Oxygen Gradients and Structure of the Ciliate Assemblages in Floodplain Lake

Roman Babko,Grzegorz Łagód,Yaroslav Danko,Tetiana Kuzmina,Joanna Szulżyk-Cieplak

doi:10.3390/w12082084

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.

Highlights

Ciliates are one of the diverse groups of protozoa; today about 1500 morphospecies of freshwater ciliates have been described [1]
Theduring studied eutrophic lake remains stratified from the Junewater to thecolumn winter, the freezingfloodplain period, oxygen practically disappears in the
As mentioned mentioned in the methods section, a pronounced oxygen gradient was observed in the pelagic zone in the section, a pronounced gradient was observed in the pelagicIn zone the lake, of the methods lake, within which three zones oxygen of different

Summary

Introduction

Ciliates are one of the diverse groups of protozoa; today about 1500 morphospecies of freshwater ciliates have been described [1]. The diversity of ciliated protozoa on a global scale is fairly uniform. Numerous studies show that in some territories, and in water bodies of different types, the diversity of ciliated protozoa differ significantly [4,5,6,7,8,9,10,11,12]. Compared to the potential diversity, the realized diversity is dynamic and reflects the specific conditions of each water body, leading to the dissimilarity of the fauna. This local diversity remains unpredictable and varies in space and time. It has been successfully used to assess the status of aquatic ecosystems

Objectives

Methods

Results

Discussion

Conclusion