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.     

美国前寒武纪

美国地下约60％为前寒武岩石,但出露的却不超过10％。太古宙岩石分布于加拿大地盾苏必利尔克拉通和怀俄明—蒙大拿地盾怀俄明克拉通的南部。苏必利尔克拉通主要由年龄为2750～2600Ma的花岗绿岩和变质沉积片麻岩呈互层带组成。在明尼苏达和密执安州的苏必利尔克拉通南部的太古宙片麻岩,在早元古宙又部分地重新活化。这个     

Historical trends of organic pollutants in sediment cores from Hong Kong

Recent studies have indicated the occurrence of a wide range of trace organic contaminants, including polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in the Hong Kong environment. These contaminants are potentially harmful to ecological systems, particularly in coastal areas. In this study, two sediment cores (4m) were collected from southern waters of Hong Kong in 2004 to study the historical trends, distribution patterns, and potential sources of trace organic contaminants. DDTs (p,p'-DDT, o,p'-DDT, p,p'-DDD, o,p'-DDD and p,p'-DDE), hexachlorohexanes (HCHs) (alpha and gamma), hexachlorobenzene (HCB), and PCBs were detected in the samples, whereas other target compounds were all below detection limits. Many OCPs have not been produced or used for many years due to toxicological or environmental concerns and PCB use is prohibited in Hong Kong. However, some compounds were still detectable in recent years, and were found to be widely distributed in the environment, likely because of pollutant inputs from the highly industrialized Pearl River Delta region. These results provide important information on current and historical contamination in Hong Kong, and help to reconstruct the pollution history of these trace organic pollutants in Hong Kong coastal waters.     

The effects of Phaeocystis globosa bloom on the dynamics of the mineralization processes in intertidal permeable sediment in the Eastern English Channel (Wimereux, France)

In the Eastern part of the English Channel, high biomasses of the phytoplankton prymnesiophyceae Phaeocystisglobosa (reaching biomasses over 20 microg Chlal(-1)) are a recurrent spring event (March-June). A significant part of the pelagic Phaeocystis-derived organic matter can be broken down in the sandy permeable sediment that makes up most of the intertidal zone in this part of the Channel. Sediment characteristics, macrofaunal distribution, bacterial biomass, organic carbon content, sediment oxygen demand (SOD), and the sediment-water flux of dissolved inorganic nitrogen and silicates were calculated for an exposed sandy beach (Wimereux, France) over a two-year period (2004-2006). According to the data collected, the SOD remains relatively low throughout the whole survey (64-306 micromol m(-2)h(-1)), indicating limited mineralization. However, the same data reveals a temporal variability in the flux, with a sharp increase in the SOD and ammonium released in spring when Phaeocystis-derived phytodetritus was deposited. The organic carbon content and bacterial biomass values indicate similar patterns of increase in response to the phytodetritus deposit. The nitrogen cycle also appears to be modified during the Phaeocystis bloom, with a clear stimulation of nitrification. The influence of various factors (e.g., temperature, nutrient concentrations, and bacterial activity) on the temporal fluctuations of the exchanges is discussed, as are the direct effects of spring bloom. A synthesis of the annual cycle of the mineralization dynamics in this permeable sediment type is also presented.     

Ecological status assessment in the lower Eo estuary (Spain). The challenge of habitat heterogeneity integration: a benthic perspective

The implementation of the European Water Framework Directive (WFD) requires evaluation of the ecological status (ES) of benthic communities in coastal and transitional water systems, and the intercalibration of assessment methodologies therefore becomes a research challenge. Our aim was to test the suitability of applying the M-AMBI index to assess the status of the Eo estuary (northern coast of Spain). Our results showed that M-AMBI was influenced by the natural variability of benthic communities, and presented an apparent dependence on habitat characteristics. Consequently, the definition of homogeneous areas in transitional water systems should be based on the salinity gradient combined with other factors. To achieve an accurate ES assessment, habitat-specific reference conditions should then be defined prior to the application of M-AMBI; this necessitates dividing an estuary into several sections, which may be classified as different ESs. From this perspective, a novel approach to integrate habitat heterogeneity in a global ES assessment was tested.     

Recycling of harbor sediment as lightweight aggregate

Sediment sampled from Taichung Harbor was mixed with local reservoir sediment at different weight ratios to prepare lightweight aggregate at 1050, 1100, and 1150 degrees C. A pressure of 3000 or 5000 psi was used to shape the powder mixtures into pellets before the heating processes. The results indicate that the leaching levels of trace metals from the lightweight aggregate samples are considerably reduced to levels less than Taiwan Environmental Protection Administration regulatory limits. Increasing final process temperature tends to reduce the bulk density and crushing intensity of lightweight aggregate with a concomitant increase in water sorption capability. Lightweight aggregate with the lowest bulk density, 0.49 g cm(-3) for the 5000 psi sample, was obtained with the heating process to 1150 degrees C. Based on the X-ray absorption near edge structure results, FeSO(4) decomposition with a concomitant release of SO(x) (x = 2,3) is suggested to play an important role for the bloating process in present study.     

山东省“十二五”基础测绘技术进展概述

以1∶1万基础地理信息为重点的"十二五"基础地理信息更新,关乎山东省经济社会发展,如何高效、低成本做好基础测绘更新,为国民经济、社会发展提供空间定位优质服务,十分重要。综述了山东省"十二五"基础测绘更新思路、新技术应用、质量控制方法等技术进展。     

Characterizing the effect of heavy metal contamination on marine mussels using metabolomics

Marine mussels (Mytilus) are widely used as bioindicators to measure pollution in marine environments. In this study, (1)H NMR spectroscopy and multivariate statistical analyses were used to differentiate mussel groups from a heavy metal-polluted area (Onsan Bay) and a clean area (Dokdo area). Principal component analysis and orthogonal projection to latent structure-discriminant analysis revealed significant separation between extracts of mussels from Onsan Bay and from the Dokdo area. Organic osmolytes (betaine and taurine) and free amino acids (alanine, arginine, glutamine, phenylalanine, and threonine) were more highly accumulated in Onsan Bay mussels compared with Dokdo mussels. These results demonstrate that NMR-based metabolomics can be used as an efficient method for characterizing heavy metal contamination derived from polluted area compared to clean area and to identify metabolites related to environments that are contaminated with heavy metals.