Microanalysis of metals in barbs of a snow petrel (Pagodroma Nivea) from the Antarctica using synchrotron radiation X-ray fluorescence

For the first time synchrotron radiation X-ray fluorescence (SR-XRF) microanalysis was performed throughout the total length of 4 single barbs from the primaries and secondaries of a snow petrel (Pagodroma Nivea) collected in the Antarctica. Thirteen elements (S, Mg, K, Ca, Fe, Ni, Cu, Zn, Se, Sr, Ba, Hg and Pb) were detected somewhere in the barbs. Variations in levels of these elements within and among the barbs were obvious, indicating nonuniform microscale distributions. Factors influencing the fluctuations of the levels of the elements were investigated using a multivariate statistical analysis method. Five factors (F1 being associated with high loadings of Ca, Sr, and Ni, F2 with high loadings of Fe and Ba, F3 with high loadings of Se and Hg, F4 with high loadings of Ca and K, and F5 with high loadings of Zn and Pb) were found to explain about 80% of the total variance. Results from the factor analysis suggested external contamination of Fe, Ba, Pb, Zn and Hg on the feathers of the snow petrel.     

Macroalgal bioindicators (growth, tissue N, delta(15)N) detect nutrient enrichment from shrimp farm effluent entering Opunohu Bay, Moorea, French Polynesia

Nutrient enrichment from shrimp aquaculture poses an increasing environmental threat due to the industry's projected rapid growth and unsustainable management practices. Traditional methods to monitor impacts emphasize water quality sampling; however, there are many advantages to bioindicators, especially in developing countries. We investigated the usefulness of three bioindicators -- growth, tissue nitrogen content and nitrogen stable isotope signature (delta(15)N) -- in the tropical red macroalga Acanthophora spicifera. Algae were collected, cultured, and deployed in a spatial array around the outflow from a shrimp farm in Moorea, French Polynesia, to detect nitrogenous wastes. All three parameters were highest adjacent to the shrimp farm indicating nutrient enrichment, and delta(15)N values confirmed the shrimp farm as the dominant nutrient source (5.63-5.96 per thousand). Isotope ratios proved the most sensitive indicator, as delta(15)N signatures were detected at the most distant sites tested, confirming their usefulness in tracing nutrients and mapping the spatial extent of enrichment.     

俯冲带火山下岩浆的形成、上升和存储的时间尺度

现在有足够的资料可用来尝试建立一个关于俯冲带火山下熔体的产生、迁移和存储的完整的模型。在喷发前的几十万年到少于一千年的时间里,都可以发生流体从俯冲的洋壳流到地幔楔中的现象。这支持了认为流体的加入是与部分熔融紧密相关的模型,但也有一些证据可以证明流体是降压熔融的结果。流体开始加入的时间可能与俯冲的速率(例如,水供应的速率)、俯冲的角度以及由此决定的地幔楔的热结构有关。相反,俯冲沉积物到俯冲带熔岩源区的贡献在喷发前大约35万年到4百万年的时候看来就发生了。沉积组分的部分熔融证据与短的流体迁移时间、斑晶平衡温度及其他观测结果的结合都指出,地幔楔在接近于俯冲板块边界上的地方具有相当高的温度。新的226Ra资料表明,在流体加入和火山喷发之间只有很短的时间。这就要求快速的熔体分凝、沿通道流动的岩浆上升过程以及在岩石层内最短的停滞时间。一般说来,在上升期间或者在岩浆房里,发生从玄武岩到安山岩的演化是快速的,这可以从一些有关地幔的地球物理资料来推断。矿物等时线资料表明,一些安山质岩浆后来停在了更浅的岩浆房中。它们可以在那里以几万年或更短些的时间尺度通过分异作用演化成英安质成分,通常都伴有同化作用。     

古气候模拟进展

古气候模拟对研究古气候变化,检验模式模拟与现代气候状况完全不同的古气候的能力,以及未来气候预测等都具有重要的科学和社会意义.国际古气候对比项目(PMIP,Paleoclimate Modeling Intercomparison Project)开展十多年来,取得了许多成果,我国科学家在古气候模拟方面也做了相当的研究.本文通过介绍古气候模拟的方法,评述PMIP试验和其研究成果以及中国科学家所做的研究工作,以使人们更多地了解古气候模拟研究工作的重要意义.     

深埋和加热使有机质活力增加促使深海生物圈活动性增强

深埋和加热使有机质活力增加促使深海生物圈活动性增强ＰｅｔｅｒＷｅｌｓｂｕｒｙ等深海沉积物随着深度增加,温压增大,生命量大大减少,有机质的分布也变得极不规律。因此,深层沉积物中存在着丰度很高的细菌种群似乎就有些不可思议了。怎样来解释年龄高达千万年的深层...     

Post-fire recovery of Puya raimondii,vegetation and birds in the puna of Huascarán National Park,Perú

A large fire of 233 ha in Huascarán National Park in Peru provided an opportunity to compare plant and bird responses in burned and nearby unburned zones of the puna. Heights and live diameters of flagship Puya raimondii rosettes(assigned to four broad developmental phases), plant communities(66 species in 24 families and nine growth forms) and bird communities(77 species in six trophic guilds) were monitored after the fire. Although no mortality was observed, Puya raimondii plants were affected...     

桂林附近第四系粘土砾石层的扫描电镜研究

<正>一、前言 桂林地区以其峰林地形著名于世,近年来地矿部岩溶地质研究所的工作提出了桂林岩溶发育的许多新认识。但是,桂林盆地的第四系沉积物的成因仍存在着不少问题,这些问题的解决将为桂林岩溶发育的研究提供重要的线索。漓江以一条较窄的带状河谷切过了桂林盆地,与其有关的第四系及全新统阶地沉积物无疑属河流成因。然而,在盆地中还有一些其它的也可能属第四系的沉积物,对其成因问题存在着很大分歧,这些沉积物有以下特征。 首先,在桂林市区东北约10公里处,漓江东岸的崔家,王克钧等发现了一些丘状堆积物,      

SCE-UA方法在新安江模型参数优化中的应用

以前在使用新安江模型时人们遇到的最大困难可归因于缺乏有效的参数全局优化的数学方法,事实上对于一个缺乏经验的人来说,模型参数的人工试错计算的过程是一个相当不容易的过程,并且耗时颇多,为此,近些年来研究者们正在探索把概念性水文模型中的专家经验与自动优化计算相结合的方法或者数学优化中的全局优化方法,如SEC-UA方法,本文首先简述新安江模型,而后采用3个大小和气候条件各不相同的流域对SCE-UA算法就在新安江模型计算的参数优化进行了研究,研究结果表明,SCE-UA算法用来进行新安江模型的参数优化所取得的效果是好的,从率定和检验的结果来看,SCE-UA算法可以使得率定的新安江模型的参数达到全局最优并且从概念上也合理。