tVe measured quantitative variation of structurally siinllar halogenated furanones in the sea hare Aplysia parvula (Opisthobranchia; Anaspidea) and in its host alga Delisea pulchra (Rhodophyta; Bonnemaisonales). Mean total levels of furanones from D. pulchra in A. parvula were 13.3% of the dry weight of the sea hares, with one metabolite comprising on average 86% of the total metabolite load of the sea hares. Levels of furanones in the sea hares were highest in the digestive gland but were also found in other tissues, including the skin in at least mg g -' (dry wt) levels. Metabolite levels in the skin of the sea hares did not differ from those in D. pulchra (typically between 5 and 10 mg g.' dry wt). Variation of metabolites in D. pulchra on the scale of both meters and kilometers was low and only minor variation in levels of individual metabolites was observed. There was significant variation in levels of metabolites within plants, with concentrations generally higher at the distal end of the thallus. The large differences in metabolite concentrations on a scale of millimetres found in some other red algae were not observed in D, pulchra. Metabolites occurred in significantly different relative amounts in A. parvula versus D pulchra, with concentrations of ind~v~dual metabolites in A. parvula ranging between 0 and 83 times the concentrations found in host algae. These results show that the sea hares differentially bioaccumulate algal metabolites. However, only 1 metabolite was enhanced in concentration in the sea hares relative to the alga. This metabolite was the most abundant compound in the animals, and has been previously shown to be effective as a predator deterrent. A second metabolite, which was not effective as a predator deterrent in A. parvula, decreased in relative concentration in the animals. In contrast to recent suggestions in the literature for sequestered algal metabolites in sea hares, our results indicate that the distribution and level of D. pulchra metabolites in A. parvula are consistent with a role as acquired chemical defences against predators.
The geomechanical properties of organic-rich shales at different thermal maturities are investigated at nano, micro and core-scale. 10• Kerogen stiffness increases with maturity while diagenetic carbonate cementation 11 stiffens and strengthens the shale microstructure. 12• The softer clay-and kerogen-rich immature sample shows the greatest creep dis-13 placement.
Ten pollutant phenols extracted from an oil refinery discharge, urban storm water and sewage effluent were analysed by gas chromatography-mass spectrometry. Recoveries varied from 43% to 97%, with a detection limit of 0.5 μg L-1. Concentrations ranged from below the detection limit up to 114.0μg L-1, the highest being in sewage effluent. The most common were phenol and cresol. The effects of similar concentrations were determined in bioaccumulation experiments using the mussel Mytilus edulis and fish Trachurus novaezelandiae. Recoveries of phenols from tissues were 10-40%, with a detection limit of 0.5 ng g-1. 2,4-dimethylphenol, 2,4-dichlorophenol, 4-chloro, 3-methylphenol, 2,4,6-trichlorophenol and pentachlorophenol were accumulated, with bioconcentration factors ranging from 2.51 � 0.51 for dimethylphenol to 283.8 � 5.58 for pentachlorophenol; when placed in clean sea water, both species depurated all accumulated phenols to concentrations below detection within 24 h. Neither phenol nor cresol were accumulated. Phenol and o-cresol inhibited the germination of Ulva lactuca gametes at concentrations above 1 mg L-1 (100 times the concentrations detected in the water samples). Muscle and liver tissue from fish and invertebrates collected from the oil refinery discharge site in Botany Bay and control localities contained no detectable phenols.
Newcastle University ePrints -eprint.ncl.ac.uk Charlton TS, Rouainia M. A probabilistic approach to the ultimate capacity of skirted foundationsin spatially variable clay. Structural Safety 2017, 65, 126-136. AbstractSkirted foundations are used in offshore applications to resist the large horizontal and moment loads that are characteristic of the ocean environment. The combination of vertical-horizontalmoment (VHM) loading results in complicated stress conditions in the seabed and design is often based on VHM failure envelopes. These have generally been constructed by numerical analysis using a deterministic characterisation of soil properties and disregard the natural spatial variability of marine sediments. In this study, spatial variability is taken into account by coupling a random field model with finite element analysis. The paper presents a probabilistic analysis of the ultimate capacity of skirted foundations in spatially variable undrained clay. The increase of strength with depth typical of a marine clay is included in the modelling framework.Probabilistic failure envelopes are constructed to analyse the effect of spatial variability when skirted foundations are subjected to different combinations of VHM loading. The results show that the probability of failure increases under high vertical loads and at peak moment capacity in the HM plane, suggesting that care should be taken in design at these areas of the failure envelope. The methodology demonstrates a straightforward and effective way of quantifying uncertainty in the ultimate limit state design of offshore geotechnical structures and the results presented provide specific guidance for the design of skirted foundations.
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