How do grasslands contribute to water quality?

Grasslands play a significant role in enhancing water quality primarily through their ability to filter runoff and prevent erosion. The root systems of grassland plants are extensive and help to stabilize the soil. This soil stabilization is crucial because it reduces the velocity of surface water flow, allowing sediments and potential pollutants to be trapped before they can enter waterways.

As runoff passes through a grassland ecosystem, the vegetation acts as a natural filter, absorbing nutrients and contaminants, while also promoting water infiltration into the soil. This process helps maintain cleaner water in nearby lakes, rivers, and aquifers, limiting the chance of harmful algal blooms and maintaining the health of aquatic ecosystems.

In contrast, the other options provide perspectives that do not align with the positive impact of grasslands on water quality. Increasing water temperature can have detrimental effects on aquatic life, nutrient overload, while significant in other contexts, typically results from agriculture rather than functioning grasslands, and flooding relates to water management issues that are not directly influenced by the presence of grasslands in the ecosystem. Therefore, the primary function of grasslands as natural filters makes them vital for improving water quality by managing runoff effectively.