菊黄东方鲀胚胎及仔稚幼鱼的发育

本文报道了菊黄东方鲀胚胎及仔稚幼鱼发育情况.其结果表明:在水温20-21℃、盐度20-30、pH值8.0-8.3的条件下,受精卵受精后2h为2细胞期、15h为囊胚期、30h为原肠期、55h为胚体期、152h孵出仔鱼;孵出仔鱼在水温19-28℃、盐度20-30、pH8.0-8.3条件下,孵化后5d开口、18d进入稚鱼期、40d进入幼鱼期.此外,对胚胎及仔稚幼鱼各发育阶段进行较详细描述、测量并给出示意图.     

Investigating young water fractions in a small Mediterranean mountain catchment: Both precipitation forcing and sampling frequency matter

The proportion of water younger than 2–3 months (young water fraction, F_yw) has become increasingly investigated in catchment hydrology. F_yw is typically estimated by comparing seasonal tracer cycles in precipitation and streamflow, through water sampling. However, some open research questions remain, such as: (i) whether part of the summer precipitation should be discarded because the high evapotranspiration demand, (ii) how well F_yw serves as a metric to compare catchments, and (iii) how sampling frequency affects F_yw estimates. To address these questions, we investigated F_yw in soil-, ground- and stream waters for the small Mediterranean Can Vila catchment. Rainfall was sampled at 5-mm intervals. Mobile soil water and groundwater were sampled fortnightly. Stream water was sampled depending on flow at variable time intervals (30 min to 1 week). Over 58 months, this sampling provided 1,529 δ¹⁸O determinations. Isotopic analyses results led us to include summer precipitation in the input signal. We found the highest F_yw in mobile soil waters (34%), while this was almost zero for groundwater except during wet periods. For stream waters, F_yw depended on the discharge variations, so that the flow-weighted young water fraction () was 22.6%, whereas the time-weighted F_yw was just 6.2%. Both and its discharge sensitivity (S_d) varied when different 12-month sampling periods were investigated. The young water fraction that would be obtained from a virtual thorough sampling () was estimated from the S_d and the observed stream flow. This showed an underestimation of by 25% for the frequent dynamic sampling and 66% for weekly sampling, due to missing high flows. Our results confirm that F_yw and its discharge sensitivity are metrics very sensitive to meteorological forcing during the analysed period. Thus, comparisons between catchments need long-term mean annual values and their variability. Our findings also support the dependence of F_yw estimates on the sampling rate and show the advantages of flow-weighted analysis. Finally, catchment water turnover investigations should be accompanied by the analysis of flow duration curves.     

年轻地下水测年最新技术——SF6法

SF6是一种无色、无嗅、无毒、不易燃的惰性气体,具有良好的绝缘性、灭弧性和散热性,广泛用于断路器和变压器的绝缘材料。电器设备的泄漏使得大气中SF6浓度增加很快,每年达7%,造成SF6的人工来源,此外还有天然来源。SF6通常用带电子捕获器(ECD)的气相色谱仪测定。SF6是一种新型的测定年轻地下水年龄的工具,特别适合研究1990年以后补给水的年龄。SF6年龄以亨利定律为基础计算。由于大气中SF6浓度逐年增加,比CFC测年法具有更大的优越性。     

甘肃河西走廊保护地西瓜育苗的热量指标及其应用

用１９８９、１９９０年田间试验资料，结合当地气候资源和危害——西瓜生产的主要气象灾害霜冻，系统分析了西瓜育苗热量指标，得出保护地西瓜育苗适播期和育苗所需积温、气温指标，提出了相应的农技措施     

人文与经济地理学的传承与创新：青年学者的责任

2018年1月27-28日,人文与经济地理学青年论坛暨第二届中国科学院区域可持续发展分析与模拟重点实验室青年论坛在北京国家会议中心成功举办。青年论坛以“人文与经济地理学的传承与创新：青年学者的责任与行动”为主题。莅临会场的院士、前辈和主管部门领导纷纷表示鼓励、支持和关怀青年人才的更快更好的成长。在这样的背景下,以这次青年论坛主题为题,在新时代传承和创新人文与经济地理学,青年学者责无旁贷,追寻地理学家的精神,集中探讨青年学者的责任与行动,展示人文与经济地理青年学者的思考和风采。     

海带CRY-DASH基因的克隆与转录表达分析

利用cDNA末端快速克隆(RACE)技术,获得海带(Saccharina japonica) CRY-DASH基因(SjCRYDASH)全长序列,结构分析发现,其ORF区长1779 bp,编码592个氨基酸。进行氨基酸同源序列比对,其与其他藻类和高等植物间存在两个重要辅基MTHF和FAD结合的保守域。通过不同光质照射诱导海带幼孢子体,发现蓝光、白光诱导1h后,均能使SjCRY-DASH转录水平上升,且SjCRY-DASH对蓝光的响应更强烈。本研究结果为研究大型褐藻-海带CRY-DASH受光诱导调控功能打下基础。     

双棘黄姑鱼早期发育阶段的摄食习性与生长特性

2002年5~6月,在集美大学水产学院水产试验场,采用生态学方法对人工培育的双棘黄姑鱼(Nibeadiacanthus(Lacpde))仔、稚、幼鱼的摄食习性与生长特性进行分析。结果表明,在人工培育条件下,双刺黄姑鱼仔、稚、幼鱼的摄食率达93.1%,摄食量占体质量的4.09%~21.07%,日摄食量占体质量的23.67%~57.24%;摄食具明显的昼夜节律,黄昏为摄食高峰。摄食量与体质量的关系式为y=0.1267x0.7878,全长与日龄的关系式为L=1.8603e0.0723D,体质量与日龄的回归方程为M=0.0203e0.2484D。全长与体质量的回归方程为M=0.0024L3.4633。     

鲍鱼幼苗培养池附板上的危害性纤毛虫及其优势类群研究

应用纤毛虫的定性和定量方法,研究了人工养殖幼鲍培养池中危害性纤毛虫的种类组成和数量变化过程及优势类群的种群动力学变化。共观察到16目、46属、68种纤毛虫,锐利Shun纤虫Aspidisca lynicaster、钟虫Vorticella sp.和双眉虫Diophrys histrix是优势种。还对幼鲍培养过程中危害性纤毛虫的密度、种类与幼苗附板上藻类密度、鲍苗密度等关系进行了分析。     

不同饵料对点带石斑鱼幼鱼生长、存活的影响

使用5种不同的饵料，投喂全长6．72mm的点带石斑鱼，分析和比较不同饵料的营养成份对点带石斑鱼幼鱼生长、存活的影响．结果表明：尽管饵料中粗蛋白的含量在48．8％～72．8％之间，粗脂肪含量在5．4％～10．3％之间，相差很大，但点带斑鱼幼鱼均能正常生长，且存活率无明显的差异．对5种饵料的脂肪酸进行了分析，结果显示，饵料中高度不饱和脂肪酸DHA和EPA的含量之间的比例，对点带石斑鱼幼鱼的生长比其含量本身更加具有明显的影响，DHA与EPA相对含量的比值为6．3的1组，其幼鱼的生长速度明显快于比值为1．73～2．75的其他4个饵料组。     

On the nature of the unique eclipsing system H 187 (HMW 15)

We present our photometric observations of the T Tauri star H 187. They confirm our conclusion that a new extended eclipse has begun in this young object. By the end of 2005, H 187 reached its minimum light following which its brightness began to slowly increase. Comparison with the previous ～3.5-yr-long eclipse observed by Cohen et al. shows that the new eclipse follows the previous eclipse fairly closely and, hence, it was caused by a second passage of the same extended dust or gas-dust cloud around the object. We have estimated the period between these events to be 4.7 yr. The object reddened during the eclipse, suggesting that the extinction was produced by small grains ～0.1μm in size. Possible mechanisms of such unusual eclipses are discussed. We draw an analogy between these eclipses and the cycles of photometric activity observed in UX Ori stars. Light curves similar to those observed for H 187 are shown to be obtained in the model of a young binary system with a low-mass companion accreting matter from the remnants of a protostellar cloud at a rate of ～10^?9 M _⊙ yr^?1.