一株海绵附生芽孢杆菌的抗硅藻附着活性成分的分离鉴定

为寻找天然抗污损活性化合物,以抗硅藻附着活性为导向,采用有机溶剂萃取、半制备高压液相色谱对分离自海绵的芽孢杆菌UST050418-715代谢产物进行分离,纯化抗硅藻附着活性物质,并利用气相色谱-质谱联用仪、核磁共振波谱分析活性物质结构。从菌株UST050418-715代谢产物中分离得到7种具有抗硅藻附着活性的环二肽类化合物,分别鉴定为:(1)环(L-亮氨酸-反式-8-羟基-L-脯氨酸-)、(2)环(L-缬氨酸-L-脯氨酸)、(3)环(D-脯氨酸-L-亮氨酸)、(4)环(L-脯氨酸-D-亮氨酸)、(5)环(甘氨酸-L-脯氨酸)、(6)环(L-苯丙氨酸-顺式-8-羟基-D-脯氨酸-)、(7)环(L-苯丙氨酸-反式-8-羟基-L-脯氨酸-)。说明海绵附生芽孢杆菌UST050418-715代谢产物中存在大量环二肽类化合物,可以帮助宿主海绵实现对硅藻附着的化学防御。     

基于船位监控系统的拖网捕捞努力量提取方法研究

为了基于船位监控系统提取拖网捕捞努力量,通过统计航速获得3个峰值,拖网作业在第2个峰值,即1~2.1 m/s,拖网作业航向差一般在–50°~50°。利用航速、航向差阈值设定,把拖网船状态划分为慢速、作业、航行,然后提取出捕捞作业状态点,1 423艘拖网船共提取到处于捕捞状态的点318 433个,合计拖网捕捞时间15 921 h,利用反距离加权插值法生成捕捞强度分布变化趋势图。捕捞努力量在渔业资源研究中是重要的参考值之一,与传统的捕捞努力量计算方法相比,该方法具有实时、大范围、快速、分辨率高的特点,能够用于辅助渔业资源保护。     

178Hz正弦波对刺参行为、呼吸及免疫应答的影响

根据山东荣成沿岸风电机组产生的声波范围选取其中178Hz的峰值声音,声压级控制于(85±5)d B,在实验室水槽中,采用实验生态学方法研究了178Hz声波影响下的刺参(Apostichopus japonicus)幼参的行为反应、耗氧率以及体腔液抗氧化酶(CAT、SOD)浓度的变化。通过平均聚集率的变化比较,发现刺参对178Hz的声波胁迫环境的行为反应敏感;利用空瓶法测得幼参耗氧率显著低于对照组(P0.05);通过测定刺参体腔液免疫活性发现在该频率声波干扰下的刺参CAT活性显著高于对照组(P0.05),而SOD活性于对照组差异不明显(P0.05)。研究结果说明声波对刺参幼参的呼吸和免疫会产生明显影响,可为我国近海刺参养殖和风电发展策略提供参考。     

基于20a卫星高度计数据的黑潮变异特征

黑潮作为一支典型的西边界流,其路径变化特征及其相关的物理现象对于渔业和航海有着不可忽视的影响。本文基于改进的特征线方法,利用1992~2012年的高度计绝对动力地形数据提取了整个黑潮流区逐月的黑潮主轴和边界位置,并对沿轴速度、主流宽度、表层水体输运以及路径标准差等黑潮特征量进行了分析研究。结果表明,黑潮整体的沿轴速度在夏秋季较大,最大值可达0.95 m/s,而在冬季的速度较小;黑潮主流宽度在10、11月份达到最大值;黑潮表层水体输运在夏季最大,春秋两季次之,冬季最小。沿黑潮流路分区域对黑潮特征进行分析,结果表明,越往黑潮下游,其沿轴速度、主流宽度和表层水体输运越大,同时沿轴速度和表层水体输运量最大值出现的时间也越晚,黑潮主轴位置相对于其多年平均的偏离程度越大,且随时间波动也越强烈。     

Distinct groundwater recharge sources and geochemical evolution of two adjacent sub-basins in the lower Shule River Basin,northwest China

Based on analysis of groundwater hydrogeochemical and isotopic data, this study aims to identify the recharge sources and understand geochemical evolution of groundwater along the downstream section of the Shule River, northwest China, including two sub-basins. Groundwater samples from the Tashi sub-basin show markedly depleted stable isotopes compared to those in the Guazhou sub-basin. This difference suggests that groundwater in the Tashi sub-basin mainly originates from meltwater in the Qilian Mountains, while the groundwater in the Guazhou sub-basin may be recharged by seepage of the Shule River water. During the groundwater flow process in the Tashi sub-basin, minerals within the aquifer material (e.g., halite, calcite, dolomite, gypsum) dissolve in groundwater. Mineral dissolution leads to strongly linear relationships between Na⁺ and Cl^? and between Mg²⁺+ Ca²⁺ and SO₄ ^2??+?HCO₃ ^?, with stoichiometry ratios of approximately 1:1 in both cases. The ion-exchange reaction plays a dominant role in hydrogeochemical evolution of groundwater in the Guazhou sub-basin and causes a good linear relationship between (Mg²⁺+ Ca²⁺)–(SO₄ ^2??+?HCO₃ ^?) and (Na⁺+ K⁺)–Cl^? with a slope of ?0.89 and also results in positive chloroalkaline indices CAI 1 and CAI 2. The scientific results have implications for groundwater management in the downstream section of Shule River. As an important irrigation district in Hexi Corridor, groundwater in the Guazhou sub-basin should be used sustainably and rationally because its recharge source is not as abundant as expected. It is recommended that the surface water should be used efficiently and routinely, while groundwater exploitation should be limited as much as possible.     

Two-dimensional landslide dynamic simulation based on a velocity-weakening friction law

Surprisingly, hypermobility (high velocity and long run-out) is a remarkable feature of large landslides and is still poorly understood. In this paper, a velocity-weakening friction law is incorporated into a depth-averaged landslide model for explaining the higher mobility mechanism of landslides. In order to improve the precision of the calculation, a coupled numerical method based on the finite volume method is proposed to solve the model equations. Finally, several numerical tests are performed to verify the stability of the algorithm and reliability of the model. The comparison between numerical results and experimental data indicates that the presented model can predict the movement of landslide accurately. Considering the effect of velocity-weakening friction law, the presented model can better reflect the hypermobility of landslide than the conventional Mohr–Coulomb friction model. This work shows that the application of a universal velocity-weakening friction law is effective in describing the hypermobility of landslide and predicting the extent of landslides.     

Molybdenum Mass Fractions and Isotopic Compositions of International Geological Reference Materials

The double‐spike method with multi‐collector inductively coupled plasma‐mass spectrometry was used to measure the Mo mass fractions and isotopic compositions of a set of geological reference materials including the mineral molybdenite, seawater, coral, as well as igneous and sedimentary rocks. The long‐term reproducibility of the Mo isotopic measurements, based on two‐year analyses of NIST SRM 3134 reference solutions and seawater samples, was ≤ 0.07‰ (two standard deviations, 2s, n = 167) for δ^98/95Mo. Accuracy was evaluated by analyses of Atlantic seawater, which yielded a mean δ^98/95Mo of 2.03 ± 0.06‰ (2s, n = 30, relative to NIST SRM 3134 = 0‰) and mass fraction of 0.0104 ± 0.0006 μg g^?1 (2s, n = 30), which is indistinguishable from seawater samples taken world‐wide and measured in other laboratories. The comprehensive data set presented in this study serves as a reference for quality assurance and interlaboratory comparison of high‐precision Mo mass fractions and isotopic compositions.     

经略21世纪海上丝路:重要航线、节点及港口特征

为了更好地认识21世纪海上丝绸之路(简称"海上丝路"),文章对"海上丝路"涉及的重要航线、节点及港口的地理位置、气候状况、水文特征、商业价值、人文背景等进行梳理。重要航线、节点及港口的使用与管理作为"海上丝路"建设的基础要素,是与造船能力并列的核心资源,三者之间环环相扣,构成"海上丝路"健康运营的完整体系。与沿"海上丝路"国家稳步推进航线、节点及港口的管理、开发与维护,打造坚实的战略支撑点、现代之"海上驿站",是成功实现我国资源多样化、产业走出去、贸易全球化的最佳路径之一,以此为契机,融入现有国际海洋法公约并在践行过程中制定利我的海上政策体制,助力"海之梦"、"中国梦"。     

经略21世纪海上丝路之海洋环境特征:海流特征

海流对于海洋渔业、海洋表层初级生产力分布、海洋物质输运等理化生现象有着重要影响。文章利用海洋再分析流场资料,简要分析印度洋海区和南海海区(20°S—30°N,30°E—130°E)的流场年平均以及季节变化特点,得出以下结论:1南海海区流场的季节变化显著,受到季风、黑潮和地形的共同影响作用,在东北季风期间存在沿粤东沿岸至海南岛南侧转向沿越南沿岸的一支流系,该流系的强度变化影响爪哇海等南海南侧海区流场变化。2苏拉威西岛东侧和加里曼丹岛西侧流系有明显的季节变化,在流动强盛的时期这两支流系均是偏南向流动;从爪哇海流出的海流常年存在,夏季附近流速最大,最大流速分布在1.0m/s。3赤道印度洋海区和非洲东岸的沿岸流存在明显的季节变化,上层海区流动的低流速区存在流向切变;沿岸流最大流速在5-9月出现,可达1.8m/s以上,而赤道流系则在11月,可达0.8m/s以上。     

硫酸镁对仿刺参幼参麻醉效果的研究

本研究以硫酸镁作为麻醉剂,比较了在不同水温条件下硫酸镁对仿刺参幼参的麻醉效果,分析了不同浓度硫酸镁对仿刺参幼参的麻醉效果。实验水温设置11℃、13℃、15℃、17℃、19℃和21℃六个温度梯度,实验用仿刺参幼参规格分为大规格(L)40.26±1.84g、中规格(M)21.83±1.72g、小规格(S)11.03±1.63g。实验结果显示:1.在硫酸镁麻醉剂浓度相同时,仿刺参规格越大麻醉所需时间越长,复苏时间却越短;随着麻醉剂浓度增加,对仿刺参幼参麻醉时间相应缩短,但复苏时间呈现逐渐延长。不同浓度硫酸镁麻醉剂对不同规格仿刺参的麻醉效果具有显著差异(P0.05)。2.在水温11℃~20℃范围内,随着水温的升高,对仿刺参幼参的麻醉时间从26.13±17.78min缩短到21.47±3.52min,但复苏时间从26.13±17.78min增加到71.05±12.32min,不同水温条件下硫酸镁对仿刺参幼参麻醉效果影响显著(P0.05)。研究表明,仿刺参体重在20g以下的适宜麻醉浓度为0.1~0.25mol·L-1,体重在20g以上的适宜麻醉浓度为0.25~0.35mol·L~(-1)。