Somatic and population growth responses of Ceriodaphnia dubia and Daphnia pulex (Cladocera) to changes in food (Chlorella vulgaris) level and temperature.
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Date
2011-07
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Abstract
We quantified the combined effects of three food levels (0.01 X106, 0.1 X106 and 1.0X106 cells ml-1) and three
temperature levels (15, 20 and 25oC) on the somatic and the clonal population growth of two cladocerans
Ceriodaphnia dubia and Daphnia pulex for 24 to 42 days. The somatic growth data showed that both the
cladoceran species began to increase their body size within 3 days and remained stable beyond a week.
Food density had a significant effect on the body size of C. dubia while for D. pulex, food level and temperature
as well as their interaction had significant effect on the body size. The population growth of both the cladoceran
species was affected by temperature. At 15oC, C. dubia showed little growth at the highest food density, while
at low food level, there was some increase in the population abundances, especially after a long lag phase of
about 2 weeks. At 15oC and under the lowest tested food level, the population of D. pulex did not increase
beyond the inoculation density. Optimal population growth of D. pulex was observed at intermediate temperature
and at 1.0X106 cells ml-1 of food level while for C. dubia 25oC and the highest food level yielded highest growth.
At low food level and low temperature, the rate of population increase (r) of C. dubia was much lower than that
of D. pulex at comparable conditions. On the hand, at higher food levels and temperature regimes, the r of D.
pulex was much higher than that of C.dubia. Regardless of the food levels and temperature, the r of C. dubia
varied from 0.03 to 0.07 while that of D. pulex varied from 0.01 to 0.08 day-1.
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Keywords
Growth response, Cladocerans, Food and temperature effect
Citation
Gama-Flores Jose Luis, Huidobro-Salas Maria Elena, Sarma S S S, Nandini S. Somatic and population growth responses of Ceriodaphnia dubia and Daphnia pulex (Cladocera) to changes in food (Chlorella vulgaris) level and temperature. Journal of Environmental Biology. 2011 July; 32(4): 489-495.