首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
Despite a large number of gas platforms existing in the Adriatic Sea, which is a semi-enclosed basin characterized by a slow turnover rate and increasing industrial as well as other anthropogenic activities, the effects of these structures on the aquatic ecosystem require further investigation. Since 1998, multidisciplinary studies have been performed by CNR-ISMAR to comply with legislation and to support the development of protocols for the monitoring of offshore activities in the Adriatic Sea. The present study was developed to implement a biomonitoring plan to assess the ecotoxicological effects of the extraction activities of an off-shore gas platform. Biomarkers were evaluated in mussels collected from the platform in relation to physiological stress, DNA damage, cellular damage, oxidative stress and exposure effects. Organic contaminants and trace element bioaccumulation were also assessed in the soft body of the mussels to correlate bioaccumulation of pollutants with biomarker responses. The results indicate an absence of platform-related environmental stress.  相似文献   

2.
The results of long-term seasonal oceanographic observations conducted by YugNIRO from 1955 to 1991 in standard cross-sections on the northwestern shelf of the Black Sea and data obtained by monitoring oil and chemical pollution of the marine environment from 1987 to 1993 in the area of gas deposit development are systematized and statistically treated. The oceanographic conditions of pollution field formation in this region are studied. The dynamics and distribution of total concentrations of oil products and microelements (Hg, Cu, Pb, Cd, and Cr) in water and bottom sediments are examined in the areas in Karkinitskii Bay where permanent offshore platforms are operated. The obtained results are compared with data on the background environmental pollution of the Black Sea and World Ocean. A hypothesis is offered to elucidate the possible causes and mechanisms through which offshore gas production affects the hydrochemical conditions on the shelf. The monitoring data are said to be a necessary information basis for the prediction of pollution dynamics in Karkinitskii Bay with the use of a box-type hydroecological model of petroleum hydrocarbon biotransformations in water, and approaches for the use of these data for this purpose are outlined.  相似文献   

3.
Severe sea states in the North Sea present a challenge to wave forecasting systems and a threat to offshore installations such as oil and gas platforms and offshore wind farms. Here, we study the ability of a third-generation spectral wave model to reproduce winter sea states in the North Sea. Measured and modeled time series of integral wave parameters and directional wave spectra are compared for a 12-day period in the winter of 2013–2014 when successive severe storms moved across the North Atlantic and the North Sea. Records were obtained from a Doppler radar and wave buoys. The hindcast was performed with the WAVEWATCH III model (Tolman 2014) with high spectral resolution both in frequency and direction. A good general agreement was obtained for integrated parameters, but discrepancies were found to occur in spectral shapes.  相似文献   

4.
本文首先基于渤海海域的地震环境及地震危险性特征,根据46个海洋平台的设计地震动参数,分析了不同设防水准的设计地震动参数之间的关系;然后,采用与其他工程类比的方法,确定了海洋平台抗震设防的两级目标;通过与国内其他规范的类比,确定了海洋平台强度设计地震的概率水准取重现期200年,变形设计地震的概率水准取重现期1000—2500年,并深入分析论证了其合理性;最后,根据渤海地区的地震危险性分区和地震动参数区划给出了相应的设防参数。本文是对渤海地区多年来海洋平台抗震设防经验的总结,是对我国海洋平台抗震设防标准的探索性研究。  相似文献   

5.
Fisheries have been vital to coastal communities around the North Sea for centuries, but this semi-enclosed sea also receives large amounts of waste. It is therefore important to monitor and control inputs of contaminants into the North Sea. Inputs of effluents from offshore oil and gas production platforms (produced water) in the Norwegian sector have been monitored through an integrated chemical and biological effects programme since 2001. The programme has used caged Atlantic cod and blue mussels. PAH tissue residues in blue mussels and PAH bile metabolites in cod have confirmed exposure to effluents, but there was variation between years. Results for a range of biological effects methods reflected exposure gradients and indicated that exposure levels were low and caused minor environmental impact at the deployment locations. There is a need to develop methods that are sufficiently sensitive to components in produced water at levels found in marine ecosystems.  相似文献   

6.
The Tan-Lu fault zone across the eastern margin of the Cenozoic basins offshore the Bohai Sea is a NNE-trending right-lateral strike-slip fault system developed in the Cenozoic basin cover. It cuts through NE-to NNE-striking major extensional faults that controlled the formation of Paleogene basins. Recent petroleum exploration indicates that Cenozoic structural activities of the Tan-Lu fault system have directly or indirectly affected oil and gas distribution offshore the Bohai Sea. As part of a deep fault zone the Tan-Lu fault zone has been activated since the Oligocene,and obviously affected the tectonic evolution of offshore Bohai basins since then. The formation of Paleogene rift basins offshore the Bohai Sea has utilized the pre-existing structural elements of the Tan-Lu fault zone that developed in the late Mesozoic.  相似文献   

7.
美国API RP2A-WSD规范对我国海洋石油平台抗震设防的启示   总被引:3,自引:1,他引:2  
我国尚未制定海洋石油平台的抗震设计规范,目前世界海洋油气行业的抗震标准主要执行的是美国RP2A—WSD规范,该规范是基于是美国近海岸地震危险性区划结果而制定.本文介绍了RP2A-WSD规范及美国近海岸地震区划研究结果,论述了我国渤海海域地震活动性特性与地震动参数的研究内容,渤海海域是我国海洋石油开发的主要场所,且地震活动性较高,与美国南加利福尼亚近海岸具有可比性,然后对两者进行对比分析,并依据两者之间的对比结果,以及海洋石油平台的重要性和使用特征,对我国海洋石油平台的抗震设防标准和设防水准提出建议。  相似文献   

8.
Despite meiofauna being one of the most popular tool for detecting the ecological effects of different sources of impact, the application of structured experimental designs to this benthic component is typically neglected, especially in subtidal rocky shores. In this study, an asymmetrical design was used to detect hard-bottom meiofaunal abundance and biodiversity response to sewage discharge. Sampling was carried out at a depth of 3-4 m by SCUBA diving, by means of a modified manual corer. Six replicate cores were collected at three sites (80-100 m apart), at each of three locations (one purportedly impacted [I] and two controls [Cs]). A total of 84,994 specimens were collected. The outfall affected meiofaunal assemblages in terms of taxon richness, by determining a significant reduction of the number of taxa in the disturbed location, and community structure, by causing functional changes in terms of a decrease of the abundance of nematodes and an increase of the hydrozoan component. Nematodes and syllid polychaetes showed significant lower average abundance at I. Multivariate analyses showed that both meiofaunal assemblage and syllids were significantly different at I compared with Cs. The sewage outfall also affected patterns of spatial distribution at the scale of site (100 m apart) and of replicate units (centimetres apart), both in syllids and in nematodes. Our results provide evidence that the selection of multiple controls is crucial to prevent the widespread risk of Type II error, highlighting the need of more accurate experimental designs when dealing with meiofauna.  相似文献   

9.
This study reports a newly established sub-population of Lophelia pertusa, the dominant reef-framework forming coral species in the north-east Atlantic, on oil and gas platforms in the northern North Sea. L. pertusa was positively identified on 13 of 14 platforms examined using existing oil and gas industry visual inspections. Two platforms were inspected in more detail to examine depth and colony size distributions. We recorded 947 colonies occurring between 59 and 132 m depth that coincides with cold Atlantic water at depths below the summer thermocline in the northern North Sea. We suggest that these colonies provide evidence for a planktonic larval stage of L. pertusa with recruits initially originating from populations in the north-east Atlantic and now self recruiting to the platforms. Size class distribution showed a continuous range of size classes, but with few outlying large colonies. The break between the largest colonies and the rest of the population is considered as the point when colonies began self recruiting to the platforms, resulting in greater colonization success. We present the first documented in situ colony growth rate estimate (26 +/- 5 mm yr(-1)) for L. pertusa based on 15 colonies from the Tern Alpha platform with evidence for yearly recruitment events starting the year the platform was installed. Evidence of contamination from drill muds and cuttings was observed on the Heather platform but appeared limited to regions close to drilling discharge points, where colonies experience partial as well as whole colony mortality.  相似文献   

10.
Persistent organochlorine pollutants (POPs) such as polychlorinated biphenyls (PCBs), dichlorodiphenyl trichloroethane and its metabolites (DDTs), chlordane compounds (CHLs), and hexachlorocyclohexanes (HCHs) were determined in Japanese common squid collected from the offshore waters of Korea. Liver accumulated higher levels of contaminants than mantle. The sums of DDTs, PCBs, CHLs and HCHs in liver were in the ranges of 164-4430 ng g−1, 95-1030 ng g−1, 15-121 ng g−1, and 13-98 ng g−1 on a lipid weight basis, respectively. Among the POPs, DDTs showed distinct regional difference in concentration levels and composition between the western and eastern offshore of Korea. One of the highest concentrations of DDTs so far recorded in the western offshore of Korea, that is Yellow Sea. This implies ongoing fresh input of technical DDT to this regional sea. HCHs were relatively high in the Yellow Sea as well, with an enhanced signal of γ-HCH indicating recent input of lindane. In contrast, CHLs showed higher level in the eastern offshore of Korea, that is East Sea, but PCBs showed an even distribution in both regions. Squid could be a useful bio-indicator for monitoring offshore water contamination by POPs.  相似文献   

11.
热演化历史的研究对于盆地分析和油气勘探具有重要意义.北黄海盆地是中国近海海域油气勘探程度较低的盆地之一,迄今未见专门的热演化研究报道.笔者利用北黄海盆地中生代砂岩的磷灰石裂变径迹分析结果,结合地质条件约束,模拟获得了中生代以来盆地的热演化史.结果表明,北黄海盆地经历了两次增温和两次冷却的热演化过程,并在100-80 Ma时盆地的热历史出现明显变化,表明在晚白垩世北黄海盆地发生过一次较大的构造-热事件.磷灰石裂变径迹分析所表明的北黄海盆地的热历史与盆地原型演化阶段相对应,而这种热历史和盆地的演化过程与区域构造背景相关.磷灰石裂变径迹所揭示的热演化史对于深化认识北黄海盆地的地质演化过程和油气勘探潜力具有重要意义.  相似文献   

12.
Using data from 31 ponds, we investigated the importance of environmental (e.g. habitat complexity, nutrient content, pH) and biotic factors (i.e. fish predation) on the spatial patterns of planktonic (phytoplankton and zooplankton) and benthic (macroinvertebrates) assemblages. We also evaluated the degree of concordance among assemblages and between the functional and taxonomic composition of assemblages, and test the hypothesis that surrogates of biodiversity (e.g. taxonomic or functional groups) can be used in pond conservation and biomonitoring studies. We found that the spatial patterns of benthic and pelagic assemblages were determined by macrophyte coverage, water quality and, to a lesser extent, fish. However, shifts in the taxonomic and functional composition were not congruent. Moreover, local environmental variation was slightly more important for the taxonomic than the functional composition of assemblages, except for phytoplankton. The degree of concordance among assemblages was also weak, which may be partly due to the fact that species respond individualistically to environmental variation. These findings also suggest that the coupling between benthic and pelagic habitats in flatland ponds is weak, and that the use of surrogate measures or indicator groups in pond conservation studies may not be appropriate.  相似文献   

13.
The Aral Sea, in 1960 the fourth largest lake on Earth, has since experienced a catastrophic environmental change, which appears to be mainly a result of human impact. Here, we attempt to add to a better understanding of environmental changes during the last millennium by using fossil mollusc assemblages obtained from 10 sediment cores, which were taken by gravity coring in 1991. The biogeographical analysis demonstrates that no endemic molluscs have existed in the Aral Sea during the last 1000 years. The investigated taxa are of Caspian and Palaearctic origin. The molluscan biodiversity is much lower than previously assumed and particularly low for such a large lake, indicating unstable ecological conditions during the period investigated. Using comparative ecological analyses of thanatocoenoses and stable isotope ratios in gastropod shells, we conclude that the main lake level changes of the last millennium were strong and abrupt, showing relative high stands at about 1300 AD and 1650 AD.  相似文献   

14.
The exploration and production of North Sea oil and gas reserves has resulted in the accumulation of large quantities of drill cuttings on the seabed surrounding drill sites. This complex mixture of man-made and natural substances contains higher concentrations of certain metals (Ba, Cr, Cu, Ni, Pb, and Zn) and hydrocarbons than are observed in background sediments. With decommissioning of older platforms underway, an evaluation of the environmental interactions and chemical fate of the drill cuttings accumulations is required.This review concentrates on contaminants within drill cutting accumulations in the Northern and Central North Sea (56 degrees N-62 degrees N). Present literature reviewed reveals that hydrocarbons within the cuttings piles remain relatively unchanged with time. A considerable proportion of the associated contaminants are likely to remain within the cuttings pile unless they are disturbed which will then increase exchanges of porewater and solids back to the seabed surface resulting in pathways of exposure for organisms.  相似文献   

15.
Geological conditions of coal and gas(oil)-bearing basins in China   总被引:2,自引:2,他引:0  
Coal is the richest fossil fuel in the world. Theby-product formed during incoalation is gas that iscomposed primarily of methane (CH4)[1,2]. This gascan generally be named coal measure gas. Accordingto the occurrence conditions, coal measure gas can befurther divided into humic gas and coal-bed methane.Humic gas refers to coal measure gas that generatesfrom the coal measure source rocks (coal and dark-coloured argillaceous rocks in coal measures), and canbe expelled and migrate into various …  相似文献   

16.
海洋石油平台的工程地震问题   总被引:4,自引:1,他引:3  
对于海洋石油平台,结构抗震设计要求提供地震动峰值、反应谱、持续时间以及速度时程等参数,由于海洋石油平台的结构和形式的特殊性,以及海域地震环境特征,考虑海洋石油平台地震动作用时要有不同的方法及侧重点,本文对海洋石油平台地震作用分析中涉及的一些工程地震问题研究进行了讨论,包括设防地震动水准、设定地震、地震动衰减关系、长周期地震动及其相关问题。  相似文献   

17.
南海东北部973剖面BSR及其热流特征   总被引:7,自引:5,他引:2       下载免费PDF全文
对南海东北部973项目采集的地震测线进行了处理,阐明了恒春海脊处天然气水合物似海底反射(BSR)的特征.不同类型剖面的分析表明,单道地震剖面可以揭示南海东北部地区BSR一定的分布,但地震处理对揭示BSR分布全貌起重要作用.南海东北部的BSR具有世界大陆边缘BSR典型的特征,切穿了沉积层理反射,与海底起伏大体平行,为一强振幅的负极性反射.该BSR特征明显,意味着南海东北部地区存在含天然气水合物沉积.利用甲烷水合物与多组分天然气水合物相平衡曲线,计算了稳定带底界的埋深,并与BSR深度进行了对比分析.无论是甲烷水合物稳定带底界还是多组分天然气水合物稳定带的底界,单一地温梯度计算的结果不可能与BSR深度在整个剖面上对应.可知本区横向上地温梯度变化较大.利用BSR资料估算了地温梯度并求得热流值.计算表明,地温梯度与热流值由西向东,随着离海沟距离的增大、离岛弧距离的减小而减小.BSR计算得到的热流值为28~64 mW/m2,与台湾西南实测热流值的结果基本可以对比.  相似文献   

18.
本文假设马尼拉海沟北段为潜在海啸源,基于中国地震台网对马尼拉海沟地区震级测定偏差,采用COMCOT(comell Multi-grid Coupled Tsunami Model)海啸数值模型,模拟南海海啸波传播.选取南海北缘3个特定地点,其中两个位于华南近海区域,另一个位于台湾岛南端近海区域,此外还在临近马尼拉海沟北段的深海地区选取了1个特定地点.分析这些特定地点最大海啸波以及最大海啸波到时对于震级测定偏差的敏感性.结果表明:马尼拉海沟北段地震如触发海啸,华南近海区域以及台湾岛南部近海区域最大海啸波振幅对震级偏差敏感,但最大海啸波振幅到时对于震级测定偏差不敏感;振幅最大的海啸波,二十几分钟即可波及台湾岛南端近岸区域,大约1小时后波及大陆华南近海北部区域.  相似文献   

19.
A total of 92,934 fish larvae representing 19 families were sampled monthly from the Sangga Kecil estuary (Matang Mangrove Forest Reserve) and adjacent coastal waters from May 2002 to October 2003. Larval fish assemblages were numerically dominated by Gobiidae (50.1%) and Engraulidae (38.4%). Canonical Correspondence Analysis (CCA) revealed that the larval fish assemblages, including their ontogenetic stages, differed between the mangrove estuary and adjacent offshore waters, and that salinity, turbidity and zooplankton food are the major environmental factors structuring the larval fish assemblages. Estuarine preflexion gobiid larvae were ubiquitous in the coastal and estuarine waters. Larval stages of euryhaline species that were spawned in offshore waters, such as Engraulidae and Clupeidae, were largely advected into mangrove areas at the postflexion stages. Larvae of other euryhaline fishes (Sciaenidae, Blenniidae and Cynoglossidae) that may have been spawned inside the estuary were, however, exported to offshore waters. Given that the collective number of juvenile and adult fish families in the Matang estuary was 53, while the number of larval families was only 17, the former is quite disconnected from the existing larval fish population in the estuary.  相似文献   

20.
我国尚未制定海洋平台的抗震标准.本文首先介绍了美国RP2A-WSD规范的内容,并与我国相关规范进行对比分析,认为我国目前采用的海洋平台强度设计和变形设计水准过于保守.从海洋平台的结构特征出发,探讨了海洋平台的工程地震问题.在此基础上,根据我国海域地震活动特征、海洋平台的设计基准期和设防目标等因素,参照相关行业工程抗震设防标准的经验,提出我国海洋平台用于强度设计的正常使用极限地震重现期取200年、用于延性设计的变形极限地震重现期取1000年.最后通过一个工程实例,分析了海底泥面对设计地震动参数的影响,以及不同抗震标准下设计地震动参数的差别,认为本文提出的平台抗震设防水准是安全合理的,同时又兼顾到我国经济承受能力以及与现行标准的连贯性.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号