Contamination of marine biogenic habitats and effects upon associated epifauna

Habitat-forming organisms are frequently used as biomonitors in marine environments due to a widespread ability to accumulate toxic contaminants. Few studies, however, have considered the consequences of these accumulated contaminants on the abundant and diverse fauna associated with these habitats. In this review, we summarize research which has investigated the contamination of biogenic habitats (including seagrasses, macroalgae, ascidians, sponges and bivalve reefs) and the impact of this contamination on the habitat use, feeding behaviour and survival of associated epifauna. In many cases, ecological impacts upon epifauna are not simply predicted by levels of contamination in their habitat, but are determined by the foraging, feeding and reproductive behaviours of the inhabiting organisms. Thus, a thorough understanding of these ecological processes is essential in order to understand the effects of contaminants upon epifaunal communities. The scope of biomonitoring studies which assess the contamination of biogenic habitats should be expanded to include an assessment of potential effects upon associated epifauna. When combined with manipulative field experiments such an approach would greatly assist in our understanding of indirect effects of contaminants in these important benthic habitats.     

Studies of dust grain properties in infrared reflection nebulae

We have developed a model for reflection nebulae around luminous infrared sources embedded in dense dust clouds. The aim of this study is to determine the sizes of the scattering grains. In our analysis, we have adopted an MRN-like power-law size distribution (Mathis, Rumpl, and Nordsieck) of graphite and silicate grains, but other current dust models would give results which were substantially the same. In the optically thin limit, the intensity of the scattered light is proportional to the dust column density, while in the optically thick limit, it reflects the grain albedo. The results show that the shape of the infrared spectrum is the result of a combination of the scattering properties of the dust, the spectrum of the illuminating source, and foreground extinction, while geometry plays a minor role. Comparison of our model results with infrared observations of the reflection nebula surrounding OMC-2/IRS 1 shows that either a grain size distribution like that found in the diffuse interstellar medium, or one consisting of larger grains, can explain the observed shape of the spectrum. However, the absolute intensity level of the scattered light, as well as the observed polarization, requires large grains (approximately 5000 angstroms). By adding water ice mantles to the silicate and graphite cores, we have modeled the 3.08 micrometers ice band feature, which has been observed in the spectra of several infrared reflection nebulae. We show that this ice band arises naturally in optically thick reflection nebulae containing ice-coated grains. We show that the shape of the ice band is diagnostic of the presence of large grains, as previously suggested by Knacke and McCorkle. Comparison with observations of the BN/KL reflection nebula in the OMC-1 cloud shows that large ice grains (approximately 5000 angstroms) contribute substantially to the scattered light.     

张北6.2级地震生命损失

张北６．２级地震死亡４９人,重伤６５６人,轻伤１０７８３人,地震灾区考察表明,灾区房屋结构不合理,抗震性能极差,造成重灾区房屋建筑大片倒塌和严重破坏,是这次地震严重生命损失的重要原因。     

印度深水油气的勘探机遇与挑战

科学与技术的发展使海上油田钻探和生产技术在过去５０ａ发生了显著进步 ,导致１９４７年在墨西哥湾水深２０英尺处安装了第一个海上平台 ,随后深浅海区在确定、开发和利用新、老油田的方法上取得了巨大进展。随着技术的发展 ,深水定义也随时间发生了变化。２０世纪７０年代深水界限为１００ｍ ,到８０年代晚期则为３００ｍ。遥控器（ＲＯＶｓ）和电子遥控系统的发展将深水的范围扩展至现今的３０００ｍ。现已在世界数个深水地区发现了油气储量。过去８ａ在墨西哥湾水深５００～１８００ｍ圈定储量超过５０亿桶 ;在巴西的Ｃａｍｐｏｓ盆地 ,…     

河北廊坊地区的设定地震灾害评估

本文对1700年以来的历史地震烈度资料进行了分析,并结合地震地质资料来确定设定地震(Scenario Earthquake),然后利用模拟强地面运动确定了廊坊地区的强地面运动灾害.研究结果表明,按照目前的地震活动趋势,廊坊地区出现大于或等于地震烈度8度的周期大约是600年.也就是说,在未来50年廊坊地区出现地震烈度8度的超越概率为8％.为此,本文建议廊坊地区应该考虑0.3g峰值加速度(Ⅷ度)作为基本地震工程设计参数.     

Inter-annual variability of wet season freshwater plume extent into the Great Barrier Reef lagoon based on satellite coastal ocean colour observations

Riverine freshwater plumes are the major transport mechanism for nutrients, sediments and pollutants into the Great Barrier Reef (GBR) lagoon and connect the land with the receiving coastal and marine waters. Knowledge of the variability of the freshwater extent into the GBR lagoon is relevant for marine park management to develop strategies for improving ecosystem health and risk assessments. In this study, freshwater extent has been estimated for the entire GBR lagoon area from daily satellite observations of the Moderate Resolution Imaging Spectroradiometer (MODIS) between 2002 and 2010. To enable a reliable mapping of freshwater plumes we applied a physics-based coastal ocean colour algorithm, that simultaneously retrieves chlorophyll-a, non-algal particulate matter and coloured dissolved organic matter (CDOM), from which we used CDOM as a surrogate for salinity (S) for mapping the freshwater extent.     

沧州地区NWW向隐伏断裂存在依据及其地震地质意义

经过对河北沧州地区中强地震和小震空间分布分析发现,存在NNE向条带分布,与大规模的河北平原地震带的走向一致;同时也呈现了明显的NWW向条带,与NNE向组成共轭构造图象。对比2次中强地震,其震源机制解基本相同,有近于直立的NWW向节面做左旋走向滑动;3次地震烈度的极震区长轴方向也是NWW;1967年河间6.3级地震之后5天的余震分布也是NWW方向。这和历史上5级地震分布方向一致。虽然没有浅表断层的对应,多种资料的相互验证表明沧州地区深部存在一条NWW向的隐伏断层,对于判别区内地震危险性具有重要意义。