About the interest of a zooplankton compartment in pond systems: methodology to study the growth kinetic of Daphnia pulex on Scenedesmus sp.

Abstract

A reliable characterization of cladocerans' growth kinetic on their substrates is crucial for the estimation of their biochemical conversion rate in pond models. Although many studies reported cladocerans' growth inhibitions by high chlorophyceae contents, their growth kinetics had continued to be described in many pond system models by Monod-type kinetic, which describes growth saturation by high substrate contents, but fails to explain the disappearance of cladocerans observed during chlorophyceae's bloom periods. This study aimed to develop a methodology and assess whether growth-inhibition-type models used to describe microbial growth kinetics can be applicable to cladocerans. Experiments were carried out using Daphnia pulex populations and Scenedesmus sp. First, biomass of D. pulex was measured through digital image processing (DIP) during growth experiments. Then, three candidate models (i.e., Andrews, Edward and Haldane models), along with the Monod model, were fitted to the observed data and compared. The results showed that the DIP technique provided reliable results for estimating the biomass of D. pulex. Our findings show that the candidate growth inhibition-type models satisfactorily described D. pulex's growth kinetic (86% variance accounted for). Scenesdemus sp. were not strong inhibitors of the growth of D. pulex (high inhibition constant and low half-saturation constant found).

Valorization of various sources of rabbit manure in agro-piscicultural system in Benin (West Africa): dynamics and effect of mineralization upon quality of fresh water

“…Microbial activity started thus after these 3 days and showed a fast variation of these parameters (Table 3); pH and P-PO 4 3-increased, whereas nitrogen forms showed great fluctuation (nitrification process) providing a favourable environment for phytoplankton production (Fig. 1e), and consequently that of zooplankton when phytoplankton biomass is not so high to cause growth inhibition (Liady et al 2015 and references there in). Indeed, the extent of pH preferences for fish is usually 5-7 to 7-9 (Peterson et al 1989).…”

Effect of Different Doses of Rabbit Manure on the Abundance, Growth Rate and Production of Zooplankton in Plurispecific System for Fish Larvae Feeding

“…Zooplankton counting was carried out according to Liady et al (2015), by image treatment using Image Pro-Plus following species representativeness (at least 100 individuals were counted) in 1-2 mL of sample that were successively observed in a plastic saltcellar at densities that do not provoke overlapping among individuals. …”

“…Zooplankton counting was carried out according to Liady et al (2015), by image treatment using Image Pro-Plus ® software (Figure 1). Pictures were first captured from a microscope Optim Jeulin (X10) equipped by a photograph device (Figure 2).…”

“…The first consisted to the comparison of different densities obtained in treatments; the second consisted to compare specific growth rates of organisms during their exponential growth stage according to Liady et al (2015). In this second method, growth curves of zooplankton in non-renewed area presenting identical stages to those observed in microorganism's cultures in non-renewed area, identical mathematical laws were considered.…”

“…Several studies were based on the relationship between algae biomasses and zooplankton production (Sendacz et al, 2006; Ekelumu et al, 2011). This relationship could be characterized by optimal concentrations lower than which zooplankton growth is exponential and upper than which this growth is inhibited (Ovie et al, 2002;Liady et al, 2015). This matter could explain low productions of zooplankton observed in T5 and T3 compared to those observed in T2 and T4.…”