Effects of light, temperature and ground water level on the CO2 flux of the sediment in the high water temperature seasons at the artificial north salt marsh of Osaka Nanko bird sanctuary, Japan.

Field investigations and indoor experiment were carried out to clarify the effect of temperature and chlorophyll a concentration of the sediment, photon flux density, and ground water level on the absorption and emission of CO 2 from the surface sediment of the artificial salt marsh. The flux of CO 2 absorption was closely related to sediment temperature, chlorophyll a and photon flux density. On the other hand, flux of CO 2 emission changed depending on the sediment temperature and ground water level. The ground water level was thought to be indispensable for estimating CO 2 emission from the sediment of the intertidal zone of the salt marsh. Using equations of CO 2 flux with sediment temperature, chlorophyll a, photon flux density and ground water level, the total CO 2 absorption and emission of the artificial north salt marsh of Osaka Nanko bird sanctuary was estimated as ca. 23 tons (4.3 g CO 2 m −2 day −1 ) for absorption and ca.14 tons (2.6 g CO 2 m −2 day −1 ) for emission in May to September 2014. These results suggest that a net of 9 tons of CO 2 (1.7 g CO 2 m −2 day −1 ) was absorbed, and that this salt marsh performs the function of a CO 2 sink in high temperature seasons. [ABSTRACT FROM AUTHOR]