METHANE FLUX FROM A SUBTROPICAL RESERVOIR LOCATED IN THE FLOODPLAINS OF RIVER YAMUNA, INDIA
Applied Ecology and Environmental Research
Tropical and subtropical reservoirs are considered to be a strong anthropogenic source of methane (CH 4 ) emissions worldwide due to high temperature, augmented carbon and nutrient loadings. Thus, CH 4 emission estimation from tropical/subtropical reservoirs is critical for preparation of green house gas emission budgets. The Present study estimates CH 4 flux from a subtropical freshwater manmade Okhla reservoir located on the river Yamuna, National Capital Region, India. Results showed that
... la reservoir transformed into a potential CH 4 emission source after flooding as the CH 4 flux increased by 3.81 orders of magnitude with a net contribution of 171.96 mgm -2 d -1 . Enhanced CH 4 flux is primarily attributed to elevated organic and nutrient loadings to reservoir via river's inflow water, high percentage of shallow areas and presence of dense aquatic vegetation mainly Eichhornia crassipes and Typha angustifolia. These aquatic weeds not only facilitate vascular CH 4 transport but also provide substantial amounts of biomass for methanogens to generate CH 4 . Results also revealed that the summer season exhibited significantly higher CH 4 flux (Kruskal-Wallis H-Test; p < 0.05) as compared to monsoon and winter seasons due to prevalence of more favorable water and soil conditions for CH 4 emissions including temperature, redox potential, water depth, dissolved oxygen, biological oxygen demand and plant biomass.