The effect of potentially toxic cyanobacteria on ciliates (Ciliophora)

Abstract

The most frequently observed cyanotoxins are microcystins. They trigger a cascade of events leading to cellular responses. The hypothesis of the study was that cyanobacteria affect ciliates as solitary species and as assemblages. The aim of our study was to determine whether ciliates respond to cyanobacteria because of the presence of cyanotoxins (microcystins-MC). We set up experiments with toxic (Planktothrix agardhii and Microcystis aeruginosa) and non-toxic (Aphanizomenon flos-aquae) cyanobacteria, solitary Spirostomum sp. (Ciliophora), and a simple ciliate assemblage. Predicted values showed statistically significant increase during the solitary Spirostomum sp. abundance in the presence of toxic P. agardhii (MC total concentration in cells 323.9 lg/l) and M. aeruginosa (MC total concentration in cells 31.9 lg/l) but a decrease in the presence of non-toxic A. flos-aquae. The abundance of Spirostomum sp., being a component of ciliate assemblage, decreased significantly in the presence of all the three species of cyanobacteria due to competition from small-sized ciliate species that graze bacteria more effectively compared to large-cell-sized Spirostomum. We conclude that toxic cyanobacteria may affect ciliates in various ways, not necessarily because of production of toxins. As a consequence of the presence cyanotoxins, a cascading effect of passing carbon in the food web might be induced.

Cyanobacterial Blooms and Zooplankton Structure in Lake Ecosystem under Limited Human Impact

“…The zooplankton-cyanobacteria and/or cyanobacteria-zooplankton relationships differ in various ecosystems, and in the case of larger-sized zooplankton they may be positive [67] or negative [57]. Considering the small-sized protozoan ciliates (e.g., algivorous Rimostrombidium humile, omnivorous Mesodinium pulex, bacterivorous Halteria grandinella), their effect on cyanobacteria is not so obvious [68]. Considering the smallest-sized heterotrophic nanoflagellates (HNF), their positive impacts can be confirmed for both single-celled and colonial picocyanobacteria with 0.2-2.0 µm size because they usually participate in the nutrient regeneration as it was previously found [69].…”

Use of ciliate communities for monitoring ecological restoration of grain for the green in north-western China

“…Traditionally studies of soil ciliates focused mainly on their morphology, assemblage, ecology, and use in toxicology, but in recent years increasing emphasis is placed on molecular phylogeny, relationships with other microorganisms, and the effects of environmental pollution on soil ciliate community structure. (Liu et al, 2008;Buonanno and Ortenzi, 2010;Ning et al, 2011a;Shao et al, 2014aShao et al, , 2014bGeisen et al, 2016;Lin et al, 2017;Luo et al, 2017;Kosiba et al, 2019;Wanner et al, 2020).…”