Persistent organic pollutants in European background air: derivation of temporal and latitudinal trends

Data are presented for polynuclear aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), polybrominated diphenyls ethers (PBDEs) and selected organochlorine compounds (OCs) in passive air samplers (PAS) along a rural/remote latitudinal transect from southern UK to northern Norway during 2002-2004. This study is part of an ongoing campaign, using semi-permeable membrane devices (SPMDs) as PAS over two year intervals since 1994. Data for PCBs, selected OCs and PBDEs are compared with that from previous campaigns. Absolute sequestered amounts of selected PCB congeners have decreased in a first order fashion between 1994-2004, with an average atmospheric clearance rate of 4.1 +/- 0.6 years and continue to fractionate with latitude. HCB has also declined between 1998-2004, with a clearance rate of 6 +/- 2.4 years. Data on DDT and its breakdown products indicate little fresh release in Europe. Comparison of PBDEs in 2000-02 and 2002-04 indicates site differences, generally with increases at UK sites and decreases in Norway. BDE-28, 47 and 49 decreased with increasing latitude (p < 0.04), while the other congeners did not show any significant latitudinal dependence. Transect data are presented for PAHs the first time. Three- and 4-ringed compounds dominated the mixture present in the SPMD. The PAH composition of the SPMDs at site 3 was compared to the average composition taken by active sampling at the same site. SPMD performance for sampling PAHs leaves many uncertainties, but they can be successfully used to semiquantitatively detect PAHs in the atmosphere. Fluorene and phenanthrene increased with latitude (p > 0.05), while 1-methylphenanthere, fluoranthene, benzo[b]fluoranthene and indeno[123-cd]pyrene decreased. Results are discussed in terms of sources, long-range atmospheric transport, global fractionation and clearance processes.     

Biomass from phytopathogens and culture conditions improve Penicillium chrysogenum antimicrobial activity and antifungal compounds production

The present study evaluated the effect of culture conditions and phytopathogenic strain co-culture on the production of antimicrobial metabolites and antifungal activity of Penicillium chrysogenum R1, which PCR identified. Antimicrobial activity was determined using the Hunter-Hunter experimental design with three factors (pH, incubation temperature, and inoculum, at two levels each). The antifungal metabolites, β 1-3 glucanase and chitinase, produced in the presence of live and inactivated Fusarium oxysporum Fsox C11 biomass, were evaluated using HPLC-MS and GC-MS. Results showed that P. chrysogenum inhibited the growth of five phytopathogenic fungal strains, and the most significant inhibition was observed for F. oxysporum Fsox C11. The best conditions to achieve the highest antifungal activity of the cell-free extract were pH 7, 28°C, 1 × 10⁶ spores/mL, and 144 h of fermentation, observing 86% inhibition of F. oxysporum Fsox C11 growth. Production of antifungal metabolites such as 1,4-benzoquinone imine, viridicatic acid, phenol-5-methyl-2-(1-methyl ethyl), and hydrolytic enzymes β 1-3 glucanase and chitinase was detected. The results define the perspective in designing new processes and products for biocontrol phytopathogens.     

Degradability Characterization of EPDM/IIR Blends by γ-irradiation

In this paper the modifications induced in butyl rubbers (pristine, chlorinated and brominated sorts) by γ-irradiation are investigated by swelling, chemiluminescence and FT-IR. The susceptibility of butyl rubbers for the generation of radicals orders their stabilities in the following sequence: IIR?>?IIR—Cl?>?IIR—Br. The incorporation of butyl rubbers into ethylene-propylene terpolymer matrix brings about increased densities of radicals initiating modifications in the oxidation state in respect with recombination, which are intensified as the processing dose increases. Based on the variation of carbonyl and hydroxyl indices the favorable route for the recycling EPDM based formulations would be suggested in this study. The chemiluminescence spectra proving the formation of peroxyl radicals at about 100?°C prove their availability as reclaiming solutions. IIR—Br is the recommendable butyl rubber for the recovery procedure by association with EPDM. The suitability of IIRs for recycling purposes is analyzed by the variation in their crosslink densities, free volumes and swelling degrees. The crosslinking behavior of stabilized EPDM/IIR blends that runs to the improvement of durability is depicted by Charlesby–Pinner representation, which involves the different simultaneous contribution of scission and crosslinking processes.     

Tipping Points and Climate Change: Metaphor Between Science and the Media

Over the past decade, scientists and journalists have prominently utilized the metaphor of a tipping point for drastic, irreversible and dangerous climate change. This paper shows how the tipping point metaphor became a multi-purpose bridge between science and the news media, describing how its meaning and use developed and diversified in interaction between these two domains. Within the scientific domain, the metaphor developed from a rhetorical device conveying a warning of drastic, irreversible and dangerous climate change to a theoretical concept driving empirical research. The news media soon picked up the tipping point metaphor for abrupt and dangerous climate change, turning it into a common part of the journalistic lexicon. Moreover, both science and the news media developed another, societal use of the tipping point metaphor, calling for radical societal change to avoid climate change catastrophe. The tipping point metaphor is hence not a monolithic notion but a highly versatile concept and expression, allowing it to be used for various communicative purposes by distinct stakeholders in different contexts.     

The net ecosystem carbon exchange of human-modified environments in the Australian Capital Region

As part of a larger study to quantify and map ecosystem services in southeast Australia, we estimated carbon stored in biomass and soils and the net ecosystem carbon exchange between the land surface and the atmosphere in the Australian Capital Region (ACR). Our aim was to understand and quantify how different human-modified landscapes provide an essential ecosystem service: the exchange and storage of carbon in the landscape. Using a remote sensing based modelling methodology, we obtained values of Net Primary Productivity (NPP), total carbon in soil and biomass and carbon turnover from meteorological and terrain inputs and vegetation attributes. We obtained a set of maps of NPP, total carbon (C) storage and C-turnover for the ACR. We superimposed a land use/cover map to assign the uptake, storage and release of carbon to different land use/cover types. Our results support the hypothesis that human-intensive land uses significantly affect the ability of terrestrial ecosystems to provide an important ecosystem service in the form of carbon storage.     

Towards the selection of a produced water enrichment for biological gas hydrate inhibitors

Economic concerns associated with the recovery of non-conventional hydrocarbon reserves include unexpected ice as well as ice-like gas hydrate formation. Antifreeze proteins (AFPs) inhibit ice growth, and experiments with fish, plant, and insect AFPs have shown promise of effective gas hydrate inhibition in lab-scale experiments. If produced on an industrial scale, AFPs could provide a more environmentally friendly alternative to kinetic inhibitors, but a large-scale production of these AFPs is not currently feasible. We believe that these difficulties could be surmounted by the production of microbial AFPs, but to date, only a few such proteins have been identified and purified, and none of these are associated with hydrocarbon reserves. Here, we have used ice-affinity and freeze-thaw stress to select microbes derived from oil and gas formation water, or produced water, as a source of anaerobic microbial communities. Ice-affinity successfully incorporated anaerobic bacteria under aerobic conditions, and the mixed culture had ice-associating properties. Under these conditions, ice-affinity selection does not result in cultivatable isolates, but similar, cultivable microbes were obtained following freeze-thaw selection under anaerobic conditions. Since these mixed cultures inhibited the growth of ice crystals, they also have the potential to inhibit hydrate growth. Overall, freeze-thaw selection provides a promising first step towards the isolation of microbes capable of the inhibition of ice and gas hydrate growth, for possible application for energy exploration and recovery at high-latitudes and in-deep, cold waters.     

Development and application of a video-mosaic survey technology to document the status of coral reef communities

The recent decline in the condition of coral reef communities worldwide has fueled the need to develop innovative assessment tools to document coral abundance and distribution rapidly and effectively. While most monitoring programs rely primarily on data collected in situ by trained divers, digital photographs and video are used increasingly to extract ecological indicators, provide a permanent visual record of reef condition, and reduce the time that divers spend underwater. In this study, we describe the development and application of a video-based reef survey methodology based on an algorithm for image registration and the estimation of image motion and camera trajectory. This technology was used to construct two-dimensional, spatially accurate, high-resolution mosaics of the reef benthos at a scale of up to 400 m². The mosaics were analyzed to estimate the size and percent cover of reef organisms and these ecological indicators of reef condition were compared to similar measurements collected by divers to evaluate the potential of the mosaics as monitoring tools. The ecological indicators collected by trained divers compared favorably with those measured directly from the video mosaics. Five out of the eight categories chosen (hard corals, octocorals, Palythoa, algal turf, and sand) showed no significant differences in percent cover based on survey method. Moreover, no significant differences based on survey method were found in the size of coral colonies. Lastly, the capability to extract the same reef location from mosaics collected at different times proved to be an important tool for documenting change in coral abundance as the removal of even small colonies (<10 cm in diameter) was easily documented. The two-dimensional video mosaics constructed in this study can provide repeatable, accurate measurements on the reef-plot scale that can complement measurements on the colony-scale made by divers and surveys conducted at regional scales using remote sensing tools.     

TNT removal from culture media by three commonly available wild plants growing in the Caribbean

Plants growing in the Caribbean, Rubia tinctorum, Lippia dulcis and Spermacoce remota, were used in vitro to remove TNT from culture media. Plants were found to be resistant to high TNT levels. S. remota was able to remove TNT in less than 48 h. Part of the TNT was physically removed from the culture media by evaporation.