Effi ciency of phosphorus accumulation by plankton,periphyton developed on submerged artifi cial substrata and metaphyton:in-situ observation in two shallow ponds

Phosphorus overenrichment of shallow ponds prevailing in wetlands leads to their eutrophication causing the collapse of those vulnerable habitats.The potential of phosphorus accumulation by periphyton developed on artificial substrata has been investigated in two shallow ponds(Bara?ka and?iroki Rit)in northwest Serbia and compared to the same ability of plankton and metaphyton.The periphyton substrate carrier has been submerged from May to October.Both continuously(CS)and monthly developed(MS)periphyton were sampled.Autotrophic component of all investigated communities has been qualitatively assessed.Maximum accumulation of only 14.7 mg TP/m^(2) was recorded in three-month exposed periphyton CS.MS exposed from July to August reached maximal 12.7 mg TP/m^(2).Plankton community that was characterized by more diverse and abundantly developed algal component was more effective in phosphorus accumulation(0.7 mg/g dry weight)in comparison with dominantly inorganic and diatom-dominated periphyton in Bara?ka.Unstable conditions caused by recent revitalization(dredging organic matter and mud from pond basin—redigging)as well as rapid desiccation of?iroki Rit disabled making an unambiguous conclusion about the efficiency of phosphorus accumulation among different communities,but suggested slight potential of phosphorus harvesting by metaphyton in this pond.Due to the shorter exposure time that brings the reduced risk of unpredictable changes in the ecosystem,as well as the considerable amount of accumulated phosphorus,large-scale application of one-month exposed periphyton developed on artificial substrates would be more advisable for phosphorus harvesting in nutrient affected shallow ponds.

Seasonal Succession of the Plankton and Microbenthos in a Hypertrophic Shallow Water Reservoir at Modra(W Slovakia)

The seasonal development of the phytoplankton, phytobenthos, zooplankton, and microbenthos in a high eutrophised intravilan water reservoir was studied. Finally, 25 genera with 44 species of Cyanobacteria/Cyanophytes and 67 genera with 102 species as well as infraspecific taxa of different groups of microscopic algae were identified. The phytoplankton in most parts of the water basin was strongly dominated by green colonial alga Golenkiniopsis longispina. From October until December a cyanophyte species Aphanocapsa delicatissima with typical cell dimensions of picoplankton/ was found in large amounts/predominated. As early as spring, a plankton bloom in all its components was observed. At that time, also a high concentration of total phosphorus was recorded, which in the second half of April dropped rapidly. The concentration of chlorophyll-a increased from 162.7 μg/L in March to 2322 μg/L in September. Massive occurrence of benthic protozoa in the plankton, as a consequence of anoxia, has been observed. Further, the detritivore and omnivore ciliate species Coleps hirtus dominated in the microbenthos. Altogether 74 of ciliate taxa were detected. Their abundance and biomass reached peak in April, but these steadily decreased from May until the end of the year. Extreme values of zooplankton density (54,016 ind/L) were recorded in spring followed by a sudden fall in summer and autumn. The contribution of rotifers (Brachionus spp., Filinia longiseta) in the total zooplankton density and biomass was 98%. Relatively a low species richness of crustaceans (4 Cladocera and 3 Copepoda) was observed.