超高压变质岩石的产生,保存和剥露

出露在西阿尔卑斯和中国的含柯石英榴辉岩记录了其峰期变质作用在２．５ＧＰａ的压力条件下，温度为５５０－９００℃。形成这些区域变质岩，需要大于４００ｋｍ＾２的上地壳物质俯冲到≥９０ｋｍ的深度，并且再连续剥露。已有的动力学资料表明，在有流体存在的情况下，纯的柯石英岩石不可能在剥露中残存这一点已被野外观察所证实。     

非双力偶地震：理论（一）

历史上多数定量地震学的分析是以地震由剪切断裂引起这一假设为根据的,这样其各向同性介质中的等效力系是一对无扭矩的力偶。然而,现在高质量和高覆盖的观测资料使人们能分辩出许多地民双力有偏离,发现一些地震,特别是在火山地区和地热区域的地震,有很强的非双力偶机制。了解非双力偶地震对于仔细研究断裂过程和辨别在某些地震中明显发生的非剪切断裂过程都是重要的。本文了等效力系的“矩阵张量”展开理论,并分析了多个非双力     

Impacts of a raw sewage spill on water and sediment quality in an urbanized estuary

A sewer main serving a large municipal wastewater system ruptured, discharging approximately 3,000,000 gallons (11,355,000 L) of raw human sewage into a multi-branched tidal creek estuary along the US East Coast. The biochemical oxygen demand caused severe hypoxia in the system, causing a large fish kill. The sewage load led to high fecal coliform bacteria concentrations in the creek (maximum of 270,000 CFU 100ml(-1)), which declined in an approximate logarithmic manner over the first few days. The spill caused elevated sediment fecal coliform bacteria and enterococcus counts that declined much more gradually than water column counts. Persistence of relatively high concentrations of fecal indicator bacteria in sediments for several weeks after the spill suggests that sediment sampling should be included in response to major sewage spills. The high concentration of nutrients in the spilled sewage led to several algal blooms. However, nutrient concentrations in the water column declined rapidly, demonstrating the value of conserving marshes because of their pollutant filtration function.     

Differences in SEM-AVS and ERM-ERL predictions of sediment impacts from metals in two US Virgin Islands marinas

Two US Virgin Islands marinas were examined for potential metal impacts by comparing sediment chemistry data with two sediment quality guideline (SQG) values: the ratio of simultaneously extractable metals to acid volatile sulfides (SEM-AVS), and effects range-low and -mean (ERL-ERM) values. ERL-ERMs predicted the marina/boatyard complex (IBY: 2118 microg/g dry weight total metals, two exceeded ERMs) would have greater impacts than the marina with no boatyard (CBM: 231 microg/g dry weight total metals, no ERMs exceeded). The AVS-SEM method predicted IBY would have fewer effects due to high AVS-forming metal sulfide complexes, reducing trace metal bioavailability. These contradictory predictions demonstrate the importance of validating the results of either of these methods with other toxicity measures before making any management or regulatory decisions regarding boating and marina impacts. This is especially important in non-temperate areas where sediment quality guidelines have not been validated.     

High molecular weight polycyclic aromatic hydrocarbons in hydrothermal petroleums from the Gulf of California and Northeast Pacific Ocean

Hydrothermal petroleums and heavy tars have been analyzed for polycyclic aromatic hydrocarbons (PAH) with molecular weights greater than that of coronene (300 da). Samples from the hydrothermal systems in the Guaymas Basin (Gulf of California) and in the Escanaba Trough and Middle Valley (Northeastern Pacific) were analyzed by gas chromatography-mass spectrometry and high pressure liquid chromatography with diode-array absorbance detection. Mass spectra and fluorescence spectra were used to characterize the compounds. Several large PAHs with six and more rings were identified among the heavy PAH. Production routes via one-ring build-up and Scholl-condensation are proposed to explain the observed structures. The variations in PAH concentrations and distributions between samples from different locales are a consequence of the hydrothermal conditions of generation, migration, and post-depositional alteration.     

A terrestrial observatory approach to the integrated investigation of the effects of deforestation on water,energy,and matter fluxes

Integrated observation platforms have been set up to investigate consequences of global change within a terrestrial network of observatories(TERENO)in Germany.The aim of TERENO is to foster the understanding of water,energy,and matter fluxes in terrestrial systems,as well as their biological and physical drivers.Part of the Lower Rhine Valley-Eifel observatory of TERENO is located within the Eifel National Park.Recently,the National Park forest management started to promote the natural regeneration of near-natural beech forest by removing a significant proportion of the spruce forest that was established for timber production after World War II.Within this context,the effects of such a disturbance on forest ecosystem functioning are currently investigated in a deforestation experiment in the Wüstebach catchment,which is one of the key experimental research sites within the Lower Rhine Valley-Eifel observatory.Here,we present the integrated observation system of the Wüstebach test site to exemplarily demonstrate the terrestrial observatory concept of TERENO that allows for a detailed monitoring of changes in hydrological and biogeochemical states and fluxes triggered by environmental disturbances.We present the observation platforms and the soil sampling campaign,as well as preliminary results including an analysis of data consistency.We specifically highlight the capability of integrated datasets to enable improved process understanding of the post-deforestation changes in ecosystem functioning.