Using Cilioplankton as an Indicator of the Ecological Condition of Aquatic Ecosystems

Abstract

We assess the quality of surface water in water bodies located in the Middle Volga region (Russian Federation). The water quality is assessed using 19 chemical compounds and cilioplankton indicators, such as the total number of species, the abundance of each species, and, based on both of them, the saprobity index and the Shannon–Weaver diversity index (H). We classify the water quality from polluted to extremely dirty by using abiotic indicators, and from conditionally clean to dirty by means of biotic indicators. Using the logistic regression method, we are able to predict the water quality (clean or dirty) in correspondence with the species diversity index (H) and to clarify how the quality of the water is related to its physicochemical properties. The seven most significant chemical predictors of both natural origin (mineralization, hydro carbonates, and chlorides) and natural-anthropogenic origin (organic substances (according to BOD5), nitrates, total petroleum hydrocarbons, iron), identified during the stepwise selection procedure, have a substantial influence on the outcome of the model. Qualitative and quantitative indicators of development of ciliates, as well as indices calculated on their basis, allow assessing with a very high level of accuracy the water quality and the condition of aquatic ecosystems in general. The Shannon index calculated for the number of ciliates can be successfully used for ranking water bodies as “clean/dirty”.

Epibiont Cohabitation in Freshwater Shrimp Neocaridina davidi with the Description of Two Species New to Science, Cladogonium kumaki sp. nov. and Monodiscus kumaki sp. nov., and Redescription of Scutariella japonica and Holtodrilus truncatus

“…After 10 h, the shrimp were individually analyzed for the presence of epibionts or traces of their activity in four different microhabitats, defined according to Maciaszek et al [9] as (1) rostral area, (2) branchial chambers, (3) pereiopodal area, and (4) pleopodal area (Figure 1). The presence of ciliates and rotifers was used as an indicator of organic matter in the water and food source for temnocephalids and branchiobdellidans [9,22,23]. Preliminary observations were carried out directly in each aquarium by secluding each shrimp with a petri dish pushed against the inner part of the tank wall, as shown in Maciaszek et al [24].…”

First report of Scutariella japonica (Matjašič, 1990), a temnocephalid epibiont from South-East Asia, found on introduced ornamental freshwater shrimp in European waters

“…Collected shrimp were observed for selected epibionts (Annellida, Ciliata, Platyhelminthes) presence under digital microscope Keyence VHX-7000 at 500-1500x magnification. Among epibionts, presence of vorticellids was used only as an indicator of organic matter quantity in the water, which can impact presence of scutariellids (Maciaszek et al, 2018;Kondrateva et al, 2019). Isolated epibionts were examined for morphological features using available literature (Matja sič, 1990;Ahn and Min, 2016).…”