Previous Year Question

A Wetland is an important Ecosystem in which land remains permanently or seasonally saturated with water or submerged. It includes Marshes, shallow lake areas, Floodplains, Mangroves, and other waterlogged regions. Wetlands play an important role in nutrient recycling, absorption of heavy metals, and improving water quality by trapping sediments. For this reason, they are also known as Natural Water Purifiers.

Nutrient Recovery and Cycling is an important function of wetlands. Microorganisms and vegetation present in wetlands help in the absorption, storage, and transformation of nutrients such as Nitrogen and Phosphorus. Decomposition of dead organic matter makes nutrients available again within the ecosystem. Additionally, microbial processes such as Nitrification and Denitrification play significant roles in the Nitrogen Cycle.

Aquatic plants present in wetlands can absorb certain Heavy Metals from contaminated water through Phytoremediation. For example, plants such as Water Hyacinth, Duckweed, and Azolla accumulate certain metals in their roots and tissues. Additionally, wetland soils and sediments can immobilize metals through processes such as Adsorption and Precipitation. Heavy metals are generally not destroyed but are transferred from water and accumulated in plants or sediments.

Wetlands also reduce the accumulation of silt in rivers and reservoirs through Sediment Trapping. When flowing water enters a wetland, vegetation reduces its velocity, allowing particles of soil, sand, and silt to settle. This can reduce Siltation and sediment-associated pollutants in downstream water bodies. Wetlands also contribute to flood control, Groundwater Recharge, and biodiversity conservation.