Microbial Biodiversity

Microbial Diversity is an integral part of wetland biodiversity which includes bacteria, archaea, fungi, algae, protozoa and protists. East Kolkata Wetland shows an immense diversity of flora and fauna not only at the micro level but at the macro level also. Microbial richness of a region is its unseen asset that needs to be explored and conserved. Soil samples collected from EKW shows the presence of various new strains of microbes which are not only ecologically important, but also have commercial value. These include Actinobacteria, which are responsible for the degradation of nitrophenol, nitroaromatic compounds, pesticides and herbicides; Proteobacteria related to the bioremediation of heavy metals, degradation and recycling of woody tissues of plants, oil contaminated soil and toxic compounds and nitrogen fixation along with the cyanobacters playing important roles in metal accumulation, oil degradation, antimicrobial compound production, enzyme production etc.

Flora
The EKW thrives with flora with over 100 plant species being identified.

Several kinds of water hyacinths grow across these wetlands. Local farmers and fisher folk use water hyacinth to create a buffer between land and water to minimize erosion.

The area is also home to a large numbers of coconut and betel nut trees. Many varieties of vegetables are farmed here, including cauliflower, eggplant, pumpkin, sunflower and sacred basil. Tracts of land are dedicated to paddy cultivation as well.


Fauna

Numerous species of fish are farmed in the sewage fed ponds called bheris in these wetlands. These include silver carp, tilapia, The area is also home to marsh mongoose and small Indian mongoose. Palm Civet and Small Indian Civet are significant in and around the Wetlands. Approximately 20 mammals are reported from this region, including variety of Snakes.

Fishing in the early morning

Gradual Building of the Wetlands

Kolkata grew to be a large urban and trade centre virtually without any proper sewerage and solid waste management system causing frequent drainage congestion, resulting in health impacts. A committee established to look into alternate solutions to the drainage problems, recommended transferring all wastes to salt lakes, as the city had a natural eastwards elevation. The wetlands were nearly 8.5 feet below the highest point of the city. This recommendation prompted construction of a series of sewers and pumping stations towards the salt lakes. In 1864, a portion of the salt lakes was acquired for dumping solid waste. The first attempt to fresh-water aquaculture was in 1918. Subsequently, construction of waste water channels in the city, increased access to waste-water, which in turn encouraged others to adopt waste-water aquaculture. This served as the foundation behind the building of the wetlands.

                  Pumping stations transfer sewage from Kolkata city to EKW

The solid waste dumping area on the western periphery of the wetlands were converted to horticulture since 1876. The whole area has come to be recognized officially as Waste Recycling Region.

Garbage farming

East Calcutta Wetlands – Location and Area

The East Calcutta Wetlands, also known as the East Kolkata Wetlands (EKW) (22 0 27’ N 88 0 27’ E), are a complex of natural and human-made wetlands lying east of the city of Calcutta (Kolkata), West Bengal in India. These wetlands from a part of the extensive inter-distributory wetland regions formed by the Gangetic Delta. They play an integral part in India’s vegetation and serve as a storehouse of many important resources.

The wetlands cover 125 square kilometers and include salt marshes and salt meadows, as well as sewage farms and settling ponds.

The map above shows the distribution of various types of vegetation across the wetland.

          The wastewater distributaries

Features of Wetland
EKW sustains the world's largest and perhaps oldest integrated resource recovery practice based on a combination of agriculture and aquaculture and provides livelihood support to a large, economically underprivileged and deprived population of around 20,000 families which depend upon the various wetland products, primarily fish and vegetables for their daily sustenance.

The wetland system currently produces over 15,000 MT of fish per annum from its 264 functioning aquaculture ponds, locally called ‘Bheries’. Additionally, nearly 150 MT of vegetables are produced daily by subsistence farmers. EKW serves as the backbone of food security of Kolkata City. It will not be incorrect to say that the vibrant bustling city of Kolkata would not have been what it is without the EKW.

The wetlands are used to treat Kolkata's sewage, and the nutrients contained in the waste water sustain fish farms and agriculture.

EKW forms the basis of food security of Kolkata

Dhapa produces 150 MT vegetable daily

Other than food security, EKW maintain a positive balance in nature as many of it’s places (like DHAPA) serve as the hub of recycling plants in Kolkata.

Co-recycling in Dhapa

Here we see the mechanism behind the substantial production of fish which plays such an integral part of the metropolitan city of Kolkata.

Fishery effluent to paddy field

Wetlands International – South Asia

WISA is the South Asia Programme of Wetlands International, a global organization dedicated to conservation and wise use of wetlands. Its ultimate mission is to sustain and restore wetlands, their resources and biodiversity for future generations. WISA provides scientific and technical support to national governments, wetland authorities, non government organizations, and the private sector for wetland management planning and implementation in South Asia region. It is registered as a non government organization under the Societies Registration Act and steered by eminent conservation planners and wetland experts.

What are Wetlands

A patch of land that develops pools of water after a rain storm would not be considered a "wetland," even though the land is wet. Wetlands have unique characteristics: they are generally distinguished from other water bodies or landforms based on their water level and on the types of plants that live within them. Specifically, wetlands are characterized as having a water table that stands at or near the land surface for a long enough period each year to support aquatic plants.

Wetlands are described as ecotones, providing a transition between dry land and water bodies.

A wetland is "an ecosystem that arises when inundation by water produces soils dominated by anaerobic processes, which, in turn, forces the biota, particularly rooted plants, to adapt to flooding."

There are four main kinds of wetlands -- marsh, swamp, bog and fen (bogs and fens both being types of mires). Some experts also recognize wet meadows and aquatic ecosystems as additional wetland types.