engleski

Effects of different phisico-chemical parameters on invertebrates in the sediment of Lake Sakadaš (Kopački Rit floodplain)

Standard limnological parameters, including sediment granulometry and organic matter content, were measured to assess their importance for the structureing of sediment invertebrate community in the period between July and November 2007 at two littoral sites of Lake Sakadaš in the Kopački rit floodplain. Ten groups of invertebrates were recorded in total: Nematoda, Rotifera, Copepoda (Eudiaptomus sp.), Ostracoda, Cladocera (Bosmina sp.), Bivalvia (Dreissena polymorpha), juveniles of Gastropoda, Oligochaeta (Chaetogaster sp.), Turbellaria and Tardigrada. Nematoda and Rotifera were dominant groups at both sites. According to regression model, Nematoda have developed during period with low O2 concentration and low pH, but with high concentration of NH4+ and total phosphorus. The size of the sediment particles were significantly lower at site 1, albeit during October the sediment at site 2 resembled site 1. For Ostracoda and Cladocera, according to regresion model, of all the variables, significance was found only for the size of the sediment particles. Their abundance and particle size are inversely proportional to each other. Oligochaeta have developed in dependence on high water level, low conductivity, low NH4+ concentration, total nitrogen and total phosphorus. Their abundance is proportional to the sediment particle size. The size and the type of the particles influence the arrangement of intersticial spaces as well as water content, O2 concentration and the amount of inorganic salts and organic matter, thus influencing distribution, abundance and composition of the sediment fauna.

floodplain; sediment; invertebrates

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