Chapter 10 - Carbon storage and mineralization in coastal wetlands

Abstract

This synthesis and conclusion chapter aims to compare the processes and drivers of carbon mineralization in different coastal wetlands and provide recommendations on “blue carbon management” in relation to greenhouse gas (GHG) emission and/or litter decomposition of different coast wetlands. Ecosystem carbon stocks in coastal wetlands almost double those of boreal, temperate, and tropical terrestrial ecosystems. Coastal wetlands are net carbon sinks as indicated by net ecosystem exchange (NEE) (output-input) ranging from −589.3 to −122.3g C m−2yr−1. We reiterate that coastal wetlands play a disproportionately important role in ameliorating climate change. Carbon use (i.e., ecosystem respiration/gross primary production) is higher in tree-dominated mangroves (0.7) than herb-dominated seagrasses (0.85) and tidal marshes (0.93). Carbon mineralization will partly counteract the potential of coastal wetlands for mitigating climate change. We synthesize knowledge on how carbon mineralization in coastal wetlands may be affected by climate change and anthropogenic activities. This knowledge will enhance understanding on the vulnerability of carbon stocks to negative global environmental changes and facilitate carbon management by reducing carbon emissions. We highlight the lessons learnt from past and current management of coastal wetland carbon budgets, to inform future research and management initiatives and practices.