The incidence of zooplankton speed and sampling depth on the sampling efficiency. Preliminary comparative data

Abstract

Abstract. The efficiency of the tubes, traps and nets is varying according to the type of the studied lake and the type of applied methodology. Thus, from one study to another, the obtained data can vary within certain limits for the same water body and season. The inherent variability led to some correlation studies between used methodologies in order to corroborate the results and render them comparable. The present study is referring to the comparative analysis of the efficiency of the tubes used for the sampling of the superficial layers in the stagnant water bodies. The Limnos and Green tubes have been compared to sampling tubes of different diameters. The water speed at the entrance in the tube is calculated and compared with the swimming speed of cladocerans (Simocephalus vetulus juveniles and adult individuals) and copepods (Cyclops sp. juveniles and adult individuals). It is demonstrated that the diameter of the tube used for sampling influences the sampling efficiency especially for the zooplankton species that are actively swimming in the water body. The present study sets the basis for a larger methodology study that, by integrating statistical analysis and hydrodynamics would establish an unified methodology for limnologists worldwide.