长江口外赤潮多发区近几十年来的古生产力记录及环境意义
Variations of paleoproductivity in the past decades and the environmental implications in the Changjiang Estuary in China
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摘要: 选取长江口外赤潮多发区沉积物柱状样,在高分辨率测年基础上,通过有机碳、有机碳同位素(δ13C)、生物硅、绿素等多项指标的分析获得了调查海区古生产力的变化信息。并结合近几十年来营养盐浓度及组成结构的变化探讨了海洋浮游藻类组成结构的变化在海洋古环境中的记录。柱状样年代可追溯到20世纪40年代初。δ13C值在柱中的分布为-26.15×10-3~-19.5×10-3,表明有机碳为陆源与海生的混合。生物标志物在柱状样中的分布可大致分为三个阶段,50年代以前含量均较低;50年代至80年代含量均增加,表明海洋浮游藻类活动强烈且以硅藻为主,与此阶段长江口营养盐浓度迅速增加相对应;80年代以后,生物硅的含量下降至整个柱中最低水平,绿素有所降低,但高于50年代前的水平,而有机碳含量增加,表明在该时段硅藻生物量降低,其他藻类生物量有所增加,这与长江口营养盐氮盐持续增加而硅酸盐逐年降低、氮与磷的含量比值、磷与硅的含量比值迅速增大有关。沉积记录还表明此阶段陆源有机碳的贡献增强。
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关键词:
- 长江口 /
- 古生产力 /
- 有机碳的稳定碳同位素 /
- 生物硅 /
- 绿素
Abstract: Stable organic carbon isotope, biogenic silicate and chlor in were studied from a sediment core for discussing the variation of paleoproductivity and environmental implications in the past decades in the Changjiang Estuary.The shifting of structures of phytoplankton community in the past decades were disscused using the records of these biomarkers with the long-term variations of nutrient concentrations and their ratios.The results show that δ13C values range from - 26.15×10-3 to - 19.5×10-3, suggesting the mixing of organic carbon sources of riverine with marine or ganisms.The biogenic proxies present three stages of paleoproductivity changes: before the 1950s with low production; the 1950s——the 1980s with increasing production dominated by diatoms, consistent with increasing of nutrient concentrations; shallower before the 1980s with decreasing production.In this stage, the diatom production decreased while the production of other phytoplankton communities increased affected by high nutrients inputs and high content ratios of nitrogen to phosphorus and phosphorus to silicon in the Changjiang Estuary.The sedimentation records also indicated that the riverine organic carbon increased after the 1980s.-
Key words:
- paleoproductivity /
- stable organic carbon isotope /
- biogenic silicate /
- chlorin /
- Changjiang Estuary
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SIGMAN D M.BOYLE E A.Glacial/interglacial variations in atmospheric carbon dioxide[J].Nature,2000,407:859-869. REDFIELD A C,KETCHUM B H,RICHARDS F A.The influence of organisms on the composition of seawater[M]//HILL M N.The Sea,2.New York:Interscience,1963:26-77. 国家海洋局.2007年中国海洋灾害公报[EB/OL].2008-01.http://www.soa.gov.cn/hyjww/hygb/zghyzhgb/A020708index-!htrm CORTUO E,YIOU P,LABEYRIE L,et al.Sedimentary record of rapid climatic variability in the North Atlantic Ocean during the last glacial cycle[J].Oceanographic Literature Review,1996,43(5):443. CHEN Jian-Fang,XIA Xiao-ming,YE Xin-rong.et al.Marine organic pollution history in the Changjiang Estuary and Zhejiang coastal area-HCHs and DDTs stratigraphical records[J].Marine Pollution Bulletin,2002,45:391-396. THUYNELL R C,MIAO Q,CALVERT S E,et al.Glacial-Holocene biogenic sedimentation patterns in the Soouth China Sea:prnductivity variations and sudace water PCO2[J].Paleoceanography,1992,7:143-162. WINN K,ZHENG L,ERLENKEUSER H,et al.Oxygen/carbon isotopes and paleoproductivity in the South China Sea during the past 110 000 years[M]//JIN X,KUDRASS H R,PAUTOT G.Marine Geology and Geophysics of the South China Sea.Beijing,Chian Ocean Press,1992:154-166. 房殿勇,翦知滑,汪品先.南沙海区甫部近代30 ka来的古生产力记录[J].科学通报,1998,43(18):2005-2008. MORTLOCK R A,CHARLES C D,FROELICH P N,et al.Evidence for lower productivity in the Antarctic Ocean during the last glaciation[J].Nature,1991,351:220-222. BERNÁRDEZ P,PREGO R,FRANCÉS G,et al.Opal content in the Ria de Vigo and Galician continental shelf:biogenic silica in the muddy fraction as an accurate paleoproductivity proxy[J].Continental Shelf Research,2005,25:1249-1 264. HARRIS P G,ZHAO M,ROSELL-MELÉ.A,et al.Chlorin accumulation rate as a proxy for Quaternary marine primary productivity[J].Nature,1996,383(5):63-65. 陈建芳.古海洋研究中的地球化学新指标[J].地球科学进展,2002,17(3):402-410. BÁRCENA M Á,ISLA E,PLAZA A.et al.Bioaccumulation record and paleoclimatic significance in the Western Bransfield Strait.The last 2000years[J].Deep-sea Research(Ⅱ),2002,49(4-5):935-950. DEMASTER D J,MCKEE B A,NITTROUER C At et al.Rates of sedimentary processes based on radiochemical profiles from continental shelf deposits in the Fast China Sea[G]//Sedimentation on the Continental Shelf,with Special Reference to the East China Sea.v2.Beijing:China Ocean Press,1983:581-589. YOU Kun-yuan,SUI Liang-ren QIAN JIang-chu.Modern sedimentation rate in the vicinity of Changjiang Estuary and adjacent Continental shelf[G]//Sedimentation on the Continental Shelf,with Special Reference to the East China Sea,v2.Beijing:China Ocean Press,1983:590-605. 李家彪.东海区域地质[M],北京:海洋出版社,2008:163-167. DEMASTER D J.The supply and accumulation of silica in the marine environment[J].Geochim Cosmochim Actat 1981,45:1715-1732. GRASSHOFF K,KREMLING K,EHRHARDT M.Methods of Seawater Analysis[M].Weinheim:Wiley-VCH,1999:193-198. HARRIS P G,MAXWELL J R.A novel method for the rapid determination of chiorin concentrations at high stratigraphic resolution in marine sediments[J].Organ Geochem,1995,23:853-856. HIGGINSON M J,MAXWELL J R.ALTABET M A.Nitrogen isotope and chlorin paleoproductivity records from the Northern South China Sea:remote vs.local forcing of millennial-and orbital-scale variability[J].Marine Geology,2003,201:223-250. 蔡德陵,TAN F C,EDMOND J M.长江口有机碳同位素地球化学[J].地球化学,1992,3:305-312. 吴莹.张经,张再峰,等.长江悬浮颗粒物中稳定碳、氨同位素的季节分布[J].海洋与朝沼,2002,33(5):546-552. EGGE J K.Are diatoms poor competitors at low phosphate concentrations?[J].Journal of Marine Systems,1998,16:191-198. 晏维金,章申,王嘉慧.长江流域氟的生物地球化学循环及其对输送无机氮的影响[J].地理学报,2001,56(5):505-514. LI Mao-tian,XU Kai-qin,WATANABE M,et al.Long-term variations in dissolved silicate,nitrogen,and phosphorus flux from the Yangtze River into the East China Sea and impacts on estuarine ecosystem[J].Estuarine.Coastal and Shelf Science,2007,71:3-12. ZHOU Ming-jiang,SHEN Zhi-liang,YU Ren-cheng.Responses of a coastal phytoplankton community to increased nutrient input from the Changiiang(Yangtze)River[J].Continental Shelf Research,2008,28:1483-1489. 王奎.长江口及邻近海区氮的分布、营养支持与生态效应[D].杭州:国家海洋局第二海洋研究所,2007,53-57. WASSMANN P,EGGE J K,REIGSTAD M,et al.Infuluence of dissolved silicate on vertical flux of particulate biogenic matter[J].Marine Pollution Bulletin.1996,33(1-6):10-21.
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