南海北部和海南岛附近海域表层沉积物中有机质的分布和降解状态的差异
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摘要
利用气相色谱法对南海北部和海南岛附近海域表层沉积物中正构烷烃(n-alkanes)和脂肪酸进行测定和分析,结合粒径、比表面积(specific surface area,SSA)、有机碳(OC%)、碳稳定同位素(δ~(13)C)等参数研究有机物来源和降解状态,并对其影响因素进行分析。研究结果表明:沉积物主要以粉砂为主,平均粒径分布范围在10.97—517.21μm之间,选取的16个站位的比表面积平均值为8.05m~2/g,最大值是S23站位的24.46m~2/g,最小值是S29站位的1.73m~2/g,OC%含量在0.15—1.18之间,δ~(13)C值为–23.05‰—–21.24‰。沉积物中正构烷烃碳链的分布范围是nC_(14)—nC_(33),低碳数峰群以nC_(16)、nC_(18)为主峰碳且具有偶碳数优势,高碳数峰群以nC_(29)为主峰碳。脂肪酸的碳数分布范围是nC_(14)—nC_(30),低碳数单峰型分布,短链饱和脂肪酸(short chain saturated fatty acids,SCSFA)和单不饱和脂肪酸(monounsaturated fatty acids,MUFA)的含量占总脂肪酸含量的70%以上,长链饱和脂肪酸(long chain saturated fatty acids,LCSFA)的含量不到10%,据此说明这两个区域有机质均以海源输入为主。在有机物保存和降解方面,海南岛附近海域有机质载荷(OC/SSA)和δ~(13)C之间的正相关,表现了良好的陆源和海源的有机物更替,但是珠江口附近海域系列样品却未见相似过程。不仅在物源更替方面,在有机质降解特征上珠江口附近海域中的有机物与海南岛附近海域和南海陆架深水区也有很大的差别。海南岛附近海域和南海陆架深水区有机质的降解符合一般规律,随着水深的增加降解程度逐渐变大,然而珠江口附近海域随着水深的增加有机质却越来越"新鲜"。结合前人对珠江口附近海域黏土矿物组成的研究,本文认为珠江口附近海域沉积物中有机质之所以会出现上述"异常"可能是因为该研究区域黏土矿物对有机质选择性吸附所导致。
The South China Sea receives sediments from multiple sources of adjacent lands and islands and hosts rich in fossil fuel resources. To understand organic carbon(OC) origination, transportation, and degradation in water and sediment, surface sediments were sampled in two maritime regions, i.e., the northern South China Sea along Zhujiang(Pearl) River delta(ZJ) and waters to the east of Hainan Island(HN), two major marine oil-gas productive fields of China. Sedimentological(grain size, specific surface area(SSA)) and geochemical(OC%, δ~(13)C-OC and n-alkanes, fatty acids) studies were performed. Samples were mostly fine-grained sand-silt sediments and showed a tendency of fining away from land. Parameters of OC%(0.15—1.18), δ~(13)C(-23.05‰—-21.24‰) were determined, and molecular biomarkers(n-alkane carbon preference index and types of fatty acids) were measured. Correlation between SSA and OC% was not significant. Correlation between OC load(OC/SSA) and δ~(13)C in HN samples was positive, showing good transition from terrestrial to marine origination from land to ocean, which is normal; however, this phenomenon was not observed in the ZJ samples. We believe that the difference shall be resulted from selective adsorption by clay minerals different in species and fraction between the two sets of samples. ZJ samples are affected by multiple sources from South China continent, Taiwan and Luzon Islands, while that of HN from nearby single Hainan Island.
The South China Sea receives sediments from multiple sources of adjacent lands and islands and hosts rich in fossil fuel resources. To understand organic carbon(OC) origination, transportation, and degradation in water and sediment, surface sediments were sampled in two maritime regions, i.e., the northern South China Sea along Zhujiang(Pearl) River delta(ZJ) and waters to the east of Hainan Island(HN), two major marine oil-gas productive fields of China. Sedimentological(grain size, specific surface area(SSA)) and geochemical(OC%, δ~(13)C-OC and n-alkanes, fatty acids) studies were performed. Samples were mostly fine-grained sand-silt sediments and showed a tendency of fining away from land. Parameters of OC%(0.15—1.18), δ~(13)C(-23.05‰—-21.24‰) were determined, and molecular biomarkers(n-alkane carbon preference index and types of fatty acids) were measured. Correlation between SSA and OC% was not significant. Correlation between OC load(OC/SSA) and δ~(13)C in HN samples was positive, showing good transition from terrestrial to marine origination from land to ocean, which is normal; however, this phenomenon was not observed in the ZJ samples. We believe that the difference shall be resulted from selective adsorption by clay minerals different in species and fraction between the two sets of samples. ZJ samples are affected by multiple sources from South China continent, Taiwan and Luzon Islands, while that of HN from nearby single Hainan Island.
引文
蔡观强,彭学超,张玉兰,2011.南海沉积物物质来源研究的意义及其进展.海洋科学进展,29(1):113-121
马倩倩,魏星,吴莹等,2015.三峡大坝建成后长江河流表层沉积物中有机物组成与分布特征.中国环境科学,35(8):2485-2493
王毅力,芦家娟,周岩梅等,2005.沉积物颗粒表面分形特征的研究.环境科学学报,25(4):457-463
卢龙飞,蔡进功,包于进等,2006.黏土矿物保存海洋沉积有机质研究进展及其碳循环意义.地球科学进展,21(9):931-937
刘志飞,Colin C,黄维等,2007.珠江流域盆地表层沉积物的黏土矿物及其对南海沉积物的贡献.科学通报,52(4):448-456
刘志飞,2010.南海沉积物中的黏土矿物:指示东亚季风演化历史.沉积学报,28(5):1012-1019
孙蕴婕,2011.沉积物中脂类生物标志物的物源示踪及环境演变指示--以海南及中国东部若干入海河流为例.上海:华东师范大学硕士学位论文,41
吴敏,李胜荣,初凤友等,2007.海南岛周边海域表层沉积物中黏土矿物组合及其气候环境意义.矿物岩石,27(2):101-107
何家雄,苏丕波,卢振权等,2015.南海北部琼东南盆地天然气水合物气源及运聚成藏模式预测.天然气工业,35(8):19-29
邵锡斌,吴莹,胡俊等,2014.颗粒态有机物在长江口及其邻近海域的夏季分布和影响因素初析.海洋与湖沼,45(6):1288-1294
经志友,齐义泉,华祖林,2008.南海北部陆架区夏季上升流数值研究.热带海洋学报,27(3):1-8
胡建芳,彭平安,房殿勇等,2001.南海沉积物中C30-C32烷基二醇的检出及可能的古环境信息.地球化学,30(6):569-578
段毅,马兰华,1996.生物标志化合物碳同位素地球化学研究的几个相关问题.地球科学进展,11(4):356-361
葛倩,初凤友,刘敬圃等,2010.南海表层黏土矿物的分布与来源.海洋地质与第四纪地质,30(4):57-66
Bock M J,Mayer L M,2000.Mesodensity organo-clay associations in a near-shore sediment.Marine Geology,163(1-4):65-75
Calvert S E,Fontugne M R,1987.Stable carbon isotopic evidence for the marine origin of the organic matter in the holocene black sea sapropel.Chemical Geology:Isotope Geoscience Section,66(3-4):315-322
Colombo J C,Silverberg N,Gearing J N,1996.Lipid biogeochemistry in the Laurentian Trough:I-fatty acids,sterols and aliphatic hydrocarbons in rapidly settling particles.Organic Geochemistry,25(3-4):211-225
Demaison G J,Moore G T,1980.Anoxic environments and oil source bed genesis.Organic Geochemistry,2(1):9-31
Hedges J I,Keil R G,1995.Sedimentary organic matter preservation:an assessment and speculative synthesis.Marine Chemistry,49(2-3):81-115
Keil R G,Tsamakis E,Giddings J C et al,1998.Biochemical distributions(amino acids,neutral sugars,and lignin phenols)among size-classes of modern marine sediments from the Washington coast.Geochimica et Cosmochimica Acta,62(8):1347-1364
Lin F,Chen M,Tong J L et al,2014.Carbon and nitrogen isotopic composition of particulate organic matter and its biogeochemical implication in the Bering Sea.Acta Oceanologica Sinica,33(12):40-47
Liu Z F,Colin C,Huang W et al,2007.Clay minerals in surface sediments of the Pearl River drainage basin and their contribution to the South China Sea.Chinese Science Bulletin,52(8):1101-1111
Liu Z F,Zhao Y L,Colin C et al,2016.Source-to-sink transport processes of fluvial sediments in the South China Sea.Earth-Science Reviews,153:238-273
Meyers P A,1994.Preservation of elemental and isotopic source identification of sedimentary organic matter.Chemical Geology,114(3-4):289-302
Premuzic E T,Benkovitz C M,Gaffney J S et al,1982.The nature and distribution of organic matter in the surface sediments of world oceans and seas.Organic Geochemistry,4(2):63-77
Satterberg J,Arnarson T S,Lessard E J et al,2003.Sorption of organic matter from four phytoplankton species to montmorillonite,chlorite and kaolinite in seawater.Marine Chemistry,81(1-2):11-18
Vonk J E,van Dongen B E,Gustafsson?,2008.Lipid biomarker investigation of the origin and diagenetic state of sub-arctic terrestrial organic matter presently exported into the northern Bothnian Bay.Marine Chemistry,112(1-2):1-10
Vonk J E,van Dongen B E,Gustafsson?,2010.Selective preservation of old organic carbon fluvially released from sub-Arctic soils.Geophysical Research Letters,37(11):L11605
Vonk J E,Giosan L,Blusztajn J et al,2015.Spatial variations in geochemical characteristics of the modern Mackenzie Delta sedimentary system.Geochimica et Cosmochimica Acta,171:100-120
Zimmerman A R,Canuel E A,2001.Bulk organic matter and lipid biomarker composition of Chesapeake Bay surficial sediments as indicators of environmental processes.Estuarine,Coastal and Shelf Science,53(3):319-341
马倩倩,魏星,吴莹等,2015.三峡大坝建成后长江河流表层沉积物中有机物组成与分布特征.中国环境科学,35(8):2485-2493
王毅力,芦家娟,周岩梅等,2005.沉积物颗粒表面分形特征的研究.环境科学学报,25(4):457-463
卢龙飞,蔡进功,包于进等,2006.黏土矿物保存海洋沉积有机质研究进展及其碳循环意义.地球科学进展,21(9):931-937
刘志飞,Colin C,黄维等,2007.珠江流域盆地表层沉积物的黏土矿物及其对南海沉积物的贡献.科学通报,52(4):448-456
刘志飞,2010.南海沉积物中的黏土矿物:指示东亚季风演化历史.沉积学报,28(5):1012-1019
孙蕴婕,2011.沉积物中脂类生物标志物的物源示踪及环境演变指示--以海南及中国东部若干入海河流为例.上海:华东师范大学硕士学位论文,41
吴敏,李胜荣,初凤友等,2007.海南岛周边海域表层沉积物中黏土矿物组合及其气候环境意义.矿物岩石,27(2):101-107
何家雄,苏丕波,卢振权等,2015.南海北部琼东南盆地天然气水合物气源及运聚成藏模式预测.天然气工业,35(8):19-29
邵锡斌,吴莹,胡俊等,2014.颗粒态有机物在长江口及其邻近海域的夏季分布和影响因素初析.海洋与湖沼,45(6):1288-1294
经志友,齐义泉,华祖林,2008.南海北部陆架区夏季上升流数值研究.热带海洋学报,27(3):1-8
胡建芳,彭平安,房殿勇等,2001.南海沉积物中C30-C32烷基二醇的检出及可能的古环境信息.地球化学,30(6):569-578
段毅,马兰华,1996.生物标志化合物碳同位素地球化学研究的几个相关问题.地球科学进展,11(4):356-361
葛倩,初凤友,刘敬圃等,2010.南海表层黏土矿物的分布与来源.海洋地质与第四纪地质,30(4):57-66
Bock M J,Mayer L M,2000.Mesodensity organo-clay associations in a near-shore sediment.Marine Geology,163(1-4):65-75
Calvert S E,Fontugne M R,1987.Stable carbon isotopic evidence for the marine origin of the organic matter in the holocene black sea sapropel.Chemical Geology:Isotope Geoscience Section,66(3-4):315-322
Colombo J C,Silverberg N,Gearing J N,1996.Lipid biogeochemistry in the Laurentian Trough:I-fatty acids,sterols and aliphatic hydrocarbons in rapidly settling particles.Organic Geochemistry,25(3-4):211-225
Demaison G J,Moore G T,1980.Anoxic environments and oil source bed genesis.Organic Geochemistry,2(1):9-31
Hedges J I,Keil R G,1995.Sedimentary organic matter preservation:an assessment and speculative synthesis.Marine Chemistry,49(2-3):81-115
Keil R G,Tsamakis E,Giddings J C et al,1998.Biochemical distributions(amino acids,neutral sugars,and lignin phenols)among size-classes of modern marine sediments from the Washington coast.Geochimica et Cosmochimica Acta,62(8):1347-1364
Lin F,Chen M,Tong J L et al,2014.Carbon and nitrogen isotopic composition of particulate organic matter and its biogeochemical implication in the Bering Sea.Acta Oceanologica Sinica,33(12):40-47
Liu Z F,Colin C,Huang W et al,2007.Clay minerals in surface sediments of the Pearl River drainage basin and their contribution to the South China Sea.Chinese Science Bulletin,52(8):1101-1111
Liu Z F,Zhao Y L,Colin C et al,2016.Source-to-sink transport processes of fluvial sediments in the South China Sea.Earth-Science Reviews,153:238-273
Meyers P A,1994.Preservation of elemental and isotopic source identification of sedimentary organic matter.Chemical Geology,114(3-4):289-302
Premuzic E T,Benkovitz C M,Gaffney J S et al,1982.The nature and distribution of organic matter in the surface sediments of world oceans and seas.Organic Geochemistry,4(2):63-77
Satterberg J,Arnarson T S,Lessard E J et al,2003.Sorption of organic matter from four phytoplankton species to montmorillonite,chlorite and kaolinite in seawater.Marine Chemistry,81(1-2):11-18
Vonk J E,van Dongen B E,Gustafsson?,2008.Lipid biomarker investigation of the origin and diagenetic state of sub-arctic terrestrial organic matter presently exported into the northern Bothnian Bay.Marine Chemistry,112(1-2):1-10
Vonk J E,van Dongen B E,Gustafsson?,2010.Selective preservation of old organic carbon fluvially released from sub-Arctic soils.Geophysical Research Letters,37(11):L11605
Vonk J E,Giosan L,Blusztajn J et al,2015.Spatial variations in geochemical characteristics of the modern Mackenzie Delta sedimentary system.Geochimica et Cosmochimica Acta,171:100-120
Zimmerman A R,Canuel E A,2001.Bulk organic matter and lipid biomarker composition of Chesapeake Bay surficial sediments as indicators of environmental processes.Estuarine,Coastal and Shelf Science,53(3):319-341