Sublethal effects of the water-soluble fraction of ekofisk crude oil on the early larval stages of cod (Gadus morhua L.)

Low levels of dissolved oil hydrocarbons are demonstrated to produce sublethal effects on the early cod larval stages. These effects are discussed in relation to larval survival through the first critical stages.Continuous exposure of cod eggs and larvae to 0·05 and 0·25 ppm of the water-soluble fraction (WSF) of Ekofisk crude oil for 14 days caused significant reduction in growth and change in neutral buoyancy. The larvae exposed to 0·25 ppm showed malformation in the foremost part of the head and jaw, which reduced their ability to capture prey organisms at first feeding.     

Sensitivity of two psychrophilic diatoms to crude oil and fuel oil

Two pure cultures of diatoms, a Nitzschia sp. and a Chaetoceros sp., were grown at 0°C or 10°C in the presence of two crude oils and two fuel oils. The petroleum samples were absorbed onto filter paper discs and added directly to the algal cultures. In all cases the organisms were much more sensitive to the crude oils or fuel oils when growing at 0°C than at 10°C. The rate of photosynthesis measured by an oxygen electrode for Nitzschia sp. grown and tested at 0°C was not affected during 3 hours' incubation with some four times the amount of a crude oil or fuel oil that blocked growth. The experiments lead to the cautious suggestion that psychrophilic algae will prove some fivefold more sensitive than mesophilic algae to petroleum pollution.     

微波散射实验识别原油及乳化原油

海上原油泄漏在其风化迁移过程中会形成不同浓度的乳化物,严重威胁海洋生态环境。合成孔径雷达(SAR)因其不受雨、云影响,可昼夜监测的优势,在海上溢油监测过程中发挥着主力军的作用,但是它在原油乳化识别方面还存在着不足。本文利用C波段全极化散射计观测原油的自然乳化过程,并利用人工制备的不同含水率的乳化油品模拟原油乳化进程观测油膜后向散射系数(N_(RCS))的变化。实验结果表明乳化原油M_(RCS)高于未乳化原油,且油膜乳化程度越高相应的N_(RCS)越大。通过油水散射差值(Δσ~0)与阻尼比(D_R)发现能够识别乳化与未乳化原油,反映油膜乳化程度的变化,且在VV极化下效果最佳。     

An experimental marine ecosystem response to crude oil and corexit 9527: Part 1—Fate of chemically dispersed crude oil

The fate of Prudhoe Bay crude oil. labelled with n(1−¹⁴C)-hexadecane and dispersed with Corexit 9527, was studied for 24 days in a polyethylene bag enclosure of sea water by time-series observations of the alkane composition of the crude oil, oil fluorescence, ¹⁴C-labelled hexadecane in the particulate phase, bacterial biomass, amounts of sedimented material and parameters of temperature, salinity, particulate organic carbon and nitrogen, and nutrients. By the seventh day, convective and diffusive mixing, important mechanisms for the dispersion of oil, resulted in a fairly homogeneous distribution of oil throughout the enclosed water column. Rapid bacterial biodegradation removed the n-alkane fraction initially, while oil-Corexit dispersion suppressed phytoplankton growth. After 7 days, with the recovery of phytoplankton growth, much of the aged oil sedimented with sinking of diatoms.     

Experimental degradation of crude oil by marine bacteria

The ability of biodegradation for crude oil was examined for ten strains of marine bacteria. With regard to their degradation ability forn-alkanes the microorganisms tested could be divided into four groups, although the same result was not observed for microbial degradation of aromatic hydrocarbons obtained by the UV measurements.     

Natural seepage of crude oil into the marine environment

Recent global estimates of crude-oil seepage rates suggest that about 47% of crude oil currently entering the marine environment is from natural seeps, whereas 53% results from leaks and spills during the extraction, transportation, refining, storage, and utilization of petroleum. The amount of natural crude-oil seepage is currently estimated to be 600,000 metric tons per year, with a range of uncertainty of 200,000 to 2,000,000 metric tons per year. Thus, natural oil seeps may be the single most important source of oil that enters the ocean, exceeding each of the various sources of crude oil that enters the ocean through its exploitation by humankind.     

分散剂对原油影响的主成分分析

以2种原油和3种溢油分散剂的混合物为对象,借助SPSS统计分析软件,采用主成分分析法研究基于诊断比值的原油分类,旨在判别分散剂对原油的影响。KOM值近似等于0.6、Bartlett球形度检验对应概率P值为0,表明原始数据适合做主成分分析;前两个主成分F1和F2的特征值均大于1,累积贡献率为81.433%,多变量可降至2维。根据F1和F2表达式得到主成分分类图可知:两种原油中加入不同分散剂后还可在图中大致区分,富肯-2号分散剂对两种原油几乎没有影响,GM-2分散剂对渤海原油分类程度有一定影响,但对华北原油却有较大影响;海鸥4号分散剂对两种原油分类程度都有影响。结果表明:主成分分析法可用于添加分散剂的溢油分类辨别,研究发现一些分散剂对原油影响较小,而某些分散剂对原油有复杂的影响。因此,溢油指纹鉴定需考虑分散剂的影响。     

Responses of meiofauna and nematode communities to crude oil contamination in a laboratory microcosm experiment

We examined the effects of crude oil contamination on community assemblages of meiofauna and nematodes after exposure to total petroleum hydrocarbons in the laboratory. We administered a seawater solution that had been contaminated with total petroleum hydrocarbons to seven treatment groups at different concentrations, while the control group received uncontaminated filtered seawater. The average density of total meiofauna in the experimental microcosms diluted with 0.5%, 1%, 2%, and 4% contaminated seawater was higher than the density in the control. The average density of total meiofauna in the 8%, 15%, and 20% microcosms was lower than the density in the control. The density of nematodes was similar to that of the total meiofauna. Cluster analysis divided the microcosms into group 1 (control, 0.5%, 1%, 2%, and 4% microcosms) and group 2 (8%, 15%, and 20% microcosms). However, SIMPROF analysis showed no significant difference between the two groups (p > 0.05). Bolbolaimus spp. (37.1%) were dominant among the nematodes. Cluster analysis showed similar results for nematode and meiofaunal communities. The total meiofaunal density, nematode density, and number of Bolbolaimus spp. individuals were significantly negatively associated with the concentration of total petroleum hydrocarbons (Spearman correlation coefficients, p < 0.05). Within the nematodes, epistrate feeders (group 2A: 46%) were the most abundant trophic group. Among the treatment groups, the abundance of group 2A increased in low-concentration microcosms and decreased in high-concentration microcosms. Thus, our findings provide information on the effects of oil pollution on meiofauna in the intertidal zones of sandy beaches.     

Detection of DNA damage in mussels and sea urchins exposed to crude oil using comet assay

The single-cell microgel electrophoresis assay or the comet assay was used to evaluate DNA damage of dispersed crude oil on sea urchins (Strongylocentrotus droebachiensis) and mussels (Mytilus edulis L.). Sea urchins were exposed to 0.06 and 0.25 mg/L dispersed crude oil in a continuous flow system, while the mussels were exposed to 0.015, 0.06 and 0.25 mg/L dispersed crude oil. Sea urchin coelomocytes and mussel haemocytes were sampled after 4 and 5 weeks exposure, respectively. In the sea urchin coelomocytes, there was a significant concentration-related increase in the percentage of DNA in comet tail. In mussel haemocytes, there was a significantly higher percentage of DNA in comet tail for all treatments compared to the control. The responses were concentration-related up to 0.06 mg/L oil. The two highest exposure concentrations of mussels were not significantly different from each other. These results indicate that the comet assay can be used for biomonitoring of DNA damage in marine invertebrates following oil contamination.     

Hemocytes of Mytilus edulis affected by Prudhoe Bay crude oil emulsion

Hemocytes and tissues of Mytilus edulis were examined after 4–5 or 8–9 week's exposure to 390 μg/liter or 740 μg/liter Prudhoe Bay crude oil emulsion, during the animals' most metabolically active season. A reduction in hemocytes occurred in animals exposed to 740 μg/liter after 4–5 weeks. After 8–9 weeks, hemocyte counts of both test groups increased, due to higher densities of granulocytes, yet the phagocytic response was reduced. Agranulocyte densities were reduced in animals exposed to 390 μg/liter, due to lower counts of 2–3 μm agranulocytes. Further, adipogranular cell percentages in test animals were reduced. The results from oil-exposed mussels suggest a stress condition and have implications for monitoring.     

Effects of oil on phytoplankton metabolism in natural and experimental estuarine ponds

A low level oil spill was simulated in small shallow natural estuarine marsh ponds in Ocean Springs and in experimental impoundments near St. Louis Bay, Mississippi. In the natural tidal pond in situ light and dark BOD bottle experiments on the phytoplankton community revealed a 44 to 65 % reduction in primary production and a 30 to 50 % reduction in respiration 2 weeks after spillage of 1·45 mg Empire Mix crude oil per litre of water. Two months after the spill, primary productivity and respiration in the oiled pond were only 17% and 7% lower, respectively than in the control pond. In the experimental impoundments at a concentration of 0·2 mg Arabian, Empire Mix and Nigerian oil per litre of water, in situ radiocarbon uptake by phytoplankton was lower—but not significantly lower—than that of the control impoundment. One to two months later, primary productivity was significantly higher in the Nigerian and Arabian oil ponds than control and Empire Mix ponds. The changes in plankton metabolism in both natural ponds and impoundments were evaluated on the basis of data simultaneously obtained from adjoining control ponds.     

Optimization of crude enzyme preparation methods for analysis of glutamine synthetase activity in phytoplankton and field samples

Glutamine synthetase (GS) is an important enzyme involved in nitrogen assimilation and metabolism in marine phytoplankton. However, little work has been done in situ due to the limitation of crude enzyme preparation methods. In this study, three enzyme preparation methods, high-speed centrifugation (HC, <10 000 g), ultracentrifugation (UC, 70 000 g), and ultrafiltration (UF) with 100 kμ molecular weight cutoff, were compared using two diatom species (Asterionellopsis glacialis and Thalassiosira weissflogii)...     

Effects of crude oil on the supralittoral meiofauna of a sandy beach

The supralittoral zone of an open sandy beach was dosed with crude oil and changes in the meiofauna monitored. Treatments included weathered and fresh oil on the surface, fresh oil mixed with dispersant on the surface and weathered oil at the water table, all in layers 0·8 cm thick. In all cases the meiofauna was reduced 1 month after dosing but numbers had returned to normal by 5 months except in the site dosed with fresh oil mixed with dispersant. Oil on the surface had greater effects than oil at the water table; fresh oil had a greater effect than weathered oil and fresh oil with dispersant was more toxic than fresh oil alone. Nematodes were least sensitive to the oil and oligochaetes more sensitive, their numbers being correlated with oil concentrations and depth in the substrate. It is concluded that, under all but the heaviest conditions of pollution in their environment, recovery from oil contamination should occur within 5 months in the meiofauna.     

原油中的正构烷烃类在海沙和海水中风化的模拟实验

通过自然条件下沙表层和水面溢油的模拟风化实验,采用GC-MS作为检测器,研究原油中的正构烷烃在厦门地区的风化规律.结果表明,在一个月的风化模拟实验中,两种不同介质溢油风化均明显体现轻组分的正构烷烃丢失现象,且正构烷烃组分在水面溢油的风化速率低于沙表层溢油速率1～2个碳数.沙上模拟实验后期APr/APh比值明显受到风化影响,诊断比值不适用于油源鉴别.诊断比值An-C17/APr、An-C18/APh在短期风化过程中受风化影响小.水面溢油模拟实验结束后发现水体中n-C13-n-C29的正构烷烃组分含量升高2.9%～327.4%.     

The long-term effects of crude oil on microbial processes in subarctic marine sediments

Subarctic marine sediments were exposed to fresh and ‘weathered’ crude oil from Cook Inlet, Alaska. The crude oil was thoroughly mixed with the sediment at various concentrations and some of the oil-sediment mixtures were placed on top of unamended sediments. Both sediments with added oil and those overlain by oiled sediments were investigated. These sediments were placed either in trays or aquaria. The trays were incubated in situ near the site from which the sediments were originally collected. The aquaria were maintained at simulated in situ conditions by maintaining a continuous flow of fresh seawater through them. The sediments were exposed to crude oil for periods up to 1.5 years. Sediments exposed to 50‰ fresh crude oil showed significant decreases in nitrogen fixation and denitrification rates and redox potentials. Also observed were increases in CO₂ production rates and methane concentrations. These same changes were observed in sediments exposed to 1‰. When ‘weathered’ crude oil was added to the sediments, the same changes were observed except there was no reduction in nitrogen fixation activity. In most cases, the observed effects were less marked when the sediments were amended with ‘weathered’ crude oil than with the same concentration of fresh crude oil. Untreated sediments that were overlain with treated sediments showed the same changes as those sediments that were thoroughly mixed with crude oil. The presence of fresh crude oil at 50‰ essentially eliminated burrowing activity of the benthic infauna. Under these conditions, there was an accumulation of detritus particles on the oiled sediments that was not present in the untreated controls.     

The persistence and mobility of a light crude oil in a Sandy beach

The weathering of a very light crude oil (a condensate) in a sandy beach in Nova Scotia has been studied by following changes in its detailed chemical composition.Evaporation was the dominant weathering process in supratidal sand. After 4 months all oil components more volatile than n-C₁₆ had disappeared; concentrations of compounds less volatile than n-C₁₈ did not change. In the surface sand of the upper intertidal zone evaporation was much slower, with C₈ hydrocarbons still present after 3 months. Dissolution was also important in this environment with aromatic components up to the C₁-naphthalenes being removed in the first month. In subsurface (5–10 cm) sand from this zone and in both surface and subsurface samples from the middle intertidal zone, no loss of volatiles occurred over a 6-month period. Preferential Dissolution was significant in these environments, but was neither as rapid nor as extensive as in the surface sand of the upper intertidal zone. Observed dissolution rates were at least ten times slower than those predicted using equilibrium solubilities and pore water exchange rates.The mobility of the condensate through beach sand was dependent on the oil/sand ratio. At low concentrations, bulk oil movement was insignificant, but, at higher concentrations, movement was rapid, independent of interstitial water flow and exclusively upwards. Only at higher concentrations was appreciable oil free in the sand interstices where it was subject to this buoyancy transport mechanism.     

海洋原油外输软管拉伸刚度影响参数研究

海洋原油外输软管广泛用于海上FPSO和油轮的原油外输,软管在海洋环境作用下会受到轴向拉力,拉伸刚度是影响轴向受力的关键结构性能参数。根据《API SPEC 17K》标准和《GMPHOM2009》规范的要求,需要确定软管的拉伸刚度。基于Rebar方法定义海洋原油外输软管的帘线增强层,利用有限元软件ABAQUS建立某国产海洋原油外输软管的轴向拉伸模型,并计算不同结构参数条件下的软管拉伸刚度。计算结果表明：帘线增强层是海洋原油外输软管的主要抗拉伸结构层,帘线铺设角度越小其拉伸刚度越大,软管抗拉伸能力对帘线层数比较敏感,帘线层数越多软管抗拉伸能力越强;螺旋钢筋层的钢筋直径和螺距在一定程度的拉力范围内与软管的拉伸刚度保持良好的线性关系,软管的拉伸刚度随着钢筋直径的增大而增大,随着螺距的增大而减小。研究结果可为海洋原油外输软管的结构设计和实际应用提供参考。     

基于完好性的石油平台动力系统备品备件研究

基于完好性理论,提出了埕岛油田动力系统的备品备件配置策略,为复杂可维修系统的备品备件配置提供了一个通用的方法。     

原油WSF对三种海洋鱼类肝微粒体EROD活性的诱导和恢复的比较

研究了实验室条件下原油水溶性组分(WSF)暴露对黑鲷、黄鳍鲷和褐菖鲉肝微粒体EROD活性的剂量-效应,时间-效应和恢复过程。实验结果表明,在剂量诱导实验中,褐菖鲉肝EROD活性在原油WSF浓度为50μg/dm3时呈现生物统计学上的显著差异,而黑鲷和黄鳍鲷肝EROD活性在75μg/dm3时才呈现生物统计学上的显著差异;褐菖鲉肝EROD活性诱导倍数最高,但黑鲷的诱导浓度范围较广。在时间诱导实验中,在40μg/dm3原油WSF暴露下黄鳍鲷肝EROD活性在2 d时首先呈现显著差异;三种鱼肝EROD活性均在第4天达到最高,并呈现显著性变化,此后随着暴露时间的延长而逐渐下降并接近对照组水平。在恢复实验中三种鱼肝EROD活性下降并恢复到对照组水平。研究结果表明:对于石油污染物,黑鲷、黄鳍鲷和褐菖鲉肝EROD活性都可以作为污染生化效应监测指标,然而就三种鱼类比较而言,褐菖鲉最敏感,更适合于作为石油类污染及其生化效应,尤其是低剂量效应的监测生物。     

原油WSF对三种海洋鱼类肝微粒体EROD活性的诱导和恢复的比较

研究了实验室条件下原油水溶性组分(WSF)暴露对黑鲷、黄鳍鲷和褐菖鲉肝微粒体EROD活性的剂量-效应,时间-效应和恢复过程。实验结果表明,在剂量诱导实验中,褐菖鲉肝EROD活性在原油WSF浓度为50 μg/dm³时呈现生物统计学上的显著差异,而黑鲷和黄鳍鲷肝EROD活性在75 μg/dm³时才呈现生物统计学上的显著差异;褐菖鲉肝EROD活性诱导倍数最高,但黑鲷的诱导浓度范围较广。在时间诱导实验中, 在40 μg/dm³原油WSF暴露下黄鳍鲷肝EROD活性在2 d时首先呈现显著差异; 三种鱼肝EROD活性均在第4天达到最高,并呈现显著性变化,此后随着暴露时间的延长而逐渐下降并接近对照组水平。在恢复实验中三种鱼肝EROD活性下降并恢复到对照组水平。研究结果表明:对于石油污染物,黑鲷、黄鳍鲷和褐菖鲉肝EROD活性都可以作为污染生化效应监测指标,然而就三种鱼类比较而言,褐菖鲉最敏感,更适合于作为石油类污染及其生化效应,尤其是低剂量效应的监测生物。