Population growth of Daphnia pulex (Cladocera) on a mixed diet (Microcystis aeruginosa with Chlorella or Scenedesmus)
Por:
Alva-Martínez A.F., Sarma S.S.S., Nandini S.
Publicada:
1 ene 2004
Resumen:
We quantified population growth of Daphnia pulex on diets of Microcystis aeruginosa mixed with Chlorella vulgaris or Scenedesmus acutus (0, 25, 50, 75, or 100% cyanobacteria with either algal species, based on equal biomass (dry weight)). We also evaluated the possible adaptations of D. pulex to cyanobacteria when previously grown on a mixture of M. aeruginosa and Chlorella or Scenedesmus. When offered alone, M. aeruginosa did not support the population growth of D. pulex for long, while the two algal species promoted population abundance of the daphniid. In terms of population growth, S. acutus was the better of the two algal species. When mixed with C. vulgaris or S. acutus, M. aeruginosa supported the population growth of Daphnia better than when offered alone. However, regardless of the proportion of the mixed diet, S. acutus with M. aeruginosa supported population growth in D. pulex better than did a mixture of Chlorella and Microcystis. The rate of population increase (r) per day obtained for D. pulex varied from 0.003 to 0.21, depending on the type of diet. When cultured on a mixed diet, regardless of the algal species involved, D. pulex showed decreased growth rates with an increasing proportion of Microcystis. D. pulex, previously reared on a mixed diet (M. aeruginosa with Chlorella or Scenedesmus in different proportions), did not grow when transferred to M. aeruginosa alone, and even began to decline starting directly from the beginning of the experiment. Our results suggest that, together with a species of green alga, the single-celled, toxic M. aeruginosa could be used for culturing D. pulex.
Filiaciones:
Alva-Martínez A.F.:
Doctoral Programme, Autonomous Metropolitan University, Campus Xochimilco, Calzada del Hueso No. 1100, C.P. 04960, Mexico City, Mexico
Sarma S.S.S.:
Lab. de Zool. Acuática, Div. de Invest. y Posgrado, Campus Iztacala, A.P. 314, Tlalnepantla, Edo. de Mexico, Mexico
Nandini S.:
UIICSE, Div. de Invest. y Posgrado, Campus Iztacala, A.P. 314, Tlalnepantla, Edo. de Mexico, Mexico
|