Common stonewort

Common stonewort (Chara vulgaris) is a species of multicellular green algae belonging to the Characeae family. Despite its external resemblance to higher plants, it is a complex algal organism with a structure reminiscent of horsetail shoots. In an agronomic context, it is regarded as a specific biological component often found in shallow reservoirs used for irrigation or aquaculture.

This species has a cosmopolitan distribution and is found on all continents except Antarctica. The plant prefers still or slow-moving freshwater and brackish water habitats. In agriculture, the presence of Chara vulgaris in water bodies can serve as an indicator of water quality, as it is highly sensitive to organic pollution and excess phosphates.

Botanically, common stonewort consists of a thallus made up of a stem-like axis with whorls of branches arising from the nodes. The plant lacks true roots, anchoring itself in muddy or sandy bottoms using rhizoids. The body is often encrusted with calcium carbonate, which gives it a characteristic rigidity and rough texture, earning it the common name "stonewort."

Specific environmental requirements limit its commercial cultivation. It requires water with sufficient calcium content and a neutral or slightly alkaline pH. Unlike traditional crops, it does not require fertilizers; in fact, an excess of nutrients leads to the displacement of Chara by higher aquatic plants or phytoplankton.

The economic value of Chara vulgaris lies in its ability to biologically purify water and create a habitat for fish and beneficial invertebrates. In some regions, it is used as green manure for coastal soils due to its high content of calcium and micronutrients. The plant is also actively studied in phytoremediation as an agent that aids in the sequestration of heavy metals.

• High sensitivity to eutrophication of water bodies.
• Calcium accumulation in cell walls.
• Use as an indicator of water purity.
• Reduction of water turbidity by absorbing suspended particles.