Abstract:
This study investigated the dynamics of CO
2 and CH
4 emission fluxes in Jurong Reservoir based on field measurements for two years. Results show that the concentrations and fluxes of CO
2 and CH
4 showed obvious spatial variations in this reservoir. The annual average CO
2 concentration and emission flux at the inlet point A was (108.57±14.27) μmol·L
-1 and (210.55±36.58) mmol·m
-2·d
-1, respectively, and at the inlet point B was (162.74±17.86) μmol·L
-1 and (338.74±47.25) mmol·m
-2·d
-1, respectively, which were significantly higher than those at the outlet point (28.04±3.53) μmol·L
-1 and (10.05±4.04) mmol·m
-2·d
-1, respectively. The annual average CH
4 concentration and emission flux at the inlet point B (747.05±190.63) nmol·L
-1 and (1.84±0.46) mmol·m
-2·d
-1, respectively, were significantly higher than those at the outlet point (115.75±15.75) nmol·L
-1 and (0.11±0.02) mmol·m
-2·d
-1, respectively. Similarly, there were obvious seasonal variations in CO
2 and CH
4 concentrations and fluxes in the Jurong Reservoir. The concentrations and emission fluxes of both CO
2 and CH
4 showed a pattern of high in warm season and low in cold season, which were influenced by water temperature, dissolved oxygen concentration and precipitation. The input of exogenous nitrogen also participated in affecting the spatial variations of CO
2 and CH
4 concentrations and fluxes. Overall, the agricultural small watershed Jurong Reservoir is an emission source of atmospheric CO
2 and CH
4, and the carbon emission flux of this reservoir is higher than the average values of domestic reservoirs.