Influence of seston quantity and quality on growth of tropical cladocerans

Abstract

The seston of the small, shallow, and tropical lake Monte Alegre was tested for quantity and quality for cladocerans by growth bioassays, which were carried out in spring (Daphnia gessneri and Moina micrura), summer (D. gessneri, M. micrura, Ceriodaphnia cornuta, and Simocephalus mixtus), and winter (D. gessneri and D. ambigua). Cohorts of newborns originating from ovigerous females collected in the lake or from laboratory cultures were submitted, at a room temperature of 23 degrees C to the following treatments: (1) the chlorophytes Ankistrodesmus falcatus and/or Scenedesmus spinosus; (2) lake seston; and (3) lake seston + chlorophytes. Growth rate, clutch size, and fecundity were evaluated. Seston alone was not the best food for promoting cladoceran growth. There were seasonal differences in food quantity and quality with spring and summer seston being better for growth than that of the winter. Adding chlorophytes to the seston increased clutch size and fecundity for most species in summer and winter, but not in spring. Energy limitation seems to be the most important factor influencing cladoceran growth in summer and especially in winter.

A long-term study on crustacean plankton of a shallow tropical lake: the role of invertebrate predation

“…However, although temperature could occasionally cause a decline in densities of cladocerans during the cool season, it is an unlikely explanation for the observed longterm changes, since the lowest winter temperatures were similar amongst the periods. Although in this lake food quantity and quality can be limiting during the cool season (Ferrão-Filho et al, 2003, 2005, there was no indication of a long-term influence on the microcrustaceans. Finlay et al (2007), studying several temperate lakes, concluded that zooplankton were controlled mainly by primary productivity (bottom-up) and not by predators (top-down).…”

Secondary productivity of main microcrustacean species of two tropical reservoirs in Brazil and its relationship with trophic state

“…Temperature has an important role, because the population of egged females (mean 27%; maximum 37%) and the mean number of eggs per female (mean 1.38 eggs, maximum 2.0 eggs) were higher in the warm rainy period. Furthermore, the correlations between productivity of this species and concentrations of organic suspended solids in Três Marias and Furnas reservoirs indicate an additional source of food for this species, as observed for M. micrura by Ferrão-Filho et al (2005). These authors observed that only this species showed similar growth rates to a control treatment, when different food sources were offered: only chlorophyceans, only seston, or seston+chlorophyceans.…”

Horizontal distribution of Cladocera in a subtropical lake marginal to a river

“…birgei, D. brevireme, D. spinulosum, M. micrura and M. minuta was related to a greater sampling station depth and greater concentrations of suspended organic and inorganic matter from S1 to S6. Cladoceran filtration and survival rates are dependent on the quality and concentration of suspended matter in water (Ferrão-Filho et al, 2005;Fileto et al, 2010). Variation in the abundance of the species above from S1 to S6 and at stations S8, S9 and S17 correlated to water transparency may be affected by fluctuations in the amounts of suspended organic and inorganic matter.…”