M Klimko

Zooplankton community structure within various macrophyte stands of a small water body in relation to seasonal changes in water level

Zooplankton community structure within various macrophyte stands of a small water body in relation to seasonal changes in water level Different morphological features of particular water bodies, physical and chemical factors of their waters and sediments will have an impact on the development of specific aquatic vegetation types, which in turn will affect the creation of specific communities of plankton organisms. Therefore the aim of this study was to analyse the quantity and quality changes of macrophyte structure in relation to the lowering of the water level. Furthermore, the relationship between zooplankton community densities and environmental parameters was studied. Another aspect of the study was to investigate the similarity of the zooplankton communities of particular sampling stations in the three examined seasons. The study was carried out on Dąbrówka water body, a shallow and macrophyte-dominated pond, situated 10 km west of Poznań, Wielkopolska region, western Poland. The examination was conducted in the three seasons: spring, summer and autumn. The results revealed that during one vegetative period, including three seasons — spring, summer and autumn, three different layouts of aquatic vegetation were obtained, which reflected a significant transformation in the macrophyte cover. Along with the lowering of the water level the structural changes, especially in the case of submerged vegetation were recorded, which in each season was represented by different dominating species. Only three significant correlations between zooplankton densities and environmental factors observed. Negative relationship concerned total nitrogen and two positive related to biometric parameters of the macrophyte habitat (plant biomass plant stem volume). The plant biomass was a predictor of cladoceran abundance and plant stem volume referred to rotifers, which may reflect the complexity of the aquatic plant habitat, indirectly relating to the effectiveness of the macrophyte stand as anti-predator refuge. The analysis of the similarity of the zooplankton communities of particular sampling stations in the three examined seasons did not reveal any clear relationship, either in relation to a particular season or a sampling station. The participation of eutrophic species was highest in the spring and lowest during the autumn season. The open water zone possessed the highest participation of these species compared to the macrophyte zones.

Relationship between plankton assemblages and habitat characteristics of stands of Typha angustifolia and Chara hispida in Lake Wielkowiejskie

Relationship between plankton assemblages and habitat characteristics of stands of Typha angustifolia and Chara hispida in Lake Wielkowiejskie The results of investigations performed in Lake Wielkowiejskie showed the influence of macrophyte architecture, understood as plant density, on the structure of plankton communities as well as the habitat preferences of particular species in both seasonal and spatial aspects.

Phycological investigations of pelagic vs. littoral zones of shallow lake ecosystems

The main goal of this study was to examine the influence of two aquatic plants representing various ecological types (Chara tomentosa and Typha angustifolia) and comparatively the pelagic zone, on the phytoplankton communities in three shallow and macrophyte-dominated lakes.The stand dominated by Chara tomentosa was characterised by the richest taxonomical structure, the highest biomass of algae (phytoplankton sensu lato), as well as by the highest values biodiversity indices out of all the examined stations. Bacillariophyceae and Chlorophyta dominated in the biomass. There was a numerous group of species that selectively chose the Chara bed among the two groups of phytoplankton, e.g. Cymbella lanceolata (Ehr.) Kirchner, Rhopalodia gibba (Ehr.) O.Müll and Spirogyra sp.It was found that the stand of submerged macrophytes, represented by Chara tomentosa, significantly and specifically influenced the differentiation of the structure of the algal communities of shallow and eutrophic lakes.The aim of the study was to determine differences in algal communities, relating to biomass and diversity indices, between lake zones — eulittoral (with Typha), infralittoral (with Chara meadows) and pelagial.