Effects of Different Forms of Iron on Growth of Microcystis aeruginosa and Bioavailability of Iron

The effects of different complexes formed by Fe3+ and organic ligands(EDTA,NTA and DTPA) in MA medium on growth of Microcystis aeruginosa were studied in laboratory.Use MINTEQ procedure,calculate the concentrations of EDTA,NTA and DTPA which made all of Fe3+ complexed in each solution,add the proper concentrations of three organic ligands in test solutions respectively,inoculate Microcystis aeruginosa and experimentize algal growth potential(AGP) test.We mensurated the daily biomass of Microcystis aeruginosa,the content of Microcystis aeruginosa's Chl-a and the distribution of iron at the end of cultivation in each group.The results showed that:compared with the control group,all of three organic complexes of iron promoted the growth of Microcystis aeruginosa and enhanced the bioavailability of iron obviously,but there was no obvious difference among these groups;Fe-NTA enhanced the content of Microcystis aeruginosa's Chl-a obviously at the end of cultivation,synchronously Fe-EDTA and Fe-DTPA did not.The effect extent of three organic complexes of iron on the content of Microcystis aeruginosa's Chl-a at the end of cultivation was:Fe-NTA Fe-DTPA,Fe-EDTA;On promoting the growth of Microcystis aeruginosa and enhancing the bioavailability of iron,organic complex forms of iron were more effective than hydroxy complex form.