Effects of chitin on microbial emulsification, mineralization potential, and toxicity of bunker C fuel oil     

Richmond SA  Lindstrom JE  Braddock JF 《Marine pollution bulletin》2001,42(9):773-779

Bunker C, one of the most frequently spilled petroleum products in the US, is difficult to remove from oiled surfaces and is relatively recalcitrant to biodegradation; therefore, emulsification and biodegradability must be optimized before bioremediation can be considered a viable treatment option. Sand from a freshly oiled beach near Dutch Harbor, Alaska, was incubated at 10 degrees C with nutrients (Bushnell-Haas (BH)) or nutrients with crab shell chitin (BH-C). BH-C amendment resulted in greater numbers of bunker C emulsifiers and greater mineralization potentials for hexadecane, phenanthrene, and fluorene than with BH only. Compared to BH alone, mineralization potentials for bunker C also were higher in BH-C, with an estimated 8% of fuel oil mineralized after 6 weeks. Microbially emulsified oil was more toxic than in uninoculated controls (p < 0.05) as measured by Microtox assays. However, toxicity was significantly lower in BH-C than BH after 4 and 6 weeks incubation (p < 0.05).  相似文献   

Transient heterogeneity in an aquifer undergoing bioremediation of hydrocarbons     

Schillig PC  Devlin JF  Roberts JA  Tsoflias GP  McGlashan MA 《Ground water》2011,49(2):184-196

Localized, transient heterogeneity was studied in a sand aquifer undergoing benzene, toluene, ethylbenzene, and xylene bioremediation using a novel array of multilevel, in situ point velocity probes (PVPs). The experiment was conducted within a sheet-pile alleyway to maintain a constant average flow direction through time. The PVPs measured changes in groundwater velocity direction and magnitude at the centimeter scale, making them ideal to monitor small-scale changes in hydraulic conductivity (K). Velocities were shown to vary nonuniformly by up to a factor of 3 when a source of oxygen was established down-gradient of the petroleum spill. In spite of these local variations, the average groundwater velocity within the 7 m × 20 m sheet-piled test area only varied within ± 25%. The nonuniform nature of the velocity variations across the gate indicated that the changes were not due solely to seasonal hydraulic gradient fluctuations. At the conclusion of the experiment, microbial biomass levels in the aquifer sediments was approximately 1 order of magnitude higher in the oxygen-amended portion of the aquifer than at the edge of the plume or in locations up-gradient of the source. These data suggest that the transient velocities resulted, at least in part, from enhanced biological activity that caused transient heterogeneities in the porous medium.  相似文献   

Large-scale oil-in-ice experiment in the Barents Sea: monitoring of oil in water and MetOcean interactions     

Faksness LG  Brandvik PJ  Daae RL  Leirvik F  Børseth JF 《Marine pollution bulletin》2011,62(5):976-984

A large-scale field experiment took place in the marginal ice zone in the Barents Sea in May 2009. Fresh oil (7000 L) was released uncontained between the ice floes to study oil weathering and spreading in ice and surface water. A detailed monitoring of oil-in-water and ice interactions was performed throughout the six-day experiment. In addition, meteorological and oceanographic data were recorded for monitoring of the wind speed and direction, air temperature, currents and ice floe movements. The monitoring showed low concentrations of dissolved hydrocarbons and the predicted acute toxicity indicated that the acute toxicity was low. The ice field drifted nearly 80 km during the experimental period, and although the oil drifted with the ice, it remained contained between the ice floes.  相似文献   

北京道面温度特征分析和统计预报研究     

董颜  郭文利  闵晶晶  李乃杰  张丰瑶 《气象》2020,46(5):716-724

分析了北京市道面温度在冬季和夏季不同天气状况下的日变化,利用2012—2015年的道面站温度与北京区域模式输出的气象要素之间的相关关系,以5个道面站为代表站筛选不同相关因子建立多个道面冬季最低温度和夏季最高温度的线性回归统计预测模型,并对2016—2017年冬季、夏季道面温度预测检验。结果表明:在不同天气条件下道面温度与气温变化对比明显;道面温度与气温、辐射、日照时数相关较大;夏季按天气类型建模预测准确度有所提升,在晴到多云状况下,模型预测冬季最低温度误差控制在±2℃内,夏季最高温度误差控制在±3℃左右,其他天气状况下误差增大,冬季预测模型好于夏季预测模型。  相似文献   

The influence of a season of extreme wet weather events on exposure of the World Heritage Area Great Barrier Reef to pesticides     

Kennedy K  Devlin M  Bentley C  Lee-Chue K  Paxman C  Carter S  Lewis SE  Brodie J  Guy E  Vardy S  Martin KC  Jones A  Packett R  Mueller JF 《Marine pollution bulletin》2012,64(7):1495-1507

The 2010-2011 wet season was one of extreme weather for the State of Queensland, Australia. Major rivers adjacent to the Great Barrier Reef (GBR) were discharging at rates 1.5 to >3 times higher than their long term median. Exposure to photosystem II herbicides has been routinely monitored over a period of up to 5 years at 12 inshore GBR sites. The influence of this wet season on exposure to photosystem II herbicides was examined in the context of this long-term monitoring record and during flood plume events in specific regions. Median exposures expressed as diuron equivalent concentration were an average factor of 2.3 times higher but mostly not significantly different (p<0.05) to the median for the long-term monitoring record. The herbicides metolachlor and tebuthiuron were frequently detected in flood plume waters at concentrations that reached or exceeded relevant water quality guidelines (by up to 4.5 times).  相似文献   

Photosystem II herbicide pollution in Hong Kong and its potential photosynthetic effects on corals     

Shaw CM  Lam PK  Mueller JF 《Marine pollution bulletin》2008,57(6-12):473-478

Photosystem II (PSII) herbicides have been shown to affect the photosynthesis of corals at low, environmentally relevant concentrations. The recent detection of the PSII herbicide Irgarol-1051 in coastal waters of Hong Kong at concentrations above the EC(50) for reduction of photosynthesis of corals prompted further investigation into the extent of PSII herbicide pollution in coral reefs of Hong Kong. Snap-shot and passive samples were taken from coral reef sites and evaluated via HPLC/MS-MS and a novel bioanalytical technique. Low concentrations (less than 10 ng L(-1)) of diuron and atrazine were found at all study sites. Extracts from these samples concentrated by a factor of 10 were found to reduce the photosynthetic yield of zooxanthellae. It appears unlikely that herbicide pollution is a key issue in isolation but may act synergistically with other stressors to reduce the viability of Hong Kong's coral reefs. The study has also demonstrated the feasibility of combining sample extraction techniques with a coral specific bioanalytical technique for a sensitive assessment of risks associated with herbicide exposure in corals.  相似文献   

西藏西南部普兰盆地东缘伸展构造初步研究   总被引：4，自引：1，他引：3  

陈正乐 Ryer.  JF 《地质论评》1999,45(3):295-300

笔者在西南西南部普兰盆地填１：１０万地质图时,发现了一条沿盆地东缘展布的新生代伸展断层,其上盘为上新世普兰组砾岩：下盘为前寒武纪聂拉木群花岗片麻岩及花岗质糜棱岩和碳酸质糜棱岩。糜棱岩的拉伸线理为ＷＮＷ向,倾角平缓。在上下盘地层中都发育大小不同,近似平行的正断层,其中一条组成盆地东缘的大陡坎。  相似文献   

三种浅地震方法在冲积含水层研究中的应用和比较     

Ayers  JF 何雪洲 《水文地质技术方法》1990,(21):91-99

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Pigmenting agents in Martian soils: inferences from spectral, Mossbauer, and magnetic properties of nanophase and other iron oxides in Hawaiian palagonitic soil PN-9     

Morris RV  Golden DC  Bell JF rd  Lauer HV  Adams JB 《Geochimica et cosmochimica acta》1993,57(19):4597-4609

We have examined a Hawaiian palagonitic tephra sample (PN-9) that has spectroscopic similarities to Martian bright regions using a number of analytical techniques, including Mossbauer and reflectance spectroscopy, X-ray diffraction, instrumental neutron activation analysis, electron probe microanalysis, transmission electron microscopy, and dithionite-citrate-bicarbonate extraction. Chemically, PN-9 has a Hawaiitic composition with alkali (and presumably silica) loss resulting from leaching by meteoric water during palagonitization; no Ce anomaly is present in the REE pattern. Mineralogically, our results show that nanophase ferric oxide (np-Ox) particles (either nanophase hematite (np-Hm) or a mixture of ferrihydrite and np-Hm) are responsible for the distinctive ferric doublet and visible-wavelength ferric absorption edge observed in Mossbauer and reflectivity spectra, respectively, for this and other spectrally similar palagonitic samples. The np-Ox particles appear to be imbedded in a hydrated aluminosilicate matrix material; no evidence was found for phyllosilicates. Other iron-bearing phases observed are titanomagnetite, which accounts for the magnetic nature of the sample; olivine; pyroxene; and glass. By analogy, np-Ox is likely the primary pigmenting agent of the bright soils and dust of Mars.  相似文献   

Mantle redox evolution and the oxidation state of the Archean atmosphere   总被引：1，自引：0，他引：1  

Kasting JF  Eggler DH  Raeburn SP 《The Journal of geology》1993,101(2):245-257

Current models predict that the early atmosphere consisted mostly of CO2, N2, and H2O, along with traces of H2 and CO. Such models are based on the assumption that the redox state of the upper mantle has not changed, so that volcanic gas composition has remained approximately constant with time. We argue here that this assumption is probably incorrect: the upper mantle was originally more reduced than today, although not as reduced as the metal arrest level, and has become progressively more oxidized as a consequence of the release of reduced volcanic gases and the subduction of hydrated, oxidized seafloor. Data on the redox state of sulfide and chromite inclusions in diamonds imply that the process of mantle oxidation was slow, so that reduced conditions could have prevailed for as much as half of the earth's history. To be sure, other oxybarometers of ancient rocks give different results, so the question of when the mantle redox state has changed remains unresolved. Mantle redox evolution is intimately linked to the oxidation state of the primitive atmosphere: A reduced Archean atmosphere would have had a high hydrogen escape rate and should correspond to a changing mantle redox state; an oxidized Archean atmosphere should be associated with a constant mantle redox state. The converses of these statements are also true. Finally, our theory of mantle redox evolution may explain why the Archean atmosphere remained oxygen-deficient until approximately 2.0 billion years ago (Ga) despite a probable early origin for photosynthesis.  相似文献