Effect of Environmental Variables on Zooplankton Assemblages in Two Brackish Water Bodies

Resumo

The objective of the research was to determine whether the Vistula Lagoon and Lake Łebsko, both brackish water bodies, provide similar habitat conditions for zooplankton. The physical and chemical parameters of the water and biological indicators were examined based on the example of zooplankton assemblages in samples collected from June to October in 2010 and 2011. The two water bodies investigated exhibited low water transparency, fluctuating water pH from slightly acidic to slightly alkaline, good oxygen conditions, and frequent hyperoxia. The salinity profiles in both reservoirs were shaped by inflows of riverine and marine waters. The nutrient concentrations between the Vistula Lagoon and Lake Łebsko did not differ significantly, except for that of ammonium nitrogen in 2010. The values recorded for orthophosphates, total phosphorus, and chlorophyll a concentration were comparable in both water bodies. The physical and chemical parameters of the water in the research seasons differed significantly in terms of pH and temperature ranges in both of the basins investigated. No clear trends in the variability of the remaining parameters were observed either seasonally or spatially. The study demonstrated that the two water bodies provide moderately similar habitat conditions to the zooplankton that inhabit them.