How can too much algae duckweed and elodea become a problem?

Excessive growth of algae, duckweed, and elodea can lead to several ecological problems in aquatic environments. These plants can block sunlight from reaching other aquatic life, disrupting photosynthesis and harming fish and other organisms. Additionally, their rapid growth can deplete oxygen levels in the water, especially when they die and decompose, leading to hypoxic conditions that can suffocate aquatic species. This overgrowth can also result in imbalances in nutrient cycles, promoting further algal blooms and negatively affecting water quality.