When states legalised the maritime domain in the 20th century, the relationship between states and maritime space changed. Since the turn of the millennium, certain global trends have further amplified the role of the oceans in international affairs. This has led to a renewed focus on maritime space, as well as states' rights and responsibilities within this domain, delineated through the concept of a ‘boundary’ at sea. What, in essence, is a maritime boundary? Why do states end up disputing them? Perhaps more important, how do states go about settling such disputes, and how can we better understand the development of the legal and political principles that frame such endeavours? These are the questions examined in this article, which sets out to examine the concept of maritime boundaries and related disputes. Leaning on political science, international law and political geography, it reviews how the idea of a maritime boundary came about; what principles govern how they are drawn; how they at times are resolved; and possible future trends that might impact boundary-making at sea.
Fishers, and the communities they support face a range of challenges brought on by complexity and uncertainty in their social-ecological systems (SESs). This undermines their ability to achieve sustainability whilst hampering proactive planning and decision-making. To capacitate fishers to apply risk aversion strategies at smaller scales of operation and for managers to apply inclusive management approaches such as the ecosystem approach to fisheries management (EAF), a better understanding of the relationships and interactions in marine SESs must be developed. At the same time, the EAF requires the inclusion of multiple stakeholders, disciplines and objectives into decision-making processes. Previous work in the southern Cape with fishers, identified drivers of change. Building on this previous research, and using causal mapping, fishers mapped out drivers of change in an iterative process in a problem framing exercise which also highlighted hidden drivers of change and feedback loops. To explore the relative importance of key drivers of change with participants, weighted hierarchies as well as a Bayesian Belief Network (BBN) were developed. By identifying and highlighting these hidden system interactions a more integrated systems view has been facilitated, adding to the understanding of this fishery system. Drivers identified in the weighted hierarchy were consistent with those identified in the causal maps and previous research, of interest is the relative weighting attributed to these drivers. Whereas the weighted hierarchies emphasised the political dimensions, group work already indicated the range of perceptions, reflecting the considerable uncertainties in this SES. While methodologically challenging at first, the individual approach behind the BBN construction yielded a better reflection of the diversity of views and a better balance of political, economic and climate dimensions of drivers of change. We show how, by using SDMTs, the most disenfranchised community members can engage meaningfully in a structured process. As structure is crucial to management processes, the research shows that where the appropriate groundwork, capacity building and resourcing takes place, disenfranchised stakeholders can be integrated into formal management processes; fulfilling a key requirement of an EAF.
The decline in numbers of reef manta rays (Mobula alfredi) throughout their range has highlighted the need for improved information on their spatial ecology in order to design effective conservation strategies for vulnerable populations. To understand their patterns of movement in Seychelles, we used three techniques—archival pop-up satellite tags, acoustic tags, and photo-identification—and focussed on the aggregation at D’Arros Island and St. Joseph Atoll within the Amirantes Group. M. alfredi were photographed within six of the seven Island Groups of Seychelles, with 64% of individuals being resighted at least once between July 2006 and December 2019 over timeframes of 1–3,462 days (9.5 years; median = 1,018 days). Only three individuals from D’Arros Island were resighted at a second aggregation site located more than 200 km away at St. François Atoll during photo-identification surveys. Satellite-tracked M. alfredi (n = 5 tracks; maximum 180 days) remained within the boundary of the Seychelles Exclusive Economic Zone, where they spent the majority of their time (87%) in the upper 50 m of the water column in close proximity to the Amirantes Bank. The inclusion of acoustic tagging data in the models of estimated satellite-track paths significantly reduced the errors associated with the geolocation positions derived from archived light level data. The insights gained into the patterns of horizontal and vertical movements of M. alfredi using this multi-technique approach highlight the significance of D’Arros Island and St. Joseph Atoll, and the wider Amirantes Group, to M. alfredi in Seychelles, and will benefit future conservation efforts for this species within Seychelles and the broader Western Indian Ocean.
The ingestion of plastic debris has been studied in many marine fish species, although comparisons between species can be difficult due to factors thought to influence ingestion rates, such as habitat preference, feeding behaviours and trophic level. Sardines are found internationally in many coastal environments and represent a potential sentinel species for monitoring and comparing marine plastic exposure rates. We conducted a pilot study, examining the rate of plastic ingestion in 27 commercially caught sardines (Sardinops sagax) from a low populated coastal region of Western Australia. A total of 251 potentially anthropogenic particles were extracted by chemical digestion of the gastrointestinal tract and classified visually. Fibres were the dominant type of material recovered (82.9%), with both yellow (39.8%) and black (32.7%) coloured particles commonly observed. A subset of 64 particles (25.5%), were subject to Fourier transform infrared (FTIR) spectroscopy to identify polymer composition. This chemical characterisation identified seven plastic items (polypropylene, nylon and polyethylene) and a variety of cellulose-based material that was further examined and classified as natural or semi-synthetic. The mean plastic ingestion rate was 0.3 ± 0.4 particles per fish, suggesting Western Australian sardines ingest relatively low concentrations of plastic when compared to international sardine populations examined using similar methodologies. Despite comparatively low concentrations, plastic and semi-synthetic material are still being ingested by sardines from a low populated coastal region demonstrating the ubiquitous nature of the marine debris problem.
Data from coastal tide gauges, oceanographic moorings, and a numerical model show that Arctic storm surges force continental shelf waves (CSWs) that dynamically link the circumpolar Arctic continental shelf system. These trains of barotropic disturbances result from coastal convergences driven by cross-shelf Ekman transport. Observed propagation speeds of 600−3000 km day–1, periods of 2−6 days, wavelengths of 2000−7000 km, and elevation maxima near the coast but velocity maxima near the upper slope are all consistent with theoretical CSW characteristics. Other, more isolated events are tied to local responses to propagating storm systems. Energy and phase propagation is from west to east: ocean elevation anomalies in the Laptev Sea follow Kara Sea anomalies by one day and precede Chukchi and Beaufort Sea anomalies by 4−6 days. Some leakage and dissipation occurs. About half of the eastward-propagating energy in the Kara Sea passes Severnaya Zemlya into the Laptev Sea. About half of the eastward-propagating energy from the East Siberian Sea passes southward through Bering Strait, while one quarter is dissipated locally in the Chukchi Sea and another quarter passes eastward into the Beaufort Sea. Likewise, CSW generation in the Bering Sea can trigger elevation and current speed anomalies downstream in the Northeast Chukchi Sea of 25 cm and 20 cm s–1, respectively. Although each event is ephemeral, the large number of CSWs generated annually suggest that they represent a non-negligible source of time-averaged energy transport and bottom stress-induced dissipative mixing, particularly near the outer shelf and upper slope. Coastal water level and landfast ice breakout event forecasts should include CSW effects and associated lag times from distant upstream winds.
The composition, spatial structure, diversity and abundance of Antarctic nematode and copepod meiobenthic communities was examined in shallow (5–25 m) marine coastal sediments at Casey Station, East Antarctica. The sampling design incorporated spatial scales ranging from 10 meters to kilometers and included testing for human impacts by comparing polluted (metal and hydrocarbon contaminated sediments adjacent to old waste disposal sites) and control areas. A total of 38 nematode genera and 20 copepod families were recorded with nematodes being dominant, comprising up to 95% of the total abundance. Variation was greatest at the largest scale (km’s) but each location had distinct assemblages. At smaller scales there were different patterns of variation for nematodes and copepods. There were significant differences between communities at control and impacted locations. Community patterns had strong correlations with concentrations of metals introduced by human activity in sediments as well as sediment grain size and total organic content. Given the strong association with environmental patterns, particularly those associated with human impacts, we provide further evidence that meiofauna are very useful indicators of anthropogenic environmental changes in Antarctica.
Ocean acidification (OA) is projected to have profound impacts on marine ecosystems and resources, especially in estuarine habitats. Here, we describe biological risks under current levels of exposure to anthropogenic OA in the Salish Sea, an estuarine system that already experiences inherently low pH and aragonite saturation state (Ωar) conditions. We used the Pacific Northwest National Laboratory and Washington State Department of Ecology Salish Sea biogeochemical model (SSM) informed by a selection of OA-related biological thresholds of ecologically and economically important calcifiers, pteropods, and Dungeness crabs. The SSM was implemented to assess current exposure and associated risk due to reduced Ωar and pH conditions with respect to the magnitude, duration, and severity of exposure below the biological thresholds in the Salish Sea in comparison to the pre-industrial era. We further investigated the individual effects of atmospheric CO2 uptake and nutrient-driven eutrophication on changes in chemical exposure since pre-industrial times. Our model predicts average decreases in Ωar and pH since pre-industrial times of about 0.11 and 0.06, respectively, in the top 100 m of the water column of the Salish Sea. These decreases predispose pelagic calcifiers to increased duration, intensity, and severity of exposure. For pteropods, present-day exposure is below the thresholds related to sublethal effects across the entire Salish Sea basin, while mortality threshold exposure occurs on a spatially limited basis. The greatest risk for larval Dungeness crabs is associated with spatially limited exposures to low calcite saturation state in the South Sound in the springtime, triggering an increase in internal dissolution. The main anthropogenic driver behind the predicted impacts is atmospheric CO2 uptake, while nutrient-driven eutrophication plays only a marginal role over spatially and temporally limited scales. Reduction of CO2 emissions can help sustain biological species vital for ecosystem functions and society.
Active restoration is becoming an increasingly important conservation intervention to counteract the degradation of marine coastal ecosystems. Understanding what has motivated the scientific community to research the restoration of marine coastal ecosystems and how restoration research projects are funded is essential if we want to scale-up restoration interventions to meaningful extents. Here, we systematically review and synthesize data to understand the motivations for research on the restoration of coral reefs, seagrass, mangroves, saltmarsh, and oyster reefs. We base this analysis off a published database of marine restoration studies, originally designed to estimate the cost and feasibility of marine coastal restoration, derived from mostly scientific studies published in peer-reviewed and some gray literature. For the present study, the database was updated with fields aimed at assessing the motivations, outcomes, and funding sources for each project. We classify restoration motivations into five categories: biotic, experimental, idealistic, legislative, and pragmatic. Moreover, we evaluate the variables measured and outcomes reported by the researchers and evaluate whether projects adhered to the Society for Ecological Restoration's (SER) standards for the practice of ecological restoration. The most common motivation of the scientific community to study restoration in marine coastal ecosystems was experimental i.e., to seek experimental data to answer ecological research questions or improve restoration approach, as expected since mostly peer-reviewed literature was evaluated here. There were differences in motivations among the five coastal ecosystems. For instance, biodiversity enhancement was the most common case for a biotic motivation in mangrove restoration projects. The most common metrics evaluated were growth/productivity, survivorship, habitat function, physical attributes, and reproduction. For most ecosystems, ecological outcomes were frequently reported, with socio-economic implications of the restoration rarely mentioned, except for mangroves. Projects were largely funded by governmental grants with some investment from private donations, non-governmental organizations, and the involvement of volunteers. Our findings and database provide critical data to align future research of the scientific community with the real social, economic and policy needs required to scale-up marine coastal restoration projects.
Kelp forests are highly productive foundation species along much of the world’s coastline. As a result, kelp are crucial to the ecological, social, and economic well-being of coastal communities. Yet, due to a combination of acute and chronic stressors, kelp forests are under threat and have declined in many locations worldwide. Active restoration of kelp ecosystems is an emerging field that aims to reverse these declines by mitigating negative stressors and then, if needed, introducing biotic material into the environment. To date, few restoration efforts have incorporated positive species interactions. This gap presents a potential shortcoming for the field as evidence from other marine ecosystems illustrates that the inclusion of positive species interactions can enhance restoration success. Additionally, as the climate continues to warm, this approach will be particularly pertinent as positive interactions can also expand the range of physical conditions under which species can persist. Here, we highlight how practitioners can use positive density dependence within and amongst kelp species to increase the chances of restoration success. At higher trophic levels, we emphasize how co-restoring predators can prime ecosystems for restoration. We also investigate how emerging technologies in genetic and microbial selection and manipulation can increase the tolerance of target species to warming and other stressors. Finally, we provide examples of how we can use existing anthropogenic activities to facilitate restoration while performing alternative purposes. As kelp forests continue to decline and the field of kelp restoration continues to develop, it is also important that we monitor these potential advancements and ensure they do not have unintended ecosystem effects, particularly with untested techniques such as genetic and microbial manipulations. Nevertheless, incorporating positive species interactions into future restoration practice stands to promote a more holistic form of restoration that also increases the likelihood of success in a shifting seascape.
Structure-from-Motion (SfM) photogrammetry can be used with digital underwater photographs to generate high-resolution bathymetry and orthomosaics with millimeter-to-centimeter scale resolution at relatively low cost. Although these products are useful for assessing species diversity and health, they have additional utility for quantifying benthic community structure, such as coral growth and fine-scale elevation change over time, if accurate length scales and georeferencing are included. This georeferencing is commonly provided with “ground control,” such as pre-installed seafloor benchmarks or identifiable “static” features, which can be difficult and time consuming to install, survey, and maintain. To address these challenges, we developed the SfM Quantitative Underwater Imaging Device with Five Cameras (SQUID-5), a towed surface vehicle with an onboard survey-grade Global Navigation Satellite System (GNSS) and five rigidly mounted downward-looking cameras with overlapping views of the seafloor. The cameras are tightly synchronized with both the GNSS and each other to collect quintet photo sets and record the precise location of every collection event. The system was field tested in July 2019 in the U.S. Florida Keys, in water depths ranging from 3 to 9 m over a variety of bottom types. Surveying accuracy was assessed using pre-installed stations with known coordinates, machined scale bars, and two independent surveys of a site to evaluate repeatability. Under a range of sea conditions, ambient lighting, and water clarity, we were able to map living and senile coral reef habitats and sand waves at mm-scale resolution. Data were processed using best practice SfM techniques without ground control and local measurement errors of horizontal and vertical scales were consistently sub-millimeter, equivalent to 0.013% RMSE relative to water depth. Survey-to-survey repeatability RMSE was on the order of 3 cm without georeferencing but could be improved to several millimeters with the incorporation of one or more non-surveyed marker points. We demonstrate that the SQUID-5 platform can map complex coral reef and other seafloor habitats and measure mm-to-cm scale changes in the morphology and location of seafloor features over time without pre-existing ground control.
The Northeast Canyons and Seamounts Marine National Monument (NECSMNM) was designated by President Barack Obama in 2016, using his authority under the Antiquities Act of 1906. The Act allows a President to proclaim as national monuments “historic landmarks, historic and prehistoric structures, and other objects of historic or scientific interest” that are “upon the lands owned or controlled” by the United States but to reserve each designation to “the smallest area compatible with the proper care and management of the objects to be protected.” Protection in general excludes commercial scale extraction and is in perpetuity. Here we present analyses of physiographic and ecological datasets that facilitated assessment of the conservation benefits of protections for a new monument. We also review and synthesize the ecological literature to describe processes that operate in continental margin and deep-sea settings, in order to demonstrate the monument area is bounded for proper management and is an object of scientific interest. Results indicate that the current monument designation is an area of high diversity and ecological connectivity across depths and along the continental margin. The monument boundaries contain hot spots (areas of high abundance and species richness) for seafloor communities (inclusive of benthic invertebrate and demersal fish) as well as marine mammals in the epipelagic. Many species are sensitive to disturbance and vulnerable to human activities (e.g., deep-sea corals and sponges) with very long recovery times and extremely low resilience. The monument contains at least nine exemplars of offshore northwest Atlantic marine wildlife communities and habitats (e.g., deep shelf invertebrates, shelf fish, deep sea corals and sponges in canyons and on seamounts, deep sea fish, chemosynthetic communities, deep sea soft sediment, shelf edge cetaceans, and seabirds). The region is relatively undisturbed and can serve as a reference site to focus future research on ecological processes in an increasingly industrialized ocean and one subject to the synergies of regional climate effects. These results suggest that there is great potential for discovery and novel research in this first Atlantic Ocean Marine National Monument.
In the Gulf of Mexico, especially along the southwest Florida coast, blooms of the dinoflagellate Karenia brevis are a coastal natural hazard. The organism produces a potent class of toxins, known as brevetoxins, which are released following cell lysis into ocean or estuarine waters or, upon aerosolization, into the atmosphere. When exposed to sufficient levels of brevetoxins, humans may suffer from respiratory, gastrointestinal, or neurological illnesses. The hazard has been exacerbated by the geometric growth of human populations, including both residents and tourists, along Florida’s southwest coast. Impacts to marine organisms or ecosystems also may occur, such as fish kills or deaths of protected mammals, turtles, or birds. Since the occurrence of a severe Karenia brevis bloom off the southwest Florida coast three-quarters of a century ago, there has been an ongoing debate about the best way for humans to mitigate the impacts of this hazard. Because of the importance of tourism to coastal Florida, there are incentives for businesses and governments alike to obfuscate descriptions of these blooms, leading to the social amplification of risk. We argue that policies to improve the public’s ability to understand the physical attributes of blooms, specifically risk communication policies, are to be preferred over physical, chemical, or biological controls. In particular, we argue that responses to this type of hazard must emphasize maintaining the continuity of programs of scientific research, environmental monitoring, public education, and notification. We propose a common-sense approach to risk communication, comprising a simplification of the public provision of existing sources of information to be made available on a mobile website.
The marine dissolved organic carbon (DOC) pool is an important player in the functioning of marine ecosystems. DOC is at the interface between the chemical and the biological worlds, it fuels marine food webs, and is a major component of the Earth’s carbon system. Here, we review the research showing impacts of global change stressors on the DOC cycling, specifically: ocean warming and stratification, acidification, deoxygenation, glacial and sea ice melting, changed inflow from rivers, changing ocean circulation and upwelling, and wet/dry deposition. A unified outcome of the future impacts of these stressors on the global ocean DOC production and degradation is not possible, due to regional differences and differences in stressors impacts, but general patterns for each stressor are presented.
Mass coral bleaching has increased in intensity and frequency and has severely impacted shallow tropical reefs worldwide. Although extensive investigation has been conducted on the resistance and resilience of coral reefs in the Indo-Pacific and Caribbean, the unique reefs of the South Atlantic remain largely unassessed. Here we compiled primary and literature data for reefs from three biogeographical regions: Indo-Pacific, Caribbean and South Atlantic and performed comparative analyses to investigate whether the latter may be more resistant to bleaching. Our findings show that South Atlantic corals display critical features that make them less susceptible to mass coral bleaching: (i) deeper bathymetric distribution, as species have a mean maximum depth of occurrence of 70 m; (ii) higher tolerance to turbidity, as nearly 60% of species are found in turbid conditions; (iii) higher tolerance to nutrient enrichment, as nitrate concentration in the South Atlantic is naturally elevated; (iv) higher morphological resistance, as massive growth forms are dominant and comprise two thirds of species; and (v) more flexible symbiotic associations, as 75% of corals and 60% of symbiont phylotypes are generalists. Such features were associated with occurrence of fewer bleaching episodes with coral mortality in the South Atlantic, approximately 60% less than the Indo-Pacific and 50% less than the Caribbean. In addition, no mass coral mortality episodes associated with the three global mass bleaching events have been reported for the South Atlantic, which suffered considerably less bleaching. These results show that South Atlantic reefs display several remarkable features for withstanding thermal stress. Together with a historic experience of lower heat stress, our findings may explain why climate change impacts in this region have been less intense. Given the large extension and latitudinal distribution of South Atlantic coral reefs and communities, the region may be recognized as a major refugium and likely to resist climate change impacts more effectively than Indo-Pacific and Caribbean reefs.
The coasts and islands that flank Abu Dhabi, the United Arab Emirates (UAE)’s largest emirate, host the country’s most significant coastal and marine habitats including coral reefs. These reefs, although subject to a variety of pressures from urban and industrial encroachment and climate change, exhibit the highest thresholds for coral bleaching and mortality in the world. By reviewing and benchmarking global, regional and local coral reef conservation efforts, this study highlights the ecological importance and economic uniqueness of the UAE corals in light of the changing climate. The analysis provides a set of recommendations for coral reef management that includes an adapted institutional framework bringing together stakeholders, scientists, and managers. These recommendations are provided to guide coral reef conservation efforts regionally and in jurisdictions with comparable environmental challenges.
With large-scale human interventions and climate change unfolding as they are now, coastal changes at decadal timescales are not limited to incremental modifications of systems that are fixed in their general geometry, but often show significant changes in layout that may be catastrophic for populations living in previously safe areas. This poses severe challenges that are difficult to meet for existing models. A new free-form coastline model, ShorelineS, is presented that is able to describe large coastal transformations based on relatively simple principles of alongshore transport gradient driven changes as a result of coastline curvature, including under highly obliquely incident waves, and consideration of splitting and merging of coastlines, and longshore transport disturbance by hard structures. An arbitrary number of coast sections is supported, which can be open or closed and can interact with each other through relatively straightforward merging and splitting mechanisms. Rocky parts or structures may block wave energy and/or longshore sediment transport. These features allow for a rich behavior including shoreline undulations and formation of spits, migrating islands, merging of coastal shapes, salients and tombolos. The main formulations of the (open-source) model, which is freely available at www.shorelines.nl, are presented. Test cases show the capabilities of the flexible, vector-based model approach, while field validation cases for a large-scale sand nourishment (the Sand Engine; 21 million m3) and an accreting groin scheme at Al-Gamil (Egypt) show the model’s capability of computing realistic rates of coastline change as well as a good representation of the shoreline shape for real situations.
Approximately one-quarter of the World’s sandy beaches, most of which are interrupted by tidal inlets, are eroding. Understanding the long-term (50–100 year) evolution of inlet-interrupted coasts in a changing climate is, therefore of great importance for coastal zone planners and managers. This study, therefore, focuses on the development and piloting of an innovative model that can simulate the climate-change driven evolution of inlet-interrupted coasts at 50–100 year time scales, while taking into account the contributions from catchment-estuary-coastal systems in a holistic manner. In this new model, the evolution of inlet-interrupted coasts is determined by: (1) computing the variation of total sediment volume exchange between the inlet-estuary system and its adjacent coast, and (2) distributing the computed sediment volume along the inlet-interrupted coast as a spatially and temporally varying quantity. The exchange volume, as computed here, consists of three major components: variation in fluvial sediment supply, basin (or estuarine) infilling due to the sea-level rise-induced increase in accommodation space, and estuarine sediment volume change due to variations in river discharge. To pilot the model, it is here applied to three different catchment-estuary-coastal systems: the Alsea estuary (Oregon, United States), Dyfi estuary (Wales, United Kigdom), and Kalutara inlet (Sri Lanka). Results indicate that all three systems will experience sediment deficits by 2100 (i.e., sediment importing estuaries). However, processes and system characteristics governing the total sediment exchange volume, and thus coastline change, vary markedly among the systems due to differences in geomorphic settings and projected climatic conditions. These results underline the importance of accounting for the different governing processes when assessing the future evolution of inlet-interrupted coastlines.
Fishers “local ecological knowledge” (LEK) can be used to reconstruct long-term trends of species that are at very low biomass due to overfishing. In this study, we used historical memories of Sicilian fishers to understand their perception of change in abundance of cartilaginous fish in the Strait of Sicily over the last decades. We conducted interviews with 27 retired fishers from Mazara del Vallo harbor (SW Sicily) working in demersal fisheries, using a pre-defined questionnaire with a series of open and fixed questions related to the abundance of sharks and rays. The questionnaire included specific questions about the trends they perceived in catch or by-catch of cartilaginous fish abundance between the 1940s and 2000s compared to the present. Information was gathered for 18 species, including Carcharhinidae, mesopredatory demersal sharks (Squalidae, Hexanchidae, Centrophoridae, Oxynotidae, Triakidae, Scyliorhinidae, and Squatinidae) and batoids. Overall shark catches were perceived to have diminished since the early 1940s: about 95% of fishers reported the decline of commercially important species (e.g., Mustelus spp.) and indicated species that could have been depleted or locally extinct (e.g., Squatina spp., Sphyrna lewini, Mustelus asterias, etc.). Our study shows that LEK of fishers can be beneficial for reconstructing long-term population trends of exploited species when traditional standard data on fisheries catch or species relative abundance from surveys is limited or only available for recent periods. The results obtained clearly indicate the rapid and alarming decline of elasmobranchs in the Strait of Sicily highlighting the need for urgent conservation measures to be adopted.
Climate change in the Arctic is occurring at a rapid rate. In Longyearbyen, Svalbard, the world’s northernmost city, deadly avalanches and permafrost thaw-induced architectural destruction has disrupted local governance norms and responsibilities. In the North Atlantic, the warming ocean temperatures have contributed to a rapid expansion of the mackerel stock which has spurred both geo-political tensions but also tensions at the science-policy interface of fish quota setting. These local climate-induced changes have created a domino-like chain reaction that intensifies through time as a warming Arctic penetrates deeper into responsibilities of governing institutions and science institutions. In face with the increasing uncertain futures of climate-induced changes, policy choices also increase revealing a type of “snowballing” of possible futures facing decision-makers. We introduce a portmanteau-inspired concept called “The Melting Snowball Effect” that encompasses the chain reaction (“domino effect”) that increases the number of plausible scenarios (“snowball effect”) with climate change (melting snow, ice and thawing permafrost). We demonstrate the use of “The Melting Snowball Effect” as a heuristic within a Responsible Research and Innovation (RRI) framework of anticipation, engagement and reflection. To do this, we developed plausible scenarios based on participatory stakeholder workshops and narratives from in-depth interviews for deliberative discussions among academics, citizens and policymakers, designed for informed decision-making in response to climate change complexities. We observe generational differences in discussing future climate scenarios, particularly that the mixed group where three generations were represented had the most diverse and thorough deliberations.
The marine fish farming industry is growing at a significant rate, yet a number of concerns still remain with regards to environmental impacts on the surrounding coastal sea and its biota. Here, we assessed the impact of intensive farming on benthic prokaryotic communities at a Mediterranean sea bass and sea bream intensive aquaculture site over a period of 10 months, in relation to the increase in fish biomass within the cage together with the organic matter enrichment in the sediments. We report positive relationships between prokaryotic abundance and both organic matter and fish biomass, and a contextual decrease in prokaryotic diversity below the cages. A significant shift in microbial community composition occurred in fish farm sediments (FF) over time, indicating a likely impact of ongoing aquaculture activity on prokaryotic communities. Among the dominant taxa at the impacted site, we found Epsilonproteobacteria and Bacteroidetes, which showed a general increase with fish biomass. Analyses on specialist taxa underlined significant contributions of Clostridiales and Bacteroidales in the farmed sediments. Finally, sea bream and sea bass gut microbiome-related taxa were detected during the sampling period. Our results indicate that prokaryotic community composition underneath the cages is related to fish biomass and organic enrichment over the course of production, and confirms that the study of benthic microbial communities at aquaculture sites represents a useful tool to assess the impact of intensive mariculture on the surrounding environment.