MECHANISM OF CLIMATE CHANGE MITIGATION IN MANGROVE-SEAGRASS COUPLED ECOSYSTEM -MATHEMATICAL MODEL ANALYSIS-

Abstract

 Mangroves and seagrass have the potential of high climate change mitigation capacity. This capacity is governed by a series of processes: absorption of atmospheric CO₂, fixation of absorbed carbon by biological production, and storage of fixed carbon in deep sediments, however, our knowledge concerned with these processes is still far from complete. In this study, in order to clarify the mechanisms and the controlling factors of these processes, we developed a mangrove-seagrass coupled ecosystem model that comprehensively incorporates biochemical and physics processes in both the pelagic and benthic systems, and applied it to the Yutsun area, Iriomote Island, Okinawa Prefecture, where mangroves and seagrass ecosystem are found. As a result of the analysis, the main factors of carbon fixation were net primary production of mangroves and seagrasses and shell formation of benthic faunas. Mangroves also promoted the absorption of CO₂ from the atmosphere, storing 72% of the absorbed carbon and discharging 28% to offshore. On the other hand, seagrasses suppressed the release of CO₂ to the atmosphere and took in carbon from offshore, of which 62% of the carbon stored by seagrasses was from offshore.