Characterizing nutrient dynamics with relation to changes in partial pressure of CO2 in a tropical sewage-fed aquaculture pond situated in a Ramsar wetland

The changes in nutrient dynamics (nitrate, ammonium, silicate, phosphate and iron concentration) vis-a-vis partial pressure of CO2 in water [pCO(2)(water)] from tropical sewage-fed aquaculture ponds (East Kolkota Wetlands, India) were analysed by means of a microcosm. A significant relationship between these nutrient's removal from the system and reduction in pCO(2)(water) was observed (with few exceptions). These water bodies acted as significant sources of CO2 in pre-monsoon and monsoon seasons despite having substantial quantity of chlorophyll-a to make it a net autotrophic system. The study revealed that if conditions favourable for optimum photosynthesis can be maintained in these ponds, the CO2 source character of these ponds can be reversed. In the post-monsoon season, when the pH of the water column was high, the system acted as sink for CO2 which suggests the use of lime to prevent these systems from becoming hypereutrophic and carbon source at the same time.