Urban wetlands – co2 sink or source? A case study on the aquaculture ponds of east kolkata wetlands

Research Article
Protusha Biswas., Tania Bhattacharya., Abhra Chanda., Sourav Das and Sugata Hazra
East Kolkata Wetlands, Aquaculture ponds, air-water CO2 flux, CO2 source

East Kolkata Wetland (EKW) is an urban or peri-urban wetland located on the outskirts of the Kolkata City which performs multi-facet activities, carbon sink being one of them. The raw waste from the city is naturally treated in this wetland system, however, the aquaculture ponds situated in these wetlands which make use of this waste water for fishery is rarely studied. The present study aims to see whether the aquaculture ponds of EKW complex are acting as a source or a sink. Airwater carbon dioxide (CO2) flux was estimated for three consecutive seasons in a year and it was found that the system is acting as a CO2 source in all the three seasons. The average CO2 flux was 4184 µmol m-2 h-1 , 2897 µmol m-2 h-1 and 438 µmol m-2 h-1 during pre-monsoon, monsoon and postmonsoon season respectively. Effective treatment of sewage water and avoiding widespread eutrophication could lead to lowering of CO2 effluxes or may turn it to a sink as well.