Scientists report initial success in controlling didymo or "rock snot" as it is also known. The tissue paper like algae is causing problems all over the globe and can render a river unfishable if left unchecked.
"Trials by Niwa and Biosecurity New Zealand in the South Island, using a variety of chemical and organic-based solutions, had identified a copper-based formula as the most successful in killing didymo in laboratory conditions.
A 20 milligrams per-litre concentration of the formula successfully killed didymo spores without harming fish. Trials were continuing to discover if it would be effective in larger quantities in a river."
Read the entire article via Protect Your Waters.