201 resultados para anthropogenic disturbance
Resumo:
Acid sulfate soils (ASS) is a stress factor that is responsible for the failure of some mangrove restoration projects, including abandoned aquaculture ponds converted from mangrove ecosystems. Through experimental and field studies, this research provides a better understanding of the biogeochemistry of ASS disturbance and the response of mangrove seedlings (Rhizophoraceae) under high metal levels and acidic conditions. This study found that mangrove restorations under ASS disturbance can work but with lower numbers of survived seedlings. To prevent toxicity under high levels of metal, seedlings retained metals in their roots and sparingly distributed them into aerial parts with low mobility. The presence of high levels of potential acidity parameters would allow pyrite to oxidise, thus increasing metal levels and acidity, which in turn affected the survival and growth of the seedlings.
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Understanding the natural variability of the Earth's climate system and accurately identifying potential anthropogenic influences requires long term, geographically distributed records of key climate indicators, such as temperature and precipitation that extend prior to the last 400. years of the Holocene. Reef corals provide an excellent source of high resolution climate records, and importantly represent the tropical marine environment where palaeoclimate data are urgently required. Recent decades have seen significant improvement in our understanding of coral biomineralisation, the associated uptake of geochemical proxies and methods of identifying and understanding the effects of both early and late, post depositional diagenetic alteration. These processes all have significant implications for interpreting geochemical proxies relevant to palaeoclimatic reconstructions. This paper reviews the current 'state of the art' in terms of coral based palaeoclimate reconstructions and highlights a key remaining problem. The majority of coral based palaeoclimate research has been derived from massive colonies of Porites. However, massive Porites are not globally abundant and may not provide material of a particular age of interest in those regions where they are present. Therefore, there is great potential for alternate coral genera to act as complimentary climate archives. While it remains critical to consider five key factors - vital effects, differential growth morphologies, geochemical heterogeneity in the skeletal ultrastructure, transfer equation selection and diagenetic screening of skeletal material - in order to allow the highest level of accuracy in coral palaeoclimate reconstructions, it is also important to develop alternate taxa for palaeoclimate studies in regions where Porites colonies are absent or rare. Currently as many as nine genera other than Porites have proven at least limited utility in palaeothermometry, most of which are found in the Atlantic/Caribbean region where massive Porites do not exist. Even branching taxa such as Acropora have significant potential to preserve environmental archives. Increasing this capability will greatly expand the number of potential geochemical archives available for longer term temporal records of palaeoclimate.
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Anthropogenic elemental mercury (Hg0) emission is a serious worldwide environmental problem due to the extreme toxicity of the heavy metal to humans, plants and wildlife. Development of an accurate and cheap microsensor based online monitoring system which can be integrated as part of Hg0 removal and control processes in industry is still a major challenge. Here, we demonstrate that forming Au nanospike structures directly onto the electrodes of a quartz crystal microbalance (QCM) using a novel electrochemical route results in a self-regenerating, highly robust, stable, sensitive and selective Hg0 vapor sensor. The data from a 127 day continuous test performed in the presence of volatile organic compounds and high humidity levels, showed that the sensor with an electrodeposted sensitive layer had 260% higher response magnitude, 3.4 times lower detection limit (,22 mg/m3 or ,2.46 ppbv) and higher accuracy (98% Vs 35%) over a Au control based QCM (unmodified) when exposed to a Hg0 vapor concentration of 10.55 mg/m3 at 1016C. Statistical analysis of the long term data showed that the nano-engineered Hg0 sorption sites on the developed Au nanospikes sensitive layer play a critical role in the enhanced sensitivity and selectivity of the developed sensor towards Hg0 vapor.
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The New Zealand Threat Classification System (NZTCS) is a national system used to assess the risk of extinction faced by New Zealand plants, animals and fungi. The system is specifically designed to be relevant to New Zealand's unusual ecological and geographic conditions. We undertook a re-evaluation of the status of seven bat taxa based on our knowledge of New Zealand bats using revised NZTCS criteria. Five taxa were listed as Threatened or At Risk: one as Nationally Critical (long-tailed bat Chalinolobus tuberculatus ‘South Island’), one as Nationally Endangered (southern lesser short-tailed bat Mystacina tuberculata tuberculata), two as Nationally Vulnerable (long-tailed bat ‘North Island’ and northern lesser short-tailed bat M. t. aupourica) and one as Declining (central lesser short-tailed bat M. t. rhyacobia). One taxon was assessed as Data Deficient (greater short-tailed bat M. robusta) and one (little red flying fox Pteropus scapulatus) as Vagrant. We suspect declines result primarily from predation and competition from introduced mammals, habitat degradation, and disturbance.
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Large-scale integration of non-inertial generators such as wind farms will create frequency stability issues due to reduced system inertia. Inertia based frequency stability study is important to predict the performance of power system with increased level of renewables. This paper focuses on the impact large-scale wind penetration on frequency stability of the Australian Power Network. MATLAB simulink is used to develop a frequency based dynamic model utilizing the network data from a simplified 14-generator Australian power system. The loss of generation is modeled as the active power disturbance and minimum inertia required to maintain the frequency stability is determined for five-area power system.
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OBJECTIVE Women diagnosed as having breast cancer may experience difficulties with posttreatment effects such as menopausal symptoms. The aims of this pilot study were to (1) evaluate the impact of a multimodal lifestyle program on reducing menopausal symptoms in women with breast cancer and (2) examine the impact of the program on health-related quality of life (HRQoL) and adherence to lifestyle recommendations. METHODS Overall, 55 women aged 45 to 60 years with one moderate to severe menopausal symptom and a history of breast cancer were randomized into an intervention group (n = 26) or a control group (n = 29). Women in the intervention group received a lifestyle intervention (The Pink Women’s Wellness Program) that included clinical consultations and a tailored health education program. Measurements of menopausal symptoms (Greene Climacteric Scale), HRQoL (SF-12 and Functional Assessment of Cancer Therapy—Breast), and modifiable lifestyle factors (food intake, physical activity, smoking and alcohol use, and sleep disturbance) were taken at baseline and 12 weeks. RESULTS Women in the intervention group reported clinically significant reductions in many menopausal symptoms, specifically somatic symptoms (d = 0.52), vasomotor symptoms (d = 0.55), sexual dysfunction (d = .65), and overall menopausal symptoms (d = 0.54), at 12 weeks compared with the control group (d = 0.03, d = 0.24, d = 0.18, and d = 0.05, respectively). Women in the intervention group reported improvements in Functional Assessment of Cancer Therapy—Breast subscale scores, physical well-being and functional well-being, and Functional Assessment of Cancer Therapy—General total scores (intervention group: d = 0.54, d = 0.50, and d = 0.48, respectively; control group: d = 0.22, d = 0.11, and d = 0.05, respectively). CONCLUSIONS The Pink Women’s Wellness Program is effective in decreasing menopausal symptoms, thus improving HRQoL. This being a pilot study, further research is recommended to investigate the benefits of combining nonpharmacological interventions for women with breast cancer to reduce their treatment-related menopausal symptoms.
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In recent times a widespread consensus on the reality and gravity of anthropogenic climate change has emerged. Perceived inadequacies in the Australian government’s legal and policy responses to climate change issues have resulted in environmental activists increasingly turning to the courts as a strategy to promote greater action to address adverse climate impacts. The efficacy of this strategy for achieving climate goals is limited by the time and expense of litigating, the restrictions inherent in environmental law administrative challenges, and the possibility that judicial decisions may be overruled by the legislature. To date, climate change litigation in Australia has met with varied success, yet its significance extends beyond the court room as an important mechanism for raising public, political and commercial awareness about climate change issues. Ultimately, however, the types of far-reaching changes needed to mitigate and manage adverse climate impacts require strong regulatory backing. The most effective approach to addressing the complex challenges posed by climate change is a coordinated suite of regulatory measures spearheaded by the Federal Government.
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Animals are often used as symbols in policy debates and media accounts of marine pollution. Images of miserable oil-soaked marine birds and mammals are prominent following high profile oil spills such as the Exxon Valdez, Prestige and Pacific Adventurer incidents. Portrayed as hapless victims, these animal actors are not only cast as powerful symbols of the effects of anthropogenic pollution but also represent an environment in crisis. Animals, like the broader environment, are seen as something which is acted upon. Less attention has been given to the ways in which animals have been cast as either the cause of marine pollution or as having the potential to actively mitigate the potential impacts of anthropogenic marine pollution. This article explores how animals are constructed with respect to vessel-sourced sewage pollution. Through a process of interpretive policy analysis, drawing on media reports and responses to an Australian regulatory review process this study found that, when defending the perceived right to pollute recreational boaters implicated animals such as dogs, fish, turtles, dolphins and seabirds in their pollution discourses. Scapegoating was an important rhetorical feature of claims-making strategies designed to avoid responsibility for changing sewage disposal practices.
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A sizeable (and growing) proportion of the public in Western democracies deny the existence of anthropogenic climate change. It is commonly assumed that convincing deniers that climate change is real is necessary for them to act pro-environmentally. However, the likelihood of ‘conversion’ using scientific evidence is limited because these attitudes increasingly reflect ideological positions. An alternative approach is to identify outcomes of mitigation efforts that deniers find important. People have strong interests in the welfare of their society, so deniers may act in ways supporting mitigation efforts where they believe these efforts will have positive societal effects. In Study 1, climate change deniers (N D 155) intended to act more pro-environmentally where they thought climate change action would create a society where people are more considerate and caring, and where there is greater economic/technological development. Study 2 (ND347) replicated this experimentally, showing that framing climate change action as increasing consideration for others, or improving economic/technological development, led to greater pro-environmental action intentions than a frame emphasizing avoiding the risks of climate change. To motivate deniers’ pro-environmental actions, communication should focus on how mitigation efforts can promote a better society, rather than focusing on the reality of climate change and averting its risks.
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The Rhodococcus genus exhibits diverse enzymatic activity that can be exploited in the conversion of natural and anthropogenic nitrogenous compounds. This catalytic response provides a selective advantage in terms of available nutrients while also serving to remove otherwise harmful xenobiotics. This review provides a critical assessment of the literature on bioconversion of organo-nitrogen compounds with a consideration of applications in bioremediation and commercial biotechnology. By examining the major nitro-organic compounds (amino acids, amines, nitriles, amides and nitroaromatics) in turn, the considerable repertoire of Rhodococcus spp. is established. The available published enzyme reaction data is coupled with genomic characterisation to provide a molecular basis for Rhodococcus enzyme activity with an assessment of the cellular properties that aid substrate accessibility and ensure stability. The metabolic gene clusters associated with the observed reaction pathways are identified and future directions in enzyme optimisation and metabolic engineering are assessed. © 2014 Society of Chemical Industry.
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An evolving meditation upon the complex, periodic processes that mark Australia’s seasonality, and our increasing ability to disturb them. By amplifying and shining light upon a myriad of mysterious lives lived in blackness, the work presents a sensuous, deep engagement with the rich, irregular spectras of seasonal forms: whilst hinting at a far less comforting background increasingly framed by anthropogenic climate change. ’Temporal’ uses custom interactive systems, illusionary techniques and real time spatial audio processes that draw upon a rich array of media, including seasonal, nocturnal field recordings sourced in the Bundaberg region and detailed observations of foliage & flowering phases from that region. By drawing inspiration from the subtle transitions between what Europeans once named ‘Summer’ and ‘Autumn’ and the multiple seasons recognised by other cultures, whilst also including bodily disturbances within the work, ’Temporal’ creates a compellingly immersive environment that wraps audiences in luscious yet ominous atmospheres beyond sight and hearing. This work completes a two year long project of dynamic mediated installations that have been presented in Sydney, Beijing, Cairns and Bundanon, that have each been somehow choreographed by environmental cycles; alluding to a new framework for making works that we named ‘Seasonal’. These powerful, responsive & experiential works each draw attention to that which will disappear when biodiverse worlds have descended into an era of permanent darkness – an ‘extinction of human experience’. By tapping into the deeply interlocking seasonal cycles of environments that are themselves intimately linked with social, geographical & political concerns, participating audiences are therefore challenged to see the night, their locality & ecologies in new ways through extending their personal limits of perception, imagery & comprehension.
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Urbanisation significantly changes the characteristics of a catchment as natural areas are transformed to impervious surfaces such as roads, roofs and parking lots. The increased fraction of impervious surfaces leads to changes to the stormwater runoff characteristics, whilst a variety of anthropogenic activities common to urban areas generate a range of pollutants such as nutrients, solids and organic matter. These pollutants accumulate on catchment surfaces and are removed and trans- ported by stormwater runoff and thereby contribute pollutant loads to receiving waters. In summary, urbanisation influences the stormwater characteristics of a catchment, including hydrology and water quality. Due to the growing recognition that stormwater pollution is a significant environmental problem, the implementation of mitigation strategies to improve the quality of stormwater runoff is becoming increasingly common in urban areas. A scientifically robust stormwater quality treatment strategy is an essential requirement for effective urban stormwater management. The efficient design of treatment systems is closely dependent on the state of knowledge in relation to the primary factors influencing stormwater quality. In this regard, stormwater modelling outcomes provide designers with important guidance and datasets which significantly underpin the design of effective stormwater treatment systems. Therefore, the accuracy of modelling approaches and the reliability modelling outcomes are of particular concern. This book discusses the inherent complexity and key characteristics in the areas of urban hydrology and stormwater quality, based on the influence exerted by a range of rainfall and catchment characteristics. A comprehensive field sampling and testing programme in relation to pollutant build-up, an urban catchment monitoring programme in relation to stormwater quality and the outcomes from advanced statistical analyses provided the platform for the knowledge creation. Two case studies and two real-world applications are discussed to illustrate the translation of the knowledge created to practical use in relation to the role of rainfall and catchment characteristics on urban stormwater quality. An innovative rainfall classification based on stormwater quality was developed to support the effective and scientifically robust design of stormwater treatment systems. Underpinned by the rainfall classification methodology, a reliable approach for design rainfall selection is proposed in order to optimise stormwater treatment based on both, stormwater quality and quantity. This is a paradigm shift from the common approach where stormwater treatment systems are designed based solely on stormwater quantity data. Additionally, how pollutant build-up and stormwater runoff quality vary with a range of catchment characteristics was also investigated. Based on the study out- comes, it can be concluded that the use of only a limited number of catchment parameters such as land use and impervious surface percentage, as it is the case in current modelling approaches, could result in appreciable error in water quality estimation. Influential factors which should be incorporated into modelling in relation to catchment characteristics, should also include urban form and impervious surface area distribution. The knowledge created through the research investigations discussed in this monograph is expected to make a significant contribution to engineering practice such as hydrologic and stormwater quality modelling, stormwater treatment design and urban planning, as the study outcomes provide practical approaches and recommendations for urban stormwater quality enhancement. Furthermore, this monograph also demonstrates how fundamental knowledge of stormwater quality processes can be translated to provide guidance on engineering practice, the comprehensive application of multivariate data analyses techniques and a paradigm on integrative use of computer models and mathematical models to derive practical outcomes.
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Linear water wave theory suggests that wave patterns caused by a steadily moving disturbance are contained within a wedge whose half-angle depends on the depth-based Froude number $F_H$. For the problem of flow past an axisymmetric pressure distribution in a finite-depth channel, we report on the apparent angle of the wake, which is the angle of maximum peaks. For moderately deep channels, the dependence of the apparent wake angle on the Froude number is very different to the wedge angle, and varies smoothly as $F_H$ passes through the critical value $F_H=1$. For shallow water, the two angles tend to follow each other more closely, which leads to very large apparent wake angles for certain regimes.
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The Great Sandy Region (incorporating Fraser Island and the Cooloola sand-mass), south-east Queensland, contains a significant area of Ramsar-listed coastal wetlands, including the globally important patterned fen complexes. These mires form an elaborate network of pools surrounded by vegetated peat ridges and are the only known subtropical, Southern Hemisphere examples, with wetlands of this type typically located in high northern latitudes. Sedimentological, palynological and charcoal analysis from the Wathumba and Moon Point complexes on Fraser Island indicate two periods of swamp formation (that may contain patterned fens), one commencing at 12 000 years ago (Moon Point) and the other ~4300 years ago (Wathumba). Wetland formation and development is thought to be related to a combination of biological and hydrological processes with the dominant peat-forming rush, Empodisma minus, being an important component of both patterned and non-patterned mires within the region. In contrast to Northern Hemisphere paludifying systems, the patterning appears to initiate at the start of wetland development or as part of an infilling process. The wetlands dominated by E. minus are highly resilient to disturbance, particularly burning and sea level alterations, and appear to form important refuge areas for amphibians, fish and birds (both non-migratory and migratory) over thousands of years.
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Introducing nitrogen (N)-fixing legumes into cereal-based crop rotations reduces synthetic fertiliser-N use and may mitigate soil emissions of nitrous oxide (N2O). Current IPCC calculations assume 100% of legume biomass N as the anthropogenic N input and use 1% of this as an emission factor (EF)—the percentage of input N emitted as N2O. However, legumes also utilise soil inorganic N, so legume-fixed N is typically less than 100% of legume biomass N. In two field experiments, we measured soil N2O emissions from a black Vertosol in sub-tropical Australia for 12 months after sowing of chickpea (Cicer arietinum L.), canola (Brassica napus L.), faba bean (Vicia faba L.), and field pea (Pisum sativum L.). Cumulative N2O emissions from N-fertilised canola (624 g N2O-N ha−1) greatly exceeded those from chickpea (127 g N2O-N ha−1) in Experiment 1. Similarly, N2O emitted from canola (385 g N2O-N ha−1) in Experiment 2 was significantly greater than chickpea (166 g N2O-N ha−1), faba bean (166 g N2O-N ha−1) or field pea (135 g N2O-N ha−1). Highest losses from canola were recorded during the growing season, whereas 75% of the annual N2O losses from the legumes occurred post-harvest. Legume N2-fixation provided 37–43% (chickpea), 54% (field pea) and 64% (faba bean) of total plant biomass N. Using only fixed-N inputs, we calculated EFs for chickpea (0.13–0.31%), field pea (0.18%) and faba bean (0.04%) that were significantly less than N-fertilised canola (0.48–0.78%) (P < 0.05), suggesting legume-fixed N is a less emissive form of N input to the soil than fertiliser N. Inputs of legume-fixed N should be more accurately quantified to properly gauge the potential for legumes to mitigate soil N2O emissions. EF’s from legume crops need to be revised and should include a factor for the proportion of the legume’s N derived from the atmosphere.