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排序方式: 共有119条查询结果,搜索用时 15 毫秒
112.
113.
Biodegradation of polycyclic aromatic hydrocarbons (PAHs) in contaminated sediment is an attractive remediation technique and its success depends on biodegradation kinetics, and the optimal condition for the PAH-degrading isolates; however, information on this aspect is still scarce. The effects of multi-factors on biodegradation of phenanthrene, a 3-ring model PAH, in contaminated sediment slurry by Sphingomonas sp. a bacterial strain isolated from surface mangrove sediment, were investigated using the orthogonal experimental design (form L(16)(4(5))). The most significant factors were salinity and inoculum size, while the effects of phenanthrene concentrations, nutrient addition and temperatures were insignificant. The optimal biodegradation condition in contaminated mangrove sediment slurry was 30 degrees C, 15 ppt salinity, a carbon/nitrogen ratio of 100:1 (the background ratio in sediment) and an inoculum size of 10(6) most probable number g(-1) sediment. The phenanthrene biodegradation could be best described by the first order rate model, C=C(0)e(-kt), where k (the rate constant) is equaled to 0.1185, under the optimal condition. The kinetic model was verified and its validity in predicting biodegradation by Sphingomonas sp. at various phenanthrene concentrations was proved by experimental data. 相似文献
114.
By analysis of the fatty acid profiles in mussel tissues and suspended particulate matter (SPM) in water, the present study showed a significant relationship of the trophic linkage between mussels and the SPM. At seven locations from inner to outer areas along the eutrophic Tolo Harbour and Tolo Channel, Hong Kong, the composition (as percentage of total fatty acids) of both monoenoic and polyunsaturated fatty acids in the tissues of green-lipped mussels Perna viridis and SPM in water had significant correlation (p<0.01). In particular, the composition of docosahexaenoic acid (DHA, 22:6n3) (as percentage of total fatty acids) in mussel tissues was statistically correlated with that in SPM (p<0.01), implying that mussels incorporate DHA, the biomarker of dinoflagellates. Principal component analysis further demonstrated that the fatty acid profiles of SPM were different among locations in the harbour, mid and outer channel of the study area, so were the mussel tissue fatty acid profiles. Cluster analysis of phytoplankton data also revealed the dominance of diatoms in the inner harbour and channel areas, whereas dinoflagellates were abundant in the outer channel waters. The possible implications of using benthic suspension feeders such as green-lipped mussels P. viridis for controlling phytoplankton abundance in coastal waters are discussed. 相似文献
115.
1989年至1994年间,德国太阳号调查船SO-50B、SO-72A和SO-95航次在南海香港岩外做了6600km的地震测线。对剖面的地震地层学解释确定了更新纪地层中T0不整合的时代归属。东沙隆起的抬升和上覆地层的削蚀形成新第三纪T1和T9不整合,这次隆升事件由岩浆侵入上地壳所引起。地震剖面显示穿入沉积盖层的火成侵入岩体使接触带原有的层理现象消失。岩浆-构造事件也许瑟台湾和中国东部大陆边缘5-3Ma以及3-0Ma两次碰撞有关。碰撞事件以及随后台湾NNW和WNW向的拉移使台湾与中国东南大陆边缘的挤压转变为走滑。张裂活动停止洋壳冷却下沉并消亡在马尼拉海沟之下并产生拉张应力,形成张扭应力场。走滑运动使多数裂陷期和漂移期形成的断层重新活动,给岩浆上拱提供了通道。南海北部构造格局以中新世NE-SW向断裂为特征,这类断层数量虽少却在整个研究区都有分布。ENE-WSW向和NE-SW向上新世断裂集中分布在东沙岛西部,且多为走滑断裂。现代断裂总体为NW-SW走向,与裂陷期形成的断层大致平行,部分断层因局部上隆而产生,一般为正断层性质,但也有走滑性质。上述多数断裂至基底,可见这些是裂断陷和漂移期薄弱带重新活动的结果。 相似文献
116.
Mak KC Yu H Choi MC Shen X Lam MH Martin M Wu RS Wong PS Richardson BJ Lam PK 《Marine pollution bulletin》2005,51(8-12):1010-1017
Green-lipped mussels (Perna viridis) were collected from seven fish culture zones (FCZs) in Hong Kong and analyzed for okadaic acid (OA). A conventional HPLC method was modified by incorporating a proteinase K digestion step. Results suggest that a higher recovery (2.5 times higher) of OA was obtained from spiked samples after the addition of 1.08 mg proteinase K in comparison with samples incubated without the proteolytic enzyme. For the hepatopancreas (HP) of individual field-collected mussels, the additional digestion step can enhance OA extraction by 3.1 times. Spatial and temporal variations in OA concentrations in the mussels from various FCZs were investigated. The highest concentration of OA in mussel HP samples was 1164.9 ng/g HP wet wt. With respect to OA concentrations in whole mussel tissues from seven sites and four seasonal samplings, the concentrations were between 70.0 and 131.0 ng/g wet wt., which did not exceed the generally recognized international regulatory criteria (>200 ng/g) for OA. 相似文献
117.
Mangroves commonly found along tropical and subtropical coastlines are susceptible to oil pollution. In December 2000, around 500 1 m tall Kandelia candel saplings at the age of 3–5 years old located at the foreshore region of Sheung Pak Nai swamp, Hong Kong SAR, were found to be damaged by oil pollution. More than 80% of the saplings were either dead or washed away and leaving less than 5% healthy saplings with dense green leaves. Elevated concentrations of light n-alkanes (ranging from n-C14 to n-C20), pristane and phytane were recorded in surface sediments collected in December 2000. The ratio between light and total n-alkanes was 0.4. The total petroleum hydrocarbons (60–80 μg g−1 TPH) and unresolved complex mixtures (60–70 μg g−1 UCM) were higher than the background values of other mangrove sediments in Hong Kong, which were 40 and 20 μg g−1, respectively. In certain root zone sediments, TPH concentrations were above 1000 μg g−1. These results suggest that surface sediments in Sheung Pak Nai were contaminated by petroleum oil, most likely by illegal discharge of fuel oil which occurred between 1998 and 2002. One year later, in December 2001, unhealthy saplings had recovered and re-grown. The concentrations of TPH and UCM in sediments declined to around 40 μg g−1, pristane and phytane dropped by 80%, and the ratio of light to total n-alkanes was 0.15, suggesting that residual oil in sediments was weathered leading to a remarkable recovery of the unhealthy saplings. 相似文献
118.
The sea fluxes of trace metals, POC, and settled material were studied in anoxic sea water, Saanich Inlet, B.C., Canada with sediment traps. This paper discusses the change of mass fluxes of sediment, trace metals and POC for various seasons and depths. The annual mean of settled material is 1.56 g.m-2 .a-1, 84.6 mg. m-2. a-1 for POC, 60.0 mg.m-2. a-1 for Cu, 16.5 mg.m-2.a-1 for Pb, 189 mg.m-2. a-1 for Zn, 2.20mg.m-2.a-1 for Cd,699 mg.m-2.a-1 for Fe,38.8 mg.m-2.-1 for Co, and 84.6 mg.m-2.a-1 for Ni.The relations between the average fluxes of trace metals and POC, the fluxes of trace metals and settled matter, and the sea fluxes of trace metals and Fe are in linear progression. The resident times of elements as calculated from sea flux, are 1.1 a. for Cu, 0.014 a. for Pb, 0.50 a. for Zn, 3.8 a. for Cd, 0.16 a. for Fe, 0.39 a. for Co,and 1.14 a. for Ni.The order of resident times is as follows: Pb-Fe-Co-Zn-Cu-Ni-Cd. The metal resident times in Saanich Inlet are shorter than the values estimated for the op 相似文献
119.
北冰洋楚科奇海陆架到陆坡表层沉积物有机碳载荷的变化 总被引:2,自引:0,他引:2
沉积物单位表面积上吸附的有机碳被广泛用于示踪有机碳载荷的变化。本文研究了北冰洋典型边缘海——楚科奇海表层沉积物的有机碳载荷。研究发现陆架区沉积物的有机碳载荷高于陆坡区。相比于已报道的东西伯利亚海和马更些河,楚科奇海陆坡区沉积物的有机碳载荷也较低。这种有机碳载荷的变化可能和陆坡区的初级生产力较低,以及沉积物在传输过程中经历的氧化降解有关。沉积物的有机碳含量和比表面积呈线性相关,在有机碳轴上有正截距,表明一部分有机碳来自于岩石的贡献。此外,陆架区低有机碳载荷的沉积物含有的岩石有机碳更高。本研究的数据有助于深刻理解楚科奇海区域的碳循环问题。 相似文献