Chapter 1 - Introduction

Abstract

Carbon minerelization is significant to studying the whole carbon cycling dynamics and food webs in coastal wetlands. It reflects the fate of carbon from litter decomposition to greenhouse gas emission but is often less emphasized than carbon storage in the management of coastal wetlands. This chapter presents the basic concepts, the unique characteristics of carbon mineralization, and current state of carbon cycling study in coastal wetlands. There is a lack of global perspective on carbon cycling in coastal wetlands except mangroves. We highlight that deciphering the factors influencing carbon mineralization is significant to determining the evolution of coastal wetlands and enhancing understanding on the future modification of food webs and biodiversity along the coastline. Anthropogenic activities affect carbon mineralization in coastal wetlands through related physico-chemical and biological processes. The types of anthropogenic activities include deforestation, land use change, pollution, human-induce species invasion, changes in consumer control, hydrologic alteration, resources extraction, and breakdown of landward margins. Coastal wetlands confront with climate change, including rising air temperature, precipitation fluctuation, sea level rise, and extreme weather events. They have impact on coastal wetlands through ecosystem conversion and impact on ecosystem function and health, phenology, physiological and metabolic processes, foundation species, and sediment biogeochemistry. A conceptual model of carbon mineralization in coastal wetlands is established with illustration on relevant processes, including ecosystem respiration, greenhouse gas emission from sediment- and water-air interfaces, belowground total carbon balance, as well as related processes, including bioturbation and inorganic carbon. We are motivated to synthesize research on carbon mineralization, counterbalancing the bias toward carbon storage in coastal wetlands. We highlight the necessity of systematic examination on the processes and principles of greenhouse gas production and emissions, as well as the linkage between vascular plant decomposition and greenhouse gas emission.