光强和营养盐对伪矮海链藻昼夜节律变化的影响 Ⅰ.细胞分裂、叶绿素α及活体荧光特性          下载免费PDF全文

杨小龙  朱明远 《海洋与湖沼》1993,(1)

于1989年1月—1989年8月采用连续培养和半连续培养方法进行了伪矮海链藻细胞分裂、叶绿素α含量和活体荧光特性与光、营养盐关系的研究。结果表明,细胞分裂、活体荧光、叶绿素α均呈现光照期的增长速率明显高于黑暗期的增长速率的日变化规律,荧光增强比则在光照期开始后或黑暗期结束时出现最高值;光强和营养盐不仅影响各指标日变化的幅度,而且还可改变荧光增强比峰值出现时间。因此,在研究细胞分裂、叶绿素α和荧光特性的昼夜节律时,必须考虑光和营养盐这两个重要因素。  相似文献   

西部大开发与中国经济发展     

赵建军 《海岸工程》2002,21(2):45-52

在对中国西部的区域划分进行界定并阐述中国西部区域特征的基础上,对中国西部的开发进行了历史回顾,并对中国西部开发的历史背景和现实基础、中国西部开发的优势和制约条件进行分析,最后提出了中国西部开发的发展战略和政策措施.  相似文献   

南海沉积岩芯的地球化学研究     

何良彪  辛春英 《海洋科学进展》1992,(4)

本文对南海中部陆坡区和海盆区的5个岩芯中的 Si,Al,Fe,Mn,Ca,Mg 和 CaCO_3成分做了分析,并对其分布特征与有关影响因素进行了讨论。受沉积区环境差异的影响,元素的分布具有区域性特征;受海区特定地理位置的影响,元素的分布呈现出过渡性特征(浅海到大洋的过渡);受沉积过程中环境变化的影响,元素的分布展示了周期性变化或旋回性。根据岩芯中元素的分布特征,并参考有关古地磁,氧碳同位素和钙质超微化石的测试分析结果,将本区岩芯划分为14层地球化学层,并将本区划分为两个沉积地球化学区,揭示了早更新世以来本区沉积环境的变化和存在的两种沉积模式。  相似文献   

河口涨落潮槽水动力特征及河槽类型判定   总被引：4，自引：0，他引：4  

刘高峰  沈焕庭  吴加学  吴华林 《海洋学报》2005,27(5):151-156

在前人对河口冲刷槽研究的基础上,选择长江口南支、新桥水道、南小泓和南港主槽作为典型涨、落潮槽研究对象,以2001年洪季和2003年枯季实测资料为根据,比较分析了长江口涨落潮槽的水流、泥沙、优势流和优势沙等动力特征,结果表明用单一因子分析河槽性质不够全面.提出了一个(无量纲因子)河槽类型系数(λ)来综合表述河槽的多种水文泥沙特征,可以较全面地用多个影响因子来合理地判断河槽类型.  相似文献   

Fluxes and sources of suspended organic matter in an estuarine turbidity maximum region during low discharge conditions   总被引：6，自引：1，他引：6  

Miguel A. Goni  Mary W. Cathey  Yong H. Kim  George Voulgaris 《Estuarine, Coastal and Shelf Science》2005,63(4):683-700

Water column concentrations of total suspended solids (TSS), particulate organic carbon (POC) and particulate nitrogen (PN) were measured at three different depths in four different locations bracketing the estuarine turbidity maximum (ETM) along the main channel of a temperate riverine estuary (Winyah Bay, South Carolina, USA). Measurements were carried out over full tidal cycle (over 24 h). Salinity, temperature, current magnitude and direction were also monitored at the same time throughout the water column. Tidally averaged net fluxes of salt, TSS, POC and PN were calculated by combining the current measurements with the concentration data. Under the extreme low river discharge conditions that characterized the study period, net landward fluxes of salt were measured in the lower part of the study area, suggesting that the landward transport through the main channel of the estuary was probably balanced by export out through the sides. In contrast, the net fluxes of salt in the upper reaches of the study area were near zero, indicating a closed salt balance in this part of the estuary. In contrast to salt, the net fluxes of TSS, POC and PN in the deeper parts of the water column were consistently landward at all four sites in Winyah Bay indicating the non-conservative behavior of particulate components and their active transport up the estuary in the region around the ETM.The carbon contents (%POC), carbon:nitrogen ratios (org[C:N]a) and stable carbon isotopic compositions (δ¹³C_POC) of the suspended particles varied significantly with depth, location and tidal stage. Tidally averaged compositions showed a significant increase up the estuary in the %POC and org[C:N]a values of suspended particles consistent with the preferential landward transport of carbon-rich particles with higher vascular plant debris content. The combination of tidal resuspension and flood-dominated flow appeared to be responsible for the hydrodynamic sorting of particles along the estuary that resulted in denser, organic-poor particles being transported landward less efficiently. The elemental and isotopic compositions indicated that vascular C₃ plants and estuarine algae were the major sources of the particulate organic matter of all the samples, without any significant contributions from salt marsh C₄ vegetation (Spartina alterniflora) and/or marine phytoplankton.  相似文献   

Organic matter origin and distribution in suspended particulate materials and surficial sediments from the western Adriatic Sea (Italy)   总被引：5，自引：2，他引：5  

T. Tesi  S. Miserocchi  M.A. Goi  L. Langone  A. Boldrin  M. Turchetto 《Estuarine, Coastal and Shelf Science》2007,73(3-4):431-446

In this study, organic carbon (OC), total nitrogen (TN), stable carbon isotopic (δ¹³C_OC) and CuO reaction product compositions were used to identify the sources of organic matter (OM) and to quantify the relative importance of allochthonous and autochthonous contributions to the western Adriatic Sea, Italy. Suspended particulate material (195 samples) and surficial sediments (0–1 cm, 70 samples) from shallow cross-shelf transects were collected in February and May 2003, respectively. Vertical water column profiles were acquired along the same transects. Data include depth, potential temperature, salinity, density and chlorophyll fluorimetry.Along the western Adriatic shelf in the near-shore region, the phytoplankton growth was influenced by dynamics of the buoyant plumes from the Po and Appennine rivers. A small amount of very fine terrigenous material remained suspended within the coastal current and was exported southward along the shelf to the slope. High variability in the bulk composition was detected in the Po prodelta surficial sediments, whereas the western Adriatic shelf, although a larger area, exhibited a narrower range of values.A significant decoupling was observed between suspended particles in the water column and surficial deposits. The organic material collected in the water column was compositionally heterogeneous, with contributions from marine phytoplankton, riverine–estuarine phytoplankton and soil-derived OM. Frequent physical reworking of surficial sediments likely leads to the efficient oxidation of marine OC, resulting in the observed accumulation and preservation of refractory soil-derived OC delivered by the Po and Appennine rivers.  相似文献   

Characteristic analysis on oxygen isotopic tracer in the East China Sea and waters to east of the Ryūkyū-guntō     

Hong Ashi  Yuan Yaochu 《海洋学报(英文版)》1995,14(3):371-381

Samples of O isotopic tracer were mlleMed at Sections P₃,P₂₅,P_cM-t/2-E and P_CM-1/2.w in both the Fast China Sea and the area to the east of the Ryūkyū-gunto during October-November,1991.Analytical results of the δ¹⁸O are as follows: (1) In the Kuroshio area,the δ¹⁸O isolines are almost parallel to the 200 m isobath.The value of δ¹⁸O is negative and reaches minimum mt the main axis of the Kuroshio,and increases on both sides.(2) In the Taiwan Warm Current (TWC) area there is a high δ¹⁸O tongue extending to the northeast.(3) In the area near the coast,the distribution of δ¹⁸O isoline shows that the Changjiang River runoff diffuses seaward and the land-ocean isotopic effect from the nearshore to the offshore.(4) The values of δ¹⁸O are from -1.0×10^-3 to -0.5×10^-3 in the shelf.(5) There is a low mre of δ¹⁸O value(<-1.6×10^-3) at the 600 m layer in the Kuroshio area,which is quite in accord with the existence of a low salinity mre (S G 34.30) between the 600 and 800 m layers in the same area.Finally,the mrrelations of the δ¹⁸O with the salinity and temperature,the upwelling and so on are discussed.  相似文献   

珠江口现代沉积速率及其反映的沉积特征   总被引：2，自引：0，他引：2  

陈耀泰  罗章仁 《热带海洋学报》1991,(2)

文章分析了珠江河口海区泥沙来源及淤积动态,采用以历史海图分析对比为主,~(210)Pb测年数据校核等方法,参考有关沉积速率定性方面的标志,推算出珠江口不同地段的现代沉积速率,并相应划分出高速率沉积、快速率沉积、中速率沉积和慢速率沉积或稍有侵蚀等4个分区.进而,还论述了沉积作用的特征.  相似文献   

Sea ice characteristics between the middle Weddell Sea and the Prydz Bay, Antarctica during the austral summer of 2003   总被引：1，自引：0，他引：1  

TANG Shulin  KANG Jiancheng  ZHOU Shangzhe  LI Zhijun 《海洋学报(英文版)》2005,24(2):9-15

The antarctic sea ice was investigated upon five occasions between January 4 and February 15, 2003. The investigations included: (1) estimation of sea ice distribution by ship-based observations between the middle Weddell Sea and the Prydz Bay; (2) estimation of sea ice distribution by aerial photography in the Prydz Bay; (3) direct measurements of fast ice thickness and snow cover, as well as ice core sampling in Nella Fjord; (4) estimation of melting sea ice distribution near the Zhongshan Station; and (5) observation of sea ice early freeze near the Zhongshan Station. On average, sea ice covered 14.4% of the study area. The highest sea ice concentration (80%) was observed in the Weddell Sea. First-year ice was dominant (99.7%-99.8%). Sea ice distributions in the Prydz Bay were more variable due to complex inshore topography, proximity of the Larsemann Hills, and/or grounded icebergs. The average thickness of landfast ice in NeUa Fjord was 169.5 cm. Wind-blown snow redistribution plays an important role in affecting the ice thickness in Nella Fjord. Preliminary freezing of sea ice near the Zhongshan Station follows the first two phases of the pancake cycle.  相似文献   

热带气旋对黄、渤海影响的统计特征分析   总被引：3，自引：0，他引：3  

张晓慧  卢霞  颜梅 《海洋湖沼通报》2003,(2):11-16

本文统计分析了1949—2000年共52年影响黄、渤海的热带气旋时空分布特点及ENS0、西太平洋副热带高压与影响黄、渤海的热带气旋关系。结果表明，西太平洋热带气放以四种主要路径影响黄、渤海，其影响时间、频数及强度均有不同。ENSO和西太平洋副热带高压的强度、位置将影响热带气旋对黄、渤海影响的路径和频数。  相似文献