TY - JOUR
T1 - The Remineralization of Sedimentary Organic Carbon in Different Sedimentary Regimes of the Yellow and East China Seas
AU - Zhao, Bin
AU - Yao, Peng
AU - Bianchi, Thomas S.
AU - Arellano, Ana
AU - Wang, Xuchen
AU - Yang, Jianbin
AU - Su, Rongguo
AU - Wang, Jinpeng
AU - Xu, Yahong
AU - Huang, Xinying
AU - Chen, Lin
AU - Ye, Jun
AU - Yu, Zhigang
PY - 2018/1/1
Y1 - 2018/1/1
N2 - We investigated the remineralization of sedimentary organic carbon (SOC) at 12 sites in East China Sea mobile-muds (ECSMMs) and South Yellow Sea central mud deposits (SYSMDs) - using a time-sequence sediment incubation experiment. We examined pore-water dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), fluorescent dissolved organic matter (FDOM), dissolved inorganic nitrogen (DIN) nutrients (NH 4 + , NO 3 − , and NO 2 − ), redox sensitive elements (Fe 2+ and Mn 2+ ), and major anions (SO 4 2− and Cl − ) in incubated sediments, to better constrain controlling mechanisms of SOC remineralization under different sedimentary regimes. Lower DIC production rates in SYSMDs (2.36–3.13 mmol m −2 d −1 ) than those in ECSMMs (2.94–13.5 mmol m −2 d −1 ), were mainly attributed to cold bottom water masses and a relatively stable sedimentary environment in SYS. Higher DIC production rates were observed mostly at offshore sites of ECSMMs that had relatively enriched 13 C of SOC - which indicated preferential degradation of labile SOC of marine origin. When compared with tropical mobile-muds, higher bottom-water temperatures, thicker mobile-muds, and large inputs of reactive terrestrial OC resulted in more intense remineralization of SOC in Amazon mobile-muds than in ECSMMs. Lower ratios of DOC/DIC production rates in ECSMMs (0.11–0.72) were likely indicative of efficient transformation of OC, and largely due to sulfate reduction. A rapid increase in marine protein-like FDOM components during the incubation indicated that less stable marine SOC was preferentially converted to DOC - and then to DIC. Our SOC budget indicates that 16.8% of SOC was decomposed in sediments of ECSMMs, but only about 5.4% of SOC was decomposed in SYSMDs, suggesting lower SOC preservation efficiency in mobile-muds than distal muds.
AB - We investigated the remineralization of sedimentary organic carbon (SOC) at 12 sites in East China Sea mobile-muds (ECSMMs) and South Yellow Sea central mud deposits (SYSMDs) - using a time-sequence sediment incubation experiment. We examined pore-water dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), fluorescent dissolved organic matter (FDOM), dissolved inorganic nitrogen (DIN) nutrients (NH 4 + , NO 3 − , and NO 2 − ), redox sensitive elements (Fe 2+ and Mn 2+ ), and major anions (SO 4 2− and Cl − ) in incubated sediments, to better constrain controlling mechanisms of SOC remineralization under different sedimentary regimes. Lower DIC production rates in SYSMDs (2.36–3.13 mmol m −2 d −1 ) than those in ECSMMs (2.94–13.5 mmol m −2 d −1 ), were mainly attributed to cold bottom water masses and a relatively stable sedimentary environment in SYS. Higher DIC production rates were observed mostly at offshore sites of ECSMMs that had relatively enriched 13 C of SOC - which indicated preferential degradation of labile SOC of marine origin. When compared with tropical mobile-muds, higher bottom-water temperatures, thicker mobile-muds, and large inputs of reactive terrestrial OC resulted in more intense remineralization of SOC in Amazon mobile-muds than in ECSMMs. Lower ratios of DOC/DIC production rates in ECSMMs (0.11–0.72) were likely indicative of efficient transformation of OC, and largely due to sulfate reduction. A rapid increase in marine protein-like FDOM components during the incubation indicated that less stable marine SOC was preferentially converted to DOC - and then to DIC. Our SOC budget indicates that 16.8% of SOC was decomposed in sediments of ECSMMs, but only about 5.4% of SOC was decomposed in SYSMDs, suggesting lower SOC preservation efficiency in mobile-muds than distal muds.
KW - Marginal seas
KW - Sedimentary regimes
KW - Pore waters
KW - Sedimentary organic carbon
KW - Remineralization
KW - Yellow and East China Seas
UR - https://digitalcommons.usf.edu/msc_facpub/1443
UR - https://doi.org/10.1016/j.chemgeo.2018.08.012
U2 - 10.1016/j.chemgeo.2018.08.012
DO - 10.1016/j.chemgeo.2018.08.012
M3 - Article
VL - 495
JO - Chemical Geology
JF - Chemical Geology
ER -