Oxidation of polycyclic aromatic hydrocarbons by fungal isolates from an oil contaminated refinery soil

BACKGROUND AND OBJECTIVE: Indigenous soil microorganisms are used for the biodegradation of petroleum hydrocarbons in oily waste residues from the petroleum refining industry. The objective of this investigation was to determine the potential of indigenous strains of fungi in soil contaminated with petroleum hydrocarbons to biodegrade polycyclic aromatic hydrocarbons (PAH). MATERIALS AND METHODS: Twenty one fungal strains were isolated from a soil used for land-farming of oily waste residues from the petrochemical refining industry in Singapore and identified to genus level using laboratory culture and morphological techniques. Isolates were incubated in the presence of 30 mg/L of phenanthrene over a period of 28 days at 30 degrees C. The most effective strain was further evaluated to determine its ability to oxidise a wider range of PAH compounds of various molecular weight i.e acenaphthene, fluorene, fluoranthene, chrysene, benzo(a)pyrene and dibenz(ah)anthracene RESULTS AND DISCUSSION: After 28 days of incubation, 18 of the 21 fungal cultures were capable of oxidising over 50% of the phenanthrene present in culture medium, relative to abiotic controls. Fungal isolate, Penicillium sp. 06, was able to oxidise 89% of the phenanthrene present. This isolate could also oxidise more than 75% of the acenaphthene, fluorene and fluoranthene after 30 days of incubation. However, the oxidation of high molecular weight PAH i.e. chrysene, benzo(a)pyrene and dibenz(ah)anthracene by the Penicillium sp. 06 isolate was limited, where the extent of oxidation was inversely proportional to PAH molecular weight. CONCLUSIONS: Fungal isolate, Penicillium sp. 06, was effective at oxidising a range of PAH in petroleum contaminated soils, but higher molecular weight PAH were more recalcitrant. RECOMMENDATIONS AND OUTLOOK: There is potential for the re-application of this fungal strain to soil for bioremediation purposes.     

The trophic linkage between zooplankton and benthic suspension feeders: direct evidence from analyses of bivalve faecal pellets

Using radiotracer (¹⁴C) and microscopic observation, we demonstrated that mussels (Mytilus edulis and Perna viridis) could be predators of mesozooplankton (rotifer Brachionus plicatilis). At radio-labelled rotifer densities of 0.1, 0.2, 0.5, 1.0 individual ml⁻¹, faecal pellets of mussels showed different degrees of radio signals and most of the faecal pellets were expelled 4 h after pulse feeding on rotifers. The maximum gut retention time (GRT) of ¹⁴C-labelled rotifers in the digestive diverticula did not o show any significant difference between the two mussel species or the different densities of rotifers, and the averaged GRT was 43.4±3.06 h (mean ± SE). At a rotifer density of 4.5 individual ml⁻¹, rotifer lorica pieces and rotifer bodies without eggs were found in faeces of M. edulis, while in the pseudofaeces, only complete rotifer bodies were found.     

Induced alkaloid defence inAtropa acuminata in response to mechanical and herbivore leaf damage

Summary Measurement of tropane alkaloid content in leaves ofAtropa acuminata after mechanical damage showed a maximum increase to 153% of the control 8 days later. There were no changes in the root or stem after similar damage. The plant responded to repeated mechanical damage by doubling its alkaloid content at 11 days after the initial wounding. But on further treatments, there was a slight decrease in alkaloid content with time. Mollusc feeding produced an increase of 164% in alkaloid content after 4 days. These results indicate that induced defence systems in angiosperms can vary considerably from plant species to plant species and that the effects of mechanical damage may differ in different parts of the same plant.     

Movement and environmental preferences of Greenland sharks (<Emphasis Type="Italic">Somniosus microcephalus</Emphasis>) electronically tagged in the St. Lawrence Estuary,Canada

Three Greenland sharks (Somniosus microcephalus) were tagged with electronic tags, in Baie St. Pancrace, St. Lawrence Estuary, Quebec, Canada. One shark was tagged on 23 July 2004, with an acoustic telemetry tag. Two sharks were each tagged with a pop-up satellite archival tag (PSAT) on 27 August 2004. Two of the sharks remained in or close to the bay, one for 47 days and the other for at least 66 days. The third shark left the bay immediately after tagging on 27 August 2004. This shark entered the main channel of the St. Lawrence Estuary, and had moved 114.9 km upstream by 1 November 2004 when the tag reported to ARGOS satellites. The tags provided a total of 179 days of data on the movement and environmental preferences of Greenland sharks in the St. Lawrence Estuary. Sharks that reported depth and ambient water temperature data from the bay showed significant diel differences in depth preferences and corresponding ambient temperatures. The sharks remained near the bottom of the water column during the day and displayed increased vertical movements at night. The shark that resided in the main channel did not show this pattern, but generally remained at depths between 325 and 352 m. Sharks in the bay experienced water temperatures that ranged from −1.1 to 8.6°C at depths from 0 to 67 m. In the main channel the shark experienced temperatures that ranged from 1.0 to 5.4°C at depths from 132 to 352 m. This is the first report of numerous Greenland sharks inhabiting shallow near shore bays during summer and autumn.     

Critical swimming speeds of late-stage coral reef fish larvae: variation within species,among species and between locations

The swimming abilities of larval fishes are important for their survival, potentially affecting their ability to avoid predators, obtain food and control dispersal patterns. Near settlement swimming abilities may also influence spatial and temporal patterns of recruitment. We examined Critical speed (U-crit) swimming ability in late stage larvae of 89 species of coral reef fishes from the Great Barrier Reef and the Caribbean. Coefficients of variation in U-crit calculated at the individual level were high (28.4%), and this was not explained by differences in size or condition factor of these same larvae. Among species U-crit ranged from 5.5 cm s⁻¹ to 100.8 cm s⁻¹ (mean=37.3 cm s⁻¹), with 95% of species able to swim faster than the average current speed around Lizard Island, suggesting that most species should be capable of influencing their spatial and temporal patterns of settlement. Inter-specific differences in swimming ability (at both the family and species levels) were significantly correlated with size and larval morphology. Correlations were found between swimming performance and propulsive area, fineness ratio and aspect ratio, and these morphological parameters may prove useful for predicting swimming ability in other taxa. Overall, the swimming speeds of larvae from the same families at the two locations were relatively similar, although the Lutjanidae and Acanthuridae from the Caribbean were significantly slower than those from the great barrier reef. Differences in swimming speed and body form among late stage larvae suggests that they will respond differently to factors influencing survival and transport during their pelagic phase, as well as habitat use following settlement.     

Resource Depletion and Sustainability in Small Open Economies

Exogenous price changes affect the amount that a small country exporting natural resource commodities must invest to sustain its consumption level. The necessary amount is given by the difference between Hotelling rent and the discounted sum of future terms-of-trade effects (capital gains). The latter term is found to be large relative to the former in the case of petroleum depletion in Indonesia. This suggests that resource-rich countries will need to invest more than previously expected to sustain their consumption levels, if natural resource prices continue their long-term historical decline.     

Allelochemical effects of ergoline alkaloids fromIpomoea parasitica onHeliothis virescens

Lysergol, elymoclavine and three other van Urk-positive alkaloids were identified by 2D chromatography in the seed extract ofIpomoea parasitica. The presence of the same ergoline alkaloids was also demonstrated in vegetative tissue ofI. parasitica. Heliothis virescens larvae reared on a diet containing an alkaloid extract ofI. parasitica showed an increase in the consumption index and a reduction in the effiency of conversion of food. No difference was observed in the approximated digestibility. The percentages of pupation and emergence were reduced and the malefemale ratio was altered in insects fed on a diet containing the alkaloid extract ofI. parasitica or lysergol. The increases in the concentration of ergoline alkaloids inI. parasitica at the seedling stage and at flowering support the theory that these compounds play a defensive role against herbivory in the plant.     

Cumulative ecological and socioeconomic effects of forest policies in coastal Oregon.

Forest biodiversity policies in multi-ownership landscapes are typically developed in an uncoordinated fashion with little consideration of their interactions or possible unintended cumulative effects. We conducted an assessment of some of the ecological and socioeconomic effects of recently enacted forest management policies in the 2.3-million-ha Coast Range Physiographic Province of Oregon. This mountainous area of conifer and hardwood forests includes a mosaic of landowners with a wide range of goals, from wilderness protection to high-yield timber production. We projected forest changes over 100 years in response to logging and development using models that integrate land use change and forest stand and landscape processes. We then assessed responses to those management activities using GIS models of stand structure and composition, landscape structure, habitat models for focal terrestrial and aquatic species, timber production, employment, and willingness to pay for biodiversity protection. Many of the potential outcomes of recently enacted policies are consistent with intended goals. For example, we project the area of structurally diverse older conifer forest and habitat for late successional wildlife species to strongly increase. 'Other outcomes might not be consistent with current policies: for example, hardwoods and vegetation diversity strongly decline within and across owners. Some elements of biodiversity, including streams with high potential habitat for coho salmon (Oncorhynchus kisutch) and sites of potential oak woodland, occur predominately outside federal lands and thus were not affected by the strongest biodiversity policies. Except for federal lands, biodiversity policies were not generally characterized in sufficient detail to provide clear benchmarks against which to measure the progress or success. We conclude that land management institutions and policies are not well configured to deal effectively with ecological issues that span broad spatial and temporal scales and that alternative policies could be constructed that more effectively provide for a mix of forest values from this region.     

Genetic evidence for monogamy in the cooperatively breeding red-cockaded woodpecker

We examined the genetic relationship among putative parents, offspring, and helpers in 224 red-cockaded woodpeckers (Picoides borealis) from the Sandhills of North Carolina. Comparison of DNA similarity with a pedigree constructed from 3,823 individually-marked birds observed from 1979 to 1992 provided verification of observed relatedness in the sampled population (R ² = 0.87,df = 14,P<0.001). In this population, breeding pairs may or may not have helpers, most of which are males that remain on their natal territory. Our sample included helpers assisting their parents, helpers assisting a related male and an unrelated female, and helpers assisting an unrelated pair. Band by band comparison and examination of similarity among DNA profiles indicated that all offspring from non-helped nests were sired by their putative parents (n = 28 families). Similarly, all but one offspring in helped nests were also sired by their putative parents (n = 16 families). In the exceptional case, the offspring evidently was sired by a male external to the group. Analysis of similarity values supported the conclusion that matings by helpers or extra-group males are rare or non-existent. Our results indicate that in this species advantages gained by individuals remaining on their natal territories as helpers do not generally include siring offspring. Correspondence to: S. Haig