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.

Effects of starvation on larval growth, survival and metamorphosis of Ivory shell Babylonia formosae habei Altena et al., 1981 (Neogastropoda : Buccinidae)

The impact of starvation on larvae of Ivory shell Babylonia formosae habei was studied in a laboratory experiment. Newly hatched veligers showed considerable tolerance to starvation due to their endogenous yolk material, and time to the point-of-no-return (PNR; the threshold point during starvation after which larvae can longer metamorphose even if food is provided) was calculated to be 104.5 h. However, starvation still affected larval growth, survival, and metamorphosis. Mean shell length of larvae increased 49.77 mum day(-1) for nonstarved, but only 11.13 mum day (-1) for larvae starved for 108 h. After larvae began feeding, their growth rates rapidly recovered to the level of the nonstarved following short periods of starvation (less than 48 h), but were inhibited and unable to ever reach the level of the nonstarved when being starved beyond 48 h. Percent metamorphosis was 53.75% for the nonstarved, but all larvae died before 10 days for those starved for 108 h. Starvation not only affected larval time to reach metamorphosis, but also caused the delay in the time to metamorphosis. For the nonstarved, larvae took only 11.5 days to reach spontaneous metamorphosis, but they took 20 days to reach spontaneous metamorphosis when starved for 96 h, and this duration of delayed metamorphosis reached 8.5 days. Furthermore, the importance of yolk material for maintaining larval survival of B. formosae habei during starvation periods is also discussed. (C) 2004 Elsevier B.V. All rights reserved.

高寒草甸土地退化及其恢复重建对土壤碳氮含量的影响

针对我国青藏高原草地大面积退化及由此引发的一系列生态环境问题，从土壤生态功能恢复和区域可持续发展的角度出发，将原生高寒嵩草草甸封育系统作为对照，研究了土地退化对土壤碳氮含最的影响，检验了不同人工重建措施（3个人工种植处理：混播、松耙单播、翻耕单播和1个自然恢复处理）对土壤碳含量的相对影响程度。研究结果如下：原生植被封育处理每平方米土壤平均碳、氮含量分别为7．47kg和0．647kg，而重度退化地碳、氮含量分别为3．67和0．448kg•m^-2．可以推算，由于土地退化而造成的土壤（0-20cm层）碳氮丢失量分别为3．80kg•m^-2和0．199kg•m^-2，即高寒草甸土地退化导致0～20cm土壤层中50．87％的有机碳和30．75％的氮流失，可以看出高寒草甸土壤退化后流失的碳比氮多；混播处理、松耙单播处理、翻耕单播处理和自然恢复处理土壤单位面积有机碳含量分别是原牛植被土壤有机碳的70．5％，69．0％，49．0％和80％，单位面积氮含量分别是原生植被土壤全氮的86．9％，88．7％，71．1％和91．7％。但是，与重度退化地相比，除翻耕单播处理外，其它恢复重建措施均能部分恢复系统的碳氮含量，因此，将重度退化地进行自然恢复或松耙混播重建多年生植被可以作为系统固定碳（碳汇）的一个途径。

草毡寒冻雏形土有机质补给、分解及大气CO2通量交换

调查草毡寒冻雏形土生物量及土壤有机质,利用涡度相关技术观测该区域作用层与大气CO2通量.结果表明：地下90%生物量集中于0～10 cm的表土层,年总净初级生产量约935.0 g/m2;土壤有机质含量在6.401～7.060%之间;净CO2通量呈明显的日变化和季节变化规律;5月中旬到9月底为CO2的净吸收（780 g CO2/m2）,其中以7月最高,净吸收量明显高于非生长季的,10月到翌年5月初CO2的净排放量（383 g CO2/m2）;全年固定碳高达397 g/m2.

Assessing the potential of VEGETATION sensor data for mapping snow and ice cover: a Normalized Difference Snow and Ice Index

The VEGETATION (VGT) sensor in SPOT 4 has four spectral bands that are equivalent to Landsat Thematic Mapper (TM) bands (blue, red, near-infrared and mid-infrared spectral bands) and provides daily images of the global land surface at a 1-km spatial resolution. We propose a new index for identifying and mapping of snow ice cover, namely the Normalized Difference Snow/Ice Index (NDSII), which uses reflectance values of red and mid-infrared spectral bands of Landsat TM and VGT. For Landsat TM data, NDSII is calculated as NDSIITM =(TM3 -TM5)/(TM3 +TM5); for VGT data, NDSII is calculated as NDSIIVGT =(B2- MIR)/(B2 + MIR). As a case study we used a Landsat TM image that covers the eastern part of the Qilian mountain range in the Qinghai-Xizang (Tibetan) plateau of China. NDSIITM gave similar estimates of the area and spatial distribution of snow/ice cover to the Normalized Difference Snow Index (NDSI=(TM2-TM5)/(TM2+TM5)) which has been proposed by Hall et al. The results indicated that the VGT sensor might have the potential for operational monitoring and mapping of snow/ice cover from regional to global scales, when using NDSIIVGT.

轮式移动仿人机器人的动力学建模与分析

利用高效迭代牛顿-欧拉方法对一个21自由度的轮式移动仿人机器人进行了整体动力学建模,该模型虽然维数较高,但消除了分块建模中需要对模块之间相互作用力进行建模的难点问题,并且由于机器人双臂的对称结构,当合理规划双臂运动时,动力学模型将得到部分简化。本文还对某关节运动时在各个关节所产生的力或力矩进行了仿真分析。解析及仿真结果表明,合理规划上臂各关节的协调运动,将极大地削弱车体及腰部各关节所受的力或力矩扰动,为基于动力学的机器人运动控制以及稳定性分析提供理论依据。

超高压输电线路巡检机器人越障控制问题的研究

给出了一种超高压输电线路巡检机器人控制系统的设计与实现方法.根据机器人的作业任务,提出了基于传感器信息、约束信息以及动作反馈信息作为输入,产生式系统作为动作输出的越障控制方式.仿真结果表明此方法对于机器人的越障过程是有效的.

月球水冰探测进展

月球上是否存在水冰是第二次月球探测热潮中的热点问题。1994 年克莱门汀号(Clementine)环月探测器搭载的频率为2. 273 GHz 双基地雷达探测到月球南极一些地区出现同向极化增加等独特的回波特征,这些地区正好处于极地永久阴影区,表明这些地区可能存在水冰。Arecibo 天文台频率为2. 38 GHz 的地基雷达对月球极地进行制图,也得到类似结论。1998 年月球勘探者号(Lunar Prospec2tor) 环月探测器搭载的中子探测仪在月球极地永久阴影区探测到高含量的氢信号大多认为是水冰引起的。但雷达探测和中子探测结果均存在多解性。月球表面粗糙度同样可以引起雷达回波呈现出类似水冰的异常特征,而中子探测仪测量到的仅仅是氢信号而非水,而且月球勘探者号撞击月表之后并没有探测到任何的水蒸气信号。月球极地水冰存在与否、存在形式和存在数量等科学问题的回答需要对月球极地特别是永久阴影区作进一步探索。

贵州遵义牛蹄塘组黑色岩系的硒同位素变化及其环境指示初探质系，厄巴纳61801美国

西南早寒武世牛蹄塘组是分布在中国南方扬子地台的一套黑色岩系，区域上发育有典型富集多金属元素的硫化物矿化层。选取遵义松林小竹牛蹄塘组下部富硒、钼、镍等元素的黑色岩系剖面，利用Se同位素初步探讨了该剖面岩石的沉积环境和硒的可能来源。结果表明，小竹牛蹄塘组下部剖面黑色岩系的δ^82/76SeSRM 3149比值变化较大，下部底层含碳斑脱岩与磷块岩的变化范围在-4．35％～＋4．11‰之间；中间镍钼层及碳质页岩、碳质碳酸盐岩的占82δ^82/76SeSRM 3149变化范围窄，平均值为0．91700±0．23700（n=4）；上层碳质页岩为-1．24‰。结合已发表的钼同位素数据，认为中间岩石沉积于缺氧／无氧环境，但存在盆地海水与热液或充氧水团的混合；下层的岩石曾一度位于充氧与贫氧环境的边界面，局部岩石曾暴露地表经历了较强的风化和蚀变作用，海水中硒有可能来自底部富硒斑脱岩的氧化淋滤或海底热液。据此推测遵义松林小竹牛蹄塘组下部岩石的沉积环境极可能处在局限盆地靠近陆地的边缘部分，经历了充氧→贫氧→缺氧／无氧→贫氧的演化阶段.

湘东南汝城盆地火山岩的元素地球化学及源区性质讨论

湘东南汝城盆地火山岩系由辉绿岩、玄武岩和玄武质火山碎屑岩组成，属于低钾拉斑玄武岩系。玄武岩全岩K—Ar年龄为(128．4±4．2)Ma，辉绿岩全岩K—Ar年龄为(112．1±3．2)Ma。元素地球化学分析表明火山岩系具有同一岩浆源区，其形成以部分熔融方式为主。岩石微量元素出现大离子亲石元素Rb、Ba、Th、U的富集和高场强元素Ta、Nb、Ti的亏损。强不相容元素含量的比值表明岩浆源区明显偏离原始地幔组分，具有富集型地幔的特征。岩浆源区主要受到地壳物质混染以及来自消减残留板片析出流体的交代改造作用。

A Quantitative Study on Paleo—River Environment During Late Jurassic on yaojie Region,Minhe Basin

Fluvial Sedimentation of alluvial facies prevailed during the Late Jrassic in the Minhe Basin.On the basis of the study of sedimentary facies of the Upper Jurassic series.this paper focuses on the river types suing the "Architecture Element" analysis method proposed by Miall,and calculated all the quantitative parameters to reflect the characteristics of the stream channel geometry and hydrodynamic conditions of paleo-rivers with the equations of ethrideg,schumm et al.Finally,we discussed the characteristics of environmental evolution of palsorivers on the quantitative basis.Our conclusion indicates that the evolution of paleo-rivers during the Late Jurassic,from early to late,shows such a tendency as alluvial fan river→ braid river→alluvial fan river→mid-sinuoisty river→ high-sinuosity river.

贵州早寒武世的缺氧事件沉积

贵州早寒武世的黑色岩系属中国南方该时期缺氧事件沉积的一部分,为一套沉积速率低的海侵体系域沉积.主要为黑色页岩,发育水平纹理,主要含浮游生物,其中产钼、钒等矿床.其具有独特的元素地球化学特征:SiO2、TiO2、Al2O3的含量相对较高;富集Mo、V、Ba、Ag、Au、U等元素,而Co、Sr、Ta等元素却亏损;稀土总量不高,为130×10-5～226×10-6,稀土配分曲线形态近于水平或略向右倾,具弱的负Ce异常和正Eu异常.地层特征、元素地球化学特征及特征元素比值所反映的是早寒武世黑色岩系形成于缺氧的还原环境,而缺氧沉积中有热水沉积的加入.