东海泥质区沉积物部分化学成分的组成特征及其对环境因素的响应

东海泥质区沉积物部分化学成分的组成特征及其对环境因素的响应

【中文摘要】陆架边沿海是陆海相互作用的活跃地带,其水体沉积物具有陆源和海源双重特性。海洋沉积物中主要成分及部分元素的组成情况是了解海区生物生产和物质来源的有效信息,了解其分布特征对于研究近海环境和生物生产的空间、时间变化具有重要意义。本文选取南黄海表层沉积物样品,对连续提取法测定近海沉积物主要成分(碳酸钙、水合铁锰氧化物、有机物、生源硅、残渣)的提取效率、精密度和回收率进行了研究;应用该连续提取法分析研究了2007年11月采自东海泥质区的表层沉积物主要成分的含量及其影响因素,探讨了各泥质区的物质来源;应用该连续提取法对2003年6月采集的闽浙沿岸泥质区柱状沉积物主要成分及金属元素铜的形态进行了分析,讨论了其主要成分的年际变化、相互关系及对海区环境因素的响应。结果显示,连续提取法对近岸沉积物主要成分能够有效地分离和测定。方法精密度较好,回收率为98.1～99.1%。碳酸盐、有机物与元素分析仪测定的无机碳和有机碳结果对比具有一致性,进一步确定本方法对于近岸沉积物样品分析的可靠性。东海泥质区碳酸钙含量介于6.75%～14.25%,由近岸至远海呈增加趋势,远岸济州岛西南泥质区出现碳酸钙含量最高值。所调查泥质区生源硅含量介于0.33%～0.83%,有机碳含量介于0.44%～0.67%,C/N范围为5.56～8.82。S5站柱状样碳酸钙含量均匀为6.5%,在垂向分布上没有太大的变化趋势。生源硅和有机碳的含量20世纪30年代以来特别是80年代以后,表现出明显的增加趋势。非残渣态Cu除了有机物-硫化物结合态(OSM)外,可交换态与碳酸盐结合态(EXC+CARB)和铁锰氧化物结合态(ERO)含量在20世纪80年代以后都有明显的上升。对沉积物各化学组成综合讨论得到如下结论:1.东海陆架不同的泥质区化学成分来源差异明显。长江口泥质区和闽浙沿岸泥质区受长江进海物质影响较大,沉积物中的碳酸钙主要为陆源控制,长江口泥质区有机质受陆源影响明显,而济州岛远岸泥质区有机质以海洋生物源为主。2.闽浙沿岸泥质区S5沉积物柱状样中碳酸钙主要来源于陆源碎屑,其含量在特定时期内出现的峰值在一定程度上反映出了长江流域的极端天气事件。3.除了受到早期成岩作用影响外,人类活动造成的水体富营养化可能刺激了海洋中硅藻和其它藻类的生长,使得有机碳在沉积物中的埋躲含量增加。柱状样中生源组分及重金属元素的变化特征较好地示踪了闽浙沿海地区经济的发展及人类活动的影响。4.S5沉积物中可交换态和铁锰氧化物态铜的含量在20世纪80年代以后有明显的上升,可交换态铜的变化对长江洪水事件表现出一定的响应。近年来浙江沿海一带随着产业的发展,人为活动带进海洋的重金属日趋增加,环境污染题目加重。');

【Abstract】Continentalmarginseasareactivezonesbetweencontinentalandopenocean,whichhasbothterrestrialandbiogenicsourcesinthebenthalsediments.Themajorcomponentsofmarinesedimentcontainefficientinformationtounderstandthebiologicalproductionandthematerialsourcesinaseaarea.Itisimportanttostudytheirdistributionforunderstandingthechangesofcoastalenvironmentandprimaryproductivitybothtemporallyandspatially.Calciumcarbonate,ironandmanganeseoxy-hydroxides,organicmatter,biogenicsilicaandresiduallithogenicdetritus,i.e.,themajorcomponentsofsu***cesedimentsamplesfromthesouthernYellowSeawereseparatedandmeasuredwithasequentialextractionmethod,whichtheextractionefficiency,precisionandrecoverywereexaminedanddiscussed.Thecontentofmajorcomponentsofsu***cesedimentscollectedfromintheEastChinaSea(ECS)inJune2007aremeasuredwiththissequentialextractionmethodtoidentifythematerialsourcesofeachmudarea.ThemajorcomponentsinasedimentcorecollectedfromcoastalmudoffZhejiangandFujianProvinces(CMZF)inJune2003,werealsodetermined,ofwhichtheanalogvariety,therelationshipandtheresponsetoenvironmentalfactorswereclarified.Thissequentialextractionmethodiseffectivetoseparateanddeterminethefivemajorcomponentsincoastalsediment,whichresultedfairlyfineprecisionandrecoveryof98.1～99.1%.Thecontentsofcalciumcarbonate,organicmatterareconsistentwiththeinorganicandorganiccarboncontentsdeterminedwithanelementanalyzer,anditisthusprovedthatthereliabilityofthesequentialextractionmethodindeterminationofmajorcomponentsofcoastalsediment.ThecontentofCaCO3inmudsedimentareainECSrangesfrom6.75%to14.25%,increasesgraduallyfrominshoretoopenseaandreacheshighestvalueintheSouthwesternChejuIslandMudArea(SCIMA).Thecontentsofopalandorganiccarbonare0.33%～0.83%and0.44%～0.67%,respectively,andtheC/Nratiorangesfrom6.42to10.11.TheCaCO3contenthadnodistinctvarietytrendverticallywithaverage6.5%insedimentcoreS5,whilethecontentofOCandBSiincreasedmarkedlyafter1930s,especiallysince1980s.TheCucontentofEXC+CARB(exchangeableandcarbonate)andERO(easilyreducibleoxides)hadascendeddistinctlysince1980s,exceptforOSM(organic/sulfidematter).Conclusionsweresummarizedasfollow:1.ThesourcesofeachmudareainECSaremarkedlydifferent.ThemudareaneartheYangtzRiverestuaryandCMZFareinfluencedinalargeextentbytheterrestrialmaterialfromtheYangtzRiverandtheCaCO3originatesmostlyterrestrially.TheorganicmatterinmudareaneartheYangtzRiverestuaryisdominatedoflithogenicsource,whilethebiogenicsourceispreponderantinChejuIslandMudArea(SCIMA).2.TheCaCO3insedimentcoreS5inCMZFmostlyoriginatesterrestrialsourceandthecontentpeaksinspecialperiodsmightreflecttheinfluencesondepositingprocessarousedbyextremeclimateeventsinYangtzRiverdrainagearea.3.Aswellastheearlydiagenesis,theincreaseofOCinsedimentcoremightbeduetotheupgrowthofdiatomsandotheralgaestimulatedbytheeutrophicationinwatersystem.4.ThecontentofEXC-CuandERO-CuinS5corearesucce