Monitoring contaminants from oil production at sea by measuring gill EROD activity in Atlantic cod (Gadus morhua)

An ex vivo gill EROD assay was applied in Atlantic cod (Gadus morhua) as a biomarker for waterborne CYP1A-inducing compounds derived from oil production at sea. Exposure to nominal concentrations of 1 ppm or 10 ppm North Sea crude oil in a static water system for 24 h caused a concentration-dependent gill EROD induction. Further, exposure of cod for 14 days to environmentally relevant concentrations of produced water (PW, diluted 1:200 or 1:1000) from a platform in the North Sea using a flow-through system resulted in a concentration-dependent induction of gill EROD. Crude oil (0.2 ppm) from the same oil field also proved to induce EROD. Finally, gill EROD activity in cod caged for 6 weeks at 500-10 000 m from two platforms outside Norway was measured. The activities in these fish were very low and did not differ from those in fish caged at reference sites.     

Characterization of industrial aqueous discharges by the TLC/Ames’ assay

The $\text{in situ}$ detection of mutagens by the TLC/Ames’ assay has been applied to aqueous discharges from a textile plant. The samples were fractionated in acid/neutral and basic fractions which subsequently were subject to the TLC/Ames’ test. The results demonstrate the presence of a number of both direct and indirect mutagens in the waste water. The chemical properties of these compounds are discussed in light of their chromatographic behaviour. The applicability of this method for characterizing mutagens in complex mixtures is demonstrated.     

Kinematic analysis of solute mass flows in rock fractures with spatially random parameters

Field data of physical properties in heterogeneous crystalline bedrock, like porosity and fracture aperture, is associated with uncertainty that can have a significant impact on the analysis of solute transport in rock fractures. Solutions to the central temporal moments of the residence time probability density function (PDF) are derived in a closed form for a solute Dirac pulse. The solutions are based on a model that takes into account advection along the fracture plane, diffusion into the rock matrix and sorption kinetics in the rock matrix. The most relevant rock properties including fracture aperture and several matrix properties as well as flow velocity are assumed to be spatially random along transport pathways. The mass transport is first solved in a general form along one-dimensional pathways, but the results can be extended to multi-dimensional flows simply by substituting the expected travel time for inert water parcels. Based on data obtained with rock samples taken at Asp? Hard Rock Laboratory in Sweden, the solutions indicate that the heterogeneity of the rock properties contributes to increasing significantly both the variance and the skewness of the residence time probability density function for a pulse travelling in a fracture. The Asp? data suggests that the bias introduced in the variance of the residence time PDF by neglecting the effect of heterogeneity of the rock properties on the radionuclide migration is very large for fractures thinner than a few tenths of a millimetre.     

Development of a simple selective SFE method for the determination of desorption behaviour of PCBs in two Swedish sediments

A simple selective supercritical fluid extraction (SFE) method was developed for the determination of desorption behaviour of PCBs in sediments. This method was applied to determine the distribution of individual PCB congeners among sites of differing bonding strengths in two Swedish sediments (Lake J?rnsj?n and Baltic bay Orserumsviken). Four different PCB fractions were distinguished in each sediment by applying consecutively harsher supercritical fluid extraction conditions on the same sample. Even though the two sediments had completely different textures, they showed very similar extraction behaviour. It was shown that, in both sediments, a major part of the PCBs (58% and 65%, respectively) were located at "fast sites", from which they were extractable already with the mildest extraction conditions (60 min, 40 degrees C and 120 bar). Only a small fraction of the PCBs were so tightly bound to the sediments (located at "slow sites"), that they could be extracted only under the harshest conditions (60 min, 150 degrees C and 400 bar). Information of this kind should be of great value for the determination of bioavailability of pollutants in sediments and soils, and it is the author's belief that this technique has the potential to develop into a powerful tool in environmental risk assessment.     

In search of human-associated bacterial pathogens in Antarctic wildlife: report from six penguin colonies regularly visited by tourists

We investigated the potential role of Antarctic tourism in the introduction of human-associated pathogens into Antarctic wildlife. We collected and analyzed 233 fecal samples from eight bird species. The samples were collected at six localities on the Antarctic Peninsula, which often is visited by tourists. Every sample was investigated for pathogens of potential human origin: Campylobacter jejuni, Salmonella spp., and Yersina spp. None of these bacteria was found. Our data suggest that the tourism industry so far has achieved its goal of not introducing pathogens into the Antarctic region. There is, however, an urgent need to further investigate the situation in areas closer to permanent Antarctic settlements.     

Selective supercritical fluid extraction to estimate the fraction of PCB that is bioavailable to a benthic organism in a naturally contaminated sediment

Selective supercritical fluid extraction (SFE) at 40 degrees C, 120 bar and 60 min was utilised as a means to estimate the bioavailable fraction of PCBs to chironomid larvae in a naturally contaminated limnic sediment. This extraction methodology removed about 50% of the PCBs from the sediment. According to the equilibrium partitioning theory, organisms in that sediment should decrease their uptake from the sediment to the same extent, biota-to-sediment accumulation factors (BSAFs) thus remaining constant. Surprisingly, the BSAFs for 11 PCB congeners decreased some 40% for the selectively extracted sediment as compared to BSAFs for organisms dwelling in untreated sediment. The results were statistically significant at the 0.001 level using a paired t-test. This can only be interpreted so that selective SFE removed easily available PCBs preferentially, leaving more tightly bound PCBs behind. Hence, by fine-tuning extraction conditions, this methodology might be used to estimate bioavailable fractions by chemical means.     

Effects on the function of Arctic ecosystems in the short- and long-term perspectives

Historically, the function of Arctic ecosystems in terms of cycles of nutrients and carbon has led to low levels of primary production and exchanges of energy, water and greenhouse gases have led to low local and regional cooling. Sequestration of carbon from atmospheric CO2, in extensive, cold organic soils and the high albedo from low, snow-covered vegetation have had impacts on regional climate. However, many aspects of the functioning of Arctic ecosystems are sensitive to changes in climate and its impacts on biodiversity. The current Arctic climate results in slow rates of organic matter decomposition. Arctic ecosystems therefore tend to accumulate organic matter and elements despite low inputs. As a result, soil-available elements like nitrogen and phosphorus are key limitations to increases in carbon fixation and further biomass and organic matter accumulation. Climate warming is expected to increase carbon and element turnover, particularly in soils, which may lead to initial losses of elements but eventual, slow recovery. Individual species and species diversity have clear impacts on element inputs and retention in Arctic ecosystems. Effects of increased CO2 and UV-B on whole ecosystems, on the other hand, are likely to be small although effects on plant tissue chemisty, decomposition and nitrogen fixation may become important in the long-term. Cycling of carbon in trace gas form is mainly as CO2 and CH4. Most carbon loss is in the form of CO2, produced by both plants and soil biota. Carbon emissions as methane from wet and moist tundra ecosystems are about 5% of emissions as CO2 and are responsive to warming in the absence of any other changes. Winter processes and vegetation type also affect CH4 emissions as well as exchanges of energy between biosphere and atmosphere. Arctic ecosystems exhibit the largest seasonal changes in energy exchange of any terrestrial ecosystem because of the large changes in albedo from late winter, when snow reflects most incoming radiation, to summer when the ecosystem absorbs most incoming radiation. Vegetation profoundly influences the water and energy exchange of Arctic ecosystems. Albedo during the period of snow cover declines from tundra to forest tundra to deciduous forest to evergreen forest. Shrubs and trees increase snow depth which in turn increases winter soil temperatures. Future changes in vegetation driven by climate change are therefore, very likely to profoundly alter regional climate.     

Geochemistry and acidity of sulphide-bearing postglacial sediments of western Finland

The geochemistry, mineralogy, acidity and electric conductivity of sulphide-bearing postglacial sediments located on the coastal plains of western Finland were studied. Grain size and mineralogical analysis (eight samples studied) indicated that the sediments are silts dominated by primary minerals (quartz, feldspars), and that the clay fraction (<2µm), which made up less than one-third of the bulk samples, is enriched in phyllosilicates but depleted in quartz and feldspars, relative to bulk samples. As compared to the metal contents of the fine-fraction of glacial till (data of the Geological Survey of Finland), the fine sediments appear to be enriched in sulphur (median = 0.54%) and trace metals such as Ni (31 µg g^–1), Zn (90 µg g^–1), Co (13 µg g^–1), Cr (48 µg g^–1) and V (50 µg g^–1). Statistical analysis indicated that aluminosilicates are the principal carrier phases of trace metals, and that sulphides and organic matter only partially control the distribution of elements other than S and C. A 3-g portion of 232 samples was oxidised in the laboratory by atmospheric oxygen for a period of 1 year. After this period of oxidation, 15 ml of water was added, after which pH and electric conductivity of the suspensions (sediment:water, 1:5) were measured. The quantities of elements mobilised by the oxidation was calculated from the dissolved concentrations found in 3 g of oxidised sediment suspended in 30 ml of deionised water (eight samples studied). The results of the experiment showed that the impact of sulphide oxidation on the pH and conductivity of the sediments is large, and that a high proportion (>13%) of the aqua-regia extractable contents of several elements (Co, Mn, Ca, Ni, Zn, Sr, Na and B) are mobilised at oxidation. Because of the high quantities of acidity and metals liberated at oxidation, it is argued that stream-water quality, which is poor in the study area, will not improve unless artificial draining is restricted in areas of sulphide sediments.     

Copepod nutritional condition and pelagic production during autumn in Kosterfjorden,western Sweden

The in situ grazing rate and nutritional condition of copepods were studied during October/November 1985, by analyzing gut fluorescence (feeding), body size and lipid composition (nutritional state), and electron transport system (ETS) activity (respiration rate) of copepods from surface-and deep-water in Kosterfjorden on the Swedish west coast. These parameters were related to the physical and biological environment, as defined by light, hydrography, autotrophic and bacterial production and seston in the water column. The results show a gradual build-up of the autumn phytoplankton bloom in the uppermost meters, with a peak in total autotrophic production in mid October of ca 550 mg C m^–2 d^–1, and a bacterial net production corresponding to 15% of this. Phytoplankton exudates made up, on average, 47% of the primary production and more than 50% of this was utilized by the bacteria. Copepods occurring in the surface-water exhibited grazing rates corresponding to between 11 and 18% of their body C d^–1 and potential growth rates of 0 to 9% d^–1. Copepod populations in the surface water were composed of individuals with higher average body-weight and lower lipid-proportion than those from the deep-water.Calanus finmarchicus in the deep-water showed characters indicating diapause condition, while this was not observed forAcartia clausi. Differences in lipid content and composition indicate thatC. finmarchicus, Pseudocalanus sp. andA. clausi represent three successive points on a scale of tolerance for fluctuations in the food environment. Adult femaleMetridia longa was the only one among seven species/stages of copepods in the deep-water ( 50 m depth) that contained phytoplankton pigments.Study performed through Tjärnö Marine Biological Laboratory, University of Göteborg, S-452 00 Strömstad, Sweden     

Acoustic mirror effect increases prey detection distance in trawling bats

Many different and phylogenetically distant species of bats forage for insects above water bodies and take insects from and close to the surface; the so-called trawling behaviour. Detection of surface-based prey by echolocation is facilitated by acoustically smooth backgrounds such as water surfaces that reflect sound impinging at an acute angle away from the bat and thereby render a prey object acoustically conspicuous. Previous measurements had shown that the echo amplitude of a target on a smooth surface is higher than that of the same target in mid-air, due to an acoustic mirror effect. In behavioural experiments with three pond bats (Myotis dasycneme), we tested the hypothesis that the maximum distances at which bats can detect prey are larger for prey on smooth surfaces than for the same prey in an airborne situation. We determined the moment of prey detection from a change in echolocation behaviour and measured the detection distance in 3D space from IR-video recordings using stereo-photogrammetry. The bats showed the predicted increase in detection distance for prey on smooth surfaces. The acoustic mirror effect therefore increases search efficiency and contributes to the acoustic advantages encountered by echolocating bats when foraging at low heights above smooth water surfaces. These acoustic advantages may have favoured the repeated evolution of trawling behaviour.