Species & plants
Filamentous algae
Also known as: pond scum, string algae
Filamentous algae are colonial single-celled algae that form long stringy filaments visible as bright green mats on the water surface or wrapped around docks and aquatic vegetation. Common genera: Spirogyra, Cladophora, Pithophora. Algae need sunlight, warmth, and dissolved nutrients (phosphorus is usually the limiting factor). The visible mat is the bloom; the underlying problem is nutrient loading. Copper-based algaecides kill the visible mat but the dead biomass releases its phosphorus back into the water and fuels the next bloom — see our filamentous algae post for the full mechanism.
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Related terms
- Copper sulfateA copper-based algaecide that kills filamentous algae and cyanobacteria on contact.
- Phosphorus loadingThe rate of phosphorus inputs to a water body; the limiting nutrient for most freshwater algae blooms.
- EutrophicationThe over-enrichment of a water body with nutrients, leading to chronic algae blooms and oxygen crashes.