Harnessing Chara globularis: Sustainable biomass harvest for water quality management and organic fertilizer production in Lake Titicaca

Chara globularis, a submerged macroalga dominant in high-Andean lakes, generates controversial effects on freshwater ecosystems. Although its dense coverage alters water chemistry and reduces biodiversity, its abundant biomass offers an opportunity for sustainable use. This study assessed its seasonal dynamics, ecological impact, and productive potential in Lake Titicaca (Puno, Peru), from February to July 2024. In zones with and without Chara, a maximum biomass of 705,600 kg/ha and an average of 24,800 kg/ha across 43,600 ha were recorded, totaling over 1.08 million tons. Strong positive correlations were found with pH (r = 0.91) and electrical conductivity, along with a reduction in dissolved oxygen (3.7 mg/L), indicating potential hypoxia. The richness of macroinvertebrates and macroalgae was lower in Chara-dominated areas, reflecting ecological homogenization. However, its nutrient profile revealed high levels of potassium, phosphorus, nitrogen, and organic matter, supporting its use in compost production. A sustainable harvest of 60% (648,768 t) is proposed, as a strategy that combines ecological conservation with circular bioeconomy. Thus, C. globularis emerges as both a management challenge and a renewable resource for organic agriculture and environmental restoration.