The Role of Floodplains in Terrestrial Carbon Cycling

River floodplains are fundamental building blocks of the natural landscape. Globally, floodplains are estimated to cover in excess of 2 million km 2 . As fluvial systems have increasingly been recognized as dynamic components of the terrestrial carbon cycle, the importance of understanding the role of floodplain systems in the fluvial carbon cycle has become clear. This chapter aims to summarise a thorough review of the relevant literatures, to bring together geomorphological and biogeochemical understanding of floodplain systems, to develop a conceptual model of floodplain carbon cycling, and to analyse controls on the variation of floodplain function in time and space. Integrating a biogeochemical approach into the geomorphological analysis of floodplains has the potential to explain the role of these systems in both carbon storage and carbon turnover. Floodplain systems actively cycle carbon under the control of both geomorphological and biological processes.