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2 Polish Journal of Ecology

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Composition and distribution of epiphytic midges (Diptera: Chironomidae) in relation to emergent macrophytes cover in shallow lakes

Tarkowska-Kukuryk M.

Polish Journal of Ecology

2011

Vol. 59, nr 1

141-151

The influence of emergent macrophytes (dominated by Phragmites australis (Cav.) Trin. ex Steud.) on the species composition, richness and abundance of epiphytic midges (Diptera: Chironomidae) was studied in five shallow lakes of eastern Poland during three seasons (May, July and October) of 2001. The lakes represented three states: clear (macrophyte dominated), intermediate (phytoplankton-macrophyte dominated) and turbid (phytoplankton dominated). The trophic status of lake strongly affected the assemblages of chironomids living on the surfaces of common reed. Habitat conditions regulated mostly densities and relative abundance of midge taxa and did not have any significant influence on the number of taxa. The Canonical Correspondence Analysis of epiphytic fauna showed the significance of 5 environmental variables: Secchi disc visibility, dissolved oxygen, reed density, concentration of total phosphorous and epiphytic chlorophyll-a. The analysis separated epiphytic midges into two groups. The first group included taxa limited by low oxygen content and water transparency and corresponds with clear state habitats. To the second group belong taxa typical of eutrophic waters with densities determined by the concentrations of total phosphorous and chlorophyll-a, common in lakes of intermediate state and in particular of turbid state.

Autotrophic picoplankton (APP) in four lakes of different trophic status : composition, dynamics and relation to phytoplankton

Jasser I.

Polish Journal of Ecology

2002

Vol. 50, nr 3

341-355

Abundance and dynamics of autotrophic picoplankton (APP) were studied in four temperate lakes: oligo-, meso- and eutrophic, as well as dystrophic lake. Orange fluorescing cyanobacteria prevailed in APP community in all four lakes, but in spring and autumn eukaryotic contribution increased. The densities of APP ranged between 2 x 10^4 ml^-1 and 9.5 x 10^5 ml^-1. There was a trend of increase of APP numbers along classical trophic gradient, but its share in total phytoplankton biomass was decreasing importance of picoplankton with eutrophication. Two types of APP seasonal patterns were described. One characterised by only one, spring-early summer peak, was found in mesotrophic and eutrophic lake. The second pattern described for humic lake was characterised by two peaks, in spring and Autumn.