Biological effects of oil on early development of the Baltic herring Clupea harengus membras

The effects of petroleum hydrocarbons from two crude oils and one fuel oil (No. 1) were studied on the ontogenic development of the Baltic herring Clupea harengus membras L. Herring eggs exposed to water-soluble fractions of the oils at the time of fertilization showed no decrease in numbers of fertilized eggs compared to eggs exposed 6 or 72 h after fertilization. During embryongenesis, treatment with 3.1 to 8.9 ppm or 3.3 to 11.9 ppm total oil hydrocarbons from light fuel oil and the two crude oils respectively, gave rise to alterations in embryonic activity, decreased heart rate, and premature or delayed hatching. Although many larvae hatched from eggs exposed to contaminated water (3.1 to 11.9 ppm total oil hydrocarbons), the majority of the (70 to 100%) were malformed or dead 1 day after hatching. Exposure of eggs to 5.4–5.8 ppm total oil hydrocarbons resulted in significantly (P<0.001) decreased lengths of the larvae. Increased temperature (from 9° to 14°C) aggravated the effects of the oils. The results are discussed in relation to the potential effects of oil spills and chronic oil pollution on fish eggs and larvae in the Baltic Sea.     

Investigation of the sources of aliphatic hydrocarbons in the mussel Mytilus edulis from north sea oil production platforms by Capillary glc and CGCMS†

Aliphatic hydrocarbons isolated from mussels collected over a 20 month period from three North Sea Forties field oil production platforms have been examined by capillary gas chromatography and gas chromatography‐mass spectrometry.

The biological hydrocarbons consist predominantly (300–700 μh g^‐1 lipid) of C₃₁ and C₃₃ n‐alkenes with 2, 3 and 4 double bonds probably derived from a dietary intake of Emiliania huxleyi, a microscopic coccolithophorid alga. In some of the mussels C₁₈, C₂₀ and C₂₂ n‐alkanes are present in unusually high abundance compared to their odd carbon number homologues. Possible reasons for this distribution are discussed.

The concentrations of fossil fuel hydrocarbons (mainly unresolved complex mixtures) in the mussels ranged from 330 to 5,298 μg g^‐1 of lipid. No significant increase in values was detected two months after the start of discharge of treated Forties production water from the Forties D platform.

To determine the pollutant hydrocarbon sources, the sterane and terpane distributions of hydrocarbon fractions isolated from the mussels and from a number of fossil fuels, including Forties crude oil, were examined by mass fragmentography. The steranes in the mussels from the Forties C and D platforms contained higher proportions of regular 14α(H), 17α(H) components than Forties oil in which the steranes were mainly 13ß(H), 17α(H) diasteranes. In addition, the terpane distributions of the mussel fractions differed markedly from that of Forties crude oil, particularly in the relative abundance of diterpanes to triterpanes, which was higher in the mussel fractions than in the oil, and in the absence of 17α(H), 18α(H), 21ß(H)‐18, 30‐bisnorhopane, a known component of Forties crude. Furthermore, the ratio of C₂₉ to C₃₀ triterpanes was greater than unity in the mussels but much less than unity in the Forties oil. These data preclude Forties or other similar North Sea crudes as the major source of pollutant aliphatic hydrocarbons in the mussels. The relative concentrations and distributions of steranes and triterpanes suggest that the most likely source of pollutants is a Middle Eastern based oil derived either from rig activities, or from background pollution in the North Sea. The low concentration of ≥ C₂₇ steranes in the more polluted mussels (e.g. Forties B; UCM > 200 ppm dry wt.) suggests that gas oils used on the platforms may be the major source of petrogenic hydrocarbons in these samples.     

A long-term study of the effects of water-soluble fractions of No. 2 fuel oil on the survival,development rate,and growth of the mud crab Rhithropanopeus harrisii

Mud crabs, Rhithropanopeus harrisii (Gould), were exposed continuously for 6 months after hatching to water-soluble fractions (WSF) of No. 2 fuel oil. Survival, growth and development rate were monitored during this time. The zoeal stages were the most sensitive to fuel oil. A 20% WSF (0.36 ppm total naphthalenes, 1.26 ppm total hydrocarbons) was acutely toxic to these stages. Of the zoeal stages, the first stage appeared to be the most sensitive. The combined duration of the 4 zoeal stages was significantly increased by increasing WSF exposure concentrations. The megalopa and crab stages were not particularly sensitive to continued petroleum hydrocarbon exposure, particularly when compared to zoeal stages. However, mean duration of the megalopa and first crab stages was significantly affected by oil exposure. Individuals which survived the highest exposure concentrations as larvae appeared to grow larger during the crab stages, so that at the end of 6 months comparably staged crabs were equal to or larger than both control crabs and those exposed to low WSF concentrations. Stage distributions at the end of 6 months showed no differences due to WSF exposure. Sex ratios, which could be determined at the end of 6 months, were approximately 1, indicating no sex-related differential sensitivity to WSF exposure, at least as larvae or juveniles. The data indicate that these crabs possess considerable ability to recover from the effects of chronic sublethal exposure to petroleum hydrocarbons. The most deleterious effects of oil pollution on this species may be due to its impact on larval recruitment into the adult population.     

Accumulation,release and retention of petroleum hydrocarbons by the oyster Crassostrea virginica

Two Crassostrea virginica populations, differing in fat content, were experimentally exposed to a complex petroleum-hydrocarbon fraction. The hydrocarbons in this mixture were accumulated by both groups of oysters, and their lipid content, as well as the concentration of hydrocarbon in the water, were found to affect the rate and extent of accumulation. Hydrocarbons accumulated were rapidly, although incompletely, discharged when the oysters were transferred to an uncontaminated system. Amounts of hydrocarbons discharged and amounts retained after discharge are probably related to the level of contamination. The data can be interpreted as indicating that equilibration and the occurrence of multiple compartments where hydrocarbons can reside are factors involved in the uptake and retention of nonbiogenic hydrocarbons by oysters. The petroleum hydrocarbons contained in the oysters differed from the contaminating oil by displaying a greater aromatic content. In addition, gas-liquid chromatograms of aliphatic fractions of the hydrocarbons in the oysters rapidly showed a degraded appearance; the possibility that the oysters themselves are modifying the oil cannot be excluded.Contribution No. 3098 from the Woods Hole Oceanographic Institution.     

Aliphatic and polycyclic aromatic hydrocarbon contamination in surface sediment of the Chitrapuzha River,South West India

Distribution (seasonal and spatial) of aliphatic and polycyclic aromatic hydrocarbons (PAHs) in surface sediments of the Chitrapuzha River, Cochin, India, was investigated using gas chromatography. Significantly high concentrations prevailed during the pre-monsoon season with the industrial zones of the river appearing to be hot spots with particularly elevated levels of the hydrocarbons. AHCs ranged between 7754 and 41,173?ng/g with an average of 25,256?ng/g, while total PAHs varied from 5046 to 33,087?ng/g. n-Alkane indices and PAH diagnostic ratios point to petroleum contamination in the sediments. The significance of PAHs in the sediments was explored using universally accepted interpretation tools. Observed levels of PAHs in sediments of Chitrapuzha are likely to cause adverse effects on biota.     

Polycyclic aromatic hydrocarbons in red mullet (Mullus bavbatus) and sediments from the Eastern Aegean Sea

The distribution of polycyclic aromatic hydrocarbons (PAHs) was investigated in red mullet (Mullus barbatus) and sediment samples in the eastern Aegean Sea. The data were collected during cruises in July and November 1994, in the framework of National Marine Measurement and Monitoring Programme in the Aegean Sea. PAHs were detected in the tissue of Mullus barbatus of different sex and size from nine sampling sites throughout the study area ranging from 0.03 to 0.46 ug/g (fresh weight). The observations show the high levels of PAHs were found in tissues of females. The average concentration of PAHs in Aegean Sea sediments ranged from 0.20 to 1.8 ug/g (dry weight). No significant correlation was observed between PAH and sedimentary organic carbon.     

Hydrocarbons contamination and microbial degradation in mangrove sediments of the Niger Delta region (Nigeria)

The distribution of aliphatic hydrocarbons and polycyclic aromatic hydrocarbons (PAHs), and their degradability by bacteria in epipelic and benthic sediments from Qua Iboe Estuary mangrove ecosystem and associated creeks were investigated. The research findings revealed that total aliphatic hydrocarbons in sediments ranged from 16.82 mg·kg ^?1 to 210 mg kg ^?1, wheras total PAHs ranged from 6.30 to 35.55 mg·kg ^?1 dry weight of sediment. Low molecular mass (i.e. the 2–3-ring) PAHs were predominant in almost all the sampling points, whereas the higher molecular masses (4-, 5- and 6-ring PAHs) had the lowest concentrations. In general, the sediment samples ES ₂ (39.7%), ES ₃ (24.8%), BS ₁ (46.7%), BS ₂ (49.9%) and BS ₃ (44.2%) showed<50% contributions of Σ combustion–derived PAH (COMP-PAH) concentration to the Σ PAH concentrations, whereas ES ₁ (57%) contained>50% of COMP-PAHs. Our results have also shown that many mangrove bacteria have strong capacity to utilise Qua Iboe Light (QL) crude oil as the sole source of carbon and energy, while lower number of bacterial species including Bacillus sp., Micrococcus sp., Pseudomonas aeruginosa, Alcaligenes sp. and Flavobacterium sp. exhibited detectable PAHs degradability; and as such may serve as efficient degraders of QL crude oil contamination of mangrove ecosystem.     

Biotic indexes reveal the impact of harbour enlargement on benthic fauna

Environmental effects of enlargement works in Puerto Calero (Lanzarote, Canary Islands) were analysed in the sediments using abiotic variables (total hydrocarbons, polyaromatic hydrocarbons, organic matter and granulometry) and three biotic indexes (AMBI, M-AMBI and BENTIX). A before–after/control–impact (BACI) design was developed with four sampling campaigns, before (November 2004), during (March and July 2005) and after (July 2006) works. Inner stations were characterised by high concentrations of pollutants (total hydrocarbons and polyaromatic hydrocarbons). A temporal trend (2004–2006) was observed in macrofaunal assemblage structure, and thus in AMBI, M-AMBI and BENTIX indexes. Macrobenthic assemblages also mirrored the pollution gradient, with bioindicator species in inner stations (the polychaete Pseudopolydora paucibranchiata and the mollusc Abra alba), sensitive species (the sipunculid Aspidosiphon muelleri, the crustacean Pariambus typicus and the polychaete Aponuphis bilineata) in outer stations and ubiquitous species (the polychaetes Aricidea assimilis and Armandia polyophthalma) in both stations (inner and outer).     

Saturated and unsaturated hydrocarbons in marine benthic algae

Saturated and olefinic hydrocarbons were determined in 24 species of green, brown and red benthic marine algae from the Cape Cod area (Massachusetts, USA). Among the saturated hydrocarbons, n-pentadecane predominates in the brown and n-heptadecane in the red algae. A C₁₇ alkyleyclopropane has been identified tentatively in Ulvalactuca and Enteromorpha compressa, two species of green algae. Mono-and diolefinic C₁₅ and C₁₇ hydrocarbons are common. The structures of several new C₁₇, C₁₉ and C₂₁ mono-to hexaolefins have been elucidated by gas chromatography, mass spectrometry and ozonolysis. In fruiting Ascophyllum nodosum, the polyunsaturated hydrocarbons carbons occur exclusively in the reproductive structures. The rest of the plant contains n-alkanes from C₁₅ to C₂₁. A link between the reproductive chemistry of benthic and planktonic algae and their olefin content is suggested. An intriguing speculation is based on Paffenhöfer's (1970) observation that the sex ratio of laboratory reared Calanus helgolandicus depends upon the species of algae fed to the nauplii. The percentage of males produced correlates with our analyses of heneicosahexaene in the algal food. Our analyses of the hydrocarbons in benthic marine algae from coastal environments should aid studies of the coastal food web and should enable us to distinguish between hydrocarbon pollutants and the natural hydrocarbon background in inshore waters.Contribution No. 2582 of the Woods Hole Oceanographic Institution; and Contribution No. 227, Systematics-Ecology Program.     

Effect of fuel oil and dispersant on cell cycle and macromolecular synthesis in the chlorococcal alga Scenedesmus armatus

Growth and reproductive processes in synchronous cultures of the alga Scenedesmus armatus (isolated from Baltic phytoplankton) were followed in the presence of various concentrations of dispersant DP-105, oil, and mixtures of oil and dispersant. The inhibition of protoplast fission was the most prominent effect of oil. Nuclear division was inhibited to a lesser extent. With an increasing concentration of oil, dispersant, or a mixture of both, the inhibitory effects were expressed earlier. The presence of oil compounds did not effect the timing of DNA replication, but it did reduce the number of replication rounds in a concentration dependent manner. The inhibition of DNA synthesis was accompanied by slightly delayed cessation of RNA and protein synthesis. Starch synthesis was always inhibited to a lesser extent, and at a later time, than other macromolecular syntheses. Pigment synthesis continued almost to the end of the cell cycle. Thereafter, a rapid degradation of all pigments began and the cells became bleached. No inhibitory effect on reproductive processes was found if oil or dispersant were added to cultures transferred into darkness. Furthermore, recovery from inhibition of reproductive processes caused by oil in continuously illuminated cultures was observed in darkened cells. Chemically dispersed fuel oil was only slightly more toxic than mechanically dispersed fuel oil; an additive, rather than synergistic, effect of oil/dispersant mixture was found.     

Comparative Toxicities of Polar and Non-Polar Organic Fractions From Sediments Affected By the Exxon Valdez Oil Spill in Prince William Sound,Alaska

Abstract

Standardized tests were applied to aromatic and polar fractions of sediment extracts to determine whether polar constituents or oxidative degradation products contributed significantly to the toxicity of sediments oiled by the Exxon Valdez spill. Intertidal sediment and pore-water samples were collected in September 1990 from two heavily oiled sites and an unoiled site in Prince William Sound (PWS). Methylene chloride extracts from these samples were fractionated by liquid chromatography into aliphatic, aromatic and polar fractions, and the aromatic and polar fractions were tested for toxicity using the Microtox^R test, bivalve larval mortality and development (Mytilus); several measures of genotoxicity in Mytilus, including SOS Chromotest^R, anaphase aberrations and sister chromatid exchange; and survival, anaphase aberrations and teratogenicity in coho salmon (Onchorhynchus kisutch). Microtox^R and SOS Chromotest^R protocols were applied in a screening mode to all samples, whereas other tests were applied only to selected fractions from two sites. Samples from Bay of Isles (oiled) were consistently more toxic (usually only 2 to 5-fold) than the Mooselips Bay (unoiled) samples, which gave very low responses in all tests. for both sites, however, responses to polar and aromatic fractions were about the same in most tests, suggesting that while the overall toxicity of the oil was low in these samples, at least part of that toxicity was derived from polar constituents. Compared to the parent hydrocarbons, polar oxidation products partition preferentially into pore-water and are more rapidly diluted and dispersed in the water column. These results suggest that polar oxidation products of petroleum hydrocarbons pose little risk to marine organisms, except possibly for infauna continuously exposed to pore-water in heavily oiled sediments. Independent surveys showed that sediment toxicity in PWS declined during 1989–1991 to near background levels, in accord with previous understanding of oil weathering and toxicity.     

Very long-chain aliphatic hydrocarbons in lipids of mussels (Mytilus edulis) suspended in the water column near petroleum operations off Sable Island,Nova Scotia,Canada

Mussels (Mytilus edulis) suspended in the water column in 1994 and 1995 for the monitoring of oil drilling operations off Sable Island, Nova Scotia were examined for hydrocarbon profiles, particularly aliphatic hydrocarbons. A spring bloom of phytoplankton occurred during the 90-d suspension period in 1995. Hydrocarbons isolated from the 1995 suspended mussels showed very high concentrations of both biogenic hydrocarbons and very long-chain n-alkanes from C₂₀ to C₃₂, initially thought to be petrogenic. Both types of hydrocarbons were either not detected or were only present in trace amounts in the mussels suspended in 1994 at similar sites. The biogenic hydrocarbons in the 1995 mussels were apparently of planktonic origin, from the spring bloom, and were dominated by heneicosahexaene (21:6), followed by pristance, heptadecane, and varions monounsaturated and polyunsaturated phytenes, heptadecenes, nonadecenes and heneicosenes. They could be readily hydrogenated to yield the basic alkanes. The 1995 mussels suspended within 1 km from the oil well platform were probably slightly tainted by petrogenic hydrocarbons, as evidenced by the detection of phytane and high concentrations of total aliphatic hydrocarbons, whereas the mussels suspended 10 km from the platform showed only high concentrations of biogenic hydrocarbons and the novel long-chain n-alkanes. The occurrence of an unusual phytoplankton bloom during the suspension period severely interfered with the petroleum monitoring role of mussels by altering the mussel hydrocrbon profiles through the accumulation into and probably selective depuration of xenobiotic hydrocarbons from the mussel, tissues.J. Parsons (deceased)     

Vertical infiltration of fuel oil hydrocarbons in an agricultural soil

The influence of rainfall, air temperature and soil moisture on the vertical mobility in the soil of fuel oil hydrocarbons (HC) was investigated in a field experiment. A controlled spreading of fuel oil (nC10‐nC25) was performed at a rate of 5 L HCm^‐2 on an agricultural soil in summer and in winter. Concentration, chemical composition of HC and soil moisture were regularly determined at different soil depths between 0 and 140 cm, 1 h, 3, 8and 15 days (d) after the spreading of oil. Sorption of hydrocarbons onto the organo‐mineral matrix of the soil was studied in laboratory experiments. The results showed that in summer, with an air temperature of 24°C and without water leaching in the soil profile, 65% of the initial HC remained trapped in the 0–140 cm soil layer, about 20% of the HC volatilized and around 15% migrated deeper. A vertical selective migration of the lightest (nC10‐nC15) HC (naphthas) was shown lSd after the spreading of fuel oil. Naphthas progressively reached the 120–140 cm soil layers whereas the heavy fractions of oil (nC17‐nC25) migrated and concentrated in the 0–60 cm soil layers. In winter, when soil was regularly watered by rainfalls and at low air temperatures, only 47% of the initial HC remained in the 0–140 cm profile after 15 d. A fast vertical infiltration of naphthas occurred within the first 3 d. After 15 d, all HC were detected in the same relative amounts as in the initial oil in the whole profile. Volatilization was negligible in winter and an increase in the migration of total oil at depth in the soil profile was shown. As inferred from the laboratory experiments, the high soil moisture led to the decrease in HC sorption on the organo‐mineral matter of the soil.     

Cytochrome P450 1A activity in liver and fixed wavelength fluorescence detection of polycyclic aromatic hydrocarbons in the bile of tongue-fish (Cynoglossus acrolepidotus, Bleeker) in relation to petroleum hydrocarbons in the eastern Gulf of Thailand.

This investigation was conducted in an area of oil spill along the east coast of Thailand to examine the relations among cytochrome P450 1A activity in liver and PAHs in the bile of the tonguefish and petroleum hydrocarbons in the sediments. PAH sediment concentrations in the reference and oil spill areas were 5.03 +/- 0.42 and 0.21 +/- 0.043 microg(-1) dry weight respectively Cytochrome activity in fish liver from oil spill area was 45.40 +/- 3.50 pmoles/ min/mg protein, almost threefold higher than that from the reference sites. Flourescense detection in bile metabolites at the oil spill area, 69.8 +/- 9.9 flourescense unit was significantly higher than that at the reference sites, 22.9 +/- 5.5 and 22.2 +/- 3.5 fluorescence unit. A strong correlation was found among cytochrome P450 1A activity in liver, PAH of bile metabolites and petroleum hydrocarbons. Both cytochrome and bile metabolites activity decreased seaward varying to the distance from the oil polluted area. We concluded that both detections in tonguefish can be regarded as a complementary biomarkers for the exposure of PAHs in tropical marine environments.     

Accumulation,fractionation and release of oil by the intertidal clam Macoma balthica

The bivalve mollusc Macoma balthica accumulated hydrocarbons during 180 days of continuous exposure to Prudhoe Bay crude oil in seawater dispersions with nominal concentrations of 0.03, 0.3 and 3.0 mg l^-1. The mollusc's ability to concentrate oil from seawater increased with decreasing oil-in-water concentration. Decreases in oil burden began after 30 to 120 days (depending on the oil concentration) and continued for at least 60 days after exposure to oil ceased. Aliphatic and aromatic hydrocarbons were fractionated in markedly different ways by the bivalve. Branched and cyclic aliphatics in the molecular weight-range dodecane through hexadecane were preferentially retained over straightchain and their higher homologs. Larger and more substituted aromatic compounds were selectively concentrated. There appeared to be no selective concentration of aromatic sulphur compounds.Please address requests for reprints to Dr. D. G. Shaw at the Institute of Marine Science     

Effects of chronic oil pollution on a salt-marsh grass community

A small, naturally defined saltmarsh in Chesapeake Bay (USA) was repeatedly dosed with a No. 2 fuel oil. The production, decay rates, physical characteristics and hydrocarbon content of the dominant grass species present in the marsh were routinely monitored. Spartina alterniflora was the only grass species displaying effects of the oil dosing; this is attributed to the grass's location in the marsh. A substantial portion of the S. alterniflora in the marsh was killed by the oil dosing; the remaining portion evidenced sublethal effects including delayed development in the spring, increased density, and reduced mean weight per stem. The second annual cohort of shoots, usually produced in late summer and early fall, was suppressed almost entirely. Decay rates of S. alterniflora in the oiled marsh were higher and peaked later than decay rates in a control marsh. Oil which entered the roots and rhizomes of dead S. alterniflora was retained in a relatively undergraded state for at least 7 months after dosing stopped.Virginia Institute of Marine Science Contribution No. 945     

Transformations of <Emphasis Type="Italic">n</Emphasis>-alkanes from petroleum pollutants in alluvial groundwaters

Investigations presented in this paper were aimed at defining the alterations of n-alkane composition in cases of oil-polluted alluvial sediments. Therefore, oil-polluted groundwater samples, taken in five different time intervals during a period of 28 months, were investigated. Samples of alluvial sediments were taken from two boreholes within an oil refinery at Pancevo, Yugoslavia. In both boreholes significant alterations with characteristic degradation of "oil" n-alkanes with no odd- or even-member predominance were observed, as well as subsequent synthesis of new ones with pronounced even-member predominance, and with maxima at C₁₆ and C₁₈. Since no additional contamination of boreholes was observed by analyses of steranes and triterpanes, the observed changes can only be attributed to microbial activity. It is assumed that for the degradation of oil n-alkanes, as well as for the synthesis of "new" n-alkanes, algae such as dinoflagellates are responsible. This assumption was confirmed by identification of n-alcohols with even-member predominance (C₁₄–C₂₀), by identification of cholesterol, as well as of n-fatty acids with even-member predominance (C₁₄–C₁₈) in the extract with n-alkane even-member predominance. Electronic Publication     

Brittlestars,Biomarkers and Beryl: Assessing the Toxicity of Oil-Based Drill Cuttings Using Laboratory,Mesocosm and Field Studies

Effects of drill cuttings on burrowing brittlestars (Amphiura chiajei and A. filiformls) were compared at different levels of response, from acute laboratory experiments to chronic field studies. Acute toxicity tests showed that drill cuttings containing oil-based muds had a very low toxicity (LC₅₀ 52,800 ppm total hydrocarbons in test sediment) but sub-lethal effects were detected at much lower levels using a variety of biomarkers and assays. Chronic sub-lethal effects were detected around the Beryl oil platform in the North Sea where the levels of oil in the sediment were very low (<3 ppm total hydrocarbons in sediment) and brittlestars were excluded from areas nearer the platform with higher sediment oil content. These results suggest that acute toxicity tests are a poor predictor of chronic response in these animals. the relationship between toxicity at different levels of response and the predictive power of laboratory studies is discussed.     

Accumulation and regulation of heavy metals by the intertidal snail Polinices sordidus

The gastropod Polinices sordidus was collected from an uncontaminated area in Quibray Bay, New South Wales, Australia, in 1990. The snails were exposed for 2 wk to polluted sediments collected from Port Kembla Harbour, Blackwattle Bay, Lake Illawarra, Lake Macquarie in New South Wales, Australia, and the Derwent River in Tasmania, Australia. Metal accumulation and regulation by this species were evaluated. Metal concentrations in snail tissues and total, EDTA and HCl-extractable metals in the sediments were compared. Copper concentrations were extremely varied in snails exposed to the same sediment. This was not the case for other matals tested. No accumulation of copper was found in snails exposed to different sediments. There was no zinc accumulation from sediments containing less then 10 mg Zn/g. P. sordidus could accumulate lead, manganese and iron from some of the sediments. Manganese concentrations in the snail tissues correlated with total, HCl-extractable and, more significantly, EDTA-extractable Mn in the sediments. P. sordidus was not considered to be a good bioindicator of copper and zinc contaimination in sediments; however, this species could be used as an indicator of lead and manganese contamination.     

Degradation of crude oil by a mixed population of bacteria isolated from sea-surface foams

A mixed bacteria population (EM₄) was isolated from foams formed on the surface of a zone chromically polluted by hydrocarbons (Gulf of Fos, French Mediterranean coast, October 1981). The population was able to degrade crude oil very effectively in the presence of sea water supplemented with nitrogen, phosphorus and iron. The percentage of hydrocarbon degradation was 81% at 30°C, pH 8, and partial oxygen pressure of 100%. After 12 d incubation, 92 and 83% of satured and aromatic compounds (mono-, di- and triaromatics) were degraded, respectively, as well as 63% of polar products and 48.5% of asphaltenes. Maximum degradation was attained at a sodium chloride concentration of between 400 and 800 mM with Population EM₄, which is constituted of 8 strains, four of which are weak halophiles. Bacterial growth on hydrocarbons induces the production in the culture medium of surface-active agents which are able to emulsify the substrate. There is high specificity between the nature of the growth substrate and such emulsifying activity, particularly as far as petroleum is concerned: only the culture medium from Population EM₄ is able to emulsify petroleum. These surface-active agents contain sugars and lipids (fatty acids, mono- and diglycerides). The foams, which always contain a high concentration of both hydrocarbons (100 to 180 mgl^-1) and bacteria that are able to grow on these types of substrates, have a strong emulsifying activity. Our results would seem to demonstrate the importance of biosurfactants in the elimination of hydrocarbons from polluted biotopes.