What benefit do wetlands provide in relation to surface water quality?

Wetlands play a crucial role in maintaining and improving surface water quality primarily through their ability to filter pollutants and absorb excess nutrients. This natural filtration process occurs as water flows through wetland vegetation and soil, where sediments and contaminants are trapped. Additionally, wetlands can uptake nutrients like nitrogen and phosphorus, which can otherwise contribute to problems such as algal blooms in downstream waters. By regulating the flow of water and acting as a buffer zone, wetlands mitigate the impact of runoff from agricultural and urban areas, ultimately providing cleaner water that is vital for ecosystem health and human use.

In contrast, the other options do not accurately reflect the positive environmental contributions wetlands provide to surface water quality.