Improved model calculation of atmospheric CO₂ increment in affecting carbon stock of tropical mangrove forest

Because of the difficulties in setting up arrangements in the intertidal zone for free-air carbon dioxide enrichment experimentation, the responses to increasing atmospheric carbon dioxide in mangrove forests are poorly studied. This study applied box model to overcome this limitation, and the relative changes in present level of reservoirs organic carbon contents in response to the future increase of atmospheric carbon dioxide were examined in the Avicennia-dominated mangrove forest at the land–ocean boundary of the northeast coast of the Bay of Bengal. The above- and below-ground biomass (AGB+BGB) and sediment held different carbon stock (53.20±2.87Mg C ha⁻¹ (mega gram carbon per hectare) versus 18.52±2.77Mg C ha⁻¹). Carbon uptake (0.348mg C m⁻²s⁻¹) is more than offset by losses from plant emission (0.257mg C m⁻²s⁻¹), and litter fall (13.52µg C m⁻²s⁻¹) was more than soil CO₂ and CH₄ emission (8.36 and 1.39µg C m⁻²s⁻¹, respectively). Across inventory plots, Sundarban mangrove forest carbon storage in above- and below-ground live trees and soil increased by 18.89 and 5.94Mg C ha⁻¹ between June 2009 and December 2011. Box model well predicted the dynamics of above- and below-ground biomass and soil organic carbon, and increasing atmospheric carbon dioxide concentrations could be the cause of 1.1- and 1.57-fold increases in carbon storage in live biomass and soil, respectively, across Sundarban mangrove forest rather than recovery from past disturbances.