Impact of microzooplankton and copepods on the growth of phytoplankton in the Yellow Sea and East China Sea

Dilution and copepod addition incubations were conducted in the Yellow Sea (June) and the East China Sea (September) in 2003. Microzooplankton grazing rates were in the range of 0.37-0.83 d(-1) stopin most of the experiments (except at Station A3). Correspondingly, 31-50% of the chlorophyll a (Chl a) stock and 81-179% of the Chl a production was grazed by microzooplankton. At the end of 24 h copepod addition incubations, Chl a concentrations were higher in the copepod-added bottles than in the control bottles. The Chl a growth rate in the bottles showed good linear relationship with added copepod abundance. The presence of copepods could enhance the Chl a growth at a rate (Z) of 0.03-0.25 (on average 0.0691) d(-1) ind(-1) l. This study, therefore parallels many others, which show that microzooplankton are the main grazers of primary production in the sea, whereas copepods appear to have little direct role in controlling phytoplankton.

山莨菪(茄科)的传粉生物学

茄科的多数种类具有自交不亲和的特点,主要通过异花传粉结实;但是,一些物种或者物种内的部分种群或者个体却高度自交亲合,转变为自交的繁育系统.该科植物山莨菪(Anisodus tanguticus)主要分布在青藏高原,开花较早,比其他晚开花的植物种类更加缺少有效的异花传粉昆虫.我们选择了位于不同海拔高度的2个种群进行比较研究,主要目的是检验该物种的繁育系统是否在极端环境下由于传粉者的缺乏而发生了部分改变.研究发现,山莨菪的花不完全雌性先熟,柱头和花药间的平均距离随着花开放时间的延长而不断缩小,但两者在多数花的单花花期结束时并没有发生接触.因此,山莨菪花主要表现为适应异花传粉的雌雄异位特征.然而,少数花 (4.9%)的柱头和花药发生接触,为"自动自交"的传粉解除了空间隔离.2个种群的多数个体存在自交不亲和机制,应具有异花传粉的繁育系统;但是部分个体具有明显的自交亲和能力,为自交提供了生理基础.高海拔种群的传粉昆虫主要是厕蝇(Fannia sp.),它们在不同植株间的活动能够保证异花传粉结实;同时该种群的部分个体存在"自动自交".低海拔种群的主要访花昆虫是蚂蚁,它们在花内的活动导致花粉在同一朵花内传递,而引起"协助自交";而异花传粉昆虫厕蝇的访花频率则较高海拔种群低.两个种群的结实均由于异花传粉者不足而受到传粉限制.因此两种不同类型的自交机制为该早期开花植物异花访花昆虫的不足提供了一定程度上的繁殖补偿.

月光及光照对艾虎活动的影响

采用野外研究与室内研究相结合的方法研究了月光周期和光照对夜行性动物艾虎活动的影响。野外无线电遥测结果表明，艾虎的日活动时间不受月光周期的影响，雌雄艾虎在不同的季节及繁殖期和非繁殖期都有相对稳定的活动时间，其开始活动和结束活动的时间与月光周期和日出、日落都没有明显的相关性。室内模拟研究结果也表明，由于环境条件的变化，艾虎增加了白天的活动时间，但仍然以夜间活动为主，光照强弱对艾虎的活动格局和活动时间没有明显的影响。以上结果表明昼夜变换使艾虎形成了相对稳定的生物钟节律，艾虎在取食过程中可能利用洞道等隐蔽场所降低明亮月光期的高捕食风险。

龙胆属的系统发育分析

本文运用支序分类的原理和方法,对龙胆科龙胆属的属下等级进行了重新归类和系统发育分析。龙胆属是一个单系群,以3项近裔共性为归类依据。性状分析作了性状同源性分析和性状极性分析。性状极化主要以外类群比较、性状相关性及染色体资料为依据,其它方法,如生物重演律原则、地理递进原则以及孢粉形态等也被结合使用。分析结果,双蝴蝶属和蔓龙胆属被选择为外类群,71个性状被选择作为建立数据矩阵的基本资料。使用PAUP程序对矩阵进行了运算,得到4个最简约的谱系分支图,它们均具一致性系数0.637,支序长度为160步,f-比值范围为0.179～0.189,其中具最低f-比值的图被选作为类群归类和讨论亲缘关系的基础。在支序图上龙胆属归为15个组;其中5个组又划分为系,共包括23个系,其余组为单型组,故共有33个属下类群。一个严格的一致性谱系分支图总结了所有的一致点,从而支持了支序分析的结果。

Summer diet of two sympatric species of raptors Upland Buzzard (Buteo hemilasius) and Eurasian Eagle Owl (Bubo bubo) in alpine meadow: problem of coexistence

Summer diets of two sympatric raptors Upland Buzzards (Buteo hemilasius Temminck et Schlegel) and Eurasian Eagle Owls (Bubo bubo L. subsp. Hemachalana Hume) were studied in an alpine meadow (3250 m a.s.l.) on Qinghai-Tibet Plateau, China. Root voles Microtus oeconomus Pallas, plateau pikas Ochotona curzoniae Hodgson, Gansu pikas O. cansus Lyon and plateau zokors Myospalax baileyi Thomas were the main diet components of Upland Buzzards as identified through the pellets analysis with the frequency of 57, 20, 19 and 4%, respectively. The four rodent species also were the main diet components of Eurasian Eagle Owls basing on the pellets and prey leftovers analysis with the frequency of 53, 26, 13 and 5%, respectively. The food niche breadth indexes of Upland Buzzards and Eurasian Eagle Owls were 1.60 and 1.77 respectively (higher value of the index means the food niche of the raptor is broader), and the diet overlap index of the two raptors was larger (C-ue = 0.90) (the index range from 0 - no overlap - to I - complete overlap). It means that the diets of Upland Buzzards and Eurasian Eagle Owls were similar (Two Related Samples Test, Z = -0.752, P = 0.452). The classical resource partitioning theory can not explain the coexistence of Upland Buzzards and Eurasian Eagle Owls in alpine meadows of Qinghai-Tibet Plateau. However, differences in body size, predation mode and activity rhythm between Upland Buzzards and Eurasian Eagle Owls may explain the coexistence of these two sympatric raptors.

Reproductive biology of great cormorant (Phalacrocorax carbo sinensis) in the qinghai-tibet plateau

There have been no detailed studies on reproductive biology of the Great Cormorant (Phalacrocorax carbo sinensis) in Qinghai-Tibet Plateau. We conducted such investigations during the breeding seasons of 1999 and 2000 in Qinghai-Lake Bird Isle, China. Great Cormorants began to migrate to Qinghai-Lake for reproduction from the middle of March and left from early October at the end of reproduction. Nesting periods were from early April to mid June and took 50 days. Egg-laying occurred during the three weeks from the end of April to 20 May. Females typically laid an egg every 1-2 days until clutch completion. Mean clutch size in the study area over two years was 3.3 (SE +/- 0.13, N = 68, range 1-5) and most (66.18%) fell within the range 3-4 eggs. Length of eggs averaged 61.01 mm and breadth averaged 34.13 mm. Fresh egg weight averaged 57.34 g (SE +/- 0.36, range 46.0-73.7 g, N = 179). Hatching success was 48.7% and fledging success was 64.9% over two years. Decline of available fish resources in Qinghai-Lake might be one of main causes of lower reproductive success. The causes of chick loss were possibly high altitude, high winds and prolonged rain.

Genetic variation and phylogeographic history of Picea likiangensis revealed by RAPD markers

Repeated cycles of retreat and recolonization during the Quaternary ice ages are thought to have greatly influenced current species distributions and their genetic diversity. It remains unclear how this climatic oscillation has affected the distribution of genetic diversity between populations of wind-pollinated conifers in the Qinghai-Tibetan region. In this study, we investigated the within-species genetic diversity and phylogenetic relationships of Picea likiangensis, a dominant forest species in this region using polymorphic DNA (RAPD) markers. Our results suggest that this species has high overall genetic diversity, with 85.42% of loci being polymorphic and an average expected heterozygosity (H (E)) of 0.239. However, there were relatively low levels of polymorphism at population levels and the differences between populations were not significant, with percentages of polymorphic bands (PPB) ranging from 46.88 to 69.76%, Nei's gene diversity (H (E)) from 0.179 to 0.289 and Shannon's indices (Hpop) from 0.267 to 0.421. In accordance with our proposed hypothesis, a high level of genetic differentiation among populations was detected based on Nei's genetic diversity (G (ST) = 0.256) and AMOVA analysis (Phi (st) = 0.236). Gene flow between populations was found to be limited (Nm = 1.4532) and far lower than reported for other conifer species with wide distribution ranges from other regions. No clusters corresponding to three morphological varieties found in the south, north and west, respectively, were detected in either UPGMA or PCO analyses. Our results suggest that this species may have had different refugia during the glacial stages in the southern region and that the northern variety may have multiple origins from these different refugia.

Temperature and biomass influences on interannual changes in CO2 exchange in an alpine meadow on the Qinghai-Tibetan Plateau

Three years of eddy covariance measurements were used to characterize the seasonal and interannual variability of the CO2 fluxes above an alpine meadow (3250 m a.s.l.) on the Qinghai-Tibetan Plateau, China. This alpine meadow was a weak sink for atmospheric CO2, with a net ecosystem production (NEP) of 78.5, 91.7, and 192.5 g C m(-2) yr(-1) in 2002, 2003, and 2004, respectively. The prominent, high NEP in 2004 resulted from the combination of high gross primary production (GPP) and low ecosystem respiration (R-e) during the growing season. The period of net absorption of CO2 in 2004, 179 days, was 10 days longer than that in 2002 and 5 days longer than that in 2003. Moreover, the date on which the mean air temperature first exceeded 5.0 degrees C was 10 days earlier in 2004 (DOY110) than in 2002 or 2003. This date agrees well with that on which the green aboveground biomass (Green AGB) started to increase. The relationship between light-use efficiency and Green AGB was similar among the three years. In 2002, however, earlier senescence possibly caused low autumn GPP, and thus the annual NEP, to be lower. The low summertime R-e in 2004 was apparently caused by lower soil temperatures and the relatively lower temperature dependence of R-e in comparison with the other years. These results suggest that (1) the Qinghai-Tibetan Plateau plays a potentially significant role in global carbon sequestration, because alpine meadow covers about one-third of this vast plateau, and (2) the annual NEP in the alpine meadow was comprehensively controlled by the temperature environment, including its effect on biomass growth.

黄东海及朝鲜海峡冰后期陆架沉积物的环境磁学研究

There are four chapters in this dissertation. The first chapter briefly synthesizes the basic theories, methods and present-day applying situation of environmental magnetism. The second chapter probes into the magnetic mineral diagenesis in the post-glacial muddy sediments from the southeastern South Yellow Sea and its response to marine environmental changes, using the muddy sediment of Core YSDP103 formed in the shelf since about 13 ka BP. The third chapter illustrates the high-resolution early diagenetic processes by investigating the rapidly deposited muddy sediments during the last 6 ka in Cores SSDP-102 and SSDP-103 from the near-shore shelf of Korea Strait. The fourth chapter presents the results of detailed rock magnetic investigation of the surface sediments from the fine-grained depositional area on the outer shelf of the East China Sea in an attempt to provide environmental magnetic evidence for the provenance of the fine-grained deposit. Core YSDP103 was retrieved in the muddy deposit under the cold eddy of the southeastern South Yellow Sea, and the uppermost 29.79 m core represents the muddy sediments formed in the shelf since about 13 ka BP. The lower part from 29.79 to 13.35 m, called Unit A2, was deposited during the period from the post-glacial transgression to the middle Holocene (at about 6 ~(14)C ka BP) when the rising sea level reached its maximum, while the upper part above 13.35 m (called Unit Al) was deposited in a cold eddy associated with the formation of the Yellow Sea Warm Current just after the peak of post-glacial sea level rise. For the the uppermost 29.79 m core, detailed investigation of rock-magnetic properties and analyses of grain sizes and geochemistry were made. The experimental results indicate that the magnetic mineralogy of the core is dominated by magnetite, maghemite and hematite and that, except for the uppermost 2.35 m, the magnetic minerals were subject to reductive diagenesis leading to significant decline of magnetic mineral content and the proportion of low-coercivity component. More importantly, ferrimagnetic iron sulphide (greigite) is found in Unit A2 but absent in Unit Al, suggesting the control of marine environmental conditions on the magnetic mineral diagenesis. Magnetic parameters show abrupt changes across the boundary between the Unit Al and A2, which reflects a co-effect of environmental conditions and primary magnetic components of the sediments on the diagenesis. Alternating zones of high and low magnetic parameters are observed in Unit A2 of Core YSDP103, which is presumably due to periodic changes of the concentration and/or grain size of magnetic minerals carried into the study area. Cores SSDP-102 and SSDP-103, two studied sediment cores from the Korea Strait contain mud sequences (14 m and 32.62 m in thickness) that were deposited during the last 6,000 years. Analyses of grain sizes and geochemistry of the cores have demonstrated that the sediments have uniform lithology and geochemical properties, however, marked down-core changes in magnetic properties suggest that diagenesis has significantly impacted the magnetic properties. An expanded view of early diagenetic reactions that affect magnetic mineral assemblages is evident in these rapidly deposited continental shelf sediments compared to deep-sea sediments. The studied sediments can be divided into four descending intervals, based on magnetic property variations. Interval 1 is least affected by diagenesis and has the highest concentrations of detrital magnetite and hematite, and the lowest solid-phase sulfur contents. Interval 2 is characterized by the presence of paramagnetic pyrite and sharply decreasing magnetite and hematite concentrations, which suggest active reductive dissolution of detrital magnetic minerals, the absolute minimum abundance of magnetite is reached at the end of this interval. Interval 3 is marked by a progressive loss of hematite with depth, and at the base of this interval, 82% to 88% of the hematite component was depleted and the bulk magnetic mineral concentration was reduced to the lowest value in the entire studied mud section. Interval 4 has an increasing down-core enhancement of authigenic greigite, which is interpreted to have formed due to arrested pyritization resulting from consumption of pore water sulfate with depth. This is the first clear demonstration from an active depositional environment for a delay of thousands of years for acquisition of a magnetization carried by greigite. This detailed view of diagenetic processes in continental shelf sediments suggests that studies of geomagnetic field behavior from such sediments should be conducted with care. Paleoceanographic and paleoclimatic studies based on the magnetic properties of shelf sediments with high sedimentation rates like those in the Korea Strait are also unlikely to provide a meaningful signature associated with syn-depositional environmental processes. The rock magnetic properties of the surface sediments from the fine-grained depositional area on the outer shelf of the East China Sea, an area surrounded by sands, are investigated with a view to providing information on the sediment provenance. Multiple magnetic parameters such as magnetic susceptibility (%), anhysteretic remanent magnetization (ARM), saturation rernanent magnetization (SIRM), coercivities of SIRM (Her), and S ratios (relative abundance of low-coercivity magnetic minerals) are measured for all 179 surface samples, and partial representative samples are examined for their magnetic hysteresis parameters, temperature-dependence of magnetic susceptibility and x-ray diffraction spectra. Our research indicates that the magnetic mineralogy is dominated by magnetite with a small amount of hematite and is primarily of pseudo-single domain (PSD) to multidomain (MD) nature with a detrital origin. In the surface sediments, the granulometry of magnetic fractions is basically independent of grain sizes of the sediment containing the magnetic grains, and the composition of magnetic minerals remains almost homogeneous, that is, with a relatively constant ratio of low to high coercivity fraction throughout the area. The magnetic concentration in the study area generally decreases to the east or southeast accompanied by magnetic-particle fining to the east or to the northeast. The geographic pattern of magnetic properties is most reasonably explained by a major source of sediment jointly from the erosion of the old Huanghe River deposit and the discharge of the Changjiang River. The rock magnetic data facilitate understanding of the transport mechanism of fine-grained sediments in the outer shelf of the East China Sea.

泥河湾盆地第四系有孔虫化石群锶同位素及其古环境意义

泥河湾组含有孔虫化石层位的沉积环境问题存在很大争议。本文从生物壳体的锶同位素地球化学特征对其中的有孔虫进行了进一步研究。样品采自泥河湾小渡口剖面27，28层的有孔虫化石（NonionshansiensisWang）和与其共生的介形虫和腹足类。同时，对该剖面22层介形虫以及流经该剖面的桑干河和支流壶流河河水的87Sr／86Sr值也进行了测定。结果表明，有孔虫壳体87Sr／86Sr值为0.71190～0．712018，介形虫壳体为0．710612～0．711481，腹足类碎片为0．710299～0．712057，壶流河为0．709960，合流前桑干河为0．711721，合流后桑干河为0．711508，22层介形虫壳体为0．710564～0．714240。同层位的有孔虫与介形虫、腹足类的87Sr／86Sr值相互重叠，显示出具有相近或相同银同位素组成的特点，证明他们具有相同的宿生水体。有孔虫壳体的锶同位素组成与陆相的22层介形虫壳体以及现代桑干河河水的87Sr／86Sr值相互重叠，说明当时有孔虫生活在内陆环境。以同时代海水的Sr含量（8×10-6）和87Sr/86Sr值（0.709147）为海水端员，合流后的桑干河的...

植物碳酸酐酶对稳定碳同位素分馏作用的影响

碳酸酐酶（CA）能够可逆地催化CO2和HCO2^-之间的快速转化。长久以来人们忽视了生物体中CA对稳定碳同位素分馏的影响。本文以微藻碳酸酐酶胞外酶为例，说明细胞的区室化和偶联反应可引起CA可逆催化HCO2^-和CO2的转化的不平衡，进而造成稳定碳同位素分馏，并给出体外实验和C4植物实验结果作为依据。此外，本文还讨论了CA对碳同位素分馏的影响的理论和实践意义。

胶北晚中生代煌斑岩的岩石地球化学特征及其成因研究

胶北煌斑岩分别采自龙口、烟台和威海地区，包括拉辉煌斑岩、斜闪正煌岩和角闪煌斑岩，煌斑岩K—Ar全岩年龄变化于89．3～169．5Ma，为晚中生代岩浆活动的产物。在岩石化学组成上，SiO2=42．02％～54．95％，以钙碱性系列为主．岩石以富集大离子亲石元素（LILE）（Ba，U，K，Th）和LREE，亏损高场强元素（HFSE）（Nb，Ta和Ti）为特征，Mg^#=33．9～53．9，Eu／Eu^＊=0．71～0．89，^87Sr／^86Sr初始比值0．707642～0．709791，εNd（t）为-17．6～-10．4，^206Pb／^204Pb=37．588～38．431，^207Pb／^204Pb=15．423～15．531，^206Pb／^204Pb=17．204～18．179。表明煌斑岩源自俯冲陆壳（扬子下地壳）在地幔源区发生交代作用时形成的富集型地幔的部分熔融体．考虑到煌斑岩具有大陆边缘弧玄武岩的特征，我们认为煌斑岩在成因上同样与古大洋板块的俯冲作用有关，为碰撞后弧岩浆作用形成的脉岩。

中国东南部地幔柱及其与中生代大规模成矿关系初探

中国东南部是我国的钨锡铅多金属矿床集中区，燕山期发生大规模成矿作用。研究大规模成矿的地球动力学显得尤为重要。本文结合前人的研究资料，初步讨论中国东南部地幔柱及其与中生代大规模成矿关系。通过对中国东南部地幔柱的地质和地球物理方面特征综合分析后，初步探讨了地幔柱构造的岩浆作用和成矿制约。本文认为中国东南部地幔柱不仅可能造成中生代火山－岩浆大爆发，而且可能与中生代大规模成矿有关。

湘东北中生代基性岩脉岩石地球化学及构造意义

湘东北中生代发育以辉绿岩和煌斑岩类为代表的基性岩脉，属陆内拉斑玄武岩属于碱性系列。岩石富集LREE，δEu负异常不明显，其形成主要受软流圈地幔部分熔融作用制约。煌斑岩类微量元素总体上具有洋岛玄武岩（OIB）岩浆源区特征，富集Nb、P、Cs而K、Rb、Sr、U、Th等富集程度不明显，Ta、Nb略有富集。辉绿岩类表现出Na、Nb、Ti亏损，但LILE并不富休，反映地壳染程度的增强。基性岩脉形成于陆内拉张带的构造环境，岩浆活动未受到中生生代大洋板块俯冲的影响。基性岩脉在时、空及物质组成上与湘南玄武质岩石基本一致，属于整个湘东南岩石张拉－减薄带的一部分。