deep-sea sediments (>1000 m) are often considered to be the ultimate sink for black carbon (bc), and the long-term buried bc in these sediments is believed to potentially provide a negative feedback effect on climate warming. the burial flux of bc in marine sediments is predominantly estimated based on soot bc (sbc) in most studies, frequently ignoring the contribution of char bc (cbc). while this methodology may result in an underestimation of the bc burial flux, the precise extent of this underestimation is yet to be determined.