Sources, variations, and flux of settling particulate organic matter in a subtropical karst reservoir in Southwest China

摘要: Abstract The biological carbon pump (BCP) effect is a key mechanism in karst surface freshwater ecosystems, and can transform inorganic from carbonate weathering into organic via photosynthesis sedimentation. In the process, an understanding of particulate sources, their flux, variability important for BCP effects, but these relative processes are still poorly understood. Therefore, we used sediment trap experiment to collect settling (SPOC) conducted systematic study understand sources factors that influence SPOC, as well determine amount SPOC generated by combing meteorological data monitoring modern hydrochemical Dalongdong (DLD) reservoir, groundwater-fed reservoir. Based on δ13C, δ15N, molar C/N data, models, came algae, resuspened matter, soil, domestic sewage. Among these, resuspension (45.27%) algae (31.57%) were main SPOC. Thus, seasonal variations different mainly affected water movement caused climate changing with respect air temperature rainfall. addition, sewage discharge DLD reservoir also results suggested algal was 17.07 gC/m2/a at 9.26 gC/m2/a bottom process. deposition efficiency (OCDE) 54.25%. Organic source column finally deposited buried sediment. According estimation historical stored through assimilating DIC rock much 10.84 tC/a. quantity fixed cannot be ignored reservoirs.