A dinoflagellate <Emphasis Type="Italic">Cochlodinium geminatum</Emphasis> bloom in the Zhujiang (Pearl) River estuary in autumn 2009

A severe Cochlodinium geminatum red tide (>300 km2) was observed in the Zhujiang (Pearl) River estuary, South China Sea in autumn 2009. We evaluated the environmental conditions and phytoplankton community structure during the outbreak. The red tide water mass had significantly higher dissolved inorganic phosphate (DIP), ammonia, and temperature, but significantly lower nitrite, nitrate, dissolved inorganic nitrogen (DIN), and DIN/DIP relative to the non-red-tide zones. The phytoplankton assemblage was dominated by dinoflagellates and diatoms during the red tide. C. geminatum was the most abundant species, with a peak density of 4.13×107 cell/L, accounting for >65% of the total phytoplankton density. The DIN/DIP ratio was the most important predictor of species, accounting for 12.45% of the total variation in the phytoplankton community. Heavy phosphorus loading, low precipitation, and severe saline intrusion were likely responsible for the bloom of C. geminatum.     

南海北部陆缘构造属性研究进展

南海北部陆缘位于特提斯与古太平洋两大构造域的叠合部位,构造特征十分复杂,其构造属性一直是国内外学者争论的焦点,从主动陆缘到被动陆缘,火山型被动陆缘到非火山型被动陆缘等均有表述。南海复杂的形成机制以及东、西部构造差异性所引起的地球物理、岩浆活动等认识的异同,是造成南海北部陆缘构造属性认识差异的主要原因。通过与全球典型地区的比较研究,进一步加强对南海形成演化过程分析,开展大洋钻探与多学科综合分析,揭示南海海盆的多期扩张与多盆张裂特征,是认识南海北部陆缘构造属性的关键。探讨了南海三叉裂谷张裂模式,初步认为南海第1次扩张具有非火山型被动陆缘性质,第2次扩张具有火山型陆缘性质。     

Enhanced resistance of Portunus trituberculatus to Vibrio alginolyticus by selective breeding

We established a line (screened) of Portunus trituberculatus by selectively breeding individuals that survived from challenge with Vibrio alginolyticus, and compared the response of screened and unscreened (control) P. trituberculatus challenged with V. alginolyticus. We measured superoxide dismutase, catalase, acid phosphatase, alkaline phosphatase, and peroxidase activity and the content of hemocyanin in the plasma and phenoloxidase activity in serum. The cumulative survival rate after 24-h challenge with V. alginolyticus was significantly higher in the screened crabs than in the unscreened crabs (P<0.05). T-SOD and PO activity were significantly lower in the screened stock than in the unscreened stock (P<0.05). POD, CAT, and ACP activity and hemocyanin content were significantly higher in the screened stock than in the unscreened stock. Our results suggest that the screened stock was more resistant to infection. Furthermore, the indices we measured may be used to evaluate the health state of P. trituberculatus.     

Agricultural land use optimal allocation system in developing area: Application to Yili watershed, Xinjiang Region

In developing countries, land productivity involves little market, where the agricultural land use is mainly determined by the food demands as well as the land suitability. The land use pattern will not ensure everywhere enough land for certain cropping if spatial allocation just according to land use suitability. To solve this problem, a subzone and a pre-allocation for each land use are added in spatial allocation module, and land use suitability and area optimization module are incorporated to constitute a whole agricultural land use optimal allocation (ALUOA) system. The system is developed on the platform .Net 2005 using ArcGIS Engine (version 9.2) and C# language, and is tested and validated in Yili watershed of Xinjiang Region on the newly reclaimed area. In the case study, with the help of soil data obtained from 69 points sampled in the fieldwork in 2008, main river data supplied by the Department of Water Resources of Xinjiang Uygur Autonomous Region in China, and temperature data provided by Data Center for Resources and Environmental Sciences, Chinese Academy of Sciences, land use suitability on eight common crops are evaluated one by one using linear weighted summation method in the land use suitability model. The linear programming (LP) model in area optimization model succeeds to give out land area target of each crop under three scenarios. At last, the land use targets are allotted in space both with a six subzone file and without a subzone file. The results show that the land use maps with a subzone not only ensure every part has enough land for every crop, but also gives a more fragmental land use pattern, with about 87.99% and 135.92% more patches than the one without, while at the expense of loss between 15.30% and 19.53% in the overall suitability at the same time.     

RTK技术在老挝甘蒙省钾盐矿勘查区地形图修测中的应用

以老挝人民民主共和国甘蒙省钾盐矿勘查区1∶50000地形图修测项目实例,介绍GPS RTK技术的基本原理和工作流程,总结出这种技术的优势所在以及实践操作中应该注意到的问题。     

基于数值模拟的三峡库区典型堆积层滑坡变形预测方法

目前对堆积层滑坡的变形预测大多基于数学模型或方法,忽略了引起滑坡位移显著变化的动力外因及滑坡自身的地质特征,因此,预报准确度和可信度较低。以三峡库区典型堆积层滑坡--鹤峰场镇滑坡为例,通过4组主要控制因素科学组合构建了滑坡的基本地质模型;以此为基础,重点考虑引起滑坡发生变形的库水作用动力因素,建立滑坡的数值-力学模型。通过实际监测点的变形监测结果与数值-力学模型中模型监测点的变形进行拟合分析,获取了实际时间与数值-力学模型中时步的等效关系;基于时间-时步等效关系及三峡水库设计水位调度曲线,得到了不同时步水位的波动特征;通过时步的外延,并在相应的时步段对数值-力学模型施加等效时间的库水作用,预测了滑坡在未来库水位变动条件下的变形。该预测方法既考虑了滑坡的工程地质模型又考虑了地下水作用效应,克服了纯数学方法预测的不足。     

城市雨水地下回灌过程中悬浮物表面堵塞规律

雨洪资源地下回灌是缓解城市供水压力、解决地下水过量开采引起环境负效应的有效途径之一,但堵塞问题却是制约回灌技术推广的关键问题。基于前人理论,研究了入渗介质与悬浮物粒径中值之比(D₅₀/d₅₀)对堵塞层空间分布的影响。以建立表面堵塞预测模型为目的,利用城市雨水回灌细粒石英砂介质开展室内实验,观测雨水回灌的表面堵塞过程并获取渗透性变化的观测数据。根据物理、化学与生物堵塞的产生条件及堵塞特点,判断雨水回灌产生的堵塞性质为物理堵塞。引入过滤模型描述堵塞的发展过程,确定了模型用于模拟细砂表面堵塞的参数值：孔隙堵塞系数（α）为0.15 m²/kg,阻力增长系数（f′R′）为20 000 m/kg。在不改变以上2个参数值的条件下,用该模型模拟不同悬浮物粒径悬浊水回灌细粒石英砂的堵塞过程,取得了较好的拟合效果。此过滤模型可以用于模拟入渗介质与悬浮物粒径D₅₀/d₅₀值小于5的表面堵塞的发展过程,可定量预测堵塞对回灌速率的影响。     

周期荷载作用下盐岩声发射特征试验研究

通过改变恒幅荷载条件下的上限应力、下限应力以及加载速率等试验条件,基于声发射技术对盐岩疲劳损伤特征进行试验研究。试验发现,盐岩声发射信号出现在加载阶段和卸载初期,而砂岩声发射信号一般集中出现在上限应力处;盐岩疲劳寿命对下限的依赖程度大于砂岩;随着上限应力的增大,盐岩声发射振铃数增多。加载速率的提高会加速盐岩的疲劳破坏。通过对比声发射振铃数累计曲线和应变累计曲线,发现两者有很好的对应关系,说明二者在反映盐岩疲劳损伤时具有一致性。最后对盐岩进行3级变幅荷载试验,发现第3级声发射振铃数比相同上、下限应力的恒幅荷载条件下多,说明变幅荷载造成的盐岩损伤比恒幅荷载条件下严重。     

准噶尔盆地南缘新生代沉积物碎屑锆石记录的天山隆升剥蚀过程

通过对准噶尔盆地南缘有精确古地磁年代控制的金沟河剖面新生代沉积物中7个砂岩样品碎屑锆石的U Pb LA ICP MS测年分析,确定安集海河组（28~23.3 Ma）和沙湾组（23.3~17.5 Ma）的砂岩样品碎屑锆石年龄主要集中在261~328 Ma（P-C）,塔西河组（17.5~13.2 Ma）样品的年龄主要集中在234~311 Ma（T-C）和369~403 Ma（D-S）,独山子组（13.2~6.0 Ma）和西域组（6.0~1 Ma）样品的年龄主要集中在264~333 Ma。经与流域内岩石地层的分布相对比,揭示至少在晚渐新世开始中天山已经隆升并剥蚀为盆地提供物源,从约中新世早期开始北天山的南缘开始隆升,加入物源供给区,从约中新世中晚期开始北天山开始明显隆升,并逐步阻碍了中天山的物源供给,成为物源的主要供给区。天山的这种逐步向北的隆升剥蚀过程,反映了印度欧亚板块碰撞的远程效应。     

Dynamic programming approach for segmentation of multivariate time series

In this paper, dynamic programming (DP) algorithm is applied to automatically segment multivariate time series. The definition and recursive formulation of segment errors of univariate time series are extended to multivariate time series, so that DP algorithm is computationally viable for multivariate time series. The order of autoregression and segmentation are simultaneously determined by Schwarz’s Bayesian information criterion. The segmentation procedure is evaluated with artificially synthesized and hydrometeorological multivariate time series. Synthetic multivariate time series are generated by threshold autoregressive model, and in real-world multivariate time series experiment we propose that besides the regression by constant, autoregression should be taken into account. The experimental studies show that the proposed algorithm performs well.