What is a human even that can cause an increase in freshwater algae growth?

One significant human event that can lead to increased freshwater algae growth is agricultural runoff, where fertilizers containing high levels of nitrogen and phosphorus are washed into water bodies during rainstorms. This nutrient enrichment promotes algal blooms, which can deplete oxygen levels in the water and harm aquatic ecosystems. Additionally, wastewater discharge and urban runoff can contribute similar nutrient loads, exacerbating the problem. These events highlight the impact of human activities on freshwater ecosystems.