I. Aquatic Ecosystems

Aquatic ecosystems are plant–animal communities occurring in water bodies.

Classification (by salinity):

• Freshwater (<5 ppt)
  • Lentic: ponds, lakes, bogs, swamps
  • Lotic: rivers, streams, springs
• Brackish (5–35 ppt)
  • Estuaries, mangroves, salt marshes
• Marine (≥35 ppt)
  • Seas, oceans, coral reefs

II. Wetland Ecosystem

• Wetlands are marshy or peatland areas with static or flowing water, fresh/brackish/saline, including marine waters up to 6 m depth at low tide.
• Act as ecotones (transition zones) between terrestrial and aquatic ecosystems.

Examples:

• Mangroves
• Floodplains
• Lake littorals
• Marshes and swamps

Key Characteristics:

• Periodic flooding or waterlogging
• Hydrophytes (water-adapted plants)
• Hydric soils (oxygen-deficient)

III. Wetlands in India

• Over 27,000 wetlands
  • ~23,000 inland
  • ~4,000 coastal
• Cover 4% of India’s area
• ~70% under paddy cultivation
• Range from Himalayan high-altitude wetlands to coastal lagoons, mangroves, and coral reefs

IV. Wetlands vs Lakes

 

Feature	Lake	Wetland
Depth	Usually >3 m	Usually <3 m
Dominant producers	Phytoplankton	Macrophytes
Productivity	Low	High
Trophic status	Oligotrophic	Mostly eutrophic
Flood control	Limited	Significant
Food chain	Grazing	Detritus
Vegetation	Sparse	Abundant

V. Importance of Wetlands

• Flood mitigation and shoreline protection
• Groundwater recharge
• Water purification & nutrient recycling
• Biodiversity hotspots (migratory birds, fish)
• Climate regulation
• Genetic reservoirs (e.g. rice)
• Support eco-tourism and livelihoods

VI. Causes of Wetland Degradation

• Industrial & domestic pollution
• Agricultural runoff (eutrophication)
• Encroachment & land conversion
• Overfishing & aquaculture
• Invasive species (water hyacinth)
• Sand mining & deforestation

VII. Measures to Protect Wetlands

• Scientific demarcation & legal enforcement
• Treatment of effluents before discharge
• Control of invasive species
• Sustainable aquaculture
• Afforestation & soil conservation
• Community participation
• Eco-tourism with safeguards

National Wetlands Conservation Programme (NWCP)

• Launched: 1985–86
• Nodal Ministry: MoEFCC
• Wetlands identified: 115 (national importance)
• Criteria: Same as Ramsar Convention
• Centre: Coordination, funding, guidelines
• States/UTs: On-ground management

Objectives:

• Prevent degradation
• Ensure wise use
• Wetland inventory preparation
• Monitoring & evaluation

Ramsar Convention on Wetlands

• Signed: 2 February 1971, Ramsar (Iran)
• World Wetlands Day: 2 February
• Parties: 170
• Core principle: Wise Use
  • Maintenance of ecological character within sustainable development

Ramsar Site:

• Wetland of international importance
• Government commitment to conservation

Montreux Record

• Register of Ramsar sites facing ecological threats
• Due to pollution, development, and human interference

Wetlands International

• Global NGO (not intergovernmental)
• Works on research, advocacy, policy support & field action