020), Paraná (Velho et al , 1999Alves et al 2007Alves et al , 2008Lansac-Tôha et al 2014;Arrieira et al 2017), Pernambuco (Neumann--Leitão andNogueira-Paranhos 1987), Piauí (Cunha 1916;Picapedra et al 2017), Rio de Janeiro (Wailes 1913;…”

Structure of the testate amoebae community in different habitats in a neotropical floodplain

“…In studies with plankton communities, Arcellidae is one of the predominant families, along with Difflugiidae and Centropyxidae Lansac-Tôha et al, 2007, 2008Alves et al, 2008). On the other hand, in samples from macrophytes and sediments, Lesquereusiidae stands out among the most predominant families (Dabés and Velho, 2001;Leipnitz et al, 2006;Lansac-Tôha et al, 2007;Leão et al, 2009).…”

“…Although testate amoebae are not considered by numerous authors as typically planktonic, in Brazil, the highest diversity of these protists have been recorded in plankton, when compared to macrophytes and lacustrine sediment , especially in environments from the Upper Paraná River floodplain Alves et al, 2007Alves et al, , 2008LansacTôha et al, 2007LansacTôha et al, , 2008. In this ecosystem, various habitats have been sampled, including marginal lakes and small channels and tributaries, as well as the main river.…”