What is a primary consequence of algal blooms in aquatic systems?

The primary consequence of algal blooms in aquatic systems is decreased light penetration. During an algal bloom, the excessive growth of algae leads to a thickening of the water column, which obstructs sunlight from reaching the deeper layers of the water body. This reduction in light penetration can negatively impact aquatic plants and other photosynthetic organisms, as they depend on sunlight for photosynthesis. Consequently, the lack of light can disrupt the entire ecosystem, leading to decreased plant productivity and affecting the organisms that rely on these plants for habitat and food.

In contrast to decreased light penetration, increased biodiversity would typically occur in healthy aquatic environments free from overabundant algae. Improved water clarity is the opposite of what occurs during an algal bloom, as the proliferation of algae makes the water murky. While some algal blooms may lead to oxygen being produced during the day due to photosynthesis, the decomposition of dead algal matter at night can actually lead to decreased oxygen levels in the water, highlighting the complex impacts of algal blooms on aquatic ecosystems.