A Secchi disk is a white circle that helps scientists understand how much phytoplankton is in a body of water. Follow these steps to make and use your own.
Councils in the top of the South Island are grappling with the task of installing protozoa barriers on small, rural water supplies and finding the funding to do so.
Raw sewage discharge at Golden Bay beach estuary goes undetected for six weeks stuff.co.nz - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from stuff.co.nz Daily Mail and Mail on Sunday newspapers.