Distribution of total organic carbon(TOC),total nitrogen(TN),stable isotope ratio of organic carbon and nitrogen(δ13 C andδ15 N)in 31 surface sediments were examined to quantitatively discriminate the source and bur...Distribution of total organic carbon(TOC),total nitrogen(TN),stable isotope ratio of organic carbon and nitrogen(δ13 C andδ15 N)in 31 surface sediments were examined to quantitatively discriminate the source and burial of sedimentary organic matter(SOM)in the East China Sea(ECS).Results show that high content of TOC and TN occurred in the southern inner shelf and the northeast area due to the transport of organic matter(OM)from the Changjiang(Yangtze)River southwards by the Zhejiang Fujian Coastal Current(ZFCC)and the delivery from the old Huanghe(Yellow)River estuary by the Subei Coastal Current(SbCC),respectively.The signifi cant relationship of TOC to clay provided evidence that the fi ne-grained sediment was the primary carrier for SOM from the inner shelf to open sea.The TN varied proportionally to the TOC with the neglected intercept,suggesting that most of nitrogen measured was related to the SOM and the infl uence of the sorption of inorganic nitrogen was insignifi cant.The seaward enrichment ofδ13 C and seaward depletion of C/N andδ15 N illustrated the decrease of terrestrial OM(TOM)and the increase of marine OM(MOM).The close of average C/N ratio to the Redfi eld ratio indicated the minor role of terrestrial plant debris in the SOM.Distribution of bulk OM properties was ascribed to the terrestrial and marine input by the shelf circulation and phytoplankton with the contributions of 76.1%MOM and 23.9%TOM to SOM,respectively.The burial fl ux of OC ranged within 0.34–7.56 mg/(cm 2∙a)(averaged 2.80 mg/(cm 2∙a))and enriched along the shore and in the fi ne-grained area,manifesting the signifi cant input of the land-based sources and the eff ect of shelf mud depositional process on the fate of SOM.The sharp seaward decrease of burial fl uxes of terrestrial and marine OC gave evidences that the majority of organic carbon were settled in the inner shelf with the small fraction of them further transported eastwards.展开更多
Microbial carbon fixation is a paramount process in the ocean especially below the photic zone both in water and sedimentary ecosystems. Autotrophic microbes that fix carbon dioxide are renowned. However, the question...Microbial carbon fixation is a paramount process in the ocean especially below the photic zone both in water and sedimentary ecosystems. Autotrophic microbes that fix carbon dioxide are renowned. However, the question whether heterotrophs can also fix carbon is intriguing. Ten heterotrophically grown, identified bacterial isolates from the Sino-Pacific marine sediments were tested for autotrophic uptake potential with and without addition of electron donors. Nine of the ten isolates showed carbon uptake capacity without addition of any substrate at very low rates in the order of 10^(-8) to 10^(-4) fmol/(cell·h). The addition of manganese and ammonium at 1 mmol/L final concentration enhanced the uptake potential. Addition of 1 mmol/L final concentrations of reduced iron(10^(-6) to10^(-5) fmol/(cell·h) and sulfide(10^(-5) fmol/(cell·h) decreased the uptake potential significantly at p〈0.1. Bacterial tolerance to formaldehyde suggested propensities of anaplerotic chemical reactions that form metabolic intermediates of C-1 metabolism pathways. The isolates displayed high metabolic flexibility. With the changes in electron donors, the isolates metabolically toggled between relatively anoxic reductive iron/sulfur cycles and the oxidative cycles of manganese/ammonium and vice-versa. This property makes these microbes successful survivors in the highly dynamic Sino-Pacific sediments.展开更多
To synthetically realize the character of major-element compositions as well as its significance for provenance and paleoenvironment recorded in core sediments of the West Philippine Sea over the last 700 ka,grain siz...To synthetically realize the character of major-element compositions as well as its significance for provenance and paleoenvironment recorded in core sediments of the West Philippine Sea over the last 700 ka,grain size and major elements of 221 bulk sediments,together with major-element compositions in the detrital phase of 16 typical samples,in core MD06-3047 collected from the Benham Rise were analyzed.Both discrimination plot and R-mode factor analysis indicate that vertical changes of major elements are mainly controlled by the sedimentation of nearby volcanic matter and the eolian dust input,whereas influences from marine biologic deposition and hydrothermal activity are minor.In particular,Al2O3 and K2O are representative of an eolian dust factor.The variation in the eolian dust factor score is characterized by the obviously glacial-interglacial periodicity and can be well compared with the paleotemperature record of the Antarctic ice core and the evolution of the East Asian winter monsoon(EAWM) recorded in the Chinese loess sequence,and then offers a new proxy for the evolution history of eolian dust input into the study area that is controlled by the EAWM intensity and aridity in the continental source regions of atmospheric dust.展开更多
Two sediment cores, MD06-3050 and MD06-3047, were analyzed to study the Quaternary calcareous nannofossil and microtektite records. We dated bioevents and the microtektite impact event by calibrating with oxygen isoto...Two sediment cores, MD06-3050 and MD06-3047, were analyzed to study the Quaternary calcareous nannofossil and microtektite records. We dated bioevents and the microtektite impact event by calibrating with oxygen isotope stratigraphy. Seven calcareous nannofossil bioevents were identified over the past 2.36 Ma including the last appearance of data for Discoaster brouweri, Calcidiscus macintyrei, large Gephyrocapsa and Pseudoemiliania lacunosa, the first appearance of data for large Gephyrocapsa and Emiliania huxleyi, and the abrupt increase in the abundance of Gephyrocapsa caribbeanica. In addition, we fortunately observed that Australasian microtektites were distributed in core MD06-3050 from 1340 to 1374 cm.展开更多
基金Supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB42030100)the National Special Project“Global Change and Atmosphere-ocean Interactions”(No.GASI-GEOGE-04)+1 种基金the National Natural Science Foundation of China(Nos.41830539,41576054,41976202,41576064)the Open Fund of CAS Key Laboratory of Marine Geology and Environment,Institute of Oceanology,Chinese Academy of Sciences,and the Open Fund Project of the Key Laboratory of Marine Sedimentology and Environmental Geology,Ministry of Natural Resources(No.MASEG201901)。
文摘Distribution of total organic carbon(TOC),total nitrogen(TN),stable isotope ratio of organic carbon and nitrogen(δ13 C andδ15 N)in 31 surface sediments were examined to quantitatively discriminate the source and burial of sedimentary organic matter(SOM)in the East China Sea(ECS).Results show that high content of TOC and TN occurred in the southern inner shelf and the northeast area due to the transport of organic matter(OM)from the Changjiang(Yangtze)River southwards by the Zhejiang Fujian Coastal Current(ZFCC)and the delivery from the old Huanghe(Yellow)River estuary by the Subei Coastal Current(SbCC),respectively.The signifi cant relationship of TOC to clay provided evidence that the fi ne-grained sediment was the primary carrier for SOM from the inner shelf to open sea.The TN varied proportionally to the TOC with the neglected intercept,suggesting that most of nitrogen measured was related to the SOM and the infl uence of the sorption of inorganic nitrogen was insignifi cant.The seaward enrichment ofδ13 C and seaward depletion of C/N andδ15 N illustrated the decrease of terrestrial OM(TOM)and the increase of marine OM(MOM).The close of average C/N ratio to the Redfi eld ratio indicated the minor role of terrestrial plant debris in the SOM.Distribution of bulk OM properties was ascribed to the terrestrial and marine input by the shelf circulation and phytoplankton with the contributions of 76.1%MOM and 23.9%TOM to SOM,respectively.The burial fl ux of OC ranged within 0.34–7.56 mg/(cm 2∙a)(averaged 2.80 mg/(cm 2∙a))and enriched along the shore and in the fi ne-grained area,manifesting the signifi cant input of the land-based sources and the eff ect of shelf mud depositional process on the fate of SOM.The sharp seaward decrease of burial fl uxes of terrestrial and marine OC gave evidences that the majority of organic carbon were settled in the inner shelf with the small fraction of them further transported eastwards.
基金The National Natural Science Foundation of China under contract Nos 41406062 and 41250110530the Chinese Academy of Science Fellowship for Young Foreign Scientists under contract No.2012Y1ZA0005
文摘Microbial carbon fixation is a paramount process in the ocean especially below the photic zone both in water and sedimentary ecosystems. Autotrophic microbes that fix carbon dioxide are renowned. However, the question whether heterotrophs can also fix carbon is intriguing. Ten heterotrophically grown, identified bacterial isolates from the Sino-Pacific marine sediments were tested for autotrophic uptake potential with and without addition of electron donors. Nine of the ten isolates showed carbon uptake capacity without addition of any substrate at very low rates in the order of 10^(-8) to 10^(-4) fmol/(cell·h). The addition of manganese and ammonium at 1 mmol/L final concentration enhanced the uptake potential. Addition of 1 mmol/L final concentrations of reduced iron(10^(-6) to10^(-5) fmol/(cell·h) and sulfide(10^(-5) fmol/(cell·h) decreased the uptake potential significantly at p〈0.1. Bacterial tolerance to formaldehyde suggested propensities of anaplerotic chemical reactions that form metabolic intermediates of C-1 metabolism pathways. The isolates displayed high metabolic flexibility. With the changes in electron donors, the isolates metabolically toggled between relatively anoxic reductive iron/sulfur cycles and the oxidative cycles of manganese/ammonium and vice-versa. This property makes these microbes successful survivors in the highly dynamic Sino-Pacific sediments.
基金supported by the Public Science and Technology Research Funds Projects of Ocean,State Oceanic Administration of the People's Republic of China(201005003)the Open Fund of the KLMGE,IO,CAS,the National Natural Science Foundation of China(41106043 and 41230959)+1 种基金the National Basic Research Program of China(2007CB815903)the Innovative Program of the Chinese Academy of Sciences(KZCX2-YW-221)
文摘To synthetically realize the character of major-element compositions as well as its significance for provenance and paleoenvironment recorded in core sediments of the West Philippine Sea over the last 700 ka,grain size and major elements of 221 bulk sediments,together with major-element compositions in the detrital phase of 16 typical samples,in core MD06-3047 collected from the Benham Rise were analyzed.Both discrimination plot and R-mode factor analysis indicate that vertical changes of major elements are mainly controlled by the sedimentation of nearby volcanic matter and the eolian dust input,whereas influences from marine biologic deposition and hydrothermal activity are minor.In particular,Al2O3 and K2O are representative of an eolian dust factor.The variation in the eolian dust factor score is characterized by the obviously glacial-interglacial periodicity and can be well compared with the paleotemperature record of the Antarctic ice core and the evolution of the East Asian winter monsoon(EAWM) recorded in the Chinese loess sequence,and then offers a new proxy for the evolution history of eolian dust input into the study area that is controlled by the EAWM intensity and aridity in the continental source regions of atmospheric dust.
基金supported by the Pilot Project of the National Knowledge Innovation Program of the Chinese Academy of Sciences (KZCX2-YW-221)the National Natural Science Foundation of China (40906030,40976026and40906038)the National Basic Research Program of China (2007CB815903)
文摘Two sediment cores, MD06-3050 and MD06-3047, were analyzed to study the Quaternary calcareous nannofossil and microtektite records. We dated bioevents and the microtektite impact event by calibrating with oxygen isotope stratigraphy. Seven calcareous nannofossil bioevents were identified over the past 2.36 Ma including the last appearance of data for Discoaster brouweri, Calcidiscus macintyrei, large Gephyrocapsa and Pseudoemiliania lacunosa, the first appearance of data for large Gephyrocapsa and Emiliania huxleyi, and the abrupt increase in the abundance of Gephyrocapsa caribbeanica. In addition, we fortunately observed that Australasian microtektites were distributed in core MD06-3050 from 1340 to 1374 cm.