Effects of food limitation and temperature on cladocerans from a tropical Brazilian lake

Abstract

Food limitation was tested in the laboratory by individual growth and reproduction of two cladoceran species, Ceriodaphnia richardi and Daphnia gessneri, from the shallow tropical Brazilian Lake Monte Alegre. The cladocerans were fed cultivated green alga Scenedesmus spinosus in concentrations of 0.20, 0.10, 0.05, and 0.025 mg C l À1 . Higher biomass and growth rates occurred in the two highest-food concentrations; the two lowest ones negatively affected clutch size and first reproduction. The threshold food concentration is lower than 0.025 mg C l À1 and the incipient limiting level is a value between 0.10 and 0.20 mg C l À1 . The largest species, D. gessneri, was more sensitive to low food concentrations. The effects of low and high temperatures (19 and 27°C) were evaluated by life table experiments with three cladocerans from the lakeDaphnia ambigua, D. gessneri, and Moina micrurawith no food limitation (1 mg C l À1 of S. spinosus). Higher population growth rates for the three species were found at 27°C; better performance in most life table parameters was observed for the former two species at the highest temperature, D. gessneri being the most sensitive to the lowest temperature. There are indications that temperature is an important abiotic factor that constrains populations of cladocerans for a short period in winter in the lake, when temperature decreases to 18-19°C. However, its influence cannot be separated from a biotic factor such as food, whose effect is stronger in the cool season, when concentrations are lower and contribution of inedible algae is relatively higher.

Diel horizontal distribution of microcrustaceans and predators throughout a year in a shallow neotropical lake

“…In addition to algal food quantity being lower in the littoral in the lake, algal quality may be different. The estimated average algal carbon in the three stations (0.4 -0.6 mgC.L -1 ) are not limiting for some cladocerans in the lake, whose threshold food concentration and the incipient level are, respectively, < 0.025 mgC.L -1 and between 0.1 and 0.2 mgC.L -1 (Bunioto and Arcifa, 2007). Detailed analyses of food quality onshore and offshore are in progress, because laboratory experiments with cladocerans from the Lake Monte Alegre showed lower intrinsic rates of population growth (r) and fecundity of Moina micrura and Ceriodaphnia cornuta in the microplankton fraction (> 20 µm) (Fileto et al, 2004).…”

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

“…In experiments, a lower temperature influenced several life-table parameters of three species (Bunioto and Arcifa, 2007). 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.…”

Fluctuations of the population of Daphnia laevis Birge 1878: a six-year study in a tropical lake

“…Besides the importance of studies on population dynamics to understand the functioning of aquatic ecosystems, knowledge concerning the responses of tropical organisms for biotic and abiotic factors is essential to support ecological hypothesis, which are mainly based on data from temperate lakes (Mergeay et al, 2006;Bunioto and Arcifa, 2007). Thus, the present study contributes with information on long-term fluctuations of the population of Daphnia laevis Birge, 1878 in a tropical lake, monitored monthly for six years.…”

“…In the tropics, despite the small annual temperature fluctuations, population responses can be observed (Bunioto and Arcifa, 2007). This variable can influence zooplankton in two ways: directly, on the reproduction rates, filtration rates, duration of the life cycle, production and hatching of resistance eggs (Rocha et al, 1990;Crispim and Watanabe, 2000;Bunioto and Arcifa, 2007); or indirectly, through thermal stratification.…”

“…In the tropics, despite the small annual temperature fluctuations, population responses can be observed (Bunioto and Arcifa, 2007). This variable can influence zooplankton in two ways: directly, on the reproduction rates, filtration rates, duration of the life cycle, production and hatching of resistance eggs (Rocha et al, 1990;Crispim and Watanabe, 2000;Bunioto and Arcifa, 2007); or indirectly, through thermal stratification. This phenomenon creates a larger spatial heterogeneity, also causing a "zooplankton stratification", where the organisms group according to the best environment conditions or because they cannot overcome the physical-chemical barriers (Thackeray et al, 2006).…”