Oxygen Gradients and Structure of the Ciliate Assemblages in Floodplain Lake

Abstract

This paper presents the results of studies on the structure of the ciliate population in a freshwater lake. The classification of the ciliated communities based on the analysis of the distribution of ciliate population density in the lake along the oxygen gradients, taking into account their oxygen preferences, was proposed. It was shown that the distribution of ciliated protozoa in the space of a reservoir is determined not by such spatial units as the water column, bottom, and periphytal, but by the oxygen gradients. Four types of habitats with different oxygen regimes were distinguished: With stably high oxygen concentration, stably low oxygen concentration, stably oxygen-free conditions, and conditions with a high amplitude of diurnal oxygen variations. The location of these habitats in the space of the lake and their seasonal changes were determined. On the basis of the quantitative development of ciliate populations, zones of optima and tolerance ranges of some ciliate species in the oxygen gradient were established. The oxygen preferences were established for the species from four distinguished assemblages: Microoxyphilic, oxyphilic, euryoxyphilic, and anoxyphilic (anaerobic). The presence or the absence of a certain type of assemblage in the reservoirs depends solely on the parameters of the oxygen gradients. The diversity of the ciliated protozoa in water bodies also depends on the stability and diversity of the oxygen gradients.

Water Quality of Freshwater Ecosystems in a Temperate Climate

“…The authors of the next article [23] come to similar conclusions to those of Babko et al [22]. Antonowicz and Kozak [23] study the concentration of chemical parameters and biocenoses occurring in the surface microlayer, i.e., the ecotone, between the hydrosphere and the atmosphere.…”

“…Babko et al [22] present the results of studies on the structure of the ciliate population in a floodplain eutrophic lake. The authors show that the main factor responsible for the spatial distribution of ciliates in a floodplain eutrophic waterbody is the pattern of habitat oxygenation.…”

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

“…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 ). Infectiousness as well as interspecific competition were additionally addressed as a possible explanation for the disappearance of C. varicaedens despite the competitive advantage provided.…”

Spatial Distribution of Ciliate Assemblages in a Shallow Floodplain Lake with an Anaerobic Zone

“…The plant samples were taken with glass cylinders. The cylinder was dipped into Lemna trisulca thickets, plants were carefully pushed inside the cylinder with tweezers, and then the cylinder was closed on both sides with plugs [25]. In the laboratory, the samples were stored in the refrigerator at +5 • C before and during processing.…”

“…The assemblages of ciliated protozoa are very specific in such lakes; in freshwater ecosystems, they are represented by a significant number of species, including anaerobic ones [16][17][18]. The composition of ciliated protozoan assemblages in different habitats is influenced by water chemistry, nutrient availability [19][20][21][22], and especially by oxygen concentration and its dynamics [23][24][25]. Ciliated protozoa play an important role in the aquatic ecosystem as consumers of bacteria, flagellates, and periphytic algae, keeping most bacteria in an exponential growth phase [26,27].…”