11 resultados para BLUE-GREEN ALGAE

em Deakin Research Online - Australia


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Nodularia spumigena periodically proliferates to cause toxic algal blooms with some aquatic animals enduring and consuming high densities of the blue green algae or toxic lysis. N. spumigena contains toxic compounds such as nodularin and lipopolysaccharides. This current work investigates physiological effects of exposure from bloom conditions of N. spumigena cells and a post-bloom lysis. Biochemical and antioxidative biomarkers were comparatively studied over an acute 3-day exposure. In general, a post-bloom N. spumigena lysis caused opposite physiological responses to bloom densities of N. spumigena. Specifically, increases in glutathione (GSH) and glutathione peroxidase (GPx) and decreases in glutathione S-transferase (GST) were observed from the N. spumigena lysis. In contrast, N. spumigena cell densities decreased GSH and increased GST and lipid peroxidation (LPO) in mussels. Findings also suggest that at different stages of a toxic bloom, exposure may result in toxic stress to specific organs in the mussel.

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The Gippsland Lakes region in eastern Victoria is a partially flushed coastal lake system within a diverse catchment of rural and urban communities. Pressure from lakeside developments, re-occurring blue-green algal blooms, declining fisheries, sedimentation and infilling of the ocean entrance, has borne several decades of focussed studies and routine monitoring programs, along with a variety of engineering and management solutions. A recent review recommended that these disparate studies should be enhanced to formulate a coordinated monitoring network that could improve both spatial and temporal coverage, develop a capacity to trigger responsive investigations and was able to serve the needs of system management. Through a series of partnerships an integrated network was developed that comprises event and baseline monitoring of catchment loads, local meteorological forcing and an array of water quality sampling sites within the lakes system. A majority of these sites are incorporated with real-time telemetry that provides up to the minute information to stakeholders via a web-based information management system and vital operational status to technical system management.

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Scientific expertise and outcomes often give rise to controversy. An educational response that equips students to take part in such discussions is the teaching of socially acute questions (SAQs). With SAQs, the understanding of uncertainty, risk and how knowledge is developed is central. This study explores the way in which students from different disciplines and different continents are brought together via a digital platform to explore SAQs about environmental issues (a green algae outbreak linked to release of fertilisers along the coast of Brittany; the construction of a desalination plant near Melbourne to produce freshwater; and changes in meat consumption on a global scale, with regard to population projections in 2050). We have developed frameworks for looking at the quality of the collective reasoning and at the nature of students’ interactions, so that we can analyse the organisation of the learning communities and the building of collegial expertise. The results show that interdisciplinary discussions, especially on an international scale, foster the understanding of complex situations. In this paper, we discuss the modalities of one didactic scenario to enhance critical thinking and collaborative work, and to provide space for learners to support argumentation.

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The chemiluminescence from four cyclometalated iridium(III) complexes containing an ancillary bathophenanthroline-disulfonate ligand exhibited a wide range of emission colours (green to red), and in some cases intensities that are far greater than the commonly employed benchmark reagent, [Ru(bpy)3](2+). A similar complex incorporating a sulfonated triazolylpyridine-based ligand enabled the emission to be shifted into the blue region of the spectrum, but the responses with this complex were relatively poor. DFT calculations of electronic structure and emission spectra support the experimental findings.

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Increased global demand for agricultural production is being driven, in particular, by the rising middle class in the Asia-Pacific geo-region. The significant role of natural resource-based industries, especially agriculture, in the development of non-metropolitan regions is again being recognised. In this context, this article describes a spatial analysis approach to agricultural development based on the development of Production Areas (PAs) in regional/rural economies. PAs are spatial units within regions selected for the intensive sustainable development of agriculture (including forestry, agro-forestry and bio-energy), their associated activities and underpinning infrastructure. A case study in a resource-based region in Australia—Gippsland – explains the approach. This is informed by the eco-economy model of endogenous regional/rural development, which addresses the links between novel co-production and consumption networks. The methodology for the identification and analysis of PAs has, at its core, Land Suitability Analyses of those agricultural commodities currently cultivated in the region and those that could be grown in future climates. The use of GIS enables us to overlay and analyse several constraints (e.g. flood erosion and salinity risk) and resources (e.g. water and transport) to define PAs and the available land within each of them. The approach is further illustrated by focusing in one PA—Macalister, an irrigated dairy production area where recent dry climatic conditions caused a substantial decline in water resources. Key elements for the sustainable development of this PA are outlined including construction of Blue-Green Infrastructure. Comments on the approach and the need for strategic long-term planning concludes the article.

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Recent research by a team from Deakin University explored the health and wellbeing benefits of civic environmentalism – voluntary communal actions undertaken to promote ecosystem sustainability, typified by membership of a ‘friends of parks’ group. The research confirmed what was known intuitively: that belonging to such a group and undertaking the activities associated with such a group exposes people not only to the benefits of the natural environment, but also to other people and to opportunities to make a contribution which is socially valued.

On the basis of those findings, a pilot project involving intentional engagement of people suffering depression and related disorders in supported nature-based activities in a woodland environment is being implemented and evaluated. This article reports on that project and discusses the implications of its findings to date, and the findings of the three earlier projects, both for urban woodland/forest managers and for the health sector.

As this contribution indicates, there appears to be potential for the use of civic environmentalism to promote health, wellbeing and social connectedness for individuals and the wider population, as well as for groups with identified health vulnerabilities. However, the realization of the benefits of such an approach will be dependent on co-operation between the environment and health sectors to create and promote opportunities for increased civic environmentalism, and to identify and address the barriers to their effective use.

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The lipid, FA, and sterol composition of the New Zealand green lipped mussel (NZGLM, Perna canaliculus) and of the Tasmanian blue mussel (TBM, Mytilus edulis) were compared using TLC-FID and GC-MS. The respective mussel species were obtained from three different sites in both New Zealand (NZ) and Tasmania. Lipid class distribution of both mussel species was characterized by a high proportion of phospholipid (PL, 57–79%) and TG (10–25%), FFA (7–12%), and sterols (ST, 12–18%). The NZGLM had higher proportions of TG, FFA, and ST (P<0.01), whereas the TBM had a higher proportion of PL (P<0.01). There were higher proportions of total PUFA, saturated FA, n−3 FA, and hydroxy and nonmethyleneinterrupted FA (P<0.05) in the TBM compared with the NZGLM. The major FA in the NZGLM were 16∶0 (15–17%), 20∶5n-3 (14–20%), and 22∶6n-3 (11–17%). The same FA dominated lipids in the TBM, although there were significantly higher proportions of 16∶0 (P=0.000) and 22∶6 n−3 (P=0.003) and lower proportions of 20∶5n-3 (P=0.0072) in the TBM. A novel PUFA, 28∶8n-3, was detected in both mussels with higher amounts in the TBM, which probably reflects a greater dietary contribution of dinoflagellates for this species. Cholesterol was the dominant sterol in both mussels. Other major sterols included brassicasterol, 22-methylcholesterol, trans-22-dehydrocholesterol, and desmosterol. There were significant differences (P<0.05) between the NZGLM and TBM for 12 of the 20 sterols measured. Six sterols showed significant site differences for the NZGLM, and 10 for the TBM. The differences in the FA and sterol composition between the two species may be due to the diet of the NZGLM being more diatom-derived and the diet of the TBM having a greater dinoflagellate component.

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Exploiting the distinct excitation and emission properties of concomitant electrochemiluminophores in conjunction with the inherent color selectivity of a conventional digital camera, we create a new strategy for multiplexed electrogenerated chemiluminescence detection, suitable for the development of low-cost, portable clinical diagnostic devices. Red, green and blue emitters can be efficiently resolved over the three-dimensional space of ECL intensity versus applied potential and emission wavelength. As the relative contribution ratio of each emitter to the photographic RGB channels is constant, the RGB ECL intensity versus applied-potential curves could be effectively isolated to a single emitter at each potential.

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Incorporating phenylpyridine- and triazolylpyridine-based ligands decorated with methylsulfonate or tetraethylene glycol (TEG) groups, a series of iridium(III) complexes has been created for green and blue electrogenerated chemiluminescence under analytically useful aqueous conditions, with tri-n-propylamine as a coreactant. The relative electrochemiluminescence (ECL) intensities of the complexes were dependent on the sensitivity of the photodetector over the wavelength range and the pulse time of the applied electrochemical potential. In terms of the integrated area of corrected ECL spectra, with a pulse time of 0.5 s, the intensities of the Ir(III) complexes were between 18 and 102 % that of [Ru(bpy)3 ](2+) (bpy=2,2'-bipyridine). However, when the intensities were measured with a typical bialkali photomultiplier tube, the signal of the most effective blue emitter, [Ir(df-ppy)2 (pt-TEG)](+) (df-ppy=2-(2,4-difluorophenyl)pyridine anion, pt-TEG=1-(2-(2-(2-(2-hydroxyethoxy)ethoxy)ethoxy)ethyl)-4-(2-pyridyl)-1,2,3-triazole), was over 1200 % that of the orange-red emitter [Ru(bpy)3 ](2+) . A combined experimental and theoretical investigation of the electrochemical and spectroscopic properties of the Ir(III) complexes indicated that the greater intensity from [Ir(df-ppy)2 (pt-TEG)](+) relative to those of the other Ir(III) complexes resulted from a combination of many factors, rather than being significantly favored in one area.

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We examine [Ir(df-ppy)2(pt-TEG)](+) as the first highly water soluble, blue-luminescent iridium(iii) complex for chemiluminescence detection. Marked differences in selectivity were observed between the new complex and the conventional [Ru(bpy)3](2+) reagent, which will enable this mode of detection to be extended to new areas of application.