Unraveling the GHG emission patterns of inland waters in China: impact of water body types, aquatic plant life forms, and water temperature

Inland water ecosystems play key roles in the production, transportation, transformation, storage, and consumption of global greenhouse gases (GHG). Different water body types exhibit spatial and temporal differences after considering factors such as season and aquatic plant life forms. The results revealed that the annual global warming potential (GWP) (Tg CO₂-eq yr^-1) from swamps, rivers, lakes, and reservoirs in China were 1382.42, 330.41, 266.86 and 150.98, respectively. The GWP from waters covered with emergent macrophytes was 2.02 times and 3.98 times that from submerged plants and floating-leaved (or floating) plants, respectively. Eutrophication significantly intensified the GHG emissions from inland waters. The combined effects of water body type, aquatic plant life form, and water temperature indicated that reservoirs have the highest GWP per unit area at water temperatures between 20 and 30 °C. Notably, the submerged plant zones in lakes have the lowest GWP (4.79 g CO₂-eq m^-2 yr^-1), indicating that water ecological restoration projects focusing on submerged plant restoration will enhance carbon reduction from water bodies. The total annual GWP of inland waters GHG emissions in China ranged from 1806.43 to 2130.67 Tg CO₂-eq yr^-1. Projections under four Shared Socioeconomic Pathways scenarios indicated that the GWP of inland water ecosystems in China will accelerate after 2030. This study enhances the assessment of the role of inland water ecosystems in the global carbon cycle and provides a reference for inland water management to address global climate change.