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1.
Microbial degradation of five crude oils such as Arabian light, Berri, Murban, Khafji and Minas crude oil by a pure bacterial strain,Pseudomonas sp. isolated from the sea water sampled at Kawasaki Harbor in Tokyo Bay, was studied experimentally in the enriched seawater medium.The degradation of crude oils was determined in total residual oil and in four fractions of saturated, aromatics, asphaltene and column residue by use of the column chromatography with activated alumina.The saturated fraction was shown to be most biodegradable. The aromatics followed for all five crude oils examined and the asphaltene was biodegradable to some extent. The column residue was not apparently degraded byPseudomonas sp. within 30 days. Each of Arabian light, Berri or Murban crude oil was degraded from 59 to 63.5 %, Khafji crude oil 49 % and Minas crude oil, solid at room temperature, only 33 %. Degradation rate of the five crude oils was determined to be in a range from 2.88 to 17.3 mg-oil 1–1 hr–1 or from 6.0×10–12 to 1.56×10–10 mg-oil cell–1 hr–1. Relative degradation ofn-paraffins of different carbon numbers in the saturated fraction was found to be similar regardless of carbon number for the five crude oils.  相似文献   

2.
Solutions of Ekofisk crude oil in sea water were prepared by slow stirring for 21h in a closed system. Headspace and GC/MS techniques were applied to establish dose composition and levels. The standardized test medium produced in a closed system contained approximately 14 mg oil per litre and was dominated by low molecular weight aromatic hydrocarbons and phenols.The toxicity of the standarized oil-containing medium to three marine diatoms was studied in a cage culture turbidostat and by conventional batch culture technique. The three algal species differed in sensitivity to the oil compounds, but showed identical ranking in both test systems.Standardized test medium diluted to 50% with respect to oil content stopped the growth of the most sensitive alga, Skeletonema costatum. For comparison naphthalene was applied and gave 50 % growth reduction at a concentration of 400 μg litre?1. The growth of Chaetoceros ceratosporum was only slighty affected by the full strength standard test medium, which had no influence on the growth of Phaeodactylum tricornutum, the least sensitive organism. The presence of an oil layer on the surface of the standard test medium during the growth test greatly increased its toxicity and blocked completely the photosynthesis even of P. tricornutum after 4 days.  相似文献   

3.
The effects of Prudhoe Bay, Alaska, crude oil on the indigenous phytoplankton and zooplankton of tundra thaw ponds were studied under controlled conditions in situ during the summer of 1976. These effects were compared with uncontrolled oil spills on Pond Omega (a year previously) and Pond E (six years previously). In the uncontrolled spills, the phytoplankton species composition of both ponds remained appreciably different compared with control Pond C, although phytoplankton biomass did not differ greatly. Primary production remained low in Pond Omega but had recovered to control levels in Pond E. In controlled subpond experiments, oil caused a decrease of about 90–100% in primary production in five days but recovered to 40–50% of the control level within fifteen days. During that time, phytoplankton biomass decreased initially but recovered within fifteen days. Oil caused a shift in phytoplankton species composition from a predominance of cryptophytes to chrysophytes. Subponds containing two Daphnia middendorffiana and one Brachinecta paludosa per litre of pondwater were also affected by oil, causing zooplankton death within three or four days. After that time, changes in the phytoplankton species composition were similar to control subponds without zooplankton. Oil toxicity to zooplankton or experimental removal resulted in a loss of grazing pressure which caused the elimination of the cryptophyte Rhodomonas sp. This species was still absent from Pond Omega, but was seen in Pond E for the first time, when zooplankton also reappeared after six years. Oil perturbation of tundra thaw ponds causes a loss of zooplankton and a reduction in primary production. Phytoplankton primary production recovers somewhat but algal species composition remains changed because of the loss of zooplankton grazing pressure and the selective effects of oil.  相似文献   

4.
The activities of methane-producing and sulphate-reducing bacteria in intertidal sediments along the Brittany coast of France were examined in order to determine the effect of the Amoco Cadiz oil spill on sediment microbial processes. Porewater chemistry, methane production, sulphate rate and [2?14C]-acetate metabolism did not vary significantly between beach, estuary, and marsh sites, oiled or unoiled, after the Amoco Cadiz spill. Oiled sediments contained highly weathered oil of Amoco Cadiz origin, but unoiled comparison sites also contained hydrocarbons from anthropogenic sources. The additions of weathered Amoco Cadiz mousse, fresh and slightly weathered light Arabian crude oil, benzene or toluene to sediments from the oiled and unoiled marsh site did not significantly affect rates of sulphate reduction or methane production. The oxidation of [2?14C]-acetate to 14CO2, however, was significantly decreased when mousse, crude oil, benzene or toluene was added to sediments from the unoiled site. Inhibition seemed to be proportional to the extent of weathering. Sediments recently exposed to Amoco Cadiz crude oil were less affected by a second oiling, suggesting that the indigenous populations may have been replaced by organisms more resistant to oil toxicity. These results suggested that the Amoco Cadiz oil spill did not have major long-term effects on sulphate reduction or methane production.  相似文献   

5.
Bacterial biomass and production rate were measured in the surface (0–100 m) and mesopelagic layers (100–1,000 m) in the subarctic Pacific and the Bering Sea between July–September, 1997. Depth profiles were determined at stations occupied in oceanic domains including the subarctic gyres (western, Bering Sea, and Gulf of Alaska) and a boundary region south of the gyres. In the surface layer (0–100 m), both bacterial biomass and production were generally high in the western and Bering Sea gyres, with the tendency of decrease toward east. This geographic pattern was consistent with the dominant regime of phytoplankton biomass at the time of our survey. A significant portion of variation in bacterial production was explained by the concentration of chlorophyll a (r 2 = 0.340, n = 60, P < 0.001) and, to the greater extent, by the concentration of semilabile total organic carbon (SL-TOC = TOC at a given depth—TOC at 1,000 m, r 2 = 0.488, n = 59, P < 0.0001). Temperature significantly improved the regression model: temperature and chlorophyll jointly explained 60% of variation in bacterial production. These results support the hypothesis that bacteiral growth is largely regulated by the combination of temperature and the supply of dissolved organic carbon in subarctic surface waters. In the mesopelagic layer (100–1,000 m), the geographic pattern of bacterial production was strikingly different from the surface phytoplankton distribution: the production was high in the boundary region where the phytoplankton biomass was lowest. Bacterial growth appeared to be largely controlled by the supply of organic carbon, as indicated by the strong dependency of bacterial production on SL-TOC (r 2 = 0.753, n = 75, P < 0.0001). The spatial uncoupling between surface phytoplankton and mesopelagic bacterial production suggests that the supply rate of labile dissolved organic carbon in the mesopelagic zone does not simply reflect the magnitude of the particulate organic carbon flux in the subarctic Pacific.  相似文献   

6.
Four crude oils and five fuel oils have been tested for toxicity with three microalgae—a blue-green, a green and a diatom. The oils were absorbed on filter paper pads and the pads submerged in the growth medium. The crude oils were less inhibitory than equal amounts of fuel oils. Despite initial growth lags, the crude oils allowed growth at 30 μl/20 ml of culture medium (105 cells/ml) while fuel oils were lethal at 10 μl/20 ml. The toxicity patterns of two of the whole fuel oils were different from that seen with their water soluble fractions (WSF); for example, the Baton Rouge fuel oil sample was very toxic to growth of the three test organisms whereas its WSF was relatively innocuous. Photosynthesis of a sensitive organism Chlorella autotrophica, strain 580 (107 cells/ml), was only temporarily depressed by the crude oils (30 μl/20 ml). Four of the fuel oils inhibited photosynthesis, O2 output decreasing to zero without recovery. When the fuel oils were heated in a stream of helium they were detoxified. Chemical analyses of two of the toxic fuel oils before and after heating were compared with analyses of the Montana sample, a largely non-toxic fuel oil, in an effort to determine what types of compounds might be involved. Classes of aromatic compounds which were not accountable for the toxicity observed here include naphthalene, methylnaphthalenes, dibenzothiophenes, phenanthrenes and compounds with volatilities greater than methylnaphthalenes. Paraffinic and asphaltic fractions of fuel oil were also non-toxic. The accumulated chemical data suggest that the toxicity of whole fuel oils is due to the less water soluble types of compounds in the higher boiling aromatic fraction.  相似文献   

7.
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.  相似文献   

8.
Adaptation to sublethal exposure to crude oil by phytoplankton is poorly understood. Use of chemical dispersants for oil spill remediation increases petroleum hydrocarbon concentrations in water, while exposing marine organisms to potentially toxic concentrations of dispersant. Heat shock proteins (hsps) have been found to serve as an adaptive and protective mechanism against environmental stresses. The objective of this project was to examine the induction of hsps in Isochrysis galbana, a golden-brown algae, following exposure to the water-accommodated fraction (WAF) of Prudhoe Bay crude oil (PBCO) and PBCO chemically dispersed with Corexit 9527® (dispersed oil: DO). Initial experiments using 35S-labeled amino acids and 2-dimensional electrophoresis with subsequent western blotting identified and confirmed hsp60, a member of the chaperonin family of stress proteins, as being efficiently induced by heat shock in this species. One-dimensional SDS PAGE and western blotting, with hsp60 antibodies and chemiluminesence detection, were used to quantitate hsp60 following exposure to a range of environmental temperatures and concentrations of WAF and DO preparations. I. galbana cultured in 22 parts per thousand (‰) salinity showed a statistically significant increase (p<0.05) in hsp60 after exposure to 25, 30, and 35°C for 1 h compared to controls (20°C), while 34‰ cultures showed no significant increase in hsp60 with increasing temperature. Cultures (22 and 34‰) exposed to varying doses of WAF and DO exhibited statistically significant (p<0.05) increases in levels of hsp60 in all cases. A dose-related response was observed in all exposures (r2≥0.90) with the exception of 34‰ WAF. In independent exposures, a dose-related hsp60 response to naphthalene, a relatively abundant water-soluble aromatic hydrocarbon, was observed in both 22 and 34‰ cultures. Results of this study are consistent with previous studies in other species documenting increases in hsp60 levels with exposure to xenobiotics. Further studies are investigating the protective function of hsp60 against the toxic effects of exposure to WAF and DO preparations.  相似文献   

9.
No. 2 fuel oil-sea water dispersions were added to three large scale (13 m3) microcosms twice weekly for a period in 1977 and a 4 month period in 1978. Water column concentration of total hydrocarbons averaged 190 μg litre−1 in 1977 and 93 μg litre−1 in 1978. Several responses of t the phytoplankton community in the oiled microcosms, relative to control microcosms, were similar during both periods of oil addition: total phytoplankton abundance and chlorophyll concentration were elevated, species diversity was higher and diatoms represented a greater proportion of the total p phytoplankton abundance than flagellates during 4 months of oil addition in 1977 and the entire period of oil addition in 1978. Phytoplankton species composition in the oiled microcosms was similar to the source water, Narragansett Bay, but the microcosm assemblages were numerically dominated by populations of the diatom Chaetoceros spp. and nanoflagellates in 1977 and several Chaetoceros spp. in 1978. Reduced predation pressure and altered herbivore feeding behaviour combined with the low level, non-lethal (to the majority of phytoplankton populations), concentrations of No. 2 fuel oil in the water column are postulated as mechanisms that can account for the elevated phytoplankton abundance in the oiled microcosms relative to the controls.  相似文献   

10.
Available data on phytoplankton and bacterial abundance and production off the coasts of southern Africa (to the 500 m depth contour) have been assembled and analysed for a network analysis of carbon flow in the Benguela ecosystem. Phytoplankton carbon biomass (from measurements of chlorophyll a) in the northern Benguela (2 558 300 tons) was considerably higher than in the southern Benguela (671 420 and 516 400 tons for the West and South coasts respectively). However, overall annual production (from C14-uptake measurements) was similar, 77 416 608, 76 399 973 and 78 988 020 tons C·year?1 respectively. Phytoplankton respiration and sedimentation losses were calculated as functions of primary production and therefore followed similar trends. From the most conservative estimates (mean bacterial biomass of 10 mg C·m?3 and average P:B of 0,2·day?1) bacterial biomass is 2–7 per cent of phytoplankton biomass in the northern and southern Benguela, and bacterial production is 3–5 per cent of primary production. Assuming a net growth yield of 30 per cent, bacteria would need to consume 9–15 per cent of the total primary production in order to meet their requirements for carbon consumption. Calculations based on a mean bacterial biomass of 40 mg C·m?3 and a mean growth rate of 0,5·day?1 in the upper 30 m of the water column show bacterial biomass to be 8–27 per cent of phytoplankton biomass and bacterial production to be 26–44 per cent of phytoplankton production. Bacterial carbon consumption requirements at these rates amount to 86–147 per cent of total primary production.  相似文献   

11.
Abstract

Bacterial numbers and production were measured in the upper water column in the winter and spring of 1993 in five water masses surrounding the South Island of New Zealand. Average bacterial numbers and production were found to be higher in spring (8.5 × 105 cells ml?1 and 0.20 mg m3 h?1, respectively) than winter (5.5 × 105 cells ml?1 and 0.05 mg C m3 h?1 respectively). Bacterial production was strongly correlated with chlorophyll a and primary production (P < 0.001) in spring but not in winter. Spring bacterial production and at 10 m depth averaged across 28 stations was 23% of primary production, and with a growth efficency of 40%, may have consumed up to 57% of primary production. Bacterial biomass was greater than phytoplankton biomass for 75% of the 10 m depth comparisons during winter sampling and 44% during the spring sampling. The bacterial biomass was found to represent 24.6–33.5% of the nitrogen in particulate organic matter (<200 μm) supporting the concept that in New Zealand oceanic water masses bacteria are of significant biogeochemical importance.  相似文献   

12.
J. Hua   《Ocean Engineering》2006,33(2):152-167
Biodegradation of marine fuel oil was studied by monitoring changes in residual oil and populations of microorganisms in marine sediments. Biodegradation rates for dispersant and soap water were 2.09 and 2.27 g/kg per day, respectively, under pre-application strategy, suggesting that the strategy may promote MFO dispersion and provide with sufficient source of food. The effect of temperature on the effectiveness of pre-application strategy is particularly obvious for the growth of fungi and Pseudomonas maltophilia. The effect of pre-application of soap water on the tolerance of aerobic bacteria, Escherichia coli, and P. maltophilia, was gradually diminished within 25–33 days.  相似文献   

13.
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.  相似文献   

14.
Four experiments were carried out to determine the effect of different temperatures, light levels and biological activities on the residence times of petroleum hydrocarbons. No. 2 fuel oil was added as a seawater dispersion to give an initial concentration of 150 to 300 μg/litre in the water columns of large, outdoor marine microcosms. Hydrocarbons in water samples fractionated on passage through glass fibre filters (0·3 μm pore size) according to the solubilities, so that 80–90 % of the aromatics entered the filtrate while all of the saturates were trapped by the filter. The removal of oil compounds from the water columns was exponential, with rates which appeared to be determined chiefly by the temperature. The half life of total hydrocarbons varied from more than 10 days in March to ～30 h in July and September. Volatilisation was hypothesised to be an important removal mechanism for the 40–60% of the saturates which were not sedimented with suspended particulate matter. In warm water, the residence times of normal alkanes were increased up to 50 % by poisoning the water column, but no similar increase was noted for the bulk of the F1 hydrocarbons. Aromatic (F2) hydrocarbons appeared to be removed slowly volatilisation from cold water (t12 > 200 h) and rapidly by biodegradation from warm water (t12 < 40 h).  相似文献   

15.
We present evidence that there are significant interactions between heterotrophic microorganisms, doliolids and Fritillaria within intrusions of nutrient-rich Gulf Stream water stranding on the continental shelf. During the summer of 1981 cold, nutrient-rich water from below the surface of the Gulf Stream was repeatedly intruded and stranded on the continental shelf off northeastern Florida. On August 6 old, stranded Gulf Stream water depleted of nitrate occupied the lower layer on the outer shelf. The upper water was continental shelf water, older but of undefined age. On August 6 free-living bacteria were >106ml−1 everywhere at all depths, an order of magnitude greater than normal bacterial numbers on the northeastern Florida continental shelf. Over 10 days the numbers of free bacteria doubled while bacteria attached to particles increased by a factor of four. The adenylate/chlorophyll ratio showed that phytoplankton dominated the lower layers of intruded water, while the surface water became increasingly dominated by heterotrophic microorganisms (bacteria and protozoa) over 10 days. There were significant, negative correlations between bacteria and doliolids and between bacteria and Fritillaria. Regions of maximum bacterial numbers did not coincide with locations of salp swarms. The increased numbers of bacteria at all depths in a highly stratified system in which most phytoplankton are in the lower layer suggests a diverse source of bacterial growth substrates, some of which involve zooplankton as intermediaries. Production of autotrophs is more than twice that of microheterotrophs on average, but because of their differential distribution, microheterotrophs are the dominant biomass in much of the surface water and may be significant in energy flux to metazoan consumers as well as competitors for mutually useable sources of nutrition.  相似文献   

16.
By using TPA (12-tetra-decanoyl-phorbol-13-acetate) an artificial inducer for metamorphosis, it was possible to determine the effect of crude oil on settlement and metamorphosis of planulae of the soft coral Heteroxenia fuscescens. In the absence of crude oil, TPA induced metamorphosis in 97% of these planulae. The effect of crude oil on metamorphosis and appearance of deformed primary polyps was concentration dependent. Only 50% of the planulae grown in experimental vessels with crude oil at a concentration of 0.1 ppm covering the bottom and walls of the vessels underwent metamorphosis when triggered by TPA. Of those planulae exposed to 100 ppm of the pollutant only 3% metamorphosed after being induced by TPA. Furthermore, oil film on the water surface was less toxic to the larvae than the crude oil covering the bottom and walls of the experimental vessels. Some of the oil treated planulae died, while others remained viable, looked normal, but did not metamorphose after being presented with TPA. These findings suggest that even at very low concentrations crude oil affects larvae of H. fuscescens preventing their settlement and metamorphosis. Therefore it is possible that oil spills affect coral recruitment by decreasing the viability and the settlement of coral planulae. This assay represents a new sensitive bioindicator to detect the impact of oil pollution on tropical and subtropical marine environments.  相似文献   

17.
Mussels (Mytilus edulis L.) were exposed to North Sea crude oil, microencapsulated oil and dispersants, singly and in combination, and growth rates measured at 24–48 h intervals.Exposure to microencapsulated pure oil (2·0–2·1 mg litre−1) and to microencapsulated mixtures of oil (2·2−2·5 mg litre-1+5 % of the different dispersants (FINASOL OSR 5, COREXIT 9527, DISPOLENE 36 S) gave approximately the same reduction in growth rate (80–90%) within 170h.Oil chemically dispersed with DISPOLENE 36 S and a pure oil mechanically dispersed in water were significantly less toxic. In high concentrations (2 mg litre−1) all disperants are toxic, DISPOLENE 36 S ssignificantly more than the others.Mussels exposed for 170 h to microencapsulated oil and to microencapsulated oil dispersant mixtures recovered to control growth within 300 h in clean seawater, while in those given pure oil-in-water suspension, the recovery was slower.It is concluded that the toxicity of oil is mainly related to size and concentration of oil particles, while the effect of 5% dispersants added is negligible.  相似文献   

18.
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.  相似文献   

19.
Mangroves are coastal ecosystems, found in tropical and subtropical regions around the world. They are found in the transitional zones between land, sea, and rivers. Petroleum hydrocarbons are the most common environmental pollutants, and oil spills pose a great hazard to mangroves forests. This research was focused on the isolation and characterization of crude oil‐degrading bacteria from mangrove ecosystems at the Persian Gulf. Sixty‐one crude oil‐degrading bacteria were isolated from mangrove samples (plant, sediment, and seawater) that enriched in ONR7a medium with crude oil as only carbon source. Some screening tests such as growth at high concentration of crude oil, bioemulsifier production, and surface hydrophobicity were done to select the most efficient strains for crude oil degradation. Molecular identification of strains was carried out by amplification of the 16S rRNA gene by PCR. The results of this study were indicated that the quantity of crude oil‐degrading bacteria was higher in the root of mangrove plants compare to other mangrove samples (sediment and seawater). Also, identification results confirmed that these isolated strains belong to Vibrio sp. strain NW4, Idiomarina sp. strain BW32, Kangiella sp. strain DP40, Marinobacter sp. strain DW44, Halomonas sp. strain BS53, and Vibrio sp. strain DS35. The application of bioremediation strategies with these bacteria can reduce crude oil pollution in this important marine environment.  相似文献   

20.
Field and laboratory experiments were carried out to investigate the effects of Alberta crude oil and an oil dispersant (Corexit 9527) on the larval settlement, survival, siphon activities and behaviour of the littleneck clam (Protothaca staminea). Corexit 9527 was much more toxic than crude oil, and the highest toxicity was obtained when Corexit 9527 was mixed with crude oil. Siphon activities were impaired and abnormal behaviour was exhibited when adult clams were treated with 100 ppm Corexit 9527, 1000 ppm crude oil or a combination of both. Larval settlement was not affected when the substratum was treated with 1000ppm crude oil but was retarded when the substratum was treated with a mixture of 1000 ppm oil and 100 ppm Corexit 9527. Gas chromatograms also showed that the retention time and depth of penetration of hydrocarbons in the substratum was increased when Corexit 9527 was used with crude oil.  相似文献   

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