What regulates net carbon uptake in coastal ecosystems?

Coastal ecosystems are hotspots of biological activity and carbon storage, accounting for a disproportionately high level of carbon burial relative to their land area. However, they are undergoing rapid land-use change due to increasing population pressure, with about 1 billion people living within 10 km of the coast globally in 2018 (Cosby et al. 2024). When coastal wetlands are converted to croplands, they can switch from CO2 sinks to sources owing to factors like increased decomposition of soil carbon by microbes (Tan et al. 2020). Moreover, coastal regions are vulnerable to threats from climate change such as flooding, saltwater intrusion, and erosion.