Why does an increase in phosphate levels cause a decrease in biodiversity?

An increase in phosphate levels, often due to agricultural runoff and wastewater discharge, can lead to eutrophication in aquatic ecosystems. This process stimulates excessive algal blooms, which deplete oxygen levels in the water as they decay, creating hypoxic conditions harmful to many aquatic species. As oxygen levels drop, sensitive species may die off or be unable to thrive, reducing overall biodiversity. Additionally, the dominance of certain algal species can outcompete and displace native organisms, further contributing to biodiversity loss.