Dispersion and toxicity to non-target aquatic organisms of pesticides used to treat sea lice on salmon in net pen enclosures

Pesticides are used extensively in the finfish aquaculture industry to control sea lice infestations on farmed salmon. The most prevalent method of use is to enclose a net pen with an impervious tarpaulin and mix a pesticide solution within that enclosure. After treatment for short periods (1 h) the pesticide solution is released to the environment. Concerns have been raised that there is a potential risk to non-target aquatic organisms from those releases. The fate of dispersing pesticide solutions was measured after six simulated treatments in the Lower Bay of Fundy, New Brunswick. Three simulated treatments were done with azamethiphos and three with cypermethrin. Rhodamine dye was added to all pesticide solutions in order to facilitate tracking of the dispersing plume through real-time measurements of dye concentrations by a flow-through fluorometer coupled with a differential global positioning system (DGPS). Water samples were obtained from within the plumes at various times after release and analysed for pesticide content and toxicity to a benthic amphipod Eohaustorius estuaris. Dye concentrations were detectable for time periods after release which varied from 2 to 5.5 h. Distances travelled by the dye patches ranged from 900 to 3000 m and the dye concentrations at the final sampling period were generally 1/200-1/3000 the pre-release concentrations and cypermethrin concentrations were generally 1/1000-1/2000 the pre-release concentrations. Cypermethrin concentrations in water samples were closely correlated with dye concentrations, indicating that dye analyses were an accurate surrogate for cypermethrin concentrations. Most samples taken after the releases of azamethiphos were not toxic to test organisms in 48 h exposures and none were beyond 20 min post-release. By contrast, almost all samples taken after the release of cypermethrin, even up to 5-h post-release, were toxic. Data indicate the potential to cause toxic effects over areas of hectares from a single release of cypermethrin.     

同心挠性管单井蒸汽辅助重力驱

绝热同心挠性管的设计和制造，业已完成了推广研究，并已装配了几口单井蒸汽辅助重力驱，现已投入生产。本文回顾了早期一些井采用的这一工艺，并举例说明其生产效果。初步结果表明，第一代单井蒸汽辅助重力驱完井 效果非常好。这一工艺已成功地应用了不同地区，结果表明其原理适用于重油油藏。     

美国亚利桑那州凤凰市地面沉降和地面裂缝的起源

1980年1月，凤凰市出现首例地裂缝。该区水位下降已超过90m，测得沉降量是1.05m，间接沉降证据为1.5m，地下水位埋深达170多m，最大沉降速率为0.13m/a。地下水位上降始于50年代中期，10年后，当地下水位下降30m～45m后，沉降开始发生，沉降漏斗每年扩大5km^2，先是向西，最近向北向东发展，沉降漏斗还将继续扩大，沉降量可能要超过3m。     

黄陵树木年轮稳定C同位素与气候变化

采用消除大气CO_2影响后的油松树轮6~(13)C序列及附近气象站的气象记录,分析了树轮6~(13)C的气候响应。结果表明:黄陵地区高频6~(13)C的振荡与6月平均气温及5月、6月和7月3个月的降水总和密切相关,在一定程度上反映了东亚夏季风在这一地区的某些特点。     

里海海域水情变化分析的模拟

近80年,里海海平面(ＣＳＬ)的变化原因已为学术界密切关注。1933～1940年里海水位急剧下降1.7ｍ,1979年末又下降1.3ｍ,观测事实推动了有关的科学研究。与气候因素相比,水资源不可逆消耗的增长对河流流量的影响是主要的,里海水位的缓慢下降也与此有关,因此,水位的进一步下降是不可避免的。里海水位在1978年突然回升,直至1995年中期水位持续回升了2.5ｍ左右,但当预期的水位下降时,沿岸地区仍将会有更多的灾难性后果发生。从1995年7月开始,里海水位年平均下降速度加快,至1997年最大下降速度超过40ｃｍ,1997～1998年8月(最新资料)变化不大,这与…     

利用多子波方法对宽频带地震数据的时间残差进行多信道估计

介绍了一种用于估计地震台阵数据到时残差的多信道处理的新方法。该方法综合了3种传统台阵处理方法的特点:频率域波束形成、时间域波束形成和主成分分析。首先对数据进行多子波变换,从而产生一组窄频带地震图。我们利用多子波变換替代加窗的傅里叶变换,以控制时间和频率的分辨率。我们还使用了一种波束形成程序,对转换过的、按时间排齐的数据进行主成分分析。主成分矢量值和成对数值被用来计算衡量波外形相似的相干性。主成分矢量的相差可作为数据与平面波模型拟合偏差的一种量度。相位差可以直接转换成时间差,但它们只能分辩一部分波长。因此,我们的方法是从较低的分析频带移至较高的分析频带的逐步分析法。我们提供了两个实例来说明这种方法在很宽的时空尺度范围均可采用。第一,1994年的玻利维亚深源地震期间,我们测定了一组覆盖南加利福尼亚大部分地区的宽频带地震台的时间残差。时间残差的范围为2s,将它们消除后,我们可以在1.0Hz上把数据叠加。第二,我们研究了在土库曼斯坦的直径不足1km的地震台阵的高频传感器记录的地方震数据。我们发现,时间残差范围只有0.02s,将其消除后,我们显著地改善了信号的主频数据的叠加。     

年青的九州俯冲带的地震结构和岩浆作用

地震层析成像表明，在九州北部深达俯冲的菲律宾海板块的地幔楔存在低速异常，且扩展到弧前区。我们还用岩石学资料采用数值模拟方法估计地幔楔的流体分布。地震学的数值模拟结果表明，年青的板块俯冲带的熔融和岩浆作用不同于老板块。脱水和熔融发生在年青（且热）板块如九州北部（≤26Ma）之上的板块弧和弧前底下，而流体（水溶液和熔融）主要发生在老板块区的弧后。     

Sanidine—olivine—diopside Association in a Metasomatized Garnet Lherzolite Xenolith from Southeastern China

A garnet lherzolite xenolith hosted in olivine nephelinite from Xilong,Zhejiang Province ,southeastern China, shows clear evidence of modal metasomatism involving a special sanidine-olivine-diopside(SOD) association which was produced by replacement of primary orthopyroxene.The fluid responsible for the measomatism was a silica-undersaturated vapour,rich in K,Ba,Sr and Ti.It is suggested that the SOD assemblage is the product of metasomatism of a depleted lherzolite precursor,and formed in the upper mantle prior to entrainment and eruption.