Which is a likely consequence of increased sediment in waterways?

Increased sediment in waterways can significantly impact aquatic ecosystems, and one of the most detrimental consequences is the smothering of reefs and spawning beds. This phenomenon occurs when excessive sediment settles on the substrate, covering critical habitats for various marine species. Reefs and spawning beds are essential for the reproduction and survival of fish and other organisms, providing safe environments for eggs and juvenile stages. When these areas become buried under sediment, the delicate balance required for healthy aquatic life is disrupted, leading to declines in fish populations and overall biodiversity.

The other options do not align with the real effects of increased sedimentation. For example, while enhanced aquatic biodiversity or improved commercial fishing yields might seem beneficial, they are not typically outcomes of sediment overload. Likewise, increased sediment generally leads to lowered rather than increased oxygen levels in water, as sediment can create anaerobic conditions. Thus, the correct answer highlights a serious ecological issue linked to sediment pollution.