Impact of sediment organic matter quality on the fate and effects of fluoranthene in the infaunal brittle star Amphiura filiformis

Hydrophobic contaminants, such as polycyclic aromatic hydrocarbons (PAHs) readily adsorb to organic matter. The aim of this study was to determine the importance of the quality of sedimentary organic matter for the uptake, biotransformation and toxicity of the PAH, fluoranthene (Flu), in the infaunal brittle star Amphiura filiformis. Brittle stars were exposed to a base sediment covered by a 2 cm Flu-spiked top layer (30 microg Flu/g dry wt. sed.), enriched to the same total organic carbon content with either refractory or labile organic matter. The labile carbon source was concentrated green flagellate: Tetraselmis spp. The refractory carbon source was lignin from a paper mill. Tissue concentrations of Flu both in disk and arm-fractions were determined as total Flu, parent Flu (i.e. untransformed), aqueous Flu-metabolites, polar Flu-metabolites and tissue residue Flu (i.e. unextractable). Our results showed that sediment particle ingestion is a pathway by which Flu can enter benthic food webs. Flu toxicity (measured as arm-regeneration), but not net accumulation, was dependent on the nutritional quality of the ingested sediment particles. Flu bioaccumulation could not be attributed solely to equilibrium partitioning between organism lipid content and organic content of the sediment. Biotransformation of Flu by brittle stars was very limited and unaffected by organic matter quality. A. filiformis contributed to the downward transport of Flu from the surface sediment to the burrow lining. The limited breakdown of parent Flu by brittle stars and/or microorganisms was relatively higher in burrows compared to surface sediment, and highest in the presence of labile organic matter. Tissue concentrations were higher in disk than in arms, but the proportion of metabolic products relative to parent Flu was higher in arms than in the disk fraction. We estimate that the yearly mobilization of sediment-associated Flu by arm-regeneration in A. filiformis is in the range of 3.8-29.4 microg total Flu eq. m(-2) year(-1) at a sediment concentration of 30 microg Flu/g dry wt. sed.     

青藏铁路昆仑山隧道工程地质条件

主要论述了昆仑山隧道这一高原冻土隧道的工程地质条件, 特别就隧道区多年冻土的认识及具体的工作方法、古冰川作用及冰锥的分布及其成因和隧道山体地下水情况分析等做了较为详尽的描述, 为隧道设计、施工提供了科学的地质依据及工程措施意见.     

东北季风期海南岛三亚湾初级生产力分布特征及其影响因素

根据2006年10月和2007年1月的监测资料,对三亚湾在东北季风初始期和盛行期初级生产力的分布特征及其受水体环境的影响因素进行了分析。三亚湾秋、冬季表层潜在初级生产力平均值分别为6.81mgC·m-3·h-1和7.47mgC·m-3·h-1;水柱初级生产力平均值分别为504.96mgC·m-2·d-1和495.33mgC·m-2·d-1。东北季风期间,三亚湾水体垂直混合作用加强,层化现象减弱,水动力过程和营养盐等环境因子是该海湾初级生产力分布特征和季节变化的重要调控因素;其中冬季较高的DIN分布对表层初级生产力有潜在促进作用,而水体扰动增强、真光层深度下降则导致水柱初级生产力低于秋季。三亚河口近岸水域秋、冬季均为营养盐、叶绿素a及初级生产力的高值区,其中表层潜在初级生产力在秋季和冬季分别达到了45.80mgC·m-3·h-1和39.27mgC·m-3·h-1,表明调查期间三亚河营养盐输入对近岸水体浮游植物初级生产过程的显著影响。     

淅川:雪后梯田美如画

正1月8日,雪后的淅川大地银装素裹、美景如画,尤其是位于该县黑水庵村的数百亩梯田,经过瑞雪"装扮"后,美得让人窒息。洁白的积雪覆盖在层层叠叠的梯田上,错落有致,宛若银带,形成了大自然独特的纹理,蔚为壮观。据悉,这是该县借助扶贫攻坚政策,积极推进农村耕地综合整治,对金河、上集等4个乡镇12个行政村的近800公顷坡耕地进行改造升级,全部打造成高标准的梯田。项目建成后,不仅能有效增加耕地面积,还能发展     

塔里木盆地北部油气田水文地质及水文地球化学特征

以实测的流体资料为基础，初步揭示了塔北地区油田水文地质和水文地球化学特征。塔北地区存在两股地下水流，南部生油区为压实水流，由南向北流动，北部为重力水流，由北向南流动，这两股水流交汇于雅克拉和轮南地区，向上封闭式内泄。无论重力水流或压实水流，皆为非海相成因、非浓缩成因溶滤水。表明：油气藏的形成绝大部分是寒武－奥陶纪生油层二次成油的结果。     

酒西盆地水动力学特征与油气运移聚集

酒西盆地可分为二大水文地质旋回,即白垩纪水文地质旋回和新生代水文地质旋回.每个旋回分为二个阶段,即沉积压实水流阶段和重力渗入水流阶段.水动力场、水化学场表明盆地南部油气富集带处于新生代水文地质旋回沉积压实水流的停滞泄水区,而北部单斜带处于重力渗入水流阶段.为了定量分析沉积压实水动力状况,本文提出了一种简便方法,即求解地上水均衡方程,可得出不同时期沉积水动力场特征.计算结果表明,白垩系原生油藏位于水动力场特定部位:高水头区中的低水头区、水头陡急变化带即停滞泄水区.     

钙质砂一维蠕变分形破碎特性宏微观试验研究

钙质砂是远洋地区港口、机场和民用建筑等构筑物的天然地基材料。通过钙质砂一维压缩蠕变试验和微观结构测试,发现了蠕变前后表面孔隙面积减小且呈分散分布的规律以及试验过程中试样瞬时变形、快速变形和衰减变形特征与粒径的高度相关性;利用基于分形理论改进的相对颗粒破碎率和质量分形维数描述了蠕变前后颗粒破碎程度,得到了分形维数和蠕变与时间的衰减形态曲线关系以及宏观质量分形维数和微观表面分形维数的线性关系,并在此基础上对单一粒径组钙质砂蠕变过程中的分形破碎行为进行了多尺度分析和宏微观跨尺度关联性研究,获得了蠕变过程中颗粒破碎发展以及微观孔隙变化规律,证明了钙质砂蠕变过程中的颗粒重组排列、破碎和研磨行为,揭示了钙质砂蠕变机制。     

Mapping water quality and substrate cover in optically complex coastal and reef waters: an integrated approach

Sustainable management of coastal and coral reef environments requires regular collection of accurate information on recognized ecosystem health indicators. Satellite image data and derived maps of water column and substrate biophysical properties provide an opportunity to develop baseline mapping and monitoring programs for coastal and coral reef ecosystem health indicators. A significant challenge for satellite image data in coastal and coral reef water bodies is the mixture of both clear and turbid waters. A new approach is presented in this paper to enable production of water quality and substrate cover type maps, linked to a field based coastal ecosystem health indicator monitoring program, for use in turbid to clear coastal and coral reef waters. An optimized optical domain method was applied to map selected water quality (Secchi depth, Kd PAR, tripton, CDOM) and substrate cover type (seagrass, algae, sand) parameters. The approach is demonstrated using commercially available Landsat 7 Enhanced Thematic Mapper image data over a coastal embayment exhibiting the range of substrate cover types and water quality conditions commonly found in sub-tropical and tropical coastal environments. Spatially extensive and quantitative maps of selected water quality and substrate cover parameters were produced for the study site. These map products were refined by interactions with management agencies to suit the information requirements of their monitoring and management programs.