1 Institute of Soil Science, Chinese Academy of Sciences, 71 East Beijing Road, Nanjing 210008, China. Electronic address: yhwu@issas.ac.cn.
2 Department of Water Supply, Sanitation and Environmental Engineering, IHE Delft Institute for Water Education, Westvest 7, 2611AX Delft, the Netherlands.
3 Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, 610041 Chengdu, China.
4 Diatom Research Laboratory, Amity Institute of Biotechnology, Amity University, India.