Constraining the genetic relationships of 25-norhopanes,hopanoic and 25-norhopanoic acids in onshore Niger Delta oils using a temperature-dependent material balance

Analysis of oil samples from the Niger Delta (Nigeria) revealed a range of structurally related hopanes, including 25-norhopanes, and hopanoic and 25-norhopanoic acids. 25-Norhopanes were detected in all medium and heavily biodegraded oils and were most abundant in the heavily degraded oils. Hopanoic acids (C₃₀-C₃₃) and 25-norhopanoic acids (C₃₀-C₃₁) were most abundant in moderately degraded oils and occurred in reduced concentration in heavily degraded oils but were absent from, or in trace concentration in, slightly degraded oils. Consideration of the structures suggests that 25-norhopanoic acids form via carboxylation of 25-norhopanes or demethylation of hopanoic acids. Mass balance for the onshore Niger Delta oils suggests that formation of 25-norhopanes operates independently of 25-norhopanoic acid formation and that 25-norhopanoic acids are likely transient intermediates for only a small proportion of the 25-norhopanes.     

Degradation of crude oil in a contaminated tidal flat area and the resilience of bacterial community

Crude oil spills, Hebei Spirit in South Korea, is considered as one of the worst environmental disasters of the region. Our understanding on activation of oil-degrading bacteria and resilience of microbial community in oil contaminated sites are limited due to scarcity of such event. In the present study, tidal flat sediment contaminated by the oil spill were investigated for duration of 13 months to identify temporal change in microbial community and functional genes responsible for PAH-degradation. The results showed predominance of previously known oil-degrading genera, such as Cycloclasticus, Alcanivorax, and Thalassolituus, displaying significant increase within first four months of the accident. The disturbance caused by the oil spill altered the microbial community and its functional structures, but they were almost restored to the original state after 13 months. Present study demonstrated high detoxification capacity of indigenous bacterial populations in the tidal flat sediments and its resilience of microbial community.     

A probabilistic model of petroleum discovery

We discuss a petroleum discovery model that greatly simplifies the approach initiated by Barouch and Kaufman (1976) in which exploration is viewed as a sampling without replacement process, and the probability of discovery of a pool is proportional to its size. Calculations that formerly required lengthy Monte Carlo simulations have been reduced to compact formulas.     

雅克拉凝析气田油气地球化学特征

雅克拉凝析气田天然气组分以甲烷为主,含量79.13%￣89.30%;重烃含量较高,平均占9.67%;干燥系数(C1/C1-5)介于0.89～0.92之间,属典型的湿气。δ13C1为-40.8‰～-39.4‰,δ13C2为-32.0‰～-30.2‰,δ13C3为-30.5‰～-28.9‰,表明天然气为典型的油型气。原油及其族组分的碳同位素组成和生物标志化合物呈现出典型的海相原油特征。原油成熟度较高,与天然气的成熟度基本相同,表明油气同源、同阶,为一次油气充注的产物,而与塔河油田存在较大差异。     

胜利原油和Corexit 9527分散剂对海洋围隔实验生态系中浮游动物的影响

本文分析了Corexit 9527分散剂和中国胜利原油对海洋实验生态系中浮游动物群落的影响,得出的主要结论是:1.单独的Corexit 9527对草食性桡足类的生长发育稍有抑制作用,但种群可得恢复和发展,对肉食性桡足类及其他各类浮游动物没有影响;2.Corexit 9527和原油的混合物对所有类别浮游动物均有极大的抑制作用,它导致种群的迅速缩小且无法得以恢复。     

The Sea Empress oil spill (Wales, UK): effects on Common Scoter Melanitta nigra in Carmarthen Bay and status ten years later

Carmarthen Bay, UK, regularly supports internationally important numbers (>16,000) of non-breeding Common Scoters Melanitta nigra. The spill of 72,000 tonnes of crude oil from the Sea Empress in 1996 affected birds both through direct mortality and likely pollution of key food resources. Numbers were greatly reduced following the spill, whilst changes in the distribution of birds within Carmarthen Bay suggested that potentially sub-optimal foraging zones were used. However, ten years after the incident, numbers of Common Scoter were no different to those recorded immediately before the spill. Compared to some other spills, rapid revival is evident. Numbers increased to pre-spill levels within three winters and distributional changes suggested a concurrent return to previously contaminated feeding areas, implying that the ecosystem had regenerated sufficiently to support its top predator. The importance of prolonged, standardised monitoring of bird numbers and distribution as indicators of ecological recovery from environmental damage is emphasised.     

Cold-region environments along the China-Russia Crude Oil Pipeline and their management

The cold-region eco-environments along the China-Russia Crude Oil Pipeline (CRCOP) in northern Northeast China are in disequilibrium due to the combined influences of pronounced climate warming and intensive anthropogenic activities.This is evidenced by the sharp areal reduction and northward shifting of the boreal forests,shrinking of wetlands,enhancing of soil erosion,accelerating degradation of permafrost and deteriorating of cold-region eco-environments.The degradation of permafrost plays an important role as an internal drive in the eco-environmental changes.Many components of the cold-region eco-environments,including frozen ground,forests,wetlands and peatlands,forest fires and heating island effect of rapid urbanization,are interdependent,interactive,and integrated in the boreal ecosystems.The construction and long-term operation of the CRCOP system will inevitably disturb the cold-region environments along the pipeline.Therefore,a mandatory and carefully-elaborated environ-mental impact statement is indispensable for the proper mitigation of the ensued adverse impacts.Proper management,effective protection and practical rehabilitation of the damaged cold-region environments are a daunting,costly and long-term commitment.The recommended measures for protection and restoration of permafrost eco-environments along the pipeline route include adequate investigation,assessment and monitoring of permafrost and cold-region environments,compliance of pipeline construction and operation codes for environmental management,proper and timely re-vegetation,returning the cultivated lands to forests and grasslands,and effective mitigation of forest fire hazards.     

漠河-加格达奇段多年冻土区中俄原油管道运营以来的次生地质灾害研究——以MDX364处的季节性冻胀丘为例

通过对中俄原油管道漠河-加格达奇段多年冻土区的现场勘查研究, 统计了管道运营以来出现的冻土次生地质灾害主要有冻胀、融沉、水毁、冻胀丘、冰椎等. 在研究区域特定的气候背景下, 管道的修建和季节性变化的正油温运营, 破坏了管道周围冻土的水热平衡, 使得管道周围土体出现差异性冻胀和融沉, 这种差异性位移量的累积对管道安全稳定长期运营造成了威胁. 以管道里程MDX364处的冻胀丘为例, 利用探地雷达进行了现场探测. 结果表明: 管道周围存在的融区为冻胀丘的发生和发展提供了水源补给通道, 管道的热影响加速了冻胀丘的发展和消融, 2014年3-10月管道周围地表产生的差异性位移超过了1.1 m. 针对该次生开放型季节冻胀丘, 提出了修筑或疏通管道附近的排水通道、钻孔放水和保温排水渗沟等防治措施. 研究成果能为中俄原油管道的安全稳定运营提供技术支撑, 为其他冻土区管道设计施工和运营维护提供参考和依据.