The Effect of Bioavailable Sedimentary Iron on the Growth of Cyanobacteria in Eutrophic Lakes
2018
Zhang, Shenyao | Zheng, Xiaowei | Zhang, Weizhen | Song, Qixuan | Zheng, Zheng | Luo, Xingzhang
The objectives of this study were to investigate whether sedimentary iron can promote the growth of cyanobacteria and determine the effects of different forms of iron on cyanobacterial growth. In this study, we simulated cyanobacterial growth in a eutrophic freshwater lake under Fe-deficient conditions using three systems containing artificial lake water and algae (the WA system); artificial lake water and sediment (WS system); and artificial lake water, sediment and algae (the WSA system). Results demonstrate that Fe from sediments did facilitate cyanobacterial growth. Sequential Fe extractions revealed that the majority of sedimentary iron was in the form of reactive iron (80.63%). Furthermore, cellular iron from cyanobacteria and water-soluble Fe in sediments had a strong and significant negative correlation (− 0.792, P < 0.01), indicating that water-soluble Fe in sediments is the most important form of iron for influencing cyanobacterial growth. Further studies on water-soluble Fe mobility showed that up to 47.5% of the released water-soluble Fe could be absorbed into cyanobacterial cells, thereby indicating that water-soluble Fe is significant for cyanobacterial growth and serves as a critical Fe source when lake water iron is limited. In addition, the study found that easily reducible Fe oxide minerals have the largest release potential. These findings provide new insights that could improve management of cyanobacterial blooms.
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