The freshwater balance derived from oxygen isotopes in the western Arctic Ocean

淡水组分的收支对北冰洋物质和能量的平衡起着重要的作用，它维持着北冰洋上层水体的层化作用，隔绝了温暖大西洋水体热量的向上传输，因而对北冰洋的海冰覆盖产生重要影响。此外，淡水组分不仅影响到北冰洋的表层环流，而且对北大西洋深层水的形成也起着调控作用，从而对全球气候变化产生影响。本研究采用S、δ18O的质量平衡关系或S、δ18O和PO4*的质量平衡关系，分别以大西洋水、冬季白令海水作为海水端元，计算获得2003年和2008年夏季楚科奇海、加拿大海盆总河水组分、北极河流河水组分、太平洋入流河水组分和海冰融化水组分的份额、积分高度和储量，揭示了这些淡水组分的时空分布特征，探讨了它们的来源、运动路径和停留时...Freshwater plays a major role in the Arctic Ocean, for example, freshwater maintains the stratification in the upper water in Arctic Ocean that inhibits the heat transfer from deep ocean to the surface, and consequently has a dramatic effect on sea ice cover in the Arctic Ocean, and even the Arctic climate system. Freshwater has an impact not only on the Arctic Ocean circulation but also on the in...学位：理学博士院系专业：海洋与地球学院_海洋化学学号：2242008015010

Distribution and source of transparent exopolymer particles in the northern Bering Sea

透明胞外聚合颗粒物(TEP)是海水中大量存在的黏性颗粒物质,它对于海洋颗粒物的聚集、有机碳的埋藏、食物网物质的传递、痕量金属的清除与迁出等均起着重要作用。本研究开展了夏季北白令海陆架、陆坡和海盆区透明胞外聚合颗粒物含量和分布的研究。结果表明,北白令海TEP含量介于34~628Mg/M3(XEQ)之间,其中陆架、陆坡和海盆区TEP的平均含量分别为240,145和83Mg/M3(XEQ),整体呈现由陆架向外海降低的趋势。在陆坡和海盆区,TEP含量随着深度的增加而降低,但在陆架近底层水中,观察到TEP高含量的特征,与近底层水高的TSM,POC相对应。TEP与荧光强度、TSM、POC等的关系分析显示,研究海域TEP存在两个来源,其一为海洋上层水体的浮游生物,其主要贡献于陆架上层、陆坡和海盆水体;其二为陆架沉积物的底栖生物,其通过沉积物再悬浮贡献于陆架近底层水。Transparent exopolymer particles(TEP) are large,sticky particles in marine environments,and play a significant role in particle dynamics,carbon export,food web energy transfer and scavenging of trace metals.Samples were collected from the northern Bering Sea during summer 2010 for measurements of TEP and other hydrographic parameters to examine the abundance,distributions and sources of TEP.Our results showed that TEP concentrations ranged from 34 to 628 mg/m3(Xeq).The averaged TEP concentrations in the shelf,slope and basin were 240,145 and 83 mg/m3(Xeq),respectively,showing a general decrease from the shelf to the basin.In the slope and basin areas,TEP concentrations decreased with the increasing depth.However,high concentrations of TEP were observed in the shelf bottom waters,coincided with the high values of TSM and POC.The correlations between TEP and fluorescence,TSM and POC suggested two sources of TEP in the northern Bering Sea:(1) in situ production from planktons in the upper water column,and(2) benthic biological processes in the sediments.High TEP concentrations in the shelf bottom waters was predominantly derived from sediment resuspension,which may have a potential effect on carbon biogeochemical cycle and scavenging of trace elements in shelf regions.中国第四次北极科学考察项目;海洋公益性行业科研专项(201105022-4);福建省自然科学基金项目(2009J06026

Distribution of Primary Production in the Yellow Sea and the East China Sea in Summer

利用14 C示踪法实测了黄、东海海域2006年6—8月的初级生产力,结果表明,积分初级生产力介于378.65~6 403.47Mg/(M2.d)之间,平均为2 059.56Mg/(M2.d)。初级生产力的空间变化表现出3个特点:1)东海的积分初级生产力明显高于黄海;2)受黑潮水影响,海域的初级生产力比陆架区明显低;3)长江口东南海域和济州岛西南海域存在较高的初级生产力。对初级生产力和环境因子的关系进行分析表明,初级生产力的高值大多出现在水温为21~26℃的水体中,光强和营养盐共同调控着黄、东海海域初级生产力的分布。受黑潮水影响,海域初级生产力较低与其贫乏的营养盐有关,而长江冲淡水和冷涡输送的丰富营养盐维持着长江口东南海域和济州岛西南海域较高的初级生产力。Primary production supports substantial biomass and higher trophic level organisms in the coastal waters,but the mechanisms regulating primary production in coastal waters are still difficult to assess.In this study,primary production in the Yellow Sea and the East China Sea was measured via 14C tracer in summer 2006 to reveal their distribution features and the impact factors.Our results showed that the depth-integrated primary production ranged from 378.65 to 6 403.47 mg/(m2·d) with an average of 2 059.56 mg/(m2·d).The distribution of primary production indicated that(1) primary production in the East China Sea was higher than those in the Yellow Sea;(2) primary production in sea areas influenced by the Kuroshio waters was significantly lower than those in the shelf regions;and(3) high primary production was observed in the southeastern region of Changjiang estuary and the southwestern region of Jelu Island.The relationship between primary production and environmental factors suggested that high primary production mostly occurred in seawaters with temperature of 21-26 ℃,and the primary production was regulated by the availability of nutrients and lights.The low primary production in the regions influenced by the Kuroshio waters was ascribed to the low nutrients,and the high primary production in the southeastern region of Changjiang estuary and the southwestern region of Jelu Island was ascribed to the abundant nutrients supplied by the Changjiang river and the cold eddy.国家重点基础研究发展规划项目课题“典型水域生源要素循环及浮游植物多样性对海洋物理环境演变的响应”(2005CB422305);国家自然科学基金杰出青年基金项目“同位素海洋化学研究”(41125020

Distribution of river water and sea-ice melted water in Chukchi Sea in summer

通过对2008年夏季楚科奇海水氧同位素组成的分析,运用S、δ18 O的质量平衡关系计算出河水组分和海冰融化水组分的份额,揭示出楚科奇海河水和海冰融化水组分的空间变化规律,并探讨其影响因素。楚科奇海河水组分的份额介于1.9%~18.4%之间,呈现随深度增加而降低的趋势;河水组分积分高度的变化范围为1.3~16.6M,平均为(4.8±4.0)M。河水组分份额与积分高度均呈现东高西低、北强南弱的特征,与太平洋入流东侧为富含河水组分的阿拉斯加沿岸流、西侧为低河水组分的白令海陆架水,以及北部海域受波弗特流涡埃克曼辐聚作用的影响有关。海冰融化水份额呈现随深度增加而降低的趋势,20~30M以深受到冬季海冰形成时所释放盐卤水的明显影响。海冰融化水积分高度的变化范围为-3.2~1.7M,平均值为(-0.3±1.2)M,其空间分布呈现东低西高、南强北弱的特征,与太平洋入流输入通量的时间变化以及输入路径的西偏有关。On the basis of the measured oxygen isotopic composition of seawater,the Sandδ18 O mass balance was employed to determine the fraction of river water and sea-ice melted water in Chukchi Sea in summer 2008.The spatial patterns of river water and sea-ice melted water were revealed and the affecting factors were disccussed.The fractions of river water decreased with the increasing depth,with a range from 1.9%to 18.4%.The integrated heights of river water(IfR)were 1.3~16.6m,with an average of(4.8±4.0)m.IfRshowed a spatial characteristic with high values in the east and north and low values in the west and south.This spatial variation of river water was ascribed to the difference amount of river water carried by the Pacific inflows(e.g.,high river water components in the Alaska Current Water and low river water components in the Bering Shelf water),the pathway of the Pacific inflows and the Ekman pumping of Beaufort Gyre.The fractions of sea-ice melted water decreased dramaticly with the increasing depth.A negative value was observed at depth of about 20 mto 30m.The integrated heights of sea-ice melted water(IfI)were from-3.2mto 1.7m,with an average of(0.3±1.2)m.IfIwas higher in the west and south,but lower in the east and north.The spatial variation of sea-ice melted water was attributed to the strength and time of the Pacific inflows,as well as the topographically impact which diverted the Pacific inflow westward.南北极环境综合考察与评估专项(CHINARE2014-03-04-03;CHINARE2014-04-03-05); 海洋公益性行业科研专项(201105022-4); 国家自然科学基金杰出青年基金项目(41125020

Export Fluxes of POC and Biogenic Silica in the Kuroshio by Means of ~(234)Th/~(238)U Disequilibria

对东海陆架外黑潮区颗粒有机碳(POC)和生物硅(bSIO2)的研究表明:台湾东北部黑潮主流真光层(100 M)POC和bSIO2的平均浓度分别为3.31μMOl/l和0.68μMOl/l;234TH/238u不平衡法获得POC和bSIO2的输出通量分别为3.7 MMOl/(M2·d)和1.6 MMOl/(M2·d).黑潮沿东海陆架北进过程中,POC和bSIO2的含量及输出通量均呈增加趋势.位于日本西南的黑潮主流中,POC和bSIO2的平均浓度分别为3.85μMOl/l和2.63μMOl/l,输出通量分别为6.7 MMOl/(M2·d)和4.0 MMOl/(M2·d).黑潮与陆架水形成的锋面区,POC和bSIO2浓度均高于黑潮主流.To reveal the primary characteristics of the POC and biogenic silica( bSiO2) in the Kuroshio,as well as their export from the euphotic zone,POC,bSiO2 and234Th were examined.The average concentrations of POC and bSiO2 were 3.31 μmol / L and 0.68 μmol / L in the main Kuroshio stream to northeast Taiwan respectively,corresponding to their respective export fluxes of 3.7 mmol /( m2·d) and1.6 mmol /( m2·d).Along the flow of Kuroshio northwards,the concentrations of both POC and bSiO2 increased to a varying degree.To southwest Japan,the contents of POC and bSiO2increased up to3.85 μmol / L and 2.63 μmol / L respectively.The export fluxes of POC increased to 6.7 mmol /( m2·d),accompanying the bSiO2flux of 4.0 mmol /( m2·d).The average concentrations of POC and bSiO2 in the Kuroshio frontal zone were higher than the values in the main stream.中国大洋协会课题资助项目;编号DY125-13-E-01; 国家自然科学基金资助项目;编号41076043;4112502

Biological N_2 fixation rates in the East China Sea in spring 2009

2009年4~5月间,应用15n2示踪法实测了东海25个站位的生物固氮速率,结合温度、盐度等要素的分布,分析生物固氮速率的空间变化及其影响因素.结果表明,春季东海的生物固氮速率介于102~16 349 nMOl/(M3·d)之间,平均为2 441 nMOl/(M3·d).生物固氮速率的空间变化呈现径流影响区最高,黑潮影响区与陆架其他区域相近的特点,径流影响区的平均生物固氮速率约为黑潮影响区和陆架其他区域的2倍,这可能与固氮生物种类的空间变化有关.春季东海的积分固氮速率平均为129μMOl/(M2·d),结合此前获得的夏、秋、冬季的积分固氮速率,估算出东海生物固氮速率的年均值为50μMOl/(M2·d),因而东海的年固氮通量估计为1.4x1010MOl/A,约占全球海洋年固氮通量的0.15%.对东海进行的氮源汇分析表明,生物固氮作用、长江径流输入和大气沉降输入等氮输入通量分别为1.4x1010、7.9x1010和3.9x1010MOl/A,反硝化作用和沉积物颗粒氮埋藏的迁出通量分别为9.5x1010和3.7x1010MOl/A,东海氮的源汇通量均为13.2x1010MOl/A,表明东海氮的收支基本处于平衡状态.Biological N2fixation rates at 26 stations in the East China Sea were measured with15N2tracer assay during April and May 2009.Combined with temperature and salinity,the distribution of N2fixation rates and their influencing factors were discussed.Our results showed that the N2fixation rates ranged from 102 to 16 349 nmol/(m3·d) with an average of 2 441 nmol/(m3·d).The highest rates were observed in regions influenced by the river plume,which was about two times what observed in regions influenced by the Kuroshio current and the shelf waters,probably reflecting the spatial variation of the nitrogen fixers.The integrated N2fixation rate in the East China Sea in spring was129 μmol/(m2·d) in average,and the annual N2fixation rate was estimated as 50 μmol/(m2·d) compared with previous data in summer,autumn and winter.This meant that the new nitrogen flux supply by N2fixation to the East China Sea was 1.4×1010mol/a,contributing to about 0.15% of the N2fixation flux in global oceans.The nitrogen budget in the East China Sea was evaluated in views of sources and sinks.The fluxes of nitrogen supply to the East China Sea via the nitrogen fixation,the river runoff and the atmospheric deposition were estimated as 1.4×1010,7.9 ×1010and 3.9×1010mol/a,respectively.The removal fluxes of nitrogen via denitrification and sedimentary burial were 9.5×1010and 3.7×1010mol/a,respectively.Both the nitrogen flux of the sources and the sinks were 13.2×1010mol/a,indicating a balance of nitrogen budget in the East China Sea.国家自然科学基金杰出青年基金资助项目(41125020); 国家海洋局大洋专项资助项目(DY125-13-E-01