Magna Acute Studies

Acute data analysis Due to the insignificant difference in the buffered and unbuffered D. magna acute studies, my hypothesis of the unbuffered concentration having a lower LC50 concentration was not supported. However, the indifference might suggest that the toxicity comes from the structure of the compound and not the fact that it is acidic. The pH in the buffered 625 mg/L was essentially neutral and yet it had caused the same mortality of its unbuffered counterpart. This information rejects the reasoning behind my hypothesis as mortality was not definitively caused by the acidity of gibberellic acid. While there may not have been a statistical difference in the LC50 concentrations between the daphnid species, D. pulex did have a much higher LC50 concentration. This may suggest D. pulex is more tolerant to gibberellic acid as compared D. magna. However, this is where the limitation of the study comes into play. Due to mortality being less than 50% in any concentration in the buffered D. pulex acute study, the LC50 concentration was extrapolated beyond the experimental scope. This also explains the high
pulex study was the only acute study where offspring were counted, it does provide valuable insight into the sub-lethal effects of gibberellic acid. The mean number of offspring in the control and 1 mg/L may not be statistically different but they are observantly different. The mean offspring count in 1 mg/L was half of the control’s offspring count. This could have been due to a redistribution of their energy expenditure. Knops et al. (2001) exposed D. magna to toxicants, which displayed a reduced weight and reproduction rate while keeping their metabolic rate constant. Hence the D. pulex may have reproduced less due to expending more energy into breaking down gibberellic acid that entered their body. Therefore, I suggest for future research, more definitive tests in how gibberellic acid affects the number of offspring should be