蚤状溞的海水驯化研究

蚤状溞(Daphnia pulex)是一种习见的淡水枝角类,是鱼虾类苗种培育中理想的活饵料.目前,对淡水枝角类的耐盐性及驯化的研究尚不多见,国内仅何志辉等[1,2]对蒙古裸腹 (Moina mongolica)、大型溞(D. magna)等进行过研究.本文作者曾就老年低额溞(Simocephalus vetulus)和蚤状溞(D.pulex)的耐盐性进行过初步试验[3].为了探究淡水枝角类作为海产动物人工育苗中活饵料的可能性,作者对蚤状溞进行了海水驯化的研究.     

蚤状溞(Daphnia pulex)热休克蛋白Hsp90基因的克隆与表达分析

利用RACE技术从蚤状溞(Daphnia pulex)中克隆到Hsp90基因cDNA全长为2568bp,开放阅读框为2155bp,编码718个氨基酸残基,Hsp90蛋白中存在GxxGxG、LxxLL模块(亮氨酸拉链)和C末端的MEEVD序列。同源性比对结果显示蚤状溞Hsp90基因与日本对虾和刀额新对虾的同源性最高为85%,与其它甲壳纲物种的同源性保持在79%及以上。进化分析发现,蚤状溞Hsp90基因与剑水蚤、日本沼虾、红螯相手蟹等甲壳纲的亲缘关系最近。用Real Time PCR技术,检测了Hsp90mRNA在蚤状溞不同生殖状态下的表达水平:Hsp90 mRNA在两性溞(带冬卵)中的表达量明显高于孤雌溞(带夏卵)(P0.05),且在冬卵中的表达量最低。推测Hsp90可能参与了蚤状溞的生殖转化调控。Hsp90 mRNA在雄溞中的表达量是孤雌溞的2.4倍,说明Hsp90可能参与了精子的形成过程。     

摄食紫菜粉等4种单一饵料的蚤状潘脂肪酸组成的比较

用GC／MS法分析比较了紫菜粉、小球藻、酵母、Banta液（牛粪1．5g＋干稻草2g＋沃土20g＋水1000cm3）4种食物条件下蚤状潘的脂肪酸组成．结果表明：4种食物培养下,蚤状潘的总脂含量依次为39．80、60．10、44．60、52．30mg／g．一共检测出脂肪酸14种,其中8种饱和脂肪酸（SFA）,2种单不饱和脂肪酸（MUFA）,4种多不饱和脂肪酸（PUFA）．紫菜粉培养组与小球藻组PUFA含量显著高于酵母组和Banta液组（P〈0．05）,占总脂肪酸的1／3以上,酵母组MUFA质量分数最高（P〈0．05）,达55．73％,Banta液组以SFA质量分数最高（P〈0．05）,为52．45％．其中紫菜粉组的PUFA中缺乏C18：3,但C20：5（EPA）和C20：4（AA）质量分数高达22．67％和9．02％是小球藻组的1．6倍和4．5倍（P〈0．05）,而且EPA和AA的实际含量也显著高于小球藻组（P〈0．05）,达到9．02mg／g和3．59mg／g;比较得出,紫菜粉培养组的20碳以上必需不饱和脂肪酸含量丰富,明显高于其他3组．本实验证实蚤状潘的脂肪酸组成与食物脂肪酸成正相关．分析认为,用紫菜粉培养枝角类用于海水育苗会取得更佳的营养效果．     

RNA干扰蚤状溞(Daphnia pulex)doublesex1基因的表达研究

为了探索doublesex1(dsx1)基因是否在蚤状溞的生殖转换过程中发挥作用,利用蚤状溞滤食摄食的特点将体外合成的dsx1双链RNA(ds RNA)通过浸泡得方法分别摄入不同生殖状态的溞体中,实现dsx1基因的表达沉默。随后采用荧光定量PCR(q PCR)以及整体原位杂交分别检测不同生殖状态下蚤状溞在RNAi前后体内dsx1的表达水平变化,进而研究dsx1在蚤状溞生殖转换过程中的作用。结果表明:雄性溞、两性溞、孤雌溞在RNAi后均出现了dsx1 m RNA表达水平的显著下调,且下调量具有显著性差异(P0.05)其中在孤雌溞中下调68%,在三种生殖状态中最为显著,其次是雄性溞(56%)和两性溞(20%)。同时发现,干扰前能够在溞的第一触角、第一胸肢和复眼上检测到明显的信号位点,而在RNAi后,仅在溞体的第一触角上发现少量dsx1基因表达位点,且第一胸肢及复眼上未检测到相关信号。结合未干扰前dsx1在不同生殖状态溞的表达定量以及定位结果,我们推测dsx1可能在蚤状溞的生殖转化基因调控过程中扮演关键角色,并且在维持雄性蚤状溞性别特征的机制中发挥重要作用。     

Impact of the displacement damage in channel and source/drain regions on the DC characteristics degradation in deep-submicron MOSFETs after heavy ion irradiation

This paper mainly reports the permanent impact of displacement damage induced by heavy-ion strikes on the deep-submicron MOSFETs. Upon the heavy ion track through the device, it can lead to displacement damage, including the vacancies and the interstitials. As the featured size of device scales down, the damage can change the dopant distribution in the channel and source/drain regions through the generation of radiation-induced defects and thus have significant impacts on their electrical characteristics. The measured results show that the radiation-induced damage can cause DC characteristics degradations including the threshold voltage, subthreshold swing, saturation drain current, transconductance, etc. The radiation-induced displacement damage may become the dominant issue while it was the secondary concern for the traditional devices after the heavy ion irradiation. The samples are also irradiated by Co-60 gamma ray for comparison with the heavy ion irradiation results. Corresponding explanations and analysis are discussed.     

气候变化对鲑鱼丰富度和繁殖影响的研究进展

鲑鱼是人类重要的食品来源之一,具有巨大的经济价值。同时,鲑鱼资源通过输送营养物质对维持溪流和陆地生态系统的结构、功能和过程等有重要作用。而鲑鱼是对温度极为敏感的冷水性鱼类,对气候变化的反应尤为明显。作者通过文献综述法梳理相关研究,从气候变化引起的温度变化、淡水和海洋环境的变化以及鱼病传播4个方面探讨对鲑鱼丰富度和繁殖的影响,并提出研究展望。研究显示:温度变化对鲑鱼的产卵和迁徙有较大影响;溪流和河流流量的改变会影响鲑鱼的迁徙和幼年鲑鱼的存活数量;温度和二氧化碳浓度的变化使海洋食物供应减少,鲑鱼丰富度降低;水温的升高使病原体增加,鲑鱼死亡率增加。本研究成果可为鲑鱼种群应对气候变化的研究及管理提供一定的理论支持。     

DDT对细巧华哲水蚤（Sinocalanus tenellus）摄食、呼吸、存活和生殖的影响研究

DDT(dichloro-diphenyl-trichloroethane) as a type of organochlorine pesticides, is an important component of pesticides pollution whose impact on the marine ecosystem is urgently to be evaluated. To investigate the biological effects of DDT on the marine ecosystem, copepods being the main contributor of secondary productivity in the marine ecosystem, were selected as target animals. The influence of DDT on the feeding, respiration, survival, and reproduction of Sinocalanus tenellus(S. tenellus) was analyzed and the antioxidant enzymes activities in the individuals were measured under different exposure concentrations of DDT. The 48 h median lethal concentration(LC50) and 96 h LC50 of DDT to S. tenellus were 5.44 and 2.50 μg/dm3, respectively. The filtration rates, grazing rates, and respiration of S. tenellus decreased apparently with increased DDT concentrations. Under lower concentration(625 ng/dm3) of DDT, the activities of the antioxidant enzymes, including superoxide dismutase and catalase in the animals increased significantly compared with those in the animals without any exposure to DDT, which suggested that the antioxidant enzymes can protect the animals from oxidative damage. However, the activity of the antioxidant enzyme decreased when the animals were exposed to higher concentration(1 250–2 500 ng/dm3) of DDT. The survival rate of both females and males was reduced when they were exposed to DDT less than 250 ng/dm3, but females showed higher survival rate than males when they are under the same concentration. The hatching ratio and the egg diameters of S. tenellus decreased significantly when they were exposed to DDT with a concentration of 25 and 250 ng/dm3, however, the cumulative egg production did not show any significant variation when the animals were exposed to the above DDT concentration. These data in the preset study suggested that exposure to DDT can cause the variation of the species composition of copepods, and further affect the marine ecosystem.     

弱流场调制下的海面微波散射模拟研究

根据海面微波散射的多尺度模型以及波流相互作用理论,对一维弱流场调制下的海面微波散射截面进行了数值模拟。结果表明,利用数值方法直接求解波作用量方程获得的海浪调制谱并结合多尺度模型可以较好地模拟弱流场引起的雷达散射截面的变化。内波等海洋现象调制了海浪谱,使得雷达散射截面反映出这些海洋特征,整个调制过程的模拟对于分析这些海洋现象并更好地利用其雷达数据具有重要意义。     

西湖硅藻对桡足类浮游动物繁殖的影响

本文报道从杭州西湖筛选分离的两种淡水硅藻,即尖针杆藻Ｓｙｎｅｄｒａａｃｕｓ和谷皮菱形藻Ｎｉｔｚｓｃｈｉａｐａｌｅａ对西湖两种淡水浮游桡足类,即近亲拟剑水蚤Ｐａｒａｃｙｃｌｏｐｓａｆｆｉｎｉｓ和大尾真剑水蚤Ｅｕｃｙｃｌｏｐｓｍｕｃｒｒｏｉｄｅｓ卵孵化率的影响。结果表明,在较高密度的硅藻培养液（１．２×１０４～５．４×１０４个／ｃｍ３）中培养的桡足类动物,其卵的孵化率比生活在自然水体中的有明显降低,并发现该密度的实验硅藻对其摄食者——桡足类的母体也产生一定的毒害作用。该实验结果与已报道的某些海洋硅藻对海洋桡足类存在毒害作用的结果,对水域生态系食物链（网）中硅藻作用的传统概念提出了挑战,对水域生态学研究提出了新课题。     

Assessment of the initial sea surface temperature product of the scanning microwave radiometer aboard on HY-2 satellite

HY-2 satellite is the first satellite for dynamic environmental parameters measurement of China,which was launched on 16th August 2011.A scanning microwave radiometer（RM） is carried for sea surface temperature（SST）,sea surface wind speed,columnar water vapor and columnar cloud liquid water detection.In this paper,the initial SST product of RM was validated with in-situ data of National Data of Buoy Center（NDBC） mooring and Argo buoy.The validation results indicate the accuracy of RM SST is better than 1.7 C.The comparison of RM SST and WindSat SST shows the former is warmer than the latter at high sea surface wind speed and the difference between these SSTs is depend on the sea surface wind speed.Then,the relationship between the errors of RM SST and sea surface wind speed was analyzed using NDBC mooring measurements.Based on the results of assessment and errors analysis,the suggestions of taking account of the affection of sea surface wind speed and using sea surface wind speed and direction derived from the microwave scatteromter aboard on HY-2 for SST product calibration were given for retrieval algorithm improvement.     

Sea surface temperature retrieval based on simulated microwave polarimetric measurements of a one-dimensional synthetic aperture microwave radiometer

Compared with traditional real aperture microwave radiometers, one-dimensional synthetic aperture microwave radiometers have higher spatial resolution. In this paper, we proposed to retrieve sea surface temperature using a one-dimensional synthetic aperture microwave radiometer that operates at frequencies of 6.9 GHz, 10.65 GHz,18.7 GHz and 23.8 GHz at multiple incidence angles. We used the ERA5 reanalysis data provided by the European Centre for Medium-Range Weather Forecasts and a radiation transmission forward model to calculate the model brightness temperature. The brightness temperature measured by the spaceborne one-dimensional synthetic aperture microwave radiometer was simulated by adding Gaussian noise to the model brightness temperature.Then, a backpropagation(BP) neural network algorithm, a random forest(RF) algorithm and two multiple linear regression algorithms(RE1 and RE2) were developed to retrieve sea surface temperature from the measured brightness temperature within the incidence angle range of 0°–65°. The results show that the retrieval errors of the four algorithms increase with the increasing Gaussian noise. The BP achieves the lowest retrieval errors at all incidence angles. The retrieval error of the RE1 and RE2 decrease first and then increase with the incidence angle and the retrieval error of the RF is contrary to that of RE1 and RE2.     

渤海海面太阳辐照强度的观测分析与计算方法研究

对渤海海面(1998-09-24～10-07和1999-04-28～05-11)实测太阳辐射日总量同云量的关系和春、秋季的对比关系及其与插值计算出的晴日太阳辐射日总量的关系进行了分析,并同烟台(福山)测站的结果进行了对比分析.通过分析发现,渤海海面太阳辐射日总量春季远大于秋季,其无云条件下的太阳辐射日总量与插值计算出的晴日太阳辐射日总量的差异秋季大于春季.分析表明,海陆温差引起的海面大气垂直输送与水汽物的产生是造成这种差异的主要原因.采用经验公式对渤海海面太阳辐射日总量进行计算,计算结果与实测结果具有较好的一致性.结果表明所用经验公式及推算出的参数适合于春、秋季渤海海面太阳辐照度的计算.     

Merging satellite infrared and microwave SSTs: Methodology and evaluation of the new SST

The Global Ocean Data Assimilation Experiment (GODAE) requires the availability of a global analyzed SST field with high-resolution in space (at least 10 km) and time (at least 24 hours). The new generation SST products would be based on the merging of SSTs from various satellites data and in situ measurements. The merging of satellite infrared and microwave SST data is investigated in this paper. After pre-processing of the individual satellite data, objective analysis was applied to merge the SST data from NOAA AVHRR (National Oceanic and Atmospheric Administration, Advanced Very High Resolution Radiometer), GMS S-VISSR (Geostationary Meteorological Satellite, Stretched-Visible Infrared Spin Scan Radiometer), TRMM MI (Tropical Rainfall Measuring Mission, Microwave Imager: TMI) and VIRS (Visible and Infrared Scanner). The 0.05° daily cloud-free SST products were generated in three regions, viz., the Kuroshio region, the Asia-Pacific Region and the Pacific, during one-year period of October 1999 to September 2000. Comparisons of the merged SSTs with Japan Meteorological Agency (JMA) buoy SSTs show that, with considerable error sources from individual satellite data and merging procedure, an accuracy of 0.95 K is achieved. The results demonstrate the practicality and advantages of merging SST measurements from various satellite sensors.