46 resultados para 770300 Marine Environment

em Deakin Research Online - Australia


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The objective of the work reported in this thesis was to design and implement an ecological effects environmental monitoring program which would: 1) Collect baseline biological information on sessile epibiotic fouling communities from an area adjacent to a petroleum refinery located on Corio Bay, Victoria, to allow comparison with results of future monitoring for the assessment of long term temporal water quality trends. 2) Detect and — if possible - estimate the magnitude of any influence on epibiotic fouling communities within the Corio Bay marine ecosystem attributable to operations at the Shell Petroleum Refinery. 3) Investigate the extent of thermal stratification and rate of dispersal of the petroleum refinery main cooling-water outfall plume (discharging up to 350,000 tonnes of warmed seawater per day), and its effect on epibiotic communities within the EPA-defined mixing zone. A major component of the work undertaken was the design and development of artificial-substrate biological sampling stations suitable for use under the conditions prevailing in Corio Bay, and the development of appropriate quantitative underwater photographic sampling techniques to fulfil the experimental criteria outlined above. Experimental and other constraints imposed on the design of the stations precluded the simple suspension of frames from jetties or pylons, a technique widely used in previous work of this type. Artificial substrate panels were deployed along three radial transects centred within and extending beyond the petroleum refinery main cooling-water mixing zone. Identical substrate panels were deployed at a number of control sites located throughout Corio Bay, each chosen for differences in their degree of exposure to such factors as water movement, depth, shipping traffic and/or comparable industrial activity. The rate of colonisation (space utilisation) and the development of epibiotic fouling communities on artificial substrate panels was monitored over two twelve-month sampling periods using quantitative underwater photographic sampling techniques. Sampling was conducted at 4-8 week intervals with the rate of panel colonisation and community structure determined via coverage measurements. Various species of marine algae, polychaete tubeworms, hydroids, barnacles, simple and colonial ascidians, sponges, bivalve molluscs and encrusting bryozoans were all detected growing on panels. Communities which established on panels within the cooling-water mixing-zone and those at control sites were compared using statistical procedures including agglomerative hierarchical cluster analysis. A photographic sample archive has been established to allow comparison with similar future studies.

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The oceans of the world are regularly depicted as under threat from human exploitation with the problem portrayed as being of 'global' concern. In a world market characterised by the division of labour, many of those who eat fish do so without directly experiencing the ocean as a domain of productive utility. Rather, their encounters are with representations that depict the 'natural' world as an aesthetic object of contemplation, and environmentalist discourses that identify human activities as' threatening marine ecosystems. So prevalent is this experience that tangible institutions, such as state fisheries management bodies, have emerged, acting to reinforce the ontology of this 'contemplated' ocean, giving weight to the illusion that humans can, and should, appreciate it only from afar. In this representation, commercial fishers are regularly depicted as transgressing a 'natural' boundary between humans and the environment. It is when the world is simultaneously encountered as an object of consumptive utility and aesthetic utility that the human role in the environment becomes ambiguous and a sense of crisis arises. This paper investigates disjunctions in experiences and understandings that contribute to environmental anxiety, and debates over the appropriate use of the ocean.

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The application of the 'ecosystem approach' to marine conservation management demands knowledge of the distribution patterns of the target species or communities. This information is commonly obtained from species distribution models (SDMs). This article explores an important but rarely acknowledged assumption in these models: almost all species may be present, but simply not detected by the particular survey method. However, nearly all of these SDM approaches neglect this important characteristic. This leads to the violation of a fundamental assumption of these models, which presuppose the detection of a species is equal to one (i.e. at each survey locality, a species is perfectly detected). In this article, the concept of imperfect detection is discussed, how it potentially influences the prediction of species' distributions is examined, and some statistical methods that could be used to incorporate the detection probability of species in estimates of their distribution are suggested. The approaches discussed here could improve the collection and interpretation of marine biological survey data and provide a coherent way to incorporate detection probability estimates in the modelling of species distributions. This will ultimately lead to an unbiased and more rigorous understanding of the distribution of species in the marine environment.

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Animals respond to environmental variation by exhibiting a number of different behaviours and/or rates of activity, which result in corresponding variation in energy expenditure. Successful animals generally maximize efficiency or rate of energy gain through foraging. Quantification of all features that modulate energy expenditure can theoretically be modelled as an animal energetic niche or power envelope; with total power being represented by the vertical axis and n-dimensional horizontal axes representing extents of processes that affect energy expenditure. Such an energetic niche could be used to assess the energetic consequences of animals adopting particular behaviours under various environmental conditions. This value of this approach was tested by constructing a simple mechanistic energetics model based on data collected from recording devices deployed on 41 free-living Magellanic penguins (Spheniscus magellanicus), foraging from four different colonies in Argentina and consequently catching four different types of prey. Energy expenditure was calculated as a function of total distance swum underwater (horizontal axis 1) and maximum depth reached (horizontal axis 2). The resultant power envelope was invariant, irrespective of colony location, but penguins from the different colonies tended to use different areas of the envelope. The different colony solutions appeared to represent particular behavioural options for exploiting the available prey and demonstrate how penguins respond to environmental circumstance (prey distribution), the energetic consequences that this has for them, and how this affects the balance of energy acquisition through foraging and expenditure strategy.

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1Reproductive fitness is often compromised at the margins of a species’ range due to sub-optimal conditions.2Set against this backdrop, the Mediterranean's largest loggerhead sea turtle (Caretta caretta) rookery at Zakynthos (Greece) presents a conundrum, being at a very high latitude for this species, yet hosting a high concentration of nesting.3We used visual surveys combined with global positioning system (GPS) tracking to show that at the start of the breeding season, individuals showed microhabitat selection, with females residing in transient patches of warm water. As the sea warmed in the summer, this selection was no longer evident.4As loggerhead turtles are ectothermic, this early season warm-water selection presumably speeds up egg maturation rates before oviposition, thereby allowing more clutches to be incubated when sand conditions are optimal during the summer.5Active selection of warm waters may allow turtles to initiate nesting at an earlier date.

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Carbon fibre reinforced polymer (CFRP) sheet has gained its popularity to retrofit civil structures which is bonded externally, typically on the soffit of a beam. In this study, the bond between carbon fibre reinforced polymer (CFRP) and concrete is improved by modifying the property of commercial epoxy and compared against normal epoxy. The deterioration in bond strength was produced by placing the beam into salt water under wet dry cycles. Also, a model is proposed to determine the bond strength from flexural test and compared against the available bond strength models which are typically obtained from pull out test. This proposed model shows promising results in terms of predicting the bond strength from flexural test. In addition, a strength reduction factor is introduced to incorporate the effect of wet dry cycles to predict the long term behaviour. It is found that the modified epoxy enhance the ductile property and bond strength.

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The performance of carbon fibre reinforced polymer (CFRP) wrapped square column under the wet/dry cycle of marine environment is studied in this paper. Two different types of epoxies (one commercial and one modified) are used to bond CFRP with concrete to investigate their suitability under the harsh environmental exposure. The experimental results are verified against the available theoretical models of square column and a reduction factor is derived to incorporate the effect of marine exposure to estimate the strength reduction for the columns in general. The accuracy of the proposed reduction factor is then verified by predicting the degraded strength of the columns which are currently available in the literature.

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This This article reports findings from observational and questionnaire surveys of visitors to a Marine Protected Area (MPA) at Point Lonsdale, Victoria. The MPA was established primarily to protect the biodiversity of intertidal rock platforms, with only limited restrictions being placed on fishing. Visitor surveys were undertaken to identify and quantify recreational uses, assess level of compliance with regulations, identify the uses most likely to have damaging impacts on biota, and to assess awareness of, and support for, this MPA and for MPAs in general. A questionnaire survey of visitors supported observational survey findings concerning recreational use patterns and provided information on awareness about and attitudes towards conservation measures for this location and for Victoria's marine environment. The finding that about half the visitors were not aware that
they were visiting a marine protected area has implications for future management of this area and MPAs in general. Most visitors indicated support for the concept of marine conservation areas and marine protected areas.

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Deakin University along with the CRC for Coastal Zone, Estuary and Waterway Management, the Glenelg Hopkins CMA and the Marine & Coastal Community Network have formed a partnership to map the benthic habitats at 14 sites across approximately 5% of Victorian State waters. The project is funded through the Federal Government by the Natural Heritage Trust and brings together expertise from universities, government agencies and private enterprise. We will be using hydro-acoustic sonar technologies, towed video camera and remotely operated vehicles to collect information on the types of substrate and bathymetry to derive habitat maps. The coastal fringe of Victoria encompasses rich and diverse ecosystems which support a range of human uses including commercial and recreational fisheries, whale watching, navigation, aquaculture and gas development. The Deakin lead initiative will map from the 10-metre contour (safe ship passage) to the three nautical mile mark for selected regions and will provide a geospatial framework for managing and gaining better understanding of the near-shore marine environment Research products will be used for management, educational and research purposes over the coming years.

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In 2004, a Community Based Monitoring (CBM) program for Victoria’s Marine National Parks and Marine Sanctuaries was developed. A key performance area for Victoria’s Marine Protected Area (MPA) Management Strategy is community engagement. This program was developed to incorporate the key performance principles of community education, participation and engagement. CBM involves scientific protocols to monitor different habitat types in a MPA. As part of the CBM project, perceptions and values of MPAs were investigated through a pilot survey of 125 community group volunteers from 4 volunteer groups. Surveys were sent to all community group members which included participants and non-participants in the CBM program. Questions sought qualitative and quantitative information, focusing on personal values of MPAs. The surveys included questions associated with CBM, MPA management and environmental issues affecting the marine environment. Responses from the pilot study indicated that 50% of the volunteers participated in CBM to learn more about scientific research, and 30% wanted to work close to nature. This pilot study will form the basis of a larger-scale study to investigate community group perceptions of MPAs and identifying how to maintain volunteer enthusiasm, interest and motivation in a CBM program.

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An evaluation of the effectiveness of Marine Protected Areas (MPAs) in temperate waters of Australasia has been conducted for this thesis. The aim was to identify key elements needed in a strategy for establishment and management of MPA’s in temperate waters of Australasia. This aim was achieved by assessing how effective a sample of MPA’s has been in meeting the conservation objectives for their establishment and by identifying factors that have contributed to success or failure of the MPA’s in meeting these objectives. Particular attention was paid to the objectives of ecological sustainability and biodiversity preservation. A MPA for the purposes of this research was defined as an area of coastal or marine environment, with a substantial subtidal component, set aside by law primarily for conservation purposes. The study region encompassed the coastal zones of Victoria, Tasmania and South Australia (Australia) and New Zealand. The questions posed in order to address the aim of this thesis were; a) Have existing MPA’s been effective in achieving conservation objectives? b) What have been the important influences on effectiveness of existing MPA’s? c) What are the key elements required for implementation of effective MPA’s? The thesis is divided into three parts. Part I is a review of the literature on implementation and effectiveness of MPA’s. Part II presents a detailed evaluation of one MPA: Point Lonsdale Marine Reserve (PLMR), Victoria, Australia. Part in is an evaluation of a number of Australasian temperate MPA’s based on information provided in a survey of people involved in management of MPA’s, and from a variety of published and unpublished documents. The MPA’s are described, evidence about ecological effectiveness is presented and factors that have enhanced and limited the ability of these MPA’s to achieve conservation objectives are derived. A substantial amount of scientific evidence was found for increases in abundance, mean size and size range of fish and invertebrate populations within the boundaries of ‘no-take’ MPA’s, Some evidence was found for ‘spillover’ of adults and juveniles into adjacent fishing grounds. Ecological effects detected within ‘no-take’ MPA’s in Australasia matched those described in the literature. The abundance and mean size of a number of previously exploited species have increased, migration into adjacent fishing grounds has been documented, and species richness has increased in at least one MPA. The PLMR was established primarily to protect the scientifically significant intertidal rock platforms. The results of the case study suggest that this objective has been achieved. Opinions about effectiveness were obtained for 28 MPA’s. Of these 19 were considered to be achieving some objectives and 10 were considered to be performing well in terms of overall ecological effectiveness. Positive effects on biodiversity were generally assumed as a result of reduction of damaging anthropogenic effects on habitat. Many questionnaire respondents noted an increase in community awareness about and support for marine conservation as a result of proclamation of MPA’s, Overall, the results support the value of MPA’s for sustainability of fish stocks and preservation of biodiversity, but there is substantial doubt over whether some of the MPA’s are too small to maintain benefits in the long-term. ‘No-take’ MPA’s, particularly those more remote from the impacts of human activities, have been the most effective in achieving objectives. A number of interacting factors important to eventual success of MPA’s were identified. The most important enhancing factors identified for the PLMR were physical attributes that limit the extent of human use and a strong conservation ethic amongst many of the visitors to this marine reserve. Limiting factors were far more numerous. Of most concern is the inadequacy of at-site management. Almost half of visitors to the area were not aware of its marine reserve status, despite the fact many were frequent visitors. The need for better educational and interpretative material on-site is highlighted by the results of the PLMR visitor survey. A total of 56 factors that have enhanced effectiveness and 46 factors that have limited effectiveness of Australasian temperate MPA’s were identified. A number of factors were important in more than one MPA and this was used to derive a set of critical, or key, factors. For example, a conclusion of all three approaches used in this study is that failure to implement day-to-day management through lack of resources was a major constraint on effectiveness. The importance of MPA’s to marine conservation depends, in part, on how well they are managed. The key factors that influence MPA effectiveness were used as the basis for derivation of the main requirements for implementation of MPA’s that will be capable of meeting the objectives for their establishment. The most important needs are: • that ‘no-take’ areas surrounded by buffer zones form the basis for a system of MPA’s; • that a high level of protection is bestowed by legislation and regulations; • that a minimum size be set for the ‘no-take’ core areas; • that the selection of sites for MPA’s takes into account land-based impacts; • that institutional arrangements are developed specifically for MPA’s; • that funding for MPA’s is increased to enable effective management; • that day-to-day management is implemented in all MPA’s, with enforcement and education programs as priority areas; • that a monitoring program for one or more MPA in each 'State' is established to provide evidence of ecological effects of reservation; • that public and stakeholder involvement in development and implementation of MPA’s is encouraged as this will influence the degree of public support and compliance; • that community-based programs to educate the general public, stakeholders, the media and decision-makers about the value of MPA’s are essential; and • that measures to reduce financial impact on affected stakeholders be implemented.

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Improved access to multibeam sonar and underwater video technology is enabling scientists to use spatially-explicit, predictive modelling to improve our understanding of marine ecosystems. With the growing number of modelling approaches available, knowledge of the relative performance of different models in the marine environment is required. Habitat suitability of 5 demersal fish taxa in Discovery Bay, south-east Australia, were modelled using 10 presence-only algorithms: BIOCLIM, DOMAIN, ENFA (distance geometric mean [GM], distance harmonic mean [HM], median [M], area-adjusted median [Ma], median + extremum [Me], area-adjusted median + extremum [Mae] and minimum distance [Min]), and MAXENT. Model performance was assessed using kappa and area under curve (AUC) of the receiver operator characteristic. The influence of spatial range (area of occupancy) and environmental niches (marginality and tolerance) on modelling performance were also tested. MAXENT generally performed best, followed by ENFA-GM and -HM, DOMAIN, BIOCLIM, ENFA-M, -Min, -Ma, -Mae and -Me algorithms. Fish with clearly definable niches (i.e. high marginality) were most accurately modelled. Generally, Euclidean distance to nearest reef, HSI-b (backscatter), rugosity and maximum curvature were the most important variables in determining suitable habitat for the 5 demersal fish taxa investigated. This comparative study encourages ongoing use of presence-only approaches, particularly MAXENT, in modelling suitable habitat for demersal marine fishes.

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An expanding body of scientific research indicates that the marine environment is emerging as a unique resource of functional food ingredients with health-promoting properties. Significant attention has been paid to exploration of potential nutraceuticals and pharmaceuticals derived from the ocean. Marine-based  nutraceuticals are gaining attention due to their unique features, which are absent in terrestrial-based resources. A number of new marine nutraceutical products have been introduced in the nutraceuticals and functional foods markets. The main sources and products of primary interest for marine nutraceuticals and ingredients include omega-3 fish/algal oil, phospholipids, micro/macro algal nutrition supplements, fish proteins and peptides, hydrolysates, shellfish chitin, fish collagen, and mineral supplements.