When dealing with dense algal mats, which approach is recommended?

• A. Break up mats or use high pressure surface applications.
• B. Let mats decay naturally.
• C. Use aerial spraying.
• D. Add more copper.

Answer: (A)

Dense algal mats are tough to treat because their thickness and shading prevent the treatment from reaching all the algae. The recommended approach is to physically break up the mats or use high pressure surface applications. Breaking up mats increases surface area and exposes more of the algae to the product, improving contact and penetration. Using high pressure at the surface helps the herbicide stay on and reach the mat rather than simply washing away or drifting off. This combination gives better control of dense mats while reducing the need for broad, less targeted treatments. Letting mats decay naturally can harm water quality and oxygen levels as they decompose; aerial spraying is unlikely to uniformly affect a thick mat and can cause drift and non-target effects; adding more copper can raise copper concentrations to harmful levels for aquatic life and is not appropriate for dense mats.