Comparing the variation and influencing factors of CO emission from subsidence waterbodies under different restoration modes in coal mining area.

Subsidence waterbodies play an important role in carbon cycle in coal mining area. However, little effort has been made to explore the carbon dioxide (CO) release characteristics and influencing factors in subsidence waterbodies, especially under different restoration modes. Here, we measured CO release fluxes (F(CO)) across Anguo wetland (AW), louts pond (LP), fishpond (FP), fishery-floating photovoltaic wetland (FFPV), floating photovoltaic wetland (FPV) in coal mining subsidence area, with unrestored subsidence waterbodies (SW) and unaffected normal Dasha river (DR) as the control area. We sampled each waterbody and tested which physical, chemical, and biological characteristics of water and sediment related to variability in CO. The results indicated that F(CO) exhibited the following patterns: FFPV > FPV > FP > SW > DR > LP > AW. Trophic lake index (TLI) and microbial biomass carbon content (MBC) in sediment had a positive impact on F(CO). The dominant archaea Euryarchaeota and Thaumarchaeota, and dominant bacteria Proteobacteria promoted F(CO). This study can help more accurately quantify CO emissions and guide CO future emission reduction and subsidence waterbodies estoration.