Assessment of cytochrome P450 1A in harbour seals (Phoca vitulina) using a minimally-invasive biopsy approach

Biomarkers of organochlorine exposure, such as the induction of cytochrome P450 1A (CYP1A), can be used to assess the impact of environmental contaminants on the health of free-ranging marine mammal populations. The objective of the present study was to measure CYP1A in skin and liver biopsies obtained from live harbour seals (Phoca vitulina). Twelve harbour seal pups, aged three to five weeks, were captured from the Fraser River estuary, British Columbia, Canada, and temporarily held in captivity. Skin ( approximately 60 mg) and liver ( approximately 40 mg) biopsies, obtained while seals were under general anaesthesia, yielded sufficient tissue for the measurement of CYP1A by immunoblot analysis and ethoxyresorufin O-deethylase activity. A short-term exposure experiment, in which harbour seals (n=3) were treated orally with beta-naphthoflavone (BNF), resulted in increased hepatic and cutaneous CYP1A protein levels, consistent with observations in other mammals. This study is the first to measure CYP1A in skin and liver biopsies from live harbour seals and to report in vivo BNF-associated CYP1A induction in a marine mammal. The results demonstrate that microsamples collected using minimally-invasive techniques can provide toxicologically-relevant information form marine mammals.     

Primordial non-Gaussianity from LAMOST surveys

The primordial non-Gaussianity (PNG) in the matter density perturbation is a very powerful probe of the physics of the very early Universe. The local PNG can induce a distinct scale-dependent bias on the large scale structure distribution of galaxies and quasars, which could be used for constraining it. We study the detection limits of PNG from the surveys of the LAMOST telescope. The cases of the main galaxy survey, the luminous red galaxy (LRG) survey, and the quasar survey of dif- ferent magnitude limits...     

Intraspecific cleaning by juvenile Cape white seabream Diplodus capensis (Sparidae) off eastern South Africa

Juveniles of the Cape white seabream Diplodus capensis were observed cleaning adult conspecifics in a large tidepool off Sodwana Bay, South Africa. Although nine other tropical fish species were present and interacted with a nearby pair of Labroides cleaner wrasses, only adults of D. capensis posed for and were cleaned by the D. capensis juveniles. Such cleaning interactions have not been reported previously for this species or among marine fishes off South Africa, and thus add to the growing list of facultative cleaners globally.     

The role of biota in the initiation and growth of islands on the floodplain of the Okavango alluvial fan,Botswana

A group of islands of varying size on the floodplain of the Okavango alluvial fan, were studied to establish the processes which lead to the initiation and growth of islands. It was found that islands are initiated by the mound-building activities of the termite Macrotermes michaelseni. These termites import fine grained materials to use as a mortar for the construction of epigeal mounds. Their activities create a topographic feature, raised above the level of seasonal flooding, and also change the physical properties and nutrient status of the mound soil. Shrubs and trees are able to colonize these mounds, which results in increased transpiration. As a result, precipitation of calcite and silica from the shallow ground water occurs preferentially beneath the mounds, resulting in vertical and especially lateral growth, causing island expansion. © 1998 John Wiley & Sons, Ltd.     

Biota: sediment partitioning of aluminium smelter related PAHs and pulp mill related diterpenes by intertidal clams at Kitimat, British Columbia

The question of polycyclic aromatic hydrocarbon (PAH) bioavailability and its relationship to specific PAH sources with different PAH binding characteristics is an important one, because bioavailability drives PAH accumulation in biota and ultimately the biochemical responses to the PAH contaminants. The industrial harbour at Kitimat (British Columbia, Canada) provides an ideal location to study the bioavailability and bioaccumulation of sediment hydrocarbons to low trophic level biota. Samples of soft shell clams (Mya arenaria) and intertidal sediment collected from multiple sites over six years at various distances from an aluminium smelter and a pulp and paper mill were analysed for 106 PAHs, plant diterpenes and other aromatic fraction hydrocarbons. Interpretation using PAH source ratios and multivariate data analysis reveals six principal hydrocarbon sources: PAHs in coke, pitch and emissions from anode combustion from the aluminium smelter, vascular plant terpenes and aromatised terpenes from the pulp and paper mill, petroleum PAHs from shipping and other anthropogenic activities and PAHs from natural plant detritus. Harbour sediments predominantly contain either pitch or pyrogenic PAHs from the smelter, while clams predominantly contain plant derived PAHs and diterpenes from the adjacent pulp mill. PAHs from the smelter have low bioavailability to clams (Biota-Sediment Accumulation Factors; BSAFs <1 for pitch and coke; <10 for anode combustion, decreasing to ∼0.1 for the mass 300 and 302 PAHs), possibly due to binding to pitch or soot carbon matrices. Decreases in PAH isomer ratios between sediments and clams likely reflect a combination of variation in uptake kinetics of petroleum PAHs and compound specific metabolism, with the importance of petroleum PAHs decreasing with increasing molecular weight. Plant derived compounds exhibit little natural bioaccumulation at reference sites, but unsaturated and aromatised diterpenes released from resins by industrial pulping processes are readily accumulated by the clams (BSAFs >500). Thus while most of the smelter associated PAHs in sediments may not be bioavailable to benthic organisms, the plant terpenes (including retene, totarol, ferruginol, manool, dehydroabietane and other plant terpenes that form the chemical defence mechanism of conifers) released by pulp mills are bioavailable and possess demonstrated toxic properties. The large scale release of plant terpenes by some of the many pulp mills located in British Columbia and elsewhere represents a largely undocumented risk to aquatic biota.     

Phylogeny of the Sepia officinalis species complex in the eastern Atlantic extends the known distribution of Sepia vermiculata across the Benguela upwelling region

Accurate species identification and biogeographic characterisation are fundamental for appropriate management of expanding cephalopod fisheries. This study addresses this topic within the common cuttlefish Sepia officinalis species complex (S. officinalis, S. hierredda and S. vermiculata), with an emphasis on occurrence in African waters. Tissue samples from the currently presumed distributions of S. vermiculata and S. hierredda (from South Africa and Ghana/Angola, respectively) were sequenced for the cytochrome c oxidase subunit I (COI) and the cytochrome b (cytb) genes of the mitochondrial genome and then compared to existing S. officinalis sequences. Three highly divergent and reciprocally monophyletic clades, corresponding to S. officinalis, S. hierredda and S. vermiculata, were resolved, representing the first molecular confirmation of the distinct species status of S. hierredda and S. vermiculata. The sequences also revealed that, contrary to expectations based on presently published information, all samples from southern Angola were S. vermiculata. These results indicate that the range of S. vermiculata extends beyond the currently described northern limit and that S. hierredda and S. vermiculata may be indiscriminately harvested in Angolan waters. Finer-scale patterns within S. vermiculata phylogeography also indicate that the Benguela Current System and/or other environmental factors serve to isolate northern and southern stocks.     

Chalk fields along the Lindesnes Ridge, Eldfisk

Eldfisk field lies on the Lindesnes Ridge northwest of the Valhall and Hod fields and to the southeast of Edda in Block 2/7 of the Norwegian North Sea. The field has a complex geological history and reservoir geometry. Seismic reflection data is strongly gas affected and degraded over the majority of the field. The geological model of the field was based exclusively on well data and the model was inadequate to explain some of the production characteristics or to identify additional prospective well locations. In 1982 a programme of Vertical Seismic Profiling (VSP) was started in the northern part of the field. The seismic data provided by VSP have improved and confirmed the geological model, provided some explanations for production variances and identified further areas of interest.     

Dusky dolphin movement patterns: short-term effects of tourism

Cetacean-oriented tourism has experienced rapid growth in the last two decades, accompanied by increasing concerns about the effects of tourism on target species. Here, we used shore-based observations of dusky dolphin (Lagenorhynchus obscurus) groups near Kaikoura, New Zealand, and generalised additive models to quantify changes in group speed, reorientation and linearity relative to natural and anthropogenic factors. Summer months were characterised by slower speeds and more changes in direction than winter months. Group speeds were higher at the beginning and end of the day, with slower speeds at midday. Speeds were slower when vessels were present, and dolphin groups changed direction more often when aircraft circled overhead. Effects were positively correlated with number of vessels present within 300 m. Short-term changes have potential to lead to long-term impacts, and further acoustic and energetic studies are proposed to elucidate whether these effects are likely to reduce individual fitness.     

Observing the reconnection region in a transequatorial loop system

A vertical current sheet is a crucial element in many flare/coronal mass ejection (CME) models. For the first time, Liu et al. reported a vertical current sheet directly imaged during the flare rising phase with the EUV Imaging Telescope (EIT) onboard the Solar and Heliospheric Observatory (SOHO). As a follow-up study, here we present the comprehensive analysis and detailed physical interpretation of the observation. The current sheet formed due to the gradual rise of a transequatorial loop system. As the l...     

Persistent organic pollutants (POPs) in killer whales (Orcinus orca) from the Crozet Archipelago, southern Indian Ocean

Persistent organic pollutants (POPs), including polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and dibenzofurans (PCDFs), are ubiquitous environmental contaminants of which significant concentrations are reported in upper trophic level animals. In 1998, we collected blubber biopsy samples (n = 11) from killer whales (Orcinus orca) inhabiting the coastal waters around Possession Island, Crozet Archipelago, southern Indian Ocean, for contaminant analyses. Despite inhabiting an isolated region far removed from industrial activities, these killer whales can presently be considered among the most PCB-contaminated cetaceans in the southern hemisphere, with concentrations ranging from 4.4 to 20.5 mg/kg lipid weight (lw). PCDD levels ranged from below the detection limit (5 ng/kg) to 77.1 ng/kg lw and PCDF levels from below the detection limit (7 ng/kg) to 36.1 ng/kg lw. Over 70% of our study animals had PCB concentrations which exceeded a 1.3 mg/kg PCB threshold established for endocrine disruption and immunotoxicity in free-ranging harbour seals, suggesting that organic contaminants cannot be ruled out as an additional threat to this declining population.