Atmospheric Ozone And Its Biosphere - Atmosphere Exchange In A Mangrove Forest Ecosystem: A Case Study From Sundarbans, NE Coast Of India

Temporal variation of atmospheric O3 and its biosphere – atmosphere exchange were monitored in the Sundarbans mangrove forest from January 2011 to December 2011 on bimonthly basis. O3 mixing ratios at 10 m and 20 m heights over the forest atmosphere ranged between 14.66 ± 1.88 to 37.90 ± 0.91 and 19.32 ± 6.27 to 39.80 ± 10.13 ppbv, respectively; having maximal premonsoon and minimal monsoon periods. Average daytime O3 mixing ratio was 1.69 times higher than nighttime; indicates significant photo chemical production of O3 in forest atmosphere. Annual averaged O3 mixing ratio in 10 m height was 13.2 % lower than 20 m height; induces exchange of O3 across mangrove biosphere – atmosphere interface depending upon micrometeorological conditions of the forest ecosystem. Annual average biosphere – atmosphere O3 exchange flux in this mangrove forest environment was – 0.441 μg m -2 s -1 . Extrapolating the value for entire forest surface area, the mangrove ecosystem acts as a sink of 58.4GgO3 annually, indicating significant contribution of Sundarbans mangroves towards regional atmospheric O3 budget as well as climate change.