1. School of Biological and Marine Sciences, University of Plymouth, PL4 8AA, UK
2. Department for Environment, Food and Rural Affairs (Defra), UK
3. Institute for Nanotechnology and Water Sustainability, College of Science, Engineering and Technology, University of South Africa, Florida Science Campus, P/Bag X6, Roodepoort, 1709, South Africa
4. Water Research Group, Unit for Environmental Sciences and Management, North-West University, Private Bag X6001, Potchefstroom 2520, South Africa
5. Wageningen University & Research, 6708 PB Wageningen, Netherlands
6. UK Centre for Ecology and Hydrology, Wallingford, OX10 8BB, UK