Seasonal and spatial variability of species occurrence of the Paramecium aurelia complex in a single natural pond (Protista, Ciliophora)

Abstract

The geographic distribution and temporal occurrence of ciliates are still little known. In the present article, the occurrence of the Paramecium aurelia species complex in a natural pond situated in Kraków (Opatkowice) was investigated in different seasons in two following years. A sequence of species occurrence of the P. aurelia complex was observed. Always, paramecia were found only in some sampling points among six points sampled each time and not necessarily in the same ones. Paramecia appearing in one habitat (water body) might occupy different niches characterized by various environmental features suitable for paramecia. The following species were found in the pond: P. biaurelia, P. triaurelia, P. tetraurelia, P. pentaurelia, and P. dodecaurelia. The occurrence of some rare species (P. tetraurelia, P. pentaurelia, and P. dodecaurelia) may be connected with migrating birds which can transport paramecia with drops of water from other water bodies. If a species was observed in successive seasons or years, the possible genetic variation was investigated by analysis of sequences of LSU rDNA and mitochondrial cytb gene fragments. Among the studied species (P. biaurelia, P. triaurelia, P. pentaurelia, and P. dodecaurelia) only P. dodecaurelia showed haplotype variation in different seasons and sampling points, probably caused by the colonization of the pond by different populations of paramecia.

Natural Shifts in Endosymbionts' Occurrence and Relative Frequency in Their Ciliate Host Population

“…Due to the advantageous killer trait mediated by C. varicaedens, P. biaurelia collected in February 2017 would have been assumed to persist over subsequent sampling events which is not supported by our data. Previous studies highlighted biotic and abiotic factors with the potential to strongly affect ciliate species composition in lake ecosystems (Przyboś et al, 2011 ; Sonntag et al, 2006 ). For example, spatial localization in the aquatic environment has been considered a highly effective parameter shaping ciliate diversity and composition (Sonntag et al, 2006 ; Babko et al, 2020 ).…”

Worldwide sampling reveals low genetic variability in populations of the freshwater ciliate Paramecium biaurelia (P. aurelia species complex, Ciliophora, Protozoa)

“…On the other hand, Paramecium biaurelia is one of the species of the P. aurelia complex that is characterized by wide distribution in areas with colder climates. Moreover, many years of sampling (since 1959) of different regions of Poland have revealed that it is a common species, recorded in 88 habitats (40.36%) among 218 studied (Przyboś et al 2011). P. biaurelia's frequent occurrence could be explained by fact that it is capable of invading marginal habitats, and adapts to circumstances that enforce inbreeding, such as intraclonal mating.…”

“…Due to the observed high incidence in the various ecosystems tested to date (Przyboś et al 2011) and the ability to invade new habitats (Gill and Hairston 1972), perhaps more accurate sampling of small areas (i.e., one or several ponds) will reveal previously hidden genetic variation of the studied microorganism.…”