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Photography is an important element of the tourist experience and provides both a method of later reliving the experiences of the journey as well as sharing elements of the journey with others. In the digital age photography has taken on a new dimension with the ability of people to enhance images as well as share them with others via new media such as the internet, Facebook, YouTube, MySpace and blogs. This paper reports on research undertaken into the taking of photographs of the Great Barrier Reef and finds that respondents rate the need for good photographic images as a high priority, are likely to use digital cameras in preference to other photographic devices, that there is a small but significant market for commercial photos and offering digital photo opportunities can provide the operator with a powerful and free marketing tool. [ABSTRACT FROM AUTHOR]

This paper proposes using an adaptive management approach to achieve water quality improvement in large catchments with multiple diffuse pollutant issues. Adaptive management involves attention to process, and commitment to continually improving knowledge and practice. It also requires an appreciation of differences in understanding of various stakeholders and an ongoing commitment to learning. Based on research with the Burdekin Dry Tropics regional Natural Resource Management group, the paper shows how the acquisition of knowledge about Water Quality Management can be an aim in itself, rather than an activity peripheral to the planning process. To this end, the paper describes the methods used to elicit stakeholders’ understandings, explores the variation in understandings between key stakeholders, and describes a process used to incorporate the various views in an adaptive management framework for managing water quality. The research findings reveal the importance of process and participation for adaptive management and suggest that success can be judged in terms of learning outcomes. [ABSTRACT FROM AUTHOR]

Abstract: The focus of this paper is to compare different evaluation frameworks for selecting landholder proposals to improve water quality. The case study is a water quality tender performed in the Burdekin region in Northern Australia in 2007/2008 where bids could be assessed using an inputs-based best management practice scorecard or an outputs-based auction metric. The scorecard approach and other variants of multi-criteria analysis are commonly applied in grant schemes, where landholder proposals are rated by a range of inputs-based criteria. Output-based approaches are typically applied in water quality and conservation tenders, where an environmental benefits index is constructed to summarise the environmental improvements generated by each proposal. These then allow projects to be selected on the basis of cost effectiveness. The case study evaluation reported in this paper demonstrates that the input focus of multi-criteria analysis type assessments are flawed, and that the efficiency of public funding can be more than doubled using auction metrics to assess proposals for landholders to improve water quality. [ABSTRACT FROM AUTHOR]

A prerequisite for meaningful environmental legislation is that it he based upon an adequate scientific understanding of the natural system to which It is applied. In 2003, the Australian Commonwealth and Queensland State governments introduced a Reef Water Quality Protection Plan. which aimed to "improve" water quality in river catchments adjacent to the Great Barrier Reef (GRR) and in nearby coastal waters. The Plan was introduced in the absence of any substantive evidence for regional degradation of GRR water quality. This paper reviews the available data regarding nutrient contents En the Tully River, north Queensland, which is cited as the best (available) evidence for human-related changes in nutrient export from (GBR) catchment [1]. It is shown that the claim of human-related nutrient enrichment in the Tully River, and regionally, is without substance. No detectable trends in GBR water quality have occurred since systematic measurements were first started in the 1980s. Environmental policies that are based on mischievous claims of chimerical damage to the Great Barrier Reef damage the reputation of science as a tool for disinterested analysis, and provoke widespread cynicism in the community regarding the integrity of contemporary environmental politics. [ABSTRACT FROM AUTHOR]

This paper investigates the use of aesthetic value as a criterion by which the significance of heritage places is assessed. It is argued that current heritage management practice has not engaged with the extensive discourse relating to aesthetics, and therefore confines aesthetics to a particular class and culture, and an inert view of only one of our sensory experiences. Historical records relating to the Great Barrier Reef are used to show how aesthetic appreciation of the area has changed over time.The data suggest that the failure to recognise an aesthetic that is primarily non-visual can lead to changes in landscape and loss of associated value. It also suggests that aesthetic values change rapidly and are influenced by social and technological factors. [ABSTRACT FROM AUTHOR]

Abstract: The use of landholder typologies to assist in the development of natural resource management (NRM) policies and agricultural extension programs has increased considerably in the past decade. In this paper we explore the potential of developing a typology of graziers to more effectively tailor policies and programs with the aim of improving land management outcomes. This is of particular importance since growing public concern about the environmental performance of the beef industry has led to increasing pressures on graziers to change their land management practices to decrease off-property impacts. To gain a better understanding of graziers’ land management practices and the factors that inform their decisions on how they manage their land we first developed a conceptual model of the relationship between grazier and grazing land where both can, ideally, thrive through conscious and timely land management decisions made and implemented by the grazier. A successful grazier land relationship is likely to be consistent with value systems and social and economic factors, although the particulars of any individual approach may vary spatially and temporally. These factors, in particular graziers’ values and motivations to follow a particular management strategy, guided the development of our typology of graziers. Australia''s Bowen-Broken basin, which has been identified as a major contributor of sediment and nutrients that enter the Great Barrier Reef lagoon, served as a case study for this research. Three broad types of graziers emerged: (1) traditionalists, (2) diversifiers, and (3) innovators. The authors argue that by understanding graziers’ values and motivations underlying each of the grazier types, government agencies and NRM organisations can more effectively tailor their policy and extension programs towards specific types of graziers and can work with specific groups to achieve reductions in sediment and nutrient runoff from grazing properties. [Copyright &y& Elsevier]

Abstract: Skeletal density and porosity characteristics are key parameters for investigations into scleractinian coral growth and for assessing the effects of a range of anthropogenic influences on coral reefs. Typically, skeletal density is measured by using planar X-rays of thin slabs cut from mound-shaped colonies or, for branching forms, by using methods based on Archimedean principles. This paper describes a novel non-destructive technique based on micro-computed tomography (micro-CT) to measure porosity of branching coral skeleton. This approach incorporates methods for segmenting internal and external portions of branch and for distinguishing between skeleton and air, whilst accounting for the effects of beam hardening. Measurements were obtained from colonies of branching Acropora pulchra collected across a reef-flat transect at King Reef, central nearshore Great Barrier Reef. The results show significant variation in porosity within and among branches sampled from individual colonies, but not within a reef-flat transect. Micro-CT techniques yield comparable results to traditional methods based on Archimedean principles, but offer advantages in their suitability for a wider range of coral specimens because of the non-destructive nature of the technique and in their more rigorous control of model parameters that can bias results. [ABSTRACT FROM AUTHOR]

Summary: This paper presents a tool for documenting and monitoring water use benefits in the Great Barrier Reef catchments that allows temporal and spatial comparison along the region. Water, water use benefits and water allocations are currently receiving much attention from Australian policy makers and conservation practitioners. Because of the inherent complexity and variability in water quality, it is essential that scientific information is presented in a meaningful way to policy makers, managers and ultimately, to the general public who have to live with the consequences of the decisions. We developed an inexpensively populated and easily understandable water use benefit index as a tool for community-based monitoring of water related trends in the Great Barrier Reef region. The index is developed based on a comparative list of selected water-related indices integrating attributes across physico-chemical, economic, social, and ecological domains currently used in the assessment of water quality, water quantity and water use benefits in Australia. Our findings indicate that the proposed index allows the identification of water performance indicators by temporal and spatial comparisons. Benefits for decision makers and conservation practitioners include a flexible way of prioritization towards the domain with highest concern. The broader community benefits from a comprehensive and user-friendly tool, communicating changes in water quality trends more effectively. [ABSTRACT FROM AUTHOR]

Summary: In many agricultural regions investments are made into improved land management and catchment restoration with the aim of reducing sediment and nutrient delivery to downstream water bodies. This paper presents the results of an 8year field study that evaluated the impact of improved grazing land management (GLM) on a 14km2 sub-catchment of the Burdekin River in northern Australia. Land condition recovery and changes to runoff and sediment yield were measured on hillslopes (using three flumes) and at the end of the catchment (using automatic water sampling). Ground cover was monitored at the beginning of the wet season at hillslope and catchment scales using direct measurement and Quickbird satellite imagery. At the catchment scale, improved GLM resulted in an increase in mean ground cover between 2003 and 2007, relative to a control grazing property. However, the total suspended sediment yield from hillslopes did not decline due to the disproportionately high yields from low (<10%) cover sites particularly in high runoff years. In 2007, when there was above-average rainfall, 97% of the hillslope derived fine sediment was coming from less than 3% of the catchment. Catchment sediment yield also increased, associated with higher rainfall and runoff in latter years of the study. In years of above-average rainfall, it is estimated that less than 40% of catchment sediment yield was derived from hillslope erosion. Channel erosion is considered to contribute the remaining sediment. Rehabilitation of hillslope scalds and gullies is likely to be an important companion to improved GLM to reduce catchment fine sediment yields in this landscape. Evaluation of gully and hillslope scald rehabilitation techniques is required, including the economic feasibility of such options. [Copyright &y& Elsevier]

Summary: Poor land condition resulting from unsustainable grazing practices can reduce enterprise profitability and increase water, sediment and associated nutrient runoff from properties and catchments. This paper presents the results of a 6year field study that used a series of hillslope flume experiments to evaluate the impact of improved grazing land management (GLM) on hillslope runoff and sediment yields. The study was carried out on a commercial grazing property in a catchment draining to the Burdekin River in northern Australia. During this study average ground cover on hillslopes increased from ∼35% to ∼75%, although average biomass and litter levels are still relatively low for this landscape type (∼60 increasing to 1100kg of dry matter per hectare). Pasture recovery was greatest on the upper and middle parts of hillslopes. Areas that did not respond to the improved grazing management had <10% cover and were on the lower slopes associated with the location of sodic soil and the initiation of gullies. Comparison of ground cover changes and soil conditions with adjacent properties suggest that grazing management, and not just improved rainfall conditions, were responsible for the improvements in ground cover in this study. The ground cover improvements resulted in progressively lower runoff coefficients for the first event in each wet season, however, runoff coefficients were not reduced at the annual time scale. The hillslope annual sediment yields declined by ∼70% on two out of three hillslopes, although where bare patches (with <10% cover) were connected to gullies and streams, annual sediment yields increased in response to higher rainfall in latter years of the study. It appears that bare patches are the primary source areas for both runoff and erosion on these hillslopes. Achieving further reductions in runoff and erosion in these landscapes may require management practices that improve ground cover and biomass in bare areas, particularly when they are located adjacent to concentrated drainage lines. [Copyright &y& Elsevier]

New regionalism encompasses a diversity of approaches to address regional planning problems. Within Australia, the Great Barrier Reef Water Quality Protection Plan was developed to enhance water quality within the World Heritage-listed Great Barrier Reef, and the plan gave responsibility to regional, natural resource management bodies to undertake several actions. This paper evaluates these initiatives in the light of the emerging theory of new regionalism and highlights six main lessons: up-scaling of the catchment approach to a reef-wide approach is essential in order to improve water quality, but must be complemented by cross-regional collaboration; new governance and institutional arrangements and strengthened partnerships must be effectively integrated; culture and history are important in determining the most effective management approaches; pilot projects must move to comprehensive and strategic implementation; science is important but needs to incorporate other branches of knowledge; and economic incentives are important in encouraging the implementation of best practices, but delivery needs to be flexible. We conclude that the new regional approach is appropriate for addressing complex, multi-scale problems such as water quality, and has incorporated several key principles of new regionalism, but that the process must move quickly to a higher level of commitment and application. [ABSTRACT FROM AUTHOR]

The tourism literature offers a number of different themes related to defining and understanding the long stay, independent travel of younger people often, referred to as backpacking. This paper focuses on the two major themes of differences between backpackers and other tourists, and change over time in backpacking, through an examination of survey data collected from tourists to Australia's Great Barrier Reef in 1996, 2001 (prior to the event of September 11) and in 2002 (prior to the Bali Bombing). Backpackers were compared to Other Younger Travellers at each of these three times on a number of variables including travel party, motivations, type of reef trip chosen, and satisfaction. The results supported three main conclusions. Firstly, Backpackers differed from Other Younger Travellers on a number of variables and they retain some of these differences over time. Secondly, both groups changed over time, reflecting impacts of changes in international travel and contexts. Finally, although significant differences continued to exist between the two groups in each time period, over time tourists in the Other Younger Travellers group became more like Backpackers. The study concludes that the concept of backpacking as a rite de passage is worthy of further consideration and research attention. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a multi-criteria based tool for assessing the relative impact of diffuse-source pollution to the Great Barrier Reef (GBR) from the river basins draining into the GBR lagoon. The assessment integrates biophysical and ecological data of water quality and pollutant concentrations with socio-economic information pertaining to non-point source pollution and (potential) pollutant impact. The tool generates scores for each river basin against four criteria, thus profiling the basins and enabling prioritization of management alternatives between and within basins. The results support policy development for pollution control through community participation, scientific data integration and expert knowledge contributed by people from across the catchment. The results specifically provided support for the Reef Water Quality Protection Plan, released in October 2003. The aim of the plan is to provide a framework for reducing discharge of sediment, nutrient and other diffuse-source loads and (potential) impact of that discharge and for prioritising management actions both between and within river basins. [Copyright &y& Elsevier]

Abstract: Along the tropical coastline of the Great Barrier Reef (GBR) region, little is known to date about submarine groundwater discharge (SGD) into the near-shore ocean. In an oceanographic sense, SGD consists of freshwater flow from land as well as seawater circulated through sediments. Recent radiochemical and geophysical studies, using the tracer 222Rn and apparent ground conductivity respectively, provide evidence for SGD to occur in a variety of hydrogeological settings. In this paper, a non-quantitative overview of different settings of SGD in the region is presented: (1) recirculation of seawater through animal burrows in mangrove forests, (2) freshwater SGD from unconfined aquifers as a narrow coastal fringe of freshwater along Wet Tropics beaches, (3) SGD from coastal dune systems in form of localised freshwater springs in the intertidal zone, (4) inner-shelf SGD from confined submarine aquifer systems comprised of riverine paleochannels incised into the shelf. [Copyright &y& Elsevier]

An Integrated Risk Assessment for Climate Change (IRACC) is developed and applied to assess the vulnerability of sharks and rays on Australia's Great Barrier Reef (GBR) to climate change. The IRACC merges a traditional climate change vulnerability framework with approaches from fisheries ecological risk assessments. This semi-quantitative assessment accommodates uncertainty and can be applied at different spatial and temporal scales to identify exposure factors, at-risk species and their key biological and ecological attributes, critical habitats a`nd ecological processes, and major knowledge gaps. Consequently, the IRACC can provide a foundation upon which to develop climate change response strategies. Here, we describe the assessment process, demonstrate its application to GBR shark and ray species, and explore the issues affecting their vulnerability to climate change. The assessment indicates that for the GBR, freshwater/estuarine and reef associated sharks and rays are most vulnerable to climate change, and that vulnerability is driven by case-specific interactions of multiple factors and species attributes. Changes in temperature, freshwater input and ocean circulation will have the most widespread effects on these species. Although relatively few GBR sharks and rays were assessed as highly vulnerable, their vulnerability increases when synergies with other factors are considered. This is especially true for freshwater/estuarine and coastal/inshore sharks and rays. Reducing the impacts of climate change on the GBR's sharks and rays requires a range of approaches including mitigating climate change and addressing habitat degradation and sustainability issues. Species-specific conservation actions may be required for higher risk species (e.g. the freshwater whipray, porcupine ray, speartooth shark and sawfishes) including reducing mortality, preserving coastal catchments and estuarine habitats, and addressing fisheries sustainability. The assessment identified many knowledge gaps concerning GBR habitats and processes, and highlights the need for improved understanding of the biology and ecology of the sharks and rays of the GBR. [ABSTRACT FROM AUTHOR]

Aim This study examines the importance of geographic proximity, host life history and regional and local differences in environment (temperature and water clarity) in driving the ecological and evolutionary processes underpinning the global patterns of diversity and distribution of symbiotic dinoflagellates. By comparing and contrasting coral–algal symbioses from isolated regions with differing environmental conditions, we may assess the potential of coral communities to respond to significant changes in climate. Location Indian Ocean. Methods Community assemblages of obligate symbiotic invertebrates were sampled at numerous sites from two regions, the north-eastern Indian Ocean (Andaman Sea, western Thailand) and the western Indian Ocean (Zanzibar, Tanzania). Molecular genetic methods, including denaturing gradient gel electrophoresis analysis of the ribosomal internal transcribed spacers, DNA sequencing and microsatellite genotyping, were used to characterize the ‘species’ diversity and evolutionary relationships of symbiotic dinoflagellates (genus Symbiodinium). Host–symbiont specificity, geographic isolation and local and regional environmental factors were evaluated in terms of their importance in governing the distribution and prevalence of certain symbiont taxa. Results Host-generalist symbionts ( C3u and D1-4, formerly D1a now designated Symbiodinium trenchi) frequently occurred alone and sometimes together in hosts with horizontal modes of symbiont acquisition. However, the majority of Symbiodinium diversity consisted of apparently host-specific ‘species’. Clade C Symbiodinium were diverse and dominated host assemblages from sites sampled in the western Indian Ocean, a pattern analogous to symbiont communities on the Great Barrier Reef with similar environmental conditions. Clade D Symbiodinium were diverse and occurred frequently in hosts from the north-eastern Indian Ocean, especially at inshore locations, where temperatures are warmer, water turbidity is high and large tidal exchanges commonly expose coral populations to aerial desiccation. Main conclusions Regional and local differences in cnidarian–algal combinations indicate that these symbioses are ecologically and evolutionarily responsive and can thrive under various environmental conditions. The high temperatures and turbid conditions of the north-eastern Indian Ocean partly explain the ecological success of Clade D Symbiodinium relative to Clade C. Phylogenetic, ecological and population genetic data further indicate that Clade D has undergone an adaptive radiation, especially in regions around Southeast Asia, during the Pleistocene. [ABSTRACT FROM AUTHOR]

Careful analysis of gut contents has resulted in the reclassification of several species of grazing fish as detritivores, shifting the trophodynamic assignment of many prominent reef grazers. Combtoothed blennies, which are among the most numerous grazing fish of the Great Barrier Reef, have been shown to target the detrital component of the epilithic algal matrix (EAM). It has been suggested that blennies have specialized dental morphology that allows them to comb through fronds of algae, collecting detritus, while leaving the algal component intact. In this study, we analysed the capability of a common reef flat blenny, Salarias fasciatus, to remove algae by (i) examining oral morphology for evidence of wear and adaptations for abrasion, and (ii) a short-term EAM feeding experiment. Examination of S. fasciatus teeth with scanning electron microscopy (SEM) showed evidence of macrowear (changes in tooth height or shape), microwear (surface chips and striae), and tooth replacement that suggests abrasion on the substrate. Energy Dispersive X-ray Spectrometry (EDS) revealed that oral teeth incorporate mineral iron. When fed artificial substrata with a developed EAM layer S. fasciatus removed 57% of photosynthetic material and 38.5% of organic biomass. Although studies have found that blenny gut contents consist predominantly of detritus, blennies are still likely to contribute to the removal of algae on coral reefs. [ABSTRACT FROM AUTHOR]

Preliminary results of a survey investigating individual well-being of residents in the Great Barrier Reef region of Australia are presented. The well-being factors were grouped into domains of: society, representing family and community issues; ecology, representing natural environment; and economy, dealing with economic issues and provision of services. The relative perceived importance of factors was quantified, allowing for a creation of individual well-being functions. In the society domain, family relations and health were identified as the most important contributors to well-being. Water quality was the ecology domain factor that received highest scores, and health services and income were the most important contributors to the economic domain. The methodological approach used in this study has a potential to integrate ecological, social, and economic values of local people into decision-making processes. The profiles of well-being thus generated would present policymakers with information beyond that available from standard data sources. [ABSTRACT FROM AUTHOR]

The sources and fluxes of sediment to the Great Barrier Reef lagoon from north-eastern Australian rivers have been the subject of much concern and study, with the large catchments of the Burdekin and Fitzroy Rivers thought to be the key sources at present. Here, the utility of newly developed magnetic ‘fingerprinting’ methods for identifying sediment provenance, both onshore and offshore, and in association with individual large flood events, is investigated. Within the Burdekin catchment, sediments are mobilized from different subcatchments by runoff generated by intense, localized rainfall events. Magnetic measurements were made on untreated and acid-treated samples of river channel sediments within the Burdekin River subcatchments and from the estuarine and inner shelf depocentres of Burdekin River sediments. The acid treatment removes all discrete magnetic particles and coatings, and leaves magnetic inclusions (protected within host silicate grains) as the basis of the measured magnetic signature of a sample. The magnetic properties of the acid-treated samples display statistically distinct sediment provenance groupings. Sand samples from the Upper Burdekin River appear magnetically distinct from samples from tributaries of the Burdekin (e.g. Hann Creek, Fanning River) and also from nearby coastal rivers, including the Haughton. Suspended sand samples from a Burdekin flood event in 2000 appear to have a different source compared with those from floods in 1998 and 1999. Comparisons of the terrestrial, acid-treated sand fractions with the same, acid-treated, sand-size fractions from transects taken offshore suggest that the surface sediments in Upstart Bay and Bowling Green Bay have different sources. Some of these sources are as yet unidentified but may represent the unsampled, lower-discharge south-western Burdekin subcatchments, and/or along-shore drift of sand from the south, perhaps even from the Fitzroy River, over millennial timescales of cyclone pumping. The magnetic inclusion method precludes any obfuscation or confounding of sediment source, which might arise from hydraulic sorting and/or post-depositional magnetic diagenesis or authigenesis. [ABSTRACT FROM AUTHOR]

As one of Australia's iconic tourism attractions and one of the seven natural wonders of the world, the Great Barrier Reef (GBR) is an important economic, social and natural resource for Queensland's Tropical North. However, the long-term prognosis for the health of the reef and by implication, the industries dependent on it, is not positive. So far much attention has focussed on the health and resilience of the reef ecosystem, as a foundation for a resilient tourism industry. In this study we explore how weather conditions have affected the reef experiences of 1000 tourists to the Cairns/Port Douglas region, suggesting that this may also be an important indicator of change on the reef. The results suggest that poor weather has a more pronounced effect on experiences than good weather and reinforce the likelihood that seasickness, cold and wet conditions, reduced water visibility, and difficult snorkelling/diving conditions will reduce overall levels of satisfaction. Poor weather was found to have a direct effect on satisfaction scores, the likelihood that reef and tour expectations were not realised, and lowered perceived value for money. These are important considerations for the reef centred tourism industry that is currently facing strong environment pressures from climate change. [ABSTRACT FROM AUTHOR]

The historical exploitation of marine resources in Queensland has only been partially documented. In particular, the history of the commercial fishing of dugongs and marine turtles has received comparatively little scholarly attention. Since European settlement in Queensland, various human activities have exploited these resources. We present documentary and oral history evidence of the scale of those industries. Based on extensive archival and oral history research, we argue that diverse fishing practices occurred and that the sustained exploitation of dugongs, green turtles, and hawksbill turtles led to observable declines in the numbers of these animals – now species of conservation concern. [ABSTRACT FROM AUTHOR]

A sedimentological and stratigraphic study of Low Isles Reef off northern Queensland, Australia was carried out to improve understanding of factors that have governed Late Holocene carbonate deposition and reef development on the inner to middle shelf of the northern Great Barrier Reef. Low Isles Reef is one of 46 low wooded island-reefs unique to the northern Great Barrier Reef, which are situated in areas that lie in reach of river flood plumes and where inter-reef sediments are dominated by terrigenous mud. Radiocarbon ages from surface and subsurface sediment samples indicate that Low Isles Reef began to form at ca 3000 y BP, several thousand years after the Holocene sea-level stillstand, and reached sea-level soon after (within ∼500 years). Maximum reef productivity, marked by the development of mature reef flats that contributed sediment to a central lagoon, was restricted to a narrow window of time, between 3000 and 2000 y BP. This interval corresponds to: (i) a fall in relative sea-level, from ∼1 m above present at ca 5500 y BP to the current datum between 3000 and 2000 y BP; and (ii) a regional climate transition from pluvial (wetter) to the more arid conditions of today. The most recent stage of development (ca 2000-0 y BP) is characterised by extremely low rates of carbonate production and a dominance of destructive reef processes, namely storm-driven remobilisation of reef-top sediments and transport of broken coral debris from the reef front and margins to the reef top. Results of the present study enhance existing models of reef development for the Great Barrier Reef that are based on regional variations in reef-surface morphology and highlight the role of climate in controlling the timing and regional distribution of carbonate production in this classic mixed carbonate-siliciclastic environment. [ABSTRACT FROM AUTHOR]

The deposition and cycling of carbon and nitrogen in carbonate sediments located between coral reefs on the northern and central sections of the Great Barrier Reef were examined. Rates of mass sediment accumulation ranged from 1.9 kg m-2 year-1 (inshore reefs) to 2.1- 4.9 kg m-2 year-1 (between mid-shelf reefs); sedimentation was minimal off outer-shelf reefs. Rates of total organic carbon decomposition ranged from 1.7 to 11.4 mol C m-2 year-1 and total nitrogen mineralization ranged from 77 to 438 mmol N m-2 year-1, declining significantly with distance from land. Sediment organic matter was highly reactive, with mineralization efficiencies ranging from 81 to 99% for organic carbon and 64-100% for nitrogen, with little C and N burial. There was no evidence of carbonate dissolution/precipitation in short-term incubation experiments. Rates of sulfate reduction (range 0-3.4 mmol S m-2 day-1) and methane release (range 0-12.8 μmol CH4 m-2 day-1) were minor or modest pathways of carbon decomposition. Aerobic respiration, estimated by difference between total O2 consumption and the sum of the other pathways, accounted for 55-98% of total carbon mineralization. Rates of ammonification ranged from 150 to 1,725 μmol NH4 m-2 day-1, sufficient to support high rates of denitrification (range 30-2,235 μmol N2 m-2 day-1). N2O release was not detected and rates of NH4 + and NO2- efflux were low, indicating that most mineralized N was denitrified. The percentage of total N input removed via denitrification averaged ≈75% (range 28-100%) with little regenerated N available for primary producers. Inter-reef environments are therefore significant sites of energy and nutrient flow, especially in spatially complex reef matrices such as the Great Barrier Reef. [ABSTRACT FROM AUTHOR]3- efflux were low, indicating that most mineralized N was denitrified. The percentage of total N input removed via denitrification averaged ≈75% (range 28-100%) with little regenerated N available for primary producers. Inter-reef environments are therefore significant sites of energy and nutrient flow, especially in spatially complex reef matrices such as the Great Barrier Reef. [ABSTRACT FROM AUTHOR]

Coral communities were monitored at Pandora Reef, nearshore Great Barrier Reef from 1981 to 2005 using photography and videography. In the 1980s, regional elevation of land-based nutrients in coastal waters (ca. 2-6 times pre-European levels of early 1800s) did not prevent overall recovery of coral cover and diversity following a sequence of environmental disturbances in the 1970s. However, prospects for a repeat of such resilience following catastrophic mortality from high-temperature bleaching in 1998 and a cyclone in 2000 are not clear. Different coral communities around the reef varied greatly in relation to impacts and recovery. Fore-reef communities dominated by acroporids (fast growing branching and tabular Acropora and foliose Montipora) recovered strongly in the 1980s following apparently severe impacts by cyclone, food and heat wave disturbances in the 1970s, attaining 60-90% cover by stabilizing rubble and outgrowing macro-algae in <10 years. In the back-reef, by contrast, poritid-dominated communities (massive and finger Porites and columnar Goniopora and Alveopora) had more stable trajectories and smaller impact from recent disturbances: recovery was well underway in 2005. The contrasting trajectories of different parts of the reef reflect differential survival of more persistent versus more ephemeral taxa, notably poritids and acroporids, respectively, both major contributors to framework and cover on reefs globally. A repeat of earlier resilience appears possible in the shallow fore-reef, but unlikely in the deeper fore-reef, which had few viable fragments or recruits in 2005. The main limits on recovery may be (1) reduced supply of coral larvae due to widespread regional losses of coral brood stock and (2) the reduced intervals between disturbances associated with global climate change. The presence of a high abundance of Acroporidae is a major pre-disposing risk factor for climate change impacts. [ABSTRACT FROM AUTHOR]

Tropical cyclones (hurricanes and typhoons) produce high winds that can generate waves capable of damaging coral reefs. As cyclones frequently pass through northeast Australia's Great Barrier Reef (GBR), it is important to understand how the spatial distribution of reef damage changes over time. However, direct measurements of wave damage, or even wave heights or wind speeds, are rare within the GBR. An important factor in estimating whether cyclone damage was possible is the magnitude and duration of high-energy wind and waves. Thus, before the spatio-temporal dynamics of past cyclone damage can be modelled, it is necessary to reconstruct the spread, intensity, and duration of high-energy conditions during individual cyclones. This was done every hour along the track taken by each of 85 cyclones that passed near the GBR from 1969 to 2003, by implementing a cyclone wind hindcasting model directly within a raster GIS using cyclone data available from the Australian Bureau of Meteorology. Three measures of cyclone energy (maximum wind speed—MAX, duration of gales—GALES, and continuous duration of gales—CGALES) were derived from these data. For three cyclones, where field data documenting actual reef damage from cyclone-generated waves were available, the predictive ability of each measure was assessed statistically. All three performed better in predicting reef damage at sites surveyed along the high-energy reef front than those surveyed along the more protected reef back. MAX performed best for cyclone Joy (r 2 = 0.5), while CGALES performed best for cyclones Ivor (r 2 = 0.23) and Justin (r 2 = 0.48). Using thresholds for MAX and GALES obtained via comparison with field data of damage, it was possible to produce a preliminary prediction of the risk of wave damage across the GBR from each of the 85 cyclones. The results suggest that while up to two-thirds of the GBR was at risk from some damage for 30–50% of the time series (∼18 out of 35 years), only scattered areas of the region were at risk more frequently than that. [ABSTRACT FROM AUTHOR]

The article presents information on a qualitative research conducted by the authors in an attempt to explore the historical context of the deterioration of the Great Barrier Reef, Queensland. The authors have presented evidence of extensive mining activity in the Great Barrier Reef over a period ranging from 1844 to 1940. They have focused on four kinds of industries including phosphatic sandstone, guano, rock phosphate and coral mining. Findings of research suggest that historical mining in the Great Barrier Reef has their impacts left over the landscape of several islands and cays.

Many attempts have been made by ichnologists to match bioerosion traces to their respective tracemakers. This task has been considered difficult, especially for fossil samples. The present study demonstrates that the Australian bioeroding sponge Aka paratypica can generate a cavity similar to the ichnospecies Entobia devonica . The modern sponge and its cavity are redescribed and compared to the fossil boring. A. paratypica has white fistules and soft, mucoid endosomal tissue. Spicules are stout oxeas with often telescoped or mucronate tips. Observed borings of A. paratypica are rounded and cavernous, with canals and apertures radiating from the chambers in all directions. It was noted that the internal openings of such canals are covered with porous nodules, which may act as sieves against larger particles or intruding endofauna. No obvious microsculpturing was observed in the erosion scars. A. paratypica borings are analogous to ancient E. devonica borings, which to date were only known from the fossil record. [ABSTRACT FROM AUTHOR]

The dynamics of carbon and nitrogen in carbonate mud were examined in the lagoons of Arlington and Sudbury Reefs, Great Barrier Reef. Most (89-93%) of the organic carbon and total nitrogen depositing to the carbonate mud zones was mineralized over a sediment depth of 1 m, with ∼50% of CO2 produced during microbial decomposition involved in carbonate precipitation/dissolution reactions. There was proportionally little burial of organic carbon (10-11%) or nitrogen (7-10%). Nitrogen budgets suggest rapid turnover of porewater inorganic N pools on the order of hours to a few days. Incubation experiments indicate carbonate dissolution in surface deposits (≤ 20 cm depth) and carbonate precipitation in deeper sediments. Depth-integrated reaction rates indicate net carbonate precipitation of 7-10 mol CaCO3 m² year-1 over a depth of 1 m. Budget calculations at the whole-reef scale imply that deposition of CaCO3 in the mud zones of both lagoons may equate to 50-90% of total reef carbonate production, with organic carbon fluxes equating to nearly all net primary production on each reef. These biogeochemical estimates point to the functional importance of carbonate mud zones in the lagoons of the shelf reefs of the Great Barrier Reef. [ABSTRACT FROM AUTHOR]

Thirty–five species (including eight that are new) of non–didemnid aplousobranch species and 25 phlebobranch (including one new) and stolidobranch species are discussed and a further 42 species in non–didemnid taxa in all suborders are newly recorded. Material was taken by scuba diving in the waters around Kangaroo I. and other southern Australian and Tasmanian locations; and further material was taken by dredge from canyons off the southeastern Continental Slope and from inter–reefal areas in the northern Great Barrier Reef region. The known geographic ranges of many southern Australian species are extended into Tasmanian waters and a new species of Rhopalaea is described from the Tasmanian Canyons. The genera Sigillina and Pseudodistoma are found to be diverse in Australian temperate waters, and they have many characters in common, suggesting a probable phylogenetic relationship that formerly was not recognised. The greatest diversity of species reported is from the vicinity of the northern Great Barrier Reef. Almost without exception these are non–indigenous tropical species often extending into Australian temperate locations where they are sympatric with indigenous species found mainly around the southern half of the continent. Pyura stolonifera has a similar range in temperate Australian waters but appears also to occur on the South African and Chilean coasts in similar habitats and may represent a Gondwana relict. [ABSTRACT FROM AUTHOR]

Eight, multicentury, Porites coral cores were used to develop a 373-year chronology by cross-dating techniques adapted from dendrochronology. Characteristic patterns of distinct luminescent lines within the coral skeletons were matched between coral cores from inshore and mid-shelf reefs in the central Great Barrier Reef, Australia. Skeleton-plots of luminescent banding were produced for each core and combined into a master chronology back to AD 1615. In addition to improving dating control, the luminescence master chronology provides a proxy for Burdekin River runoff and Queensland summer rainfall. Variations in the magnitude of the correlation between the luminescence master and the Mann et al. (2000) NINO3 sea-surface temperature reconstruction provides insights into the long-term stability of El Niño-Southern Oscillation (ENSO) teleconnections. Burdekin River runoff was significantly inversely related to ENSO variability for much of the period from the AD 1650s to 1800, suggesting that ENSO-related teleconnections were as dominant then as in recent decades. The extremely dry mid-1760s to mid-1780s stand out as a period of anomalously positive correlation between river runoff and the NINO3 reconstruction. Weak ENSO teleconnections are apparent from the 1800s to 1870s, when conditions were possibly similar to those reported for the 1920s-1950s. [ABSTRACT FROM AUTHOR]

The Great Barrier Reef (GBR) shelf contains a range of coral reefs on the highly turbid shallow inner shelf, where interaction occurs with terrigenous sediments. The modern hydrodynamic and sedimentation regimes at Paluma Shoals, a shore-attached ‘turbid-zone’ coral reef, and at Phillips Reef, a fringing reef located 20 km offshore, have been studied to document the mechanisms controlling turbidity. At each reef, waves, currents and near-bed turbidity were measured for a period of ≈1 month. Bed sediments were sampled at 135 sites. On the inner shelf, muddy sands are widespread, with admixed terrigenous and carbonate gravel components close to the reefs and islands, except on their relatively sheltered SW side, where sandy silty clays occur. At Paluma Shoals, the coral assemblage is characteristic of inner-shelf or sheltered habitats on the GBR shelf (dominated by Galaxea fascicularis, up to >50% coral cover) and is broadly similar to that at Phillips Reef, further offshore and in deeper water. The sediments of the Paluma Shoals reef flats consist of mixed terrigenous and calcareous gravels and sands, with intermixed silts and clays, whereas the reef slope is dominated by gravelly quartz sands. The main turbidity-generating process is wave-driven resuspension, and turbidity ranges up to 175 nephelometric turbidity units (NTU). In contrast, at Phillips Reef, turbidity is <15 NTU and varies little. At Paluma Shoals, turbidity of >40 NTU probably occurs for a total of >40 days each year, and relatively little time is spent at intermediate turbidities (15–50 NTU). The extended time spent at either low or high turbidities is consistent with the biological response of some species of corals to adopt two alternative mechanisms of functioning (autotrophy and heterotrophy) in response to different levels of turbidity. Sedimentation rates over periods of hours may reach the equivalent of 10 000 times the mean global background terrigenous flux... [ABSTRACT FROM AUTHOR]

On the Great Barrier Reef shelf, terrigenous sediments adjacent to the Herbert River delta are strongly partitioned within the coastal zone, in common with the regional presence of a terrigenous inner-shelf sediment wedge. Partitioning is primarily controlled by wind-driven currents and waves associated with persistent southeast trade winds. Bottom-return currents provide the likely mechanism for episodic transport of fine-grained sediment in an offshore direction, although modelled bottom-return currents appear incapable of transporting much sediment seawards beyond the 20 m isobath. This depth corresponds to the observed outer limit of the nearshore sediment wedge. [ABSTRACT FROM AUTHOR]

Previous workers have proposed that northward-directed bedload transport dominates the inner shelf of the Great Barrier Reef lagoon. Results from a sediment sampling survey along the 10 m isobath between Bowen and Cape York reveal a series of northward trends of increasing sediment maturity and demonstrate pervasive north-directed sediment transport interacting with a succession of sediment (fluvial) sources. South of the Tully River, the occurrence of limited compositional variability indicates significant mixing on the inner shelf. However, further north the data are highly variable, suggesting that sediment inputs from individual rivers may be retained relatively close to source. This may be related to a greater sediment trapping efficiency within northern embayments and/or by lower net rates of along-shelf transport. [ABSTRACT FROM AUTHOR]

Wetlands are one of the most biologically productive ecosystems. Wetland ecosystem services, ranging from provision of food security to climate change mitigation, are enormous, far outweighing those of dryland ecosystems per hectare. However, land use change and water regulation infrastructure have reduced connectivity in many river systems and with floodplain and estuarine wetlands. Mangrove forests are critical communities for carbon uptake and storage, pollution control and detoxification, and regulation of natural hazards. Although the clearing of mangroves in Australia is strictly regulated, Great Barrier Reef catchments have suffered landscape modifications and hydrological alterations that can kill mangroves. We used remote sensing datasets to investigate land cover change and both intra- and inter-annual seasonality in mangrove forests in a large estuarine region of Central Queensland, Australia, which encompasses a national park and Ramsar Wetland, and is adjacent to the Great Barrier Reef World Heritage site. We built a time series using spectral, auxiliary, and phenology variables with Landsat surface reflectance products, accessed in Google Earth Engine. Two land cover classes were generated (mangrove versus non-mangrove) in a Random Forest classification. Mangroves decreased by 1480 hectares (−2.31%) from 2009 to 2019. The overall classification accuracies and Kappa coefficient for 2008–2010 and 2018–2020 land cover maps were 95% and 95%, respectively. Using an NDVI-based time series we examined intra- and inter-annual seasonality with linear and harmonic regression models, and second with TIMESAT metrics of mangrove forests in three sections of our study region. Our findings suggest a relationship between mangrove growth phenology along with precipitation anomalies and severe tropical cyclone occurrence over the time series. The detection of responses to extreme events is important to improve understanding of the connections between climate, extreme weather events, and biodiversity in estuarine and mangrove ecosystems. [ABSTRACT FROM AUTHOR]

The delivery, flux and fate of terrigenous sediment entering the Great Barrier Reef lagoon has been a focus of recent studies and represents an ongoing environmental concern. Wave-induced bed stress is the most significant mechanism of sediment resuspension in the Great Barrier Reef, and field data and mathematical modelling indicates that the combined effects of short-period wind waves, longer period swell waves, and tidal and wind-driven currents can often exceed the critical bed stress for resuspension. Suspended-sediment concentrations at 20 m water depth indicate resuspension seldom occurs on the middle shelf under normal wave conditions. Non-cyclonic turbidity events are generally confined to the inner shelf. The wave climate in the southern sector of the central Great Barrier Reef lagoon is the most erosive, and resuspension of outer shelf sediments was hindcast for recorded cyclones. Wind-driven, longshore currents are fundamental to the northward movement of sediment, and the annual northward mass flux from embayments undergoing resuspension in the Burdekin region is estimated to be one order of magnitude larger than the mass of sediment introduced by a moderate flood plume. Strong onshore winds are estimated to generate significant three-dimensional bottom return currents on approximately 30–70 days per year, forming a potentially significant offshore-directed sediment flux during high suspended-sediment concentration events on the inner shelf. [ABSTRACT FROM AUTHOR]

The marine sediments of Australia’s continental shelves have been sparsely sampled by geological expeditions. However, there exist many qualitative descriptions of the seabed, made from visual and tactile examination of wet surficial samples, on Royal Australian Navy Hydrographic Office bathymetry charts. The reliability and geological meaning of the visual descriptions do not seem to have been investigated, making their suitability as bottom classifiers unknown. Classification schemes were devised for the descriptions, which are in a symbol form suitable for computer manipulations. The schemes were applied to nearly 5000 descriptions for the Great Barrier Reef lagoon area from Cape Flattery to Whitsunday Islands, where several sediment types are interleaved. The visual descriptions formed a consistent and reliable dataset at regional and smaller scales. Coherent surficial sediment distribution patterns were derived that closely match trends of grainsize distributions in some test areas, but which indicate that the present broadly known patterns for the Great Barrier Reef are in need of revision, particularly in coastal areas and embayments. Broad quantitative correlations were established against grainsize for several key visual descriptions, greatly enhancing their usefulness. The visual descriptions form a database of unique character, more useful than simple grainsize descriptions for many purposes. Sediment charts derived from them match everyday expectations of the in situ appearance and texture of sediments described as mud and sand in the marine environment, whereas various geological grainsize nomenclatures do not. A grainsize triangle is constructed relating the visual descriptions of wet marine surficial sediments to mud, sand and gravel size percentage weights. [ABSTRACT FROM AUTHOR]

Massive, long-lived corals in inshore waters of the Great Barrier Reef contain yellow-green fluorescent bands. These bands are due to terrestrial humic and fulvic compounds incorporated into the coral skeleton during high river flow events. Fluorescence measurements are presented for two colonies of Porites spp. from locations in the path of the Burdekin River floodwaters - the major river in north Queensland draining into the Coral Sea. The records extend from AD 1737 to 1980 and 1644 to 1986, respectively. The two independent coral records show a high degree of similarity. The two series are combined and used to reconstruct Burdekin River runoff for the period AD 1655 to 1980. The regression model accounts for 83% of the annual (water year) variability of Burdekin River flow and is verified over independent data. The 337-year reconstruction thus increases by threefold the length of record for considering interannual to decadal climate variations in northeast Australia. Instrumental and reconstructed Burdekin River runoff are closely related to an index of summer monsoon rainfall in Queensland. Thus, the reconstruction provides insights into the behaviour over the past three centuries of both a major tropical river system and the highly variable summer monsoon rainfall in northeast Australia. The reconstructed series shows wetter conditions (higher runoff) in the lae-seventeenth to mid-eighteenth centuries and in the late-nineteenth century. Drier conditions (lower runoff) are reconstructed in the late-eighteenth to mid-nineteenth centuries and in the mid-twentieth century. [ABSTRACT FROM AUTHOR]

Great Barrier Reef catchments are under pressure from the effects of climate change, landscape modifications, and hydrology alterations. With the use of remote sensing datasets covering large areas, conventional methods of change detection can expose broad transitions, whereas workflows that excerpt data for time-series trends divulge more subtle transformations of land cover modification. Here, we combine both these approaches to investigate change and trends in a large estuarine region of Central Queensland, Australia, that encompasses a national park and is adjacent to the Great Barrier Reef World Heritage site. Nine information classes were compiled in a maximum likelihood post classification change analysis in 2004–2017. Mangroves decreased (1146 hectares), as was the case with estuarine wetland (1495 hectares), and saltmarsh grass (1546 hectares). The overall classification accuracies and Kappa coefficient for 2004, 2006, 2009, 2013, 2015, and 2017 land cover maps were 85%, 88%, 88%, 89%, 81%, and 92%, respectively. The cumulative area of open forest, estuarine wetland, and saltmarsh grass (1628 hectares) was converted to pasture in a thematic change analysis showing the "from–to" change. We generated linear regression relationships to examine trends in pixel values across the time series. Our findings from a trend analysis showed a decreasing trend (p value range = 0.001–0.099) in the vegetation extent of open forest, fringing mangroves, estuarine wetlands, saltmarsh grass, and grazing areas, but this was inconsistent across the study site. Similar to reports from tropical regions elsewhere, saltmarsh grass is poorly represented in the national park. A severe tropical cyclone preceding the capture of the 2017 Landsat 8 Operational Land Imager (OLI) image was likely the main driver for reduced areas of shoreline and stream vegetation. Our research contributes to the body of knowledge on coastal ecosystem dynamics to enable planning to achieve more effective conservation outcomes. [ABSTRACT FROM AUTHOR]

Solutions to environmentally damaging human practices require cooperation between many different communities. This article explores sustainability-focused education through the lens of a current work-in-progress, Sugar vs the Reef?, which involves collaboration between sugarcane farmers and artists in the arable catchment of the Great Barrier Reef in North Queensland. This is a socially engaged art project that is addressing the fraught relationship between the region's agriculture and the fragile ecology of the Reef. We introduce some of the specific aspects of socially engaged art (SEA) which commend it as a cross-disciplinary method for bridging diverse individuals and organisations -- in particular, the notion of a "holding environment" for complex socio-ecological situations. We consider how this approach might broaden the agricultural practice of "extension" which aims to transform farming through educational outreach. Ideas emerging from contemporary socially engaged art practice may contribute to a toolkit for researchers and practitioners within and beyond the academy who are searching for ways to overcome the limitations of current methodologies and movements for social change. [ABSTRACT FROM AUTHOR]