Sedimentary organic carbon oxidation and benthic nutrient flux in the continental shelf of the southern Yellow Sea

Abstract

We investigated the total oxygen uptake ( sulfate reduction rate ( and benthic nutrient flux at the Yellow Sea cold water mass zone (N 3509 and N 3507 and the coastal area (N 3503 in the southern Yellow Sea The bottom water temperature and the organic carbon ( content of surface sediment measured at N 3503 16 0 C and 0 88 were the highest, followed by N 3509 10 0 C and 0 82 and N 3507 8 96 C and 0 22 The TOU and SRR at N 3503 were 24 5 4 99 O 2 mmol m 2 d 1 and 6 49 mmol S m 2 d 1 3 6 times higher than the values measured at N 3509 and N 3507 5 47 0 25 and 4 21 0 35 O 2 mmol m 2 d 1 and 0 94 and 0 69 mmol S m 2 d 1 respectively) The in situ benthic fluxes of nutrients 3 17 mmol N m 2 d 1 0 48 mmol P m 2 d 1 3 84 mmol Si m 2 d 1 at N 3503 were, respectively, 9 and 3 37 times higher than those measured at N 3509 The benthic nutrient flux ( at N 3503 accounted for 72 179 of the nutrients required for primary production ( By contrast, BNF contributed less than 30 for the N, P, and Si required for PP at N 3509 Our results indicated that the elevated temperature in the coastal area accelerated the OC oxidation in the sediment, thereby promoting the benthic fluxes of nutrients.