How do wetlands filter pollutants?

Wetlands play a crucial role in maintaining water quality by effectively filtering pollutants. They achieve this primarily through the process of trapping sediments and absorbing nutrients present in the water.

When water flows into a wetland area, the landscape's natural vegetation and soil structure slow down the water flow, allowing suspended particles and sediments to settle out. This sediment trapping not only reduces turbidity but also captures a variety of pollutants that may be attached to those particles.

Additionally, wetlands can uptake excess nutrients, such as nitrogen and phosphorus, often found in agricultural runoff or urban wastewater. Under the right conditions, plants and microorganisms within the wetland can transform these nutrients into less harmful forms or store them, preventing them from entering larger water bodies and contributing to problems like algal blooms.

The other options, while closely related to ecological functions, do not directly address the primary mechanism by which wetlands filter pollutants. For instance, absorbing carbon dioxide and producing oxygen relate more to the carbon cycle and oxygenation processes rather than pollutant filtration. Preventing flooding, while an important benefit of wetlands, pertains to water management rather than direct pollutant absorption or filtration.