Influences of iron and humic acid on the growth of the cyanobacterium Anabaena circinalis

摘要

Fe may play a key role in the growth of cyanobacteria,which sometimes cause water blooms in eutrophic water environments.Humic acid (HA) is also considered to be a controlling factor in algal growth,as HA is abundant around water basins and has a variety of chemical functions,including Fe-chelation and catalysis.To evaluate the influence of iron depletion and the presence of HA on the growth of Anabaena circinalis,a water bloom-forming cyanobacterium,ex situ cultivation experiments were performed using chemically defined media.The data were analyzed to characterize the effects of Fe and HA on cell growth.A Fe concentration of 10~(-8) to 10~(-7) M was the threshold for growth of the cyanobacterium.HA may have toxic effects (at [HA] > 0.01 mg Cl~(-1)) and may reduce Fe bioavailability (at [HA] >=0.1mgCl~(-1)),which delays and/or decreases the growth of the cyanobacterium.