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In this paper, we adopt a multistakeholder governance perspective to study how people collectively respond to a grand challenge. Specifically, we show how working through governance obstacles—that is, coordinating and collaborating challenges arising from a multistakeholder governance approach to responding to grand challenges—can erode actors' ability to mitigate these wicked problems. We illustrate this process through an in-depth case study of WaterHealthOrg, a multistakeholder initiative established to address degrading water health in Australia's critical Great Barrier Reef region. Our findings reveal how, in an effort to avoid group paralysis or dissolution, actors employ specific practices to address governance obstacles. By doing so, actors set off a cumulative self-reinforcing process, driving them to consolidate rather than critically reflect on and adapt their collective response. Drawing on these insights, we develop a conceptual process model of how efforts to manage multistakeholder governance obstacles can generate governance traps that shape participants' ability to collectively respond and, ultimately, mitigate grand challenges. [ABSTRACT FROM AUTHOR]

Understanding and preserving the deep sea ecosystems is paramount for marine conservation efforts. Automated object (deep-sea biota) classification can enable the creation of detailed habitat maps that not only aid in biodiversity assessments but also provide essential data to evaluate ecosystem health and resilience. Having a significant source of labelled data helps prevent overfitting and enables training deep learning models with numerous parameters. In this paper, we contribute to the establishment of a significant deep-sea remotely operated vehicle (ROV) image classification dataset with 3994 images featuring deep-sea biota belonging to 33 classes. We manually label the images through rigorous quality control with human-in-the-loop image labelling. Leveraging data from ROV equipped with advanced imaging systems, our study provides results using novel deep-learning models for image classification. We use deep learning models including ResNet, DenseNet, Inception, and Inception-ResNet to benchmark the dataset that features class imbalance with many classes. Our results show that the Inception-ResNet model provides a mean classification accuracy of 65%, with AUC scores exceeding 0.8 for each class. [ABSTRACT FROM AUTHOR]

Summary: Crowdsourcing methods facilitate the production of scientific information by non‐experts. This form of citizen science (CS) is becoming a key source of complementary data in many fields to inform data‐driven decisions and study challenging problems. However, concerns about the validity of these data often constrain their utility. In this paper, we focus on the use of citizen science data in addressing complex challenges in environmental conservation. We consider this issue from three perspectives. First, we present a literature scan of papers that have employed Bayesian models with citizen science in ecology. Second, we compare several popular majority vote algorithms and introduce a Bayesian item response model that estimates and accounts for participants' abilities after adjusting for the difficulty of the images they have classified. The model also enables participants to be clustered into groups based on ability. Third, we apply the model in a case study involving the classification of corals from underwater images from the Great Barrier Reef, Australia. We show that the model achieved superior results in general and, for difficult tasks, a weighted consensus method that uses only groups of experts and experienced participants produced better performance measures. Moreover, we found that participants learn as they have more classification opportunities, which substantially increases their abilities over time. Overall, the paper demonstrates the feasibility of CS for answering complex and challenging ecological questions when these data are appropriately analysed. This serves as motivation for future work to increase the efficacy and trustworthiness of this emerging source of data. [ABSTRACT FROM AUTHOR]

The paper 'Biodiversity values of remnant freshwater floodplain lagoons in agricultural catchments: evidence for fish of the Wet Tropics bioregion, northern Australia', published in Aquatic Conservation: Marine and Freshwater Ecosystems in 2015, has contributed in several ways to the integration of freshwater wetland science within new catchment management policies and practices for Great Barrier Reef (GBR) sustainability.The Tully–Murray biodiversity study developed novel protocols to sample larval, juvenile, and adult fish life‐history stages in floodplain lagoons using a combination of boat‐based backpack electrofishing and fyke netting. In addition, hydrological and hydrodynamic models were applied in a completely new way to quantify the timing, extent, and duration of water connectivity across floodplain streams, cane drains, and wetlands. Combining the two novel approaches enabled an analysis of lagoon fish assemblage patterns in relation to environmental gradients, especially floodplain hydrology, connectivity patterns, and measures related to agricultural land use.In demonstrating the importance of different levels of connectivity for different biodiversity outcomes in freshwater floodplain lagoons of the Tully–Murray catchment, the subject paper established that floodplain connectivity needs to be taken into consideration in wetland management practices.The timing of the subject publication was fortuitous. It coincided with the preparation of the evidence‐based 2017 Scientific Consensus Statement on land‐based water quality impacts on the GBR. As one of the few freshwater wetland ecology publications for the catchments of the GBR at that time, this paper played an important role in demonstrating freshwater wetland values, fish conservation options, and management imperatives to sustain wetland ecological health and services in GBR catchments.By advancing the understanding of factors driving biodiversity patterns, and the importance of connectivity and ecohydrological processes in freshwater floodplain wetlands of the GBR catchment, the Tully–Murray study helped to drive new policy directives for the protection and restoration of catchment, floodplain, and estuary functions, and connectivity, now embedded in the Reef 2050 Long‐Term Sustainability Plan 2018, an overarching strategy for managing the GBR over the next 35 years, and complementary Queensland environmental legislation. [ABSTRACT FROM AUTHOR]

Corals are sessile invertebrates living underwater in colorful structures known as reefs. Unfortunately, coral's temperature sensitivity is causing color bleaching, which hosts organisms that are crucial and consequently affect marine pharmacognosy. To address this problem, many researchers are developing cures and treatment procedures to restore bleached corals. However, before the cure, the researchers need to precisely localize the bleached corals in the Great Barrier Reef. The researchers have developed various visual classification frameworks to localize bleached corals. However, the performance of those techniques degrades with variations in illumination, orientation, scale, and view angle. In this paper, we develop highly noise-robust and invariant robust localization using bag-of-hybrid visual features (RL-BoHVF) for bleached corals by employing the AlexNet DNN and ColorTexture handcrafted by raw features. It is observed that the overall dimension is reduced by using the bag-of-feature method while achieving a classification accuracy of 96.20% on the balanced dataset collected from the Great Barrier Reef of Australia. Furthermore, the localization performance of the proposed model was evaluated on 342 images, which include both train and test segments. The model achieved superior performance compared to other standalone and hybrid DNN and handcrafted models reported in the literature. [ABSTRACT FROM AUTHOR]

The use of ocean colour classification algorithms, linked to water quality gradients, can be a useful tool for mapping river plumes in both tropical and temperate systems. This approach has been applied in operational water quality programs in the Great Barrier Reef to map river plumes and assess trends in marine water composition and ecosystem health during flood periods. In this study, we used the Forel–Ule colour classification algorithm for Sentinel-3 OLCI imagery in an automated process to map monthly, annual and long-term plume movement in the temperate coastal system of Liverpool Bay (UK). We compared monthly river plume extent to the river flow and in situ water quality data between 2017–2020. The results showed a strong positive correlation (Spearman's rho = 0.68) between the river plume extent and the river flow and a strong link between the FUI defined waterbodies and nutrients, SPM, turbidity and salinity, hence the potential of the Forel–Ule index to act as a proxy for water quality in the temperate Liverpool Bay water. The paper discusses how the Forel–Ule index could be used in operational water quality programs to better understand river plumes and the land-based inputs to the coastal zones in UK waters, drawing parallels with methods that have been developed in the GBR and Citclops project. Overall, this paper provides the first insight into the systematic long-term river plume mapping in UK coastal waters using a fast, cost-effective, and reproducible workflow. The study created a novel water assessment typology based on the common physical, chemical and biological ocean colour properties captured in the Forel–Ule index, which could replace the more traditional eutrophication assessment regions centred around strict geographic and political boundaries. Additionally, the Forel–Ule assessment typology is particularly important since it identifies areas of the greatest impact from the land-based loads into the marine environment, and thus potential risks to vulnerable ecosystems. [ABSTRACT FROM AUTHOR]

Coral bleaching driven by ocean warming is one of the most visible ecological impacts of climate change and perhaps the greatest threat to the persistence of reefs in the coming decades. In the absence of returning atmospheric greenhouse gas concentrations to those compatible with ocean temperatures below the mass coral bleaching temperature thresholds, the most straightforward means to reduce thermal-stress induced bleaching is to cool water at the seabed. The feasibility of reducing the seabed temperature through cool-water injections is considered first by analysing the feasibility of doing so on 19 reefs with differing physical environments using a simple residence time metric in 200 m resolution hydrodynamic model configurations. We then concentrate on the reefs around Lizard Island, the most promising candidate of the 19 locations, and develop a 40 m hydrodynamic model to investigate the effect of the injection of cool water at differing volumetric rates. Injecting 27°C seawater at a rate of 5 m³ s-1 at 4 sites in early 2017 cooled 97 ha of the reef by 0.15°C or more. The power required to pump 5 m³ s-1 through a set of pipes over a distance of 3 km from a nearby channel is*466 kW. This power applied at 4 sites for 3 months achieves a 2 Degree Heating Weeks (DHWs) reduction on 97 ha of reef. A more precise energy costing will require further expert engineering design of the pumping equipment and energy sources. Even for the most physically favourable reefs, cool-water transported through pipes and injected at a reef site is energy expensive and cannot be scaled up to any meaningful fraction of the 3,100 reefs of the GBR. Should priority be given to reducing thermal stress on one or a few high value reefs, this paper provides a framework to identify the most promising sites. [ABSTRACT FROM AUTHOR]

In this paper we examine and critique adaptive management (AM) practices for protected areas (PAs), in pursuit of practices that can account for more-than-human relations. Engaging with empirical research from Australian PAs, we reflect on the formation of PAs as "exceptional places" where Nature is implicitly/explicitly to be controlled. We find that AM practices harness the spatial and temporal characteristics of the PAs to deliberatively construct a static and timeless scene, creating a particular vision of Nature. This metaphoric vision is captured "like a postcard." It reinforces and justifies static protectionism as Nature conservation, arraigning a series of material objects that are meant to assist with maintaining that image: that "reality." Using sentipensar as an exemplar, we explore and highlight relational and everchanging human-nonhuman engagements to contest the ontological dimensions of a static Nature and ideas of control and power associated with the binaries of Nature and culture. [ABSTRACT FROM AUTHOR]

Environmental damage has been of much concern, particularly in coastal areas and the oceans, given climate change and the drastic effects of pollution and extreme climate events. Our present-day analytical capabilities, along with advancements in information acquisition techniques such as remote sensing, can be utilised for the management and study of coral reef ecosystems. In this paper, we present Reef-Insight, an unsupervised machine learning framework that features advanced clustering methods and remote sensing for reef habitat mapping. Our framework compares different clustering methods for reef habitat mapping using remote sensing data. We evaluate four major clustering approaches based on qualitative and visual assessments which include k-means, hierarchical clustering, Gaussian mixture model, and density-based clustering. We utilise remote sensing data featuring the One Tree Island reef in Australia's Southern Great Barrier Reef. Our results indicate that clustering methods using remote sensing data can well identify benthic and geomorphic clusters in reefs when compared with other studies. Our results indicate that Reef-Insight can generate detailed reef habitat maps outlining distinct reef habitats and has the potential to enable further insights for reef restoration projects. [ABSTRACT FROM AUTHOR]

The recent widespread and recurrent coral bleaching events over the Great Barrier Reef, the largest coral reef system on Earth and a hotspot of marine biodiversity, are a reminder of the vulnerability of reef ecosystems to human activities and a warming world. Protection of the Great Barrier Reef and similar reef ecosystems across Oceania requires a better understanding of environmental and socio-economic pressures, as well as the development of integrated management strategies. The rapid expansion of Earth Observation technologies and data has greatly advanced our capability to map and monitor reef habitats, ecological processing and exposure risk, providing spatially rich data essential to support and evaluate management and conservation strategies. However, these technologies are proportionally still under-utilized, and it is important to synthesise remote-sensing-derived tools and methods currently available for mapping reef ecosystems in Oceania to facilitate their intake in coral reefs studies. Publications in this Special Issue contribute toward filling this gap and explore recent advances in remote sensing of the Great Barrier Reef and other reef ecosystems in Oceania, from novel methodological approaches (sensors, algorithm development and improved thematic classification) to applications for environmental monitoring and management. [ABSTRACT FROM AUTHOR]

Achieving coastal and shallow-water bathymetry is essential for understanding the marine environment and for coastal management. Bathymetric data in shallow sea areas can currently be obtained using SDB (satellite-derived bathymetry) with multispectral satellites based on depth inversion models. In situ bathymetric data are crucial for validating empirical models but are currently limited in remote and unapproachable areas. In this paper, instead of using the measured water depth data, ICESat-2 (Ice, Cloud, and Land Elevation Satellite-2) ATL03 bathymetric points at different acquisition dates and multispectral imagery from Sentinel-2/GeoEye-1 were used to train and evaluate water depth inversion empirical models in two study regions: Shanhu Island in the South China Sea, and Heron Island in the Great Barrier Reef (GBR) in Australia. However, different sediment types also influenced the SDB results. Therefore, three types of sediments (sand, reef, and coral/algae) were analyzed for Heron Island, and four types of sediments (sand, reef, rubble and coral/algae) were analyzed for Shanhu Island. The results show that accuracy generally improved when sediment classification information was considered in both study areas. For Heron Island, the sand sediments showed the best performance in both models compared to the other sediments, with mean R2 and RMSE values of 0.90 and 1.52 m, respectively, representing a 5.6% improvement of the latter metric. For Shanhu Island, the rubble sediments showed the best accuracy in both models, and the average R2 and RMSE values were 0.97 and 0.65 m, respectively, indicating an RMSE improvement of 15.5%. Finally, bathymetric maps were generated in two regions based on the sediment classification results. [ABSTRACT FROM AUTHOR]

Herbicides used for weed management on agricultural land in Australia's Great Barrier Reef catchments are a key concern for its ecosystem, including the lagoon's marine plants and corals, whose productivity has been found to decline. The most reliable way to assess herbicide risk is by monitoring a site regularly, but this is costly and time-consuming, so numerical simulations and computer models are an alternative method. Despite the availability of low-cost and less labor-intensive modelling methods, they have been limited in their effectiveness due to a lack of specific herbicide usage data and an inadequate understanding of the breakdown and transport processes of herbicides after application. This paper reviews current findings regarding herbicide risk in all Great Barrier Reef catchments according to their agricultural land use, and the most recent Reef Water Quality Protection Plan recommendations. The various pathways for fate and transport of the herbicides were also examined, and a list of critical parameters was developed to help with computer simulations. The accuracy and reliability of modelling can be improved by including aerial drifts, interceptions by crop residues, mechanisms within the root zone, and subsurface and groundwater contributions to the herbicide load in the GBR lagoon. Moreover, the findings will provide new directions for management practices adoption data with the fate and transport model from paddock to reef and improve the reliability of model results. [ABSTRACT FROM AUTHOR]

The Great Barrier Reef Expedition (1928–1929) observed two of the earliest known examples of coral bleaching during a 13-month stay on Low Isles, northern Great Barrier Reef, Australia. The first was during austral summer in February 1929 in a shallow moat and the second during austral winter in June 1929 on a deeper seaward slope. Using Expedition records and modern analytical techniques, we geolocated previously undocumented photographs of bleaching and built a detailed picture of environmental conditions which show that the two episodes were driven by different proximate causes. The February bleaching coincided with highest annual seawater temperatures and Degree Heating Weeks, coupled with early afternoon aerial exposure leading to intense heating in tide pools and corals subjected to high solar insolation. Zooxanthellae densities would also have been at a seasonal low and the corals particularly susceptible to bleaching stress. In contrast in June, the seaward slope, normally submerged during the daytime, was aerially exposed to the afternoon sun and although seawater temperatures were 5 °C cooler than in the summer and despite relatively low sun altitudes and insolation in the winter, bleaching and mortality due to solar radiation was clearly visible on faces of exposed corals oriented towards the sun. Whilst reports of widespread temperature driven coral bleaching are commonplace today in an era of global warming, this paper demonstrates how similar environmental cues were involved a century ago and highlights the additional complexity of coral survival in the intertidal zone. [ABSTRACT FROM AUTHOR]

This paper explores how the imagined landscapes that act as a catalyst for World Heritage listing, are unable to be reconciled with formal heritage assessments. We explore this tension through two Australian World Heritage landscapes: the Great Barrier Reef and the Tasmanian Wilderness. The history of these listings suggests a teleological process driven by a desire to create authentic utopias. While utopias are imagined spaces, Paradise at the Reef and the Tasmanian Wilderness are realised through hyperreal landscapes (fakes). However, these wholistic landscapes dissolve into a series of inventories of species and numbers in official listing. We suggest the failure to recognise the hyperreal is a form of false consciousness that creates a tension between managing for formally recognised values and managing the unmanageable utopia, and that a broader use of cultural landscapes might be useful in addressing this divide. [ABSTRACT FROM AUTHOR]

This paper examines the campaign for legal personhood for the Great Barrier Reef launched by the Environmental Defenders Office of North Queensland in 2014. Although this campaign has been unofficially shelved, the paper argues that it still provides a useful chance to think through the practicality and politics of some of the current experiments in environmental law, especially contemporary attempts to expand legal definitions of personhood. The EDO campaign is held up to critical scrutiny by considering its practical efficacy, environmental merits, conceptual foundations and ethico-political import, especially in relation to Indigenous justice. It argues that such experiments are to be welcomed, whether as immediate opportunities, thought experiments or pressure points, and that public and scholarly discussion of the legal personhood mechanism needs to be alert to the dangers of unknowingly and ironically replicating dominant power relations while seeking to overthrow them, but also of shutting down alternatives at precisely the moment we need them most. [ABSTRACT FROM AUTHOR]

Coral reefs provide important ecosystem services as well as economic and cultural benefits to society. Yet they are under significant threat from anthropogenic and natural threats, including climate change. Australia's Great Barrier Reef (GBR) is one such reef undergoing significant change. More radical interventions that go beyond traditional forms of management are being considered to help repair and restore the GBR. These are based on science and technologies that have yet to be widely tested. This paper reports on a study that seeks to identify and understand support for such interventions, and to understand the antecedents that explain support. The Norm Activation Model (NAM) was extended with a sample of 468 domestic and international tourists to Cairns, Australia. Personal norms had the largest direct influence on support for interventions, followed by attitudes. Awareness of consequences had a large positive impact on personal norms and a smaller positive impact on attitudes. A negative relationship was found between information and attitudes. Personal norms and attitudes also acted as mediators between awareness of consequences, information and support. No differences were found between domestic and international tourists. The results are discussed and theoretical and practical implications outlined. [ABSTRACT FROM AUTHOR]

For more than 40 years, marine zoning has played a key role while evolving as part of the adaptive management of the Great Barrier Reef (GBR) Marine Park. The statutory zoning plan provides the primary integrating component that prohibits many threatening activities and manages the impacts of allowed human activities and competing uses by means of various zones, special management areas and other spatial management tools.How zoning is applied, however, has changed considerably since the first zoning plan was finalized in 1981. Today, zoning is applied in combination with other layers of marine spatial planning; the effective combination of these management tools provides the integrated approach, considered one of the best for managing a large marine protected area.The zoning plan provides the foundation for management of the GBR and is the fundamental component of the integrated marine spatial planning approach ensuring high levels of protection for significant areas of the GBR, while also allowing ecologically sustainable use.The paper outlines the legal and managerial contexts of zoning, providing 38 lessons that may be useful for marine zoning and ecosystem‐based management elsewhere. It outlines aspects of zoning that have worked well in the GBR Marine Park and what has changed in the light of experience and changing contexts, and seeks to clarify various misconceptions about zoning and marine spatial planning.The integrated management approach in the GBR utilizes a variety of spatial planning tools, which complement the underlying zoning; some of these comprise statutory management layers (e.g. designated shipping areas, special management areas, plans of management, fishery management arrangements, Traditional Owner agreements, defence training areas); other layers are non‐statutory (e.g. site plans).This paper is written for planners, managers and decision‐makers considering the use of zoning to achieve effective marine conservation, protection and ecologically sustainable use. [ABSTRACT FROM AUTHOR]

In this paper, we propose a novel approach for 3-D rain field reconstruction using satellite signals. It uses the estimated signal-to-noise ratio (SNR) at the ground receivers for low-earth orbit (LEO) satellites and, thus, indirectly estimates the path-integrated rain attenuation of the microwave communication links. A least-squares algorithm is employed to perform the 3-D tomographic reconstruction of the rain field. The proposed system model consists of an LEO satellite with a realistic overpass trajectory and multiple ground receivers with SNR estimators. Two synthetic rain events near the Great Barrier Reef in Australia are used to test the reconstruction outcome. Simulation results suggest that the reconstructed rain field has close agreement with the synthetic rain field. [ABSTRACT FROM AUTHOR]

Marine biodiversity and derived ecosystem services are critical to the healthy functioning of marine ecosystems, and to human economic and societal well-being. Thus, an understanding of marine biodiversity in different ecosystems is necessary for their conservation and management. Coral reefs in particular are noted for their high levels of biodiversity, and among the world's coral reefs, the subtropical Ryukyu Islands (RYS; also known as the Nansei Islands) in Japan have been shown to harbor very high levels of marine biodiversity. This study provides an overview of the state of marine biodiversity research in the RYS. First, we examined the amount of English language scientific literature in the Web of Science (WoS; 1995-2017) on six selected representative taxa spanning protists to vertebrates across six geographic sub-regions in the RYS. Our results show clear taxonomic and sub-region bias, with research on Pisces, Cnidaria, and Crustacea to be much more common than on Dinoflagellata, Echinodermata, and Mollusca. Such research was more commonly conducted in subregions with larger human populations (Okinawa, Yaeyama). Additional analyses with the Ocean Biogeographic Information System (OBIS) records show that within subregions, records are concentrated in areas directly around marine research stations and institutes (if present), further showing geographical bias within sub-regions. While not surprising, the results indicate a need to address 'understudied' taxa in 'understudied sub-regions' (Tokara, Miyako, Yakutane, Amami Oshima), particularly sub-regions away from marine research stations. Second, we compared the numbers of English language scientific papers on eight ecological topics for the RYS with numbers from selected major coral reef regions of the world; the Caribbean (CAR), Great Barrier Reef (GBR), and the Red Sea (RES). As expected, the numbers for all topics in the RYS were well below numbers from all other regions, yet within this disparity, research in the RYS on 'marine protected areas' and 'herbivory' was an order of magnitude lower than numbers in other regions. Additionally, while manuscript numbers on the RYS have increased from 1995 to 2016, the rate of increase (4.0 times) was seen to be lower than those in the CAR, RES, and GBR (4.6-8.4 times). Coral reefs in the RYS feature high levels of both endemism and anthropogenic threats, and subsequently they contain a concentration of some of the world's most critically endangered marine species. To protect these threatened species and coral reef ecosystems, more data are needed to fill the research gaps identified in this study. [ABSTRACT FROM AUTHOR]

In 2011, five German beech forest areas were declared to be part of the World Heritage property “Primeval Beech Forests of the Carpathians and the Ancient Beech Forests of Germany.” Thus, they now share the same status as Australia’s Great Barrier Reef and East Africa’s Serengeti. This paper analyzes the science-policy interface behind the nomination and inscription process in the multi-level governance setting of the World Heritage Convention. Using the Research-Integration-Utilization (RIU) model of scientific knowledge transfer, we identify and analyze different actors’ roles in the spheres of Research, Integration and Utilization across different governance levels, from the German federal states to the World Heritage Committee. In addition, the RIU model serves to normatively examine the process and determine quality criteria that were useful for a successful inscription as World Heritage. The paper highlights the opportunities of using scientific knowledge in the multi-level governance of international conventions. [ABSTRACT FROM AUTHOR]

Nutrient runoff from catchments that drain into the Great Barrier Reef (GBR) is a significant source of stress for this World Heritage Area. An alliance of collaborative on-ground water quality monitoring (Project 25) and technologically driven digital application development (Digiscape GBR) projects were formulated to provide data that highlighted the contribution of a network of Australian sugar cane farmers, amongst other sources, to nutrient runoff. This environmental data and subsequent information were extended to the farming community through scientist-led feedback sessions and the development of specialised digital technology (1622™WQ) that help build an understanding of the nutrient movements, in this case nitrogen, such that farmers might think about and eventually act to alter their fertilizer application practices. This paper reflects on a socio-environmental sustainability challenge that emerged during this case study, by utilising the nascent concept of digi-grasping. We highlight the importance of the entire agricultural knowledge and advice network being part of an innovation journey to increase the utility of digital agricultural technologies developed to increase overall sustainability. We develop the digi-MAST analytical framework, which explores modes of being and doing in the digital world, ranging from 'the everyday mystery of the digital world (M)', through digital 'awareness (A)', digitally 'sparked' being/s (S), and finally the ability of individuals and/or groups to 'transform (T)' utilising digital technologies and human imaginations. Our digi-MAST framework allows us to compare agricultural actors, in this case, to understand present modes of digi-grasping to help determine the resources and actions likely to be required to achieve impact from the development of various forms of digital technological research outputs. [ABSTRACT FROM AUTHOR]

Since the mid-1990s, Australia's Commonwealth Science Industry and Research Organisation (CSIRO) has been developing a biogeochemical (BGC) model for coupling with a hydrodynamic and sediment model for application in estuaries, coastal waters and shelf seas. The suite of coupled models is referred to as the CSIRO Environmental Modelling Suite (EMS) and has been applied at tens of locations around the Australian continent. At a mature point in the BGC model's development, this paper presents a full mathematical description, as well as links to the freely available code and user guide. The mathematical description is structured into processes so that the details of new parameterisations can be easily identified, along with their derivation. In EMS, the underwater light field is simulated by a spectrally resolved optical model that calculates vertical light attenuation from the scattering and absorption of 20+ optically active constituents. The BGC model itself cycles carbon, nitrogen, phosphorous and oxygen through multiple phytoplankton, zooplankton, detritus and dissolved organic and inorganic forms in multiple water column and sediment layers. The water column is dynamically coupled to the sediment to resolve deposition, resuspension and benthic–pelagic biogeochemical fluxes. With a focus on shallow waters, the model also includes detailed representations of benthic plants such as seagrass, macroalgae and coral polyps. A second focus has been on, where possible, the use of geometric derivations of physical limits to constrain ecological rates. This geometric approach generally requires population-based rates to be derived from initially considering the size and shape of individuals. For example, zooplankton grazing considers encounter rates of one predator on a prey field based on summing relative motion of the predator with the prey individuals and the search area; chlorophyll synthesis includes a geometrically derived self-shading term; and the bottom coverage of benthic plants is calculated from their biomass using an exponential form derived from geometric arguments. This geometric approach has led to a more algebraically complicated set of equations when compared to empirical biogeochemical model formulations based on populations. But while being algebraically complicated, the model has fewer unconstrained parameters and is therefore simpler to move between applications than it would otherwise be. The version of EMS described here is implemented in the eReefs project that delivers a near-real-time coupled hydrodynamic, sediment and biogeochemical simulation of the Great Barrier Reef, northeast Australia, and its formulation provides an example of the application of geometric reasoning in the formulation of aquatic ecological processes. [ABSTRACT FROM AUTHOR]

Identifying mechanisms that drive population divergence under varying geographic and ecological scenarios can inform our understanding of evolution and speciation. In particular, analysis of genetic data from island populations with known colonisation timelines allows us to identify potential source populations of diverging island subspecies and current relationships among populations. Silvereyes (Zosterops lateralis) are a small passerine that have served as a valuable study system to investigate evolutionary patterns on both large and small geographic scales. We examined genetic relatedness and diversity of two silvereye subspecies, the mainland Z. l. cornwalli and island Z. l. chlorocephalus, and used 18 077 single nucleotide polymorphisms (SNPs), to compare locations across southeast Queensland, Australia. Although silvereyes are prolific island colonisers our findings revealed population divergence over relatively small spatial scales was strongly influenced by geographic isolation mediated by water barriers. Strong genetic connectivity was displayed between mainland sites, but minimal inter-island connectivity was shown despite comparable sampling distances. Genetic diversity analysis showed little difference in heterozygosity between island and mainland populations, but lower inbreeding scores among the island populations. Our study confirmed the range of the Z. l. chlorocephalus subspecies throughout the southern Great Barrier Reef. Our results show that water barriers and not geographic distance per se are important in driving incipient divergence in island populations. This helps to explain the relatively high number of phenotypically differentiated, but often geographically proximate, island silvereye subspecies compared to a lower number of phenotypically less well-defined Australian continental subspecies. [ABSTRACT FROM AUTHOR]

This timely collation of case studies, written by and with Traditional Owners of diverse Australian offshore islands, offers direct insights into benefits arising from strategic and participatory action planning for biocultural island conservation and monitoring. We pay respect to the Old People and Elders whose dedicated care of their island homelands means we today can still experience their cultural and natural diversity. We extend greetings to our Pacifika neighbours, and to carers of islands around Earth. Our paper scopes socio-economic benefits arising from planning for islands, for Aboriginal peoples and Torres Strait Islanders, and more generally. Global, national, state and local co-investments support place-specific planning for some islands by Traditional Owners as a starting point toward shared governance and caring for Country. Case studies describe Country planning for Mayala Country in Australia's northwest, Woppaburra experiences within the Great Barrier Reef World Heritage Area and integrated biocultural health monitoring arising from remote island Indigenous Protected Area planning in Torres Strait. New institutional initiatives are also seeking to create solid foundations for more substantive island research collaborations. Across Australia, novel relationships grounded in culturally assured, holistically integrated approaches to island governance and caring for Country involving Traditional Owners and island resource users/managers are creating equity in livelihoods and stronger wellbeing. Australia's innovative Sea Country collaborations, with priorities initiated and led by island Traditional Owners, carry real value for sustained island conservation and provide positive inspirations for global humanity in the accelerating Anthropocene. Earth's islands face grave challenges. In Australia, innovation in island knowledge sharing between Traditional Owners and other island users and managers is moving beyond the participatory action planning space to generate equity in livelihoods and wellbeing on Sea Country. The tangible benefits arising are grounded in cultural governance and authority. [ABSTRACT FROM AUTHOR]

Suspended sediment is a significant threat to the Great Barrier Reef (GBR) ecosystem. This catchment pollutant stems primarily from terrestrial soil erosion. Bulk masses of sediments have potential to propagate from river plumes into the mid-shelf and outer-shelf regions. Existing sediment forecasting methods suffer from the problem of low-resolution predictions, making them unsuitable for wide area coverage. In this paper, a novel sediment distribution prediction model is proposed to augment existing water quality management programs for the GBR. This model is based on the state-of-the-art Transformer network in conjunction with the well-known finite element analysis. For model training, the emerging physics-informed neural network is employed to incorporate both simulated and measured sediment data. Our proposed Finite Element Transformer (FE-Transformer) model offers accurate predictions of sediment across the entire GBR. It provides unblurred outputs, which cannot be achieved with previous next-frame prediction models. This paves a way for accurate forecasting of sediment, which in turn may lead to improved water quality management for the GBR. • Vision Transformer is proposed for next-frame prediction. • Finite element analysis is integrated with the Vision Transformer. • Sediment distribution in the GBR is forecasted using the proposed FE-Transformer. • PINN is employed to merge sediment PDE solutions with in-situ measured data. • The proposed model produces highly accurate unblurred output frames. [ABSTRACT FROM AUTHOR]

An obituary for the Great Barrier Reef (the Reef) by travel and food writer Rowan Jacobsen (2016) commemorated its 'lifetime accomplishments' in Outside, the US outdoor recreational magazine. 'News' of the Reef's demise went viral and the economic and political furore that followed was immense. Tourism industries, especially reliant on international arrivals, were impacted as potential visitors accepted the Reef's passing as fact. Politicians scampered to reassure Australians and the globe that the Reef was indeed still alive and beautiful. In the Australian public sphere, climate science deniers, alongside those advocating for climate action, collided over the impacts of global warming to Reef health. Subsequent mass coral bleaching events in 2016, 2017 and 2020 sustained at the very least, the idea that the Reef was, or was soon to be, dead. Our paper follows the idea of a 'dead Reef' in the context of historical and recent debates about Reef protection. Using Google Trends, we identify Jacobsen's article as the source of increased Australian and global ideation of a 'dead Reef'. As a site of local and global environmental communication – where human relations to nature are expressed and understood - the Reef holds extraordinary story telling power. At the current junction then, the way we communicate the Reef is critical to public understanding and political action on climate change. We conclude Jacobsen's article is an example of the problems of satirical communication, serving to amplify existing conflicts and undermine efforts to foster to climate action. [ABSTRACT FROM AUTHOR]

Highlights • Ecosystem health report card for the largest port in the Great Barrier Reef. • Social, cultural, economic and environmental indicators of harbour health. • Innovative reporting infrastructure to ensure transparency and timely results. • Stakeholder-led vision underpinned by rigorous science and strong communication. Abstract Ecosystem health report cards are an increasingly popular means of summarizing the results of environmental monitoring programs for broad, non-scientific audiences. This paper describes a whole-of-system report card initiative developed to monitor the condition of a multi-use port in the Great Barrier Reef World Heritage Area, Queensland, Australia. Concerns over the impacts of major industrial expansion, fish health incidents, safety of recreational harbour users and habitat loss prompted stakeholders in the Gladstone region to unite and establish the Gladstone Healthy Harbour Partnership. The objective was to monitor and report on the health of the harbour via an annual report card (http://rc.ghhp.org.au/). We illustrate one approach to designing a report card against ten core considerations; 1) strong links to all stakeholders at all stages, 2) rigorous science, 3) effective communication, 4) setting clear goals and 5) realistic expectations, 6) flexibility in implementation, 7) transparency, open access and accountability, 8) results linked to actionable management recommendations, 9) regular evaluation, and 10) long term commitment. Innovative aspects of this report card include the combination of four components of harbour health: environmental, social, cultural and economic; underpinned by a sophisticated monitoring, modelling and reporting program. A review of the report card content and methodology, conducted in 2017, determined that the design meets the original vision and objectives set by Gladstone stakeholders. However, stakeholder perceptions of the effectiveness of the report card have not been comprehensively assessed to date. This paper provides a guide to others designing report card programs and environmental metrics, with advice on maximizing transparency and data sharing, coordinating otherwise disparate monitoring efforts, and linking with management through the provision of scenario analysis tools with which to interpret and respond to annual report card results. [ABSTRACT FROM AUTHOR]

Abstract The objective of the paper is to explore the existing conditions and possibilities for the improvement of co-operation between some Western Balkan states (Bosnia and Herzegovina, Montenegro and Republic of Serbia) which occupy the Drina River basin (DRB). The article analyses the existing international treaties with the purpose of giving an answer to the question whether they present a satisfactory legal framework. It points to the factors which determine co-operation, and explores the possibilities for the conclusion of a new international treaty on the co-operation between the three states. It explores the possibilities for the conclusion of a new international treaty on the establishment of co-operation between the three states, this implying consideration of the reasons for and against the adoption of a separate international agreement on co-operation between the states in the region. The paper considers the thesis on the need for the improvement of co-operation between the DRB states to be based on the concept of integrated water resources management. [ABSTRACT FROM AUTHOR]

Water quality outcomes affecting Australia’s Great Barrier Reef (GBR) are governed by multi-level and multi-party decision-making that influences forested and agricultural landscapes. With international concern about the GBR’s declining ecological health, this paper identifies and focuses on implementation failure (primarily at catchment scale) as a systemic risk within the overall GBR governance system. There has been limited integrated analysis of the full suite of governance subdomains that often envelop defined policies, programs and delivery activities that influence water quality in the GBR. We consider how the implementation of separate purpose-specific policies and programs at catchment scale operate against well-known, robust design concepts for integrated catchment governance. We find design concerns within ten important governance subdomains that operate within GBR catchments. At a whole-of-GBR scale, we find a weak policy focus on strengthening these delivery-oriented subdomains and on effort integration across these subdomains within catchments. These governance problems when combined may contribute to failure in the implementation of major national, state and local government policies focused on improving water quality in the GBR, a lesson relevant to landscapes globally. [ABSTRACT FROM AUTHOR]

Introduction: Natural resource management uses expert judgement to estimate facts that inform important decisions. Unfortunately, expert judgement is often derived by informal and largely untested protocols, despite evidence that the quality of judgements can be improved with structured approaches. We attribute the lack of uptake of structured protocols to the dearth of illustrative examples that demonstrate how they can be applied within pressing time and resource constraints, while also improving judgements. Aims and methods: In this paper, we demonstrate how the IDEA protocol for structured expert elicitation may be deployed to overcome operational challenges while improving the quality of judgements. The protocol was applied to the estimation of 14 future abiotic and biotic events on the Great Barrier Reef, Australia. Seventy-six participants with varying levels of expertise related to the Great Barrier Reef were recruited and allocated randomly to eight groups. Each participant provided their judgements using the four-step question format of the IDEA protocol (‘Investigate’, ‘Discuss’, ‘Estimate’, ‘Aggregate’) through remote elicitation. When the events were realised, the participant judgements were scored in terms of accuracy, calibration and informativeness. Results and conclusions: The results demonstrate that the IDEA protocol provides a practical, cost-effective, and repeatable approach to the elicitation of quantitative estimates and uncertainty via remote elicitation. We emphasise that i) the aggregation of diverse individual judgements into pooled group judgments almost always outperformed individuals, and ii) use of a modified Delphi approach helped to remove linguistic ambiguity, and further improved individual and group judgements. Importantly, the protocol encourages review, critical appraisal and replication, each of which is required if judgements are to be used in place of data in a scientific context. The results add to the growing body of literature that demonstrates the merit of using structured elicitation protocols. We urge decision-makers and analysts to use insights and examples to improve the evidence base of expert judgement in natural resource management. [ABSTRACT FROM AUTHOR]

Complex policy frameworks guide the management of the Great Barrier Reef (GBR) at multiple decision-making levels. Mounting pressure on its outstanding universal value suggests that further improvements in governance are required. There has been little examination of the role of policy actors in addressing complex governance challenges in large scale marine protected areas (LSMPAs) involving multi-layered governance conflicts across diverse contexts. Framed by street level bureaucracy, pragmatic planning theory, and lessons from MPA governance, this paper examines how policy actors improvised and collaborated to advance outcomes in the GBR LSMPA. We assessed practice-focused oral histories with experienced policy actors who negotiated agreements and achieved policy outcomes in the GBR between 1985 and 2016. These policy actors were skilled improvisers, alternating between roles as democratisers, mediators, and negotiators. They used collaboration and facilitative leadership to advance policy in the face of governance problems. This enabled them to adapt policy across multi-level decision systems, address power and information imbalances, and generally deal with conflict and uncertainty. A deeper understanding of improvisation will assist governments and others to address complex challenges in LSMPAs. [ABSTRACT FROM AUTHOR]

Increasingly, natural resource managers see the marine protected areas that they are responsible for as linked social-ecological systems. This requires an equal focus on managing for both natural and human dimensions of the protected estate. Consequently, identification of indicators that represent the human dimensions of Large Scale Marine Protected Areas (LSMPAs) such as the Great Barrier Reef (GBR) is critical if these values are to be properly considered as part of standard management practice. Assessment and monitoring of the human dimensions of LSMPAs requires a replicable, collaborative process, rolled out at local scales but comparable across vast, socially and geographically diverse areas. This paper explores the application of a process for the development, assessment, and monitoring of the GBR's human dimensions. The process includes (a) development of a conceptual framework that links indicator sets to the desired state of the GBR's human dimensions; and (b) a collaborative approach including ten practical steps to implement assessment, monitoring, and benchmarking of the human dimensions of an LSMPA. We conclude with examination of challenges and opportunities for implementing this process in the GBR context, specifically with respect to the targets and objectives of the Reef 2050 Long-Term Sustainability Plan. [ABSTRACT FROM AUTHOR]

Local meteorology over the Great Barrier Reef (GBR) can significantly influence ocean temperatures, which in turn impacts coral ecosystems. While El Niño–Southern Oscillation (ENSO) provides insight into the expected synoptic states, it lacks details of anticipated sub‐seasonal weather variability at local scales. This study explores the influence of the Madden‐Julian oscillation (MJO) on Australian tropical climate, both independently and in combination with ENSO, focusing on GBR impacts. We find that during El Niño periods, including the summer of 2009/10, faster propagating MJO patterns can disrupt background warm, dry conditions, and potentially provide cooling relief via increased cloud cover and stronger winds. In La Niña periods, such as the summer of 2021/22, the MJO tends to be prevented from passing the Maritime continent, forcing it to remain in a standing pattern in the Indian Ocean. This leads to decreased cloud cover and weaker winds over the GBR, generating warm ocean anomalies. Plain Language Summary: Bleaching is likely when tropical corals are exposed to ocean temperatures above a threshold for a prolonged period. In austral summer, tropical weather over the Great Barrier Reef (GBR) can vary from hot and sunny to stormy with rain and strong winds. During El Niño, summer weather over the GBR is typically warm, still, and dry, increasing the likelihood of coral bleaching due to increased exposure to solar radiation and decreased mixing. During La Niña, tropical storms, with cooling effects through increased rainfall and cloud cover, are more typical. The Madden‐Julian oscillation (MJO) is an eastward moving storm pattern near the equator that can also influence the background climate over the GBR. We find that the MJO can significantly influence the weather variability over the GBR, altering the expected states of El Niño and La Niña periods. Key Points: Composite maps show how the Madden‐Julian oscillation (MJO) can change meteorological patterns on the Great Barrier ReefCluster analysis is used to show the types of MJO propagation patterns likely to occur during El Niño and La Niña periodsOcean temperature variability is discussed with El Niño/La Niña phases as the background states and the MJO as a sub‐seasonal modulator [ABSTRACT FROM AUTHOR]

The Great Barrier Reef lagoon is a large, relatively shallow area of the Australian continental shelf, isolated from the open ocean by a dense matrix of coral reefs. As the lagoon is generally vertically well mixed by strong tidal currents and wind, it is perhaps not surprising there is no mention in the open literature of the occurrence of internal waves there. Nevertheless, high-resolution satellite imagery is shown in this article to reveal the characteristic surface expressions of nonlinear internal waves in the lagoon. The waves are confined to periods of low winds in austral spring and summer, making them a potentially important mechanism for the dispersal of algae and planktonic larvae. The imagery suggests a link between the waves and tidally forced submesoscale jets and vortices, but the actual mechanism generating the internal waves is unclear and requires investigation. [ABSTRACT FROM AUTHOR]

Animals are influenced by the season, yet we know little about the changes that occur in most species throughout the year. This is particularly true in tropical marine animals that experience relatively small annual temperature and daylight changes. Like many coral reef inhabitants, the crown-of-thorns starfish (COTS), well known as a notorious consumer of corals and destroyer of coral reefs, reproduces exclusively in the summer. By comparing gene expression in 7 somatic tissues procured from wild COTS sampled on the Great Barrier Reef, we identified more than 2,000 protein-coding genes that change significantly between summer and winter. COTS genes that appear to mediate conspecific communication, including both signalling factors released into the surrounding sea water and cell surface receptors, are up-regulated in external secretory and sensory tissues in the summer, often in a sex-specific manner. Sexually dimorphic gene expression appears to be underpinned by sex- and season-specific transcription factors (TFs) and gene regulatory programs. There are over 100 TFs that are seasonally expressed, 87% of which are significantly up-regulated in the summer. Six nuclear receptors are up-regulated in all tissues in the summer, suggesting that systemic seasonal changes are hormonally controlled, as in vertebrates. Unexpectedly, there is a suite of stress-related chaperone proteins and TFs, including HIFa, ATF3, C/EBP, CREB, and NF-κB, that are uniquely and widely co-expressed in gravid females. The up-regulation of these stress proteins in the summer suggests the demands of oogenesis in this highly fecund starfish affects protein stability and turnover in somatic cells. Together, these circannual changes in gene expression provide novel insights into seasonal changes in this coral reef pest and have the potential to identify vulnerabilities for targeted biocontrol. The crown-of-thorns starfish (COTS), a notorious consumer of corals and destroyer of coral reefs, reproduces exclusively in the summer. This study reveals seasonal changes in COTS gene expression, providing molecular leads for novel biocontrol methods by revealing new insights into circannual biological rhythms in tropical oceans. [ABSTRACT FROM AUTHOR]

Trade wind clouds are ubiquitous across the subtropical oceans, including the Great Barrier Reef (GBR), playing an important role in modulating the regional energy budget. These shallow clouds, however, are by their nature sensitive to perturbations in both their thermodynamic environment and microphysical background. In this study, we employ the Weather Research and Forecasting (WRF) model with a convection-permitting configuration at 1 km resolution to examine the sensitivity of the trade wind clouds to different local forcings over the GBR. A range of local forcings including coastal topography, sea surface temperature (SST), and local aerosol loading is examined. This study shows a strong response of cloud fraction and accumulated precipitation to orographic forcing both over the mountains and upwind over the GBR. Orographic lifting, low-level convergence, and lower troposphere stability are found to be crucial in explaining the cloud and precipitation features over the coastal mountains downwind of the GBR. However, clouds over the upwind ocean are more strongly constrained by the trade wind inversion, whose properties are, in part, regulated by the coastal topography. On the scales considered in this study, the warm-cloud fraction and the ensuant precipitation over the GBR show only a small response to the local SST forcing, with this response being tied to the surface flux and lower troposphere stability. Cloud microphysical properties, including cloud droplet number concentration, liquid water path, and precipitation, are sensitive to the changes in atmospheric aerosol population over the GBR. While cloud fraction shows little responses, a slight deepening of the simulated clouds is evident over the upwind region in correspondence to the increased aerosol number concentration. A downwind effect of aerosol loading on simulated cloud and precipitation properties is further noted. [ABSTRACT FROM AUTHOR]

Quantifying ecological memory could be done at several levels from the rate of physiological changes in an ecosystem all the way down to responses at the genetic level. One way of unlocking the information encoded in a collective environmental memory is to examine the recorded time-series data generated by different components of an ecosystem. In this paper, we probe into the case of the Great Barrier Reef (GBR) which is threatened by elevated sea surface temperatures (SST) and ocean acidification attributed to rising atmospheric CO2 levels. Specifically, we investigate the interrelated dynamics between the degradation of the GBR, SST, and rising atmospheric CO2 levels, by considering three datasets: (a) the mean percentage hard coral cover of the GBR from the archives of the Australian Institute of Marine Science; (b) SST close to the GBR from the National Oceanic and Atmospheric Administration; and (c) the Keeling curve for atmospheric CO2 levels measured by the Mauna Loa Observatory. We show that fluctuating observables in these datasets have the same memory behavior described by a non-Markovian stochastic process. All three datasets show a good match between empirical and analytical mean square deviation. An explicit analytical form for the corresponding probability density function is obtained which obeys a modified diffusion equation with a time dependent diffusion coefficient. This study provides a new perspective on the similarities of and interaction between the GBR's declining hard coral cover, SST, and rising atmospheric CO2 levels by putting all three systems into one unified framework indexed by a memory parameter μ and a characteristic frequency ν . The short-time dynamics of CO2 levels and SST fall in the superdiffusive regime, while the GBR exhibits hyperballistic fluctuation in percent coral cover with the highest values for μ and ν . [ABSTRACT FROM AUTHOR]

This paper provides a first assessment of fish communities associated with the submerged oceanic banks and shoals in north-west Australia. Until recently, little was known about these deeper and more inaccessible reefs. The mesophotic coral-reef habitats (20-80 m) were a major reservoir of marine biodiversity, with unique and exceptionally high fish diversity and abundance. Species richness in the study region was 1.4 times, and abundance almost twice, that recorded for similar mesophotic habitats on the Great Barrier Reef in north-east Australia. A review of the published literature revealed that Australia's NW oceanic shoals support the highest fish species richness reported for mesophotic reefs to date. We made regional comparisons of fish community structure (species composition, richness and abundance) and assessed the influence of depth, substrate and location. The presence of consolidated calcareous reef, depth and aspect (a surrogate for exposure) had the greatest influence on species richness. In contrast, aspect and the presence of benthic biota had the greatest influence on fish abundance. Sites most exposed to the prevailing currents (facing north-east) had lowest fish abundance, while highest abundances were recorded on moderately exposed sites (along the north-west and south-east edges). The most abundant species were small ( Pomacentrus coelestis) and large ( Naso hexacanthus) planktivorous fish. Currently, 29.3% of NE Australia mesophotic reefs are within no-take management zones of the Great Barrier Reef. In contrast, just 1.3% of the NW oceanic shoals are designated as no-take areas. The location and extent of mesophotic reefs remain poorly quantified globally. Because these habitats support significant biodiversity and have the potential to act as important refugia, understanding their extent is critical to maintaining coral-reef biodiversity and resilience and supporting sustainable management. [ABSTRACT FROM AUTHOR]

Aim Increasingly frequent and intense disturbances of many kinds are reducing the populations of habitat-forming species. For example, disturbances, including coral bleaching, storms and cyclones, coral disease and Crown-of-Thorns starfish (CoTS) outbreaks, have been important contributors to the global decline of coral populations. Understanding these the effects of such disturbances is challenging but necessary for their effective management. In this paper, we provide a novel spatially and temporally explicit perspective on the role of multiple and interacting disturbances on population dynamics. Location Great Barrier Reef (GBR), Australia. Time period 1995-2011. Major taxa studied Acropora species. Methods A semi-parametric Bayesian hierarchical model was used to estimate the form and strength of the cumulative effects of multiple disturbances that have affected coral populations at different locations, frequencies and intensities, and in different orders over 16 years. Boosted regression trees and random forest models were used to rank the relative importance of four types of disturbances in reducing the ability of coral populations to recover following disturbance. Results We show that while all the disturbance agents examined had clear negative impacts, coral predation by CoTS was the strongest contributor to the decline of coral cover and resilience of coral populations. The effects of multiple disturbances on individual reef sites were overwhelmingly additive. Main conclusions Reduction of coral predation through control of CoTS could substantially reduce the severity of disturbances along the GBR and promote greater resilience, and thereby recovery, of coral populations. [ABSTRACT FROM AUTHOR]

Understanding the nature of frequent floods is important for characterising channel morphology, riparian and aquatic habitat, and informing river restoration efforts. This paper presents results from an analysis on frequency estimates of low magnitude floods using the annual maximum and partial series data compared to actual flood series. Five frequency distribution models were fitted to data from 24 gauging stations in the Great Barrier Reef (GBR) lagoon catchments in north-eastern Australia. Based on the goodness of fit test, Generalised Extreme Value, Generalised Pareto and Log Pearson Type 3 models were used to estimate flood frequencies across the study region. Results suggest frequency estimates based on a partial series are better, compared to an annual series, for small to medium floods, while both methods produce similar results for large floods. Although both methods converge at a higher recurrence interval, the convergence recurrence interval varies between catchments. Results also suggest frequency estimates vary slightly between two or more partial series, depending on flood threshold, and the differences are large for the catchments that experience less frequent floods. While a partial series produces better frequency estimates, it can underestimate or overestimate the frequency if the flood threshold differs largely compared to bankfull discharge. These results have significant implications in calculating the dependency of floodplain ecosystems on the frequency of flooding and their subsequent management. [ABSTRACT FROM AUTHOR]

The Great Barrier Reef is the world's largest coral reef ecosystem and is currently in danger of irreparable destruction due to natural and human-made environmental disturbance. This paper focuses on a case, Center for Biological Diversity v. Export-Import Bank, concerning the extraterritoriality application of the Endangered Species Act to a Federal agency's funding of liquefied natural gas projects in Australia requiring, in part, the dredging of portions of the Great Barrier Reef. As the health of UNESCO World Heritage Sites and other environmentally protected and culturally important geography is jeopardized, United States' government activity in foreign jurisdictions raises the question as to whether agency activity (if it is agency action) can come under jurisdiction of United States' courts or whether the federal activity abroad remains untouchable by United States jurisprudence aimed at protecting endangered habitats and species. The Center for Biological Diversity case, at the time of this article pending appeal to the Court of Appeals for the Ninth Circuit, presents the opportunity for a court to consider application of the presumption against extraterritoriality on Federal agency activity that substantially jeopardizes the health and preservation of endangered and culturally significant ecosystems under the Endangered Species Act. [ABSTRACT FROM AUTHOR]

This paper analyzes the discursive struggle over the reach and containment of spectacle in environmental politics to provide (a) case study-based evidence of how, on one hand, transnationally shared environmental awareness and concern, emerging in part through spectacle, is translating into expectations of participation and demands for accountability, and (b) how this is already impacting the ways in which environmental politics is being understood and enacted locally, regionally and transnationally. Drawing on recent mediated debate over the Great Barrier Reef, it finds that while the transnational is clearly an ambition for environmental campaigners, and the perception that transnational publics are emerging is already impacting environmental politics, the potency of these publics and their capacity to meaningfully negotiate accountability is yet to be empirically confirmed. Nevertheless, measures to contain spectacle are providing a potency for a transnational public sphere, even if in reality it is still little more than a specter. [ABSTRACT FROM AUTHOR]

• River plumes are a source of pollutants in the Great Barrier Reef, Australia. • Plume dispersion is simulated using a coupled Lagrangian-Eulerian-ocean model. • Lagrangian particle density is computed from application of Voronoi diagrams. • Lagrangian particle densities and Eulerian tracer concentrations are comparable. • Lagrangian model is validated using satellite imagery and satellite Chlorophyll-a. In this paper, we describe methods to verify the adequacy and accuracy of Lagrangian particles from a Lagrangian model to reproduce the concentrations of a passive tracer from an Eulerian-model in river plumes. The modelling simulates plumes from two major rivers discharging in the Great Barrier Reef (GBR), Australia, under real-world scenarios. The study has been a part of a major project to aid in the protection of the GBR system from the impacts of extreme events and climate change. We employ the Regional Ocean Modelling System (ROMS) activated with its built-in Lagrangian model, and forced with wind fields from global models and recorded river volume discharges. The ROMS-Lagrangian model tracks the Lagrangian particles using the spatially interpolated velocities computed on the Eulerian ROMS three-dimensional (3D) grid. The Lagrangian particles are released in the river in proportion to the measured river volume flux. We apply a novel technique that exploits Voronoi polygon areas to convert Lagrangian particle separation into a concentration field. This facilitates comparison with the passive tracer concentrations driven by the Eulerian velocities computed on the ROMS 3D grid. We evaluate the fate of Lagrangian particles activated on a 4-km grid resolution with those of equivalent Eulerian tracer concentrations. For validation, we compare the Lagrangian particles with the Eulerian passive tracer simulated using a higher model grid resolution of 500-m, and found that the computed Lagrangian particle concentrations showed similar overall patterns compared to the passive tracer concentrations from both the coarse 4-km, and high-resolution 500-m Eulerian models. The spatial extent of the particles was in better agreement with the coarse 4-km model than with the higher resolution 500-m model. The clustering of particles resulted in structures at finer scales than the Eulerian model, over the high particle density areas that compared well against observations. The Lagrangian particles are able to capture the general river plume patterns seen in the satellite MODIS images and the satellite derived Chlorophyll-a. We further compare the online ROMS model with an offline particle tracker, OceanPARCELS and determined the similarity of results from both online and offline methods. Overall, our study demonstrates the viability to use Lagrangian particles to reproduce the Eulerian tracer properties, which can be combined with particle properties include tracer age providing to enhance the guidance on the distribution and concentration of effluent from localised flooding river events. [ABSTRACT FROM AUTHOR]

Climate change projections for coral reefs are founded exclusively on sea surface temperatures (SST). While SST projections are relevant for the shallowest reefs, neglecting ocean stratification overlooks the striking differences in temperature experienced by deeper reefs for all or part of the year. Density stratification creates a buoyancy barrier partitioning the upper and lower parts of the water column. Here, we mechanistically downscale climate models and quantify patterns of thermal stratification above mesophotic corals (depth 30 to 50 m) of the Great Barrier Reef (GBR). Stratification insulates many offshore regions of the GBR from heatwaves at the surface. However, this protection is lost once global average temperatures exceed ~3 ℃ above preindustrial, after which mesophotic temperatures surpass a recognized threshold of 30 ℃ for coral mortality. Bottom temperatures on the GBR (30 to 50 m) from 2050 to 2060 are estimated to increase by ~0.5 to 1 ℃ under lower climate emissions (SSP1-1.9) and ~1.2 to 1.7 ℃ under higher climate emissions (SSP5-8.5). In short, mesophotic coral reefs are also threatened by climate change and research might prioritize the sensitivity of such corals to stress. [ABSTRACT FROM AUTHOR]

Microbial diversity has been extensively explored in reef-building corals. However, the functional roles of coral-associated microorganisms remain poorly elucidated. Here, we recover 191 bacterial and 10 archaeal metagenome-assembled genomes (MAGs) from the coral Acropora kenti (formerly A. tenuis) and adjacent seawater, to identify microbial functions and metabolic interactions within the holobiont. We show that 82 MAGs were specific to the A. kenti holobiont, including members of the Pseudomonadota, Bacteroidota, and Desulfobacterota. A. kenti-specific MAGs displayed significant differences in their genomic features and functional potential relative to seawater-specific MAGs, with a higher prevalence of genes involved in host immune system evasion, nitrogen and carbon fixation, and synthesis of five essential B-vitamins. We find a diversity of A. kenti-specific MAGs encode the biosynthesis of essential amino acids, such as tryptophan, histidine, and lysine, which cannot be de novo synthesised by the host or Symbiodiniaceae. Across a water quality gradient spanning 2° of latitude, A. kenti microbial community composition is correlated to increased temperature and dissolved inorganic nitrogen, with corresponding enrichment in molecular chaperones, nitrate reductases, and a heat-shock protein. We reveal mechanisms of A. kenti-microbiome-symbiosis on the Great Barrier Reef, highlighting the interactions underpinning the health of this keystone holobiont. This study provides insights into the functional roles of microbial symbionts within the reef-building coral Acropora kenti. The findings reveal molecular mechanisms underpinning coral health and adaptation to local environmental stressors, which may support host resilience in the face of anthropogenic climate change and pollution. [ABSTRACT FROM AUTHOR]

Fishery stock assessments are often based on morphometric data from underwater diver surveys and landing surveys. Measurements of body length are usually converted to estimates of body weight, yet length–weight equations might differ among localities. We evaluated morphometric models for the sea cucumber, Pearsonothuria graeffei, collected at Lizard Island on the northern Great Barrier Reef, Australia, and explored differences in relative condition factor (Kn) across animal sizes. The estimation of body weight was compared among relationships with four different body size metrics: observed body length, SLW (square root of the body length–width product), recalculated body length (Le) from SLW, and body basal area. The basal area of the animals, the SLW index and Le provided more reliable estimations for body weight than using body length alone yet accounted for half of the variation in body weight. The length–weight relationship from animals at Lizard Island differed considerably from relationships published for the same species in New Caledonia and Philippines. Body condition was variable, and our model predicted a peak at 35 cm body length. Body metrics such as basal area, SLW index, and Le could offer more precise models for estimating the body weight of sea cucumbers for fishery purposes. Equations for estimating body weight from length and width of the sea cucumbers should be based on locality-specific data because morphometric relationships are spatially variable. [ABSTRACT FROM AUTHOR]

Gnathia antennacrassa sp. nov. from seagrass beds off Rottnest Island, Western Australia is the first record of any gnathiid from the entirety of Western Australia; the male can be distinguished from congeners by the stout peduncular articles of the antenna. Gnathia taurus sp. nov. is described from two adult specimens reared from praniza larvae found infecting elasmobranch fishes at Heron Island, southern Great Barrier Reef; the males can be distinguished from all congeners by the dorsally strongly elongate mandibles and smoothly rounded mediofrontal process on the anterior part of cephalosome. Gnathia aff. maculosa Ota & Hirose, 2009 is recorded from Australia, together with further records of G. trimaculata Coetzee, Smit, Grutter & Davies, 2009 and G. grandilaris Coetzee, Smit, Grutter & Davies, 2008, all from elasmobranch fishes. [ABSTRACT FROM AUTHOR]

The paper considers the influence of the geographical position and local conditions on the structure and abundance of symbiotic communities (SCs) associated with the crinoid Himerometra robustipinna. Two water areas at the coast of Vietnam (Nhatrang Bay and the Anthoy Archipelago; our data), Hansa Bay (Papua, New Guinea; Deyen et al., 2006), and the Great Barrier Reef (Australia; Fabricius and Dale, 1993) were compared. We found a similarity in the contribution from the main taxa to the structure of SCs between geographically distant water areas-Nhatrang Bay, Hansa Bay, and the Great Barrier Reef (GBR)-and strong differences between the two Vietnamese water areas. A possible reason for the differences in the SC structure in these water areas is not their geographical location, but the environmental conditions, which are more stable in the seaward part of Nhatrang Bay and less stable in the Anthoy Archipelago. The abundances of symbionts in the water areas of the coast of Vietnam are similar to each other and strongly different from Hansa Bay and the GBR. We suppose that a factor regulating the abundance of symbionts is their consumption by predatory fishes. A low abundance of fishes in the area of active coastal fishery (the coast of Vietnam) makes possible the existence of SCs with a high abundance. In Hansa Bay and the GBR where fishery pressure is low, a high number of predators leads to a low abundance of symbionts. [ABSTRACT FROM AUTHOR]

A marginal abatement cost curve (MACC) represents a set of options available to an economy to reduce pollution. MACC are valuable tools in that they help not only understand the costs associated with a variety of abatement options but also provide information about the amount of pollutants which can potentially be reduced. MACC have therefore become increasingly popular as instruments to inform policy discussions and to prioritize investment opportunities to reduce pollution. Surprisingly though, there are not many tools available to produce MACCs with the flexibility and functionality as was required in recent research the authors were involved in. This technical paper presents the new tool 'ABATE' which arose from assessing options to improve water quality in the Great Barrier Reef. [ABSTRACT FROM AUTHOR]

Adaptation, as a strategy to respond to climate change, has limits: there are conditions under which adaptation strategies fail to alleviate impacts from climate change. Research has primarily focused on identifying absolute bio-physical limits. This paper contributes empirical insight to an emerging literature on the social limits to adaptation. Such limits arise from the ways in which societies perceive, experience and respond to climate change. Using qualitative data from multi-stakeholder workshops and key-informant interviews with representatives of the fisheries and tourism sectors of the Great Barrier Reef region, we identify psycho-social and structural limits associated with key adaptation strategies, and examine how these are perceived as more or less absolute across levels of organisation. We find that actors experience social limits to adaptation when: i) the effort of pursuing a strategy exceeds the benefits of desired adaptation outcomes; ii) the particular strategy does not address the actual source of vulnerability, and; iii) the benefits derived from adaptation are undermined by external factors. We also find that social limits are not necessarily more absolute at higher levels of organisation: respondents perceived considerable opportunities to address some psycho-social limits at the national-international interface, while they considered some social limits at the local and regional levels to be effectively absolute. [ABSTRACT FROM AUTHOR]