Without proper water quality testing and analysis, it can be difficult to determine the exact causes behind a green pond. The green you’re seeing may be algae. While algae look similar to some aquatic plants, they lack true roots, stems, and leaves, and can be present in one of two forms, or both: microscopic or filamentous.

Planktonic algae are single-cell plants suspended within the water column, usually resulting in a “pea-soup” look. Microscopic algae, specifically cyanobacteria (blue-green algae), are capable of producing toxins, which can be detrimental to human and wildlife health.

Filamentous algae has a “stringy” look and often creates large mats on the water’s surface or along the bottom. Additionally, some common floating green plants can also cover a waterbody’s surface, like watermeal (Wolffia sp.) and duckweed (Lemna sp.)

Excessive pond algae growth is usually the result of an increased nutrient input, such as fertiliser or agricultural runoff; however, other causes are possible. A professional lake or pond manager can help accurately identify the source of the problem and develop an effective management plan. Contact Parklink if you need further help.