The dynamics of land-sea-scape carbon flow can reveal anthropogenic destruction and restoration of coastal carbon sequestration

Abstract

Coastal zones are a significant coupling landscape and seascape with large global populations and thus have large concentrations of carbon emissions and potential influences on global environmental changes. However, the impacts of coastal seascape pattern change, on the provision of ecosystem goods and services (e.g. carbon flows) have not been understood fully in the face of rapid human-induced changes. We aim to reveal the dynamics of integrated landscape and seascape (land-sea-scape) carbon flows under the natural and anthropogenic changes, inform coastal spatial planning and restoration, and optimize coastal land-sea-scape pattern. A spatial carbon flow network model of land-sea integration was developed to quantify coastal carbon flows under rapid urbanization. We chose a typical coastal city of Xiamen in China as an example to analyze the dynamics of carbon flows and ecological security pattern during 2000–2015. We found that the total carbon flows between sea and land was 12.78TgCO2 during 2000–2015, and carbon losses due to seascape conversion were 9.76TgCO2. These flows and losses signified the reduction of ecosystem services (carbon sequestration) resilience to further perturbations. Carbon deficit pattern was gradually increased and sprawled out to the forest-farmland landscape and coastal tidal flat seascape, which represent decline of coastal ecosystem security. Our findings indicated total coastal carbon flows were 4 times greater than terrestrial carbon flows, and carbon deficit was mainly distributed along the coastline in Xiamen. These can provide a reference for better governance of sustainable land-sea-scape pattern to enhance seascape ecology and coastal sustainability.