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Journal of Environmental BiologypISSN: 0254-8704 ; eISSN: 2394-0379 ; CODEN: JEBIDP |
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Abstract - Issue Mar 2009, 29 (2) BackCombined effects of heavy metal (Hg) concentration
and algal (Chlorella vulgaris) food density on the
population growth of Brachionus calyciflorus
Teresa Ramirez Perez and S.S.S. Sarma* Laboratory
of Aquatic Zoology, Division of Research and Postgraduate Studies, National
Autonomous University of Mexico, Campus Iztacala Av.
de los Barrios No.1, AP 314, CP 54090, Los Reyes, Tlalnepantla, State of Mexico,
Mexico (Received: August 14, 2006
; Revised received: March 01, 2007 ; Accepted: April 15, 2007) Abstract: The combined
effects of two food levels (0.5 X106 and 1.5 X106 cells ml-1 of Chlorella vulgaris) and five concentrations (0, 0.000625, 0.00125, 0.0025,
0.005 mg l-1 of HgCl2) of mercury on the population growth of the rotifer Brachionus calyciflorus was
evaluated. The growth experiments were conducted for 18 days at 23?1oC under
continuous fluorescent illumination. For each food level ? heavy metal
combination, we maintained 3 replicates. Our data showed that regardless of
food level, increase in the heavy metal concentration in the medium resulted in
decreased population growth of B. calyciflorus. At
any given heavy metal concentration, B. calyciflorus
grown under higher food levels had higher population abundance. The rate of
population increase was significantly influenced by both the heavy metal
concentration and the algal level. The highest population growth rate (0.435?0.003
per day) was observed in controls at 1.5 X106 cells ml-1. The results of this
study were discussed in relation to the protective role of algal density
against heavy metal toxicity. Key words: Heavy metal, Zooplankton, Rotifer, Alga PDF of full length paper is available with author (sarma@servidor.unam.mx) Copyright
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