【作者】 张闯；

【导师】 张正斌；

【作者基本信息】 中国海洋大学 ， 海洋化学， 2007， 硕士

【摘要】 海洋是全球碳循环至关重要的纽带,它在大陆岩石圈、海底沉积物圈、生物圈和大气圈之间碳的交换、流动过程中占主导地位。研究CO2在海洋中的转移和归宿,即海洋吸收、转移大气CO2的能力以及CO2在海洋中的循环机制等已经成为当今国际海洋科学诸多研究计划(特别是SOLAS研究)的重要内容。海水微表层(Sea Surface Microlayer, SML)是界于海洋和大气之间的一个薄层,是海-气界面间物质交换的必由之路。它有着特殊的物理-化学-生物性质,对海洋生物地球化学循环、物质的海-气界面通量、乃至气候等等都有着直接而重要的影响。因此本文将“海水微表层”引入中国陆架边缘海域海-气界面CO2循环的研究之中,同时将重点放在表面海水二氧化碳体系DIC、Alk、pH和pCO2四个参量的多层(包括海水微表层SML、海水次表层SSL和海水表层SL)研究上。我们试图通过对表面海水(特别是微表层)的研究,对中国黄海表面海水CO2体系的海洋化学和海水“微表层泵”理论做进一步的完善和补充。本文主要进行了以下几方面的工作:(1)将“海水微表层泵(SML pump)”这一新的全球碳循环理论模型引入到海-气界面CO2循环的研究中,并对中国SOLAS计划2006年4月份黄海航次调查所得表面海水CO2体系中DIC、Alk、pH、pCO2四个参量的多层分布规律作了系统地研究;(2)将2006年4月份黄海航次所得结果与2005年3月份和5月份黄海两个航次的结果进行了比较,希望可以在较大的时间尺度上发现它们的变化规律。本文的主要研究结果如下:1.黄海表面海水DIC、Alk、pH和pCO2的水平分布规律DIC、Alk的海域水平分布规律均是由近岸向外海逐渐降低。这可能是由于近岸大量的陆源物质的输入、近岸海水与大洋水间的物质交换能力弱以及“青岛冷水团”等因素的影响,从而导致近岸DIC和Alk的浓度高于外海。DIC与Alk二者之间具有很好的正相关性。pH的水平分布是由近岸向外海逐渐降低,而pCO2的水平分布规律与pH相反。在A2站位和A1站位附近出现了pH的低值区,相应的出现了pCO2的高值区,这可能是由于酸雨和黄海暖流的影响。在G11站位附近有一个pH的高值区,相对应的有一个pCO2的低值区,本文认为这主要是生物活动的影响。pH与pCO2二者之间具有很好的负相关性。2.黄海表面海水DIC、Alk、pH和pCO2的垂直分布规律黄海春季(4月份)DIC和Alk浓度在海水微表层(SML)、海水次表层(SSL)和海水表层(SL)中的垂直分布规律为:DICSML > DICSSL > DICSL,AlkSML>AlkSSL>AlkSL。在微表层中呈明显的富集状态,其富集倍数EF(enrichment factor,EF=DIC(SML)/DIC(SSL))皆大于1。DIC和Alk在从SML→SSL→SL的变化中,不是一般的线性减小,而是“非线性”的,这主要是由于海水微表层具有多层的结构特征模型和海水微表层中Gibbs吸附的异常共同作用所引起的。pH和pCO2在SML、SSL和SL中的分布规律分别为:pHSML<pHSSL<pHSL和pCO2 SML> pCO2 SSL> pCO2 SL。pH和pCO2在表面海水中的垂直变化规律是相反的,这也可以证明pH与pCO2的呈负相关性。还可以看出pCO2的数值小于370μatm,故此本文所研究的春季4月份黄海表现为大气CO2的“汇”,同时可以发现pH曲线的扭转方向为向“左”扭转,即向pH数值减小的方向扭转。3.黄海表面海水DIC、Alk、pH和pCO2的时间分布规律(1)周日变化:中国黄海春季(4月份)连续站的DIC和Alk周日变化分布趋势一致,其浓度在SML、SSL和SL中存在着明显的分层现象,在SML中的浓度最大;并且在SML、SSL和SL中的变化趋势是一致的,具有多层分布趋势相同的特点。DIC和Alk的最大和最小值分别出现在02:00~03:00和14:00~ 15:00范围内,呈“单峰”分布。pH出现最小值和最小值的时间分别为02:00~03:00和14:00~15:00时间范围内;而pCO2则与之相反,二者均呈“单峰”分布。(2)年度变化:在黄海春季表面海水的SML、SSL和SL这三层中,DIC和Alk浓度由高到低为3月份、4月份、5月份;pCO2数值高到低为3月份、4月份、5月份;pH则与pCO2相反。4.黄海表面海水DIC、Alk、pH和pCO2与其它参量间的分布规律(1)温度和盐度:DIC、Alk与温度均呈现出比较明显的负相关性,同时,DIC随温度的变化要比Alk随温度的变化更加明显。DIC、Alk与盐度呈负相关性,pH与温度略呈负相关性,而pCO2则与温度呈正相关性。pH与盐度呈负相关性,而pCO2与盐度呈正相关性,本文认为这主要是由于黄海暖流的影响。(2)经纬度:DIC、Alk均与经度呈比较明显的负相关性。DIC、Alk与纬度并没有明显的相关性。pH与经度略微呈现负相关性,而pCO2与经度略微呈现正相关性,pCO2与经度略现正相关性的原因,本文认为主要是离岸远近及温度的影响。pH与纬度呈现明显的正相关性;而pCO2与纬度呈现明显的负相关性,表现出“高纬度低pCO2”的分布规律,本文认为主要是由于温度的影响。(3)计算值与测量值:DIC、Alk和pH的计算值与测量值之间具有很好的相关性。pCO2的三个计算值之间也具有很好的相关性。5.二氧化碳通量的研究本文用四种计算碳通量方法(Liss & Merlivat方法、Peng & Takahashi方法、Tans方法、Wanninkhof方法)并采用微表层pCO2数据计算碳通量(FCO2),结果为-4.703mol?m-2?a-1,如果以tC计为-5.36×106tC。结合2005、2006两年的碳通量平均值计算而得出的碳通量数值为-5.639 mol?m-2?a-1,以tC计为-6.43×106 tC。更多还原

【Abstract】 The ocean is a very important connection in global carbon cycles, which plays a leading role in carbon exchange and transfer between the lithosphere, seabed sediment, biosphere and atmosphere.The sea surface microlayer (SML) is a thin layer situated between the ocean and atmosphere, which is the inevitable way of materials exchange in the sea-air interface. Because of its unique physical, chemical and biological properties, the SML have an important and direct effect on biogeochemical cycles in ocean, materials fluxes in sea-air interface and global climates. In this article the SML is introduced to the carbon dioxide cycle in sea-air interface of the marginal sea in China. In addition, the key study is put upon the carbon dioxide system including DIC, Alk, pH and pCO2 in SML, SSL and SL of the sea surface waters. In this article, through the study of surface water, we will do our endeavor to make more perfections and complementarities of the carbon dioxide system in the surface water of Yellow Sea and the“SML pump”.This work includes: (1) The SML pump is introduced to the carbon dioxide cycle in sea-air interface of the marginal sea in China. In addition, systematical multilayer studies on carbon dioxide system including DIC, Alk, pH and pCO2 in SML, SSL and SL of the sea surface waters in the Yellow Sea have been made. (2) Comparing the results of April, 2006 to March and May, 2005, we hope to find the variation regularities of them in a long time.The main results are summarized as following:1. Multilayer horizontal distributions of DIC, Alk, pH and pCO2 in the surface waters of the Yellow Sea The horizontal distributions also show that DIC and Alk become higher from ocean to coast. It maybe because the influence of waste input from land, the weaker exchange ability between the coast and ocean, the effect of“Qingdao Cold Water Mass”. In addition, the positive relationship between DIC and Alk is found clearly.The horizontal distribution of pH and pCO2 is opposite, and the pH value is become lower from coast to the ocean. There is a lower pH value area around A1 and A2, and a higher pCO2 value area appeared accordingly. It maybe becomes the influence of acid rain and“Yellow Sea Warm Current”. In addition, there is a higher pH value area around G11, and a lower pCO2 value area appeared accordingly. The mainly probability is the affection of the biological activities. It shows that pH and pCO2 are in a clearly negative relationship.2. Multilayer vertical distributions of DIC, Alk, pH and pCO2 in the surface waters of the Yellow SeaThere is a same vertical change regularity of DIC and Alk, and they both become lower in a turn of SML, SSL and SL. That is to say DIC and Alk show an obvious enrichment phenomenon in SML compared to their data in SSL and SL, whose enrichment factor (EF=DIC, Alk(SML)/DIC, Alk(SSL)或(SL)) is higher than 1. DIC and Alk show a“non-linearity distribution”regularity from SML to SL rather than the normal linearity distribution. It maybe because that the co-effect of the multilayer characteristic of SML and the abnormal Gibbs absorption in SML.There is an opposite vertical change regularity of pH and pCO2, and pCO2 values become lower from SML to SL. It can prove that pH and pCO2 is in a negative relation. All the pCO2 values of the Yellow Sea in April are less than 370μatm, that is to say, the Yellow Sea in April is a“sink”of the atmospheric CO2. In addition, it is found that the pH curve turn to the left direction, which is the direction of pH becomes lower. 3. Multilayer temporal distributions of DIC, Alk, pH and pCO2 in the surface waters of the Yellow Sea(1) Diurnal variation: the diurnal variation regularities of DIC, Alk, pH and pCO2 in SML, SSL, SL of the sea surface waters in the Yellow Sea in spring are as following: DIC, Alk, pH and pCO2 all have obvious multilayer distribution regularity in the SML, SSL and SL. There are a same multilayer distribution regularity in DIC and Alk, and an opposite distribution regularity in pH and pCO2.DIC and Alk are both enriched in SML. The same multilayer distribution regularity of DIC and Alk is a study feature in the article. DIC and Alk appear the maximum around 02:00~03:00, and appear the minimum around 14:00~15:00. The distributions of DIC and Alk show a“single-peak”phenomenon.The pH maximum values appear around 14:00~15:00, and the pH minimum values appear around 02:00~03:00. The pCO2 maximum values appear around 02:00~ 03:00, and the pCO2 minimum values appear around 14:00~15:00.The distributions of pH and pCO2 show a“single-peak”phenomenon.(2) Yearly variation: DIC, Alk and pCO2 all become lower in a turn of March, April and May in the SML, SSL and SL, but the pH becomes lower in a turn of May, April and March in the SML, SSL and SL.4. Multilayer distributions between DIC, Alk, pH, pCO2 and other parameters in the surface waters of the Yellow Sea(1) The relationships of DIC, Alk, pH and pCO2 versus temperature/salinity: there is an obvious negative relationship of DIC and Alk versus temperature/salinity in spring. The change trend of DIC versus temperature is more obvious than the trend of Alk versus temperature. There is a positive relationship of pCO2 versus temperature/salinity, but the pH is opposite. Because of the influence of the“Yellow Sea Warm Current”, there is a negative relation of pH and pCO2 versus salinity.(2) The relationships of DIC, Alk, pH and pCO2 versus longitude/latitude: There is an obvious negative relationship of DIC, Alk versus longitude, but there is no obvious relationship of DIC, Alk versus latitude. The pH values become lower with the longitude enhancing, but the pCO2 is opposite. There is a positive relationship of pH versus latitude, but the pCO2 and latitude is in an opposite relationship. There is a distribution regularity of“high latitude and low pCO2”. In this article, the mainly reason of“high latitude and low pCO2”is the effect of temperature change.(3) The relationship between measurement and calculation of DIC, Alk, pH and three calculation values of pCO2: There is a well positive relationship between the calculation and measurement of DIC, Alk, pH. The relationship among the three calculation pCO2 values also show a good consistency.5. Study of carbon dioxide fluxes (FCO2)In this article it is believed that the FCO2 calculated on the basis of the pCO2 data in SML is more reliable than that on the basis of that in SL. The fluxes are as following: As a“sink”of atmospheric carbon dioxide, the FCO2 of the Yellow Sea in spring is about -4.703 mol?m-2?a-1 (or -5.36×106 t C).Comparison of 2005 and 2006, as a“sink”of atmospheric carbon dioxide, the average of carbon dioxide flux of the Yellow Sea in spring is about -5.639 mol?m-2?a-1 (or -6.43×106 t C).更多还原