The Arctic Ocean is an early warning system for indicators and effects of climate change. We use a novel combination of experimental and time-series data on effects of ocean warming and acidification on the commercially important Northeast Arctic cod (Gadus morhua) to incorporate these physiological processes into the recruitment model of the fish population. By running an ecological-economic optimization model, we investigate how the interaction of ocean warming, acidification and fishing pressure affects the sustainability of the fishery in terms of ecological, economic, social and consumer-related indicators, ranging from present day conditions up to future climate change scenarios. We find that near-term climate change will benefit the fishery, but under likely future warming and acidification this large fishery is at risk of collapse by the end of the century, even with the best adaptation effort in terms of reduced fishing pressure.
Global threats to ocean biodiversity have generated a worldwide movement to take actions to improve conservation and management. Several international initiatives have recommended the adoption of marine protected areas (MPAs) in national and international waters. National governments and the Commission for the Conservation of Antarctic Marine Living Resources have successfully adopted multiple MPAs in the Southern Ocean despite the challenging nature of establishing MPAs in international waters. But are these MPAs representative of Southern Ocean biodiversity? Here we answer this question for both existing and proposed Antarctic MPAs, using benthic and pelagic regionalizations as a proxy for biodiversity. Currently about 11.98% of the Southern Ocean is protected in MPAs, with 4.61% being encompassed by no-take areas. While this is a relatively large proportion of protection when compared to other international waters, current Antarctic MPAs are not representative of the full range of benthic and pelagic ecoregions. Implementing additional protected areas, including those currently under negotiation, would encompass almost 22% of the Southern Ocean. It would also substantially improve representation with 17 benthic and pelagic ecoregions (out of 23 and 19, respectively) achieving at least 10% representation.
Coral reef ecosystems are among the first to fundamentally change in structure due to climate change, which leads to questioning of whether decades of knowledge regarding reef management is still applicable. Here we assess ecological responses to no-take marine reserves over two decades, spanning a major climate-driven coral bleaching event. Pre-bleaching reserve responses were consistent with a large literature, with higher coral cover, more species of fish, and greater fish biomass, particularly of upper trophic levels. However, in the 16 years following coral mortality, reserve effects were absent for the reef benthos, and greatly diminished for fish species richness. Positive fish biomass effects persisted, but the groups of fish benefiting from marine reserves profoundly changed, with low trophic level herbivores dominating the responses. These findings highlight that while marine reserves still have important roles on coral reefs in the face of climate change, the species and functional groups they benefit will be substantially altered.
Ocean health is critical for human well-being but is threatened by multiple stressors. Parties to the Convention on Biological Diversity agreed to protect 10% of their waters by 2020. The scientific evidence supporting the use of marine protected areas (MPAs) to conserve biodiversity stems primarily from knowledge on fully protected areas, but most of what is being established is partially protected. Here, we assess the protection levels of the 1,062 Mediterranean MPAs. While 6.01% of the Mediterranean is covered by protection, 95% of this area shows no difference between the regulations imposed inside the MPAs compared with those outside. Full and high levels of protection, the most effective for biodiversity conservation, represent only 0.23% of the basin and are unevenly distributed across political boundaries and eco-regions. Our current efforts are insufficient at managing human uses of nature at sea, and protection levels should be increased to deliver tangible benefits for biodiversity conservation.
The characteristics of coral reef sampling and monitoring are highly variable, with numbers of units and sampling effort varying from one study to another. Numerous works have been carried out to determine an appropriate effect size through statistical power; however, these were always from a univariate perspective. In this work, we used the pseudo multivariate dissimilarity-based standard error (MultSE) approach to assess the precision of sampling scleractinian coral assemblages in reefs of Venezuela between 2017 and 2018 when using different combinations of number of transects, quadrats and points. For this, the MultSE of 36 sites previously sampled was estimated, using four 30m-transects with 15 photo-quadrats each and 25 random points per quadrat. We obtained that the MultSE was highly variable between sites and is not correlated with the univariate standard error nor with the richness of species. Then, a subset of sites was re-annotated using 100 uniformly distributed points, which allowed the simulation of different numbers of transects per site, quadrats per transect and points per quadrat using resampling techniques. The magnitude of the MultSE stabilized by adding more transects, however, adding more quadrats or points does not improve the estimate. For this case study, the error was reduced by half when using 10 transects, 10 quadrats per transect and 25 points per quadrat. We recommend the use of MultSE in reef monitoring programs, in particular when conducting pilot surveys to optimize the estimation of the community structure.
Satellites collecting optical data offer a unique perspective from which to observe the problem of plastic litter in the marine environment, but few studies have successfully demonstrated their use for this purpose. For the first time, we show that patches of floating macroplastics are detectable in optical data acquired by the European Space Agency (ESA) Sentinel-2 satellites and, furthermore, are distinguishable from naturally occurring materials such as seaweed. We present case studies from four countries where suspected macroplastics were detected in Sentinel-2 Earth Observation data. Patches of materials on the ocean surface were highlighted using a novel Floating Debris Index (FDI) developed for the Sentinel-2 Multi-Spectral Instrument (MSI). In all cases, floating aggregations were detectable on sub-pixel scales, and appeared to be composed of a mix of seaweed, sea foam, and macroplastics. Building first steps toward a future monitoring system, we leveraged spectral shape to identify macroplastics, and a Naïve Bayes algorithm to classify mixed materials. Suspected plastics were successfully classified as plastics with an accuracy of 86%.
Their availability, low cost, applicability in virtually any industrial sector and any household have not only resulted in plastics becoming an everywhere used material, but owing to its specific structure resulting in an issue pertaining to environmental pollution. There are 13 monitoring stations within research area to include recreational and industrial areas differing in hydrodynamic behaviour. The research geography bearing in mind the Russia's scale is not vast so far, yet it is being expanded yearly. Research was done at seven Vladivostok beaches, two beaches at the head of the Amur Bay and three beaches of the Posyet Bay. All the samples taken at the western side of the bay at the depths of 2-6m contained microplastic particles. Quality analysis of all the samples collected was carried out using mass-spectrometric method and that of infrared microscopy. It has been found that the chemical constitution of the samples studied is represented mostly by polyethene, polypropylene, particles of polystyrene and polyvinylchloride. Coastal samples frequently contain cellulose. A certain amount of methylaniline, formaldehydes, and monocarbozides was detected. All the said gives ground for ascertaining harmful influence of microplastics not only on sea water quality but on the state of marine biota.
Aquaculture has become the fastest-growing sector of the food industry worldwide. The increase of intensive aquaculture practices, however, has been raising global concern about economic and social impacts, but mostly due to the associated potential environmental impacts. The aim of this report is to make a preliminary assessment of the impact of an intensive sea bass aquaculture (Dicentrarchus labrax, L. 1758) on surrounding coastal waters. The aquaculture site is located at the SW Iberian coast (Sines, Portugal), having 16 cages, each holding approximately 150,000 specimens at different stages of growth. We present a spatial and temporal description of environmental physical, chemical, and biological parameters taken in the course of four monitoring campaigns conducted between June 2018 and April 2019. All monitored parameters, except phosphate concentration in October only at one sampling station, showed values within the desirable ranges for marine finfish production and the natural range of Portuguese coastal waters. So far, results do not reveal any detrimental impact of the production units on local water quality, although more research is needed. The preliminary findings suggest that the lack of stress on the receiving waters may be attributed to the hydrodynamic regime in the production area, the feeding strategy, and the dimension of the production.
Protection of vulnerable marine ecosystems (VME) is a critical goal for marine conservation. Yet, in many deep-sea settings, where quantitative data are typically sparse, it is challenging to correctly identify the location and size of VMEs. Here we assess the sensitivity of a method to identify coral reef VMEs based on bottom cover and abundance of the stony coral Solenosmilia variabilis on deep seamounts, using image data from a survey off Tasmania, Australia, in 2018. Whilst there was some detectable influence from varying coral cover and the abundance of live coral heads, the distribution of coral reef VMEs was not substantially shifted by changing these criteria or altering the attributes of a moving window used to spatially aggregate coral patches. Whilst applying stricter criteria for classifying VMEs predictably produced smaller areas of coral reef VME, these differences were not sizeable and were often negligible. Coral reef VMEs formed large contiguous “blankets,” mainly on the peaks and flanks of seamounts, but were absent from the continental slope where S. variabilis occurred at low abundance (cover) and/or had no living colonies. The true size of the Tasmanian coral reef VMEs ranged from 0.02 to 1.16 km2; this was relatively large compared to reefs of S. variabilis mapped on New Zealand seamounts, but is small compared to the scales used for regional model predictions of suitable habitat (typically 1 km2 grid cell), and much smaller than the smallest units of management interest (100s–1000s km2). A model prediction of the area of suitable habitat for coral reef in the Tasmanian area was much greater than the area of coral reef estimated in this study. That the method to estimate VME size is not overly sensitive to the choice of criteria is highly encouraging in the context of designing spatial conservation measures that are robust, although its broader application, including to other VME indicator taxa, needs to be substantiated by scenario testing in different environments. Importantly, these results should give confidence for stakeholder uptake and form the basis for better predictive VME models at larger spatial scales and beyond single taxa.
The Red Sea Project (TRSP) is a development that extends over 28,000 km2 along the shores of the Red Sea that will progress to become a sustainable luxury tourism destination on the west coast of the Kingdom of Saudi Arabia. The destination incorporates the Al Wajh lagoon, a pristine 2,081 km2 area that includes 92 islands with valuable habitats (coral reefs, seagrass, and mangroves) and species of global conservation importance. The Red Sea Development Company, responsible for the execution of TRSP, has committed to achieve a net-positive impact on biodiversity while developing the site for sustainable tourism. This requires reaching conservation outcomes superior to those of a “business as usual” scenario for an undeveloped site. After careful optimization of the development plans to explore every opportunity to avoid impacts, we applied marine spatial planning to optimize the conservation of the Al Wajh lagoon in the presence of development. We subsequently tested five conservation scenarios (excluding and including development) using Marxan, a suite of tools designed to identify priority areas for protection on the basis of prescribed conservation objectives. We succeeded in creating a three-layer conservation zoning, achieving conservation outcomes as those possible in the “business as usual” scenario. Subsequently, we designed additional actions to remove existing pressures and generate net positive conservation outcomes. The results demonstrate that careful design and planning could potentially allow coastal development to enhance, rather than jeopardize, conservation.
- Animal migrations are of global ecological significance, providing mechanisms for the transport of nutrients and energy between distant locations. In much of the deep sea (>200 m water depth), the export of nutrients from the surface ocean provides a crucial but seasonally variable energy source to seafloor ecosystems. Seasonal faunal migrations have been hypothesized to occur on the deep seafloor as a result, but have not been documented.
- Here, we analyse a 7.5‐year record of photographic data from the Deep‐ocean Environmental Long‐term Observatory Systems seafloor observatories to determine whether there was evidence of seasonal (intra‐annual) migratory behaviours in a deep‐sea fish assemblage on the West African margin and, if so, identify potential cues for the behaviour.
- Our findings demonstrate a correlation between intra‐annual changes in demersal fish abundance at 1,400 m depth and satellite‐derived estimates of primary production off the coast of Angola. Highest fish abundances were observed in late November with a smaller peak in June, occurring approximately 4 months after corresponding peaks in primary production.
- Observed changes in fish abundance occurred too rapidly to be explained by recruitment or mortality, and must therefore have a behavioural driver. Given the recurrent patterns observed, and the established importance of bottom‐up trophic structuring in deep‐sea ecosystems, we hypothesize that a large fraction of the fish assemblage may conduct seasonal migrations in this region, and propose seasonal variability in surface ocean primary production as a plausible cause. Such trophic control could lead to changes in the abundance of fishes across the seafloor by affecting secondary production of prey species and/or carrion availability for example.
- In summary, we present the first evidence for seasonally recurring patterns in deep‐sea demersal fish abundances over a 7‐year period, and demonstrate a previously unobserved level of dynamism in the deep sea, potentially mirroring the great migrations so well characterized in terrestrial systems.
In the first decades of 2000s, several Italian sites affected by strong anthropogenic impact were recognized as Sites of National Interest (SINs) for a successive reclamation project, some of which also including marine sectors. These coastal areas are characterized by high complexity and diversity as regards the natural setting as well as for extent, history, type, and degree of contamination. For this, the Italian Ministry of Environment charged its scientific research Institute (earlier ICRAM, now ISPRA) with planning a flexible, adaptable, and large-scale environmental characterization. In this context, the investigation of marine sediments was identified as the primary target to assess the environmental status, because of their conservative capacity with respect to contaminants and their role in the exchange processes with other environmental matrices, such as water column and aquatic organisms. A multidisciplinary, chemical–physical, and ecotoxicological survey was identified as the most appropriate and objective criterion for assessing the sediment quality associated, when necessary, with integrative studies. The results derived from this multidisciplinary approach highlighted the main sources of contamination, together with size and extent of the environmental impact on the coastal marine areas, strictly correlated with the kind of anthropogenic activities and coastal morphology. In order to underline how the different environmental setting influences the degree of anthropogenic impact, four different case studies, selected among the more complex by geochemical and geomorphological viewpoints and more extensively studied, were considered. A comprehensive evaluation of these case studies allowed to deduce some general principles concerning the effects of anthropogenic impact, which can be applicable to other transitional and marine coastal areas.
Tropical coral reef-lined coasts are exposed to storm wave-driven flooding. In the future, flood events during storms are expected to occur more frequently and to be more severe due to sea-level rise, changes in wind and weather patterns, and the deterioration of coral reefs. Hence, disaster managers and coastal planners are in urgent need of decision-support tools. In the short-term, these tools can be applied in Early Warning Systems (EWS) that can help to prepare for and respond to impending storm-driven flood events. In the long-term, future scenarios of flooding events enable coastal communities and managers to plan and implement adequate risk-reduction strategies. Modeling tools that are used in currently available coastal flood EWS and future scenarios have been developed for open-coast sandy shorelines, which have only limited applicability for coral reef-lined shorelines. The tools need to be able to predict local sea levels, offshore waves, as well as their nearshore transformation over the reefs, and translate this information to onshore flood levels. In addition, future scenarios require long-term projections of coral reef growth, reef composition, and shoreline change. To address these challenges, we have formed the UFORiC (Understanding Flooding of Reef-lined Coasts) working group that outlines its perspectives on data and model requirements to develop EWS for storms and scenarios specific to coral reef-lined coastlines. It reviews the state-of-the-art methods that can currently be incorporated in such systems and provides an outlook on future improvements as new data sources and enhanced methods become available.
Coral reefs are threatened by climate change on a global scale with thermal stress events and mass coral bleaching being widely reported. The reefs off the east coast of Brazil (and other turbid areas) have, however, historically escaped such thermal stress events, with relatively low levels of background coral mortality (5–10%). This has recently changed. Here we show that, in 2019, degree heating weeks (DHW) of 19.65 coincided with catastrophic declines in coral cover, especially in the major reef building hydrocoral Millepora alcicornis. The decline was due to bleaching associated with exposure to high temperature stress culminating in DHW values exceeding 15 for a period of 50 days. At two independent sites, surveys showed upwards of 83.5 ± 9.0 and 89.1 ± 3.9% mortality, and a third site showed relatively lower (albeit still high) mortality rates of 43.3 ± 12.0%. The mass die-off in 2019 is unprecedented in the South Atlantic reefs and coincides with increased heating events.
To understand the restoration potential of degraded habitats, it is important to know the key processes and habitat features that allow for recovery after disturbance. As part of the EU (Horizon 2020) funded MERCES project, a group of European experts compiled and assessed current knowledge, from both past and ongoing restoration efforts, within the Mediterranean Sea, the Baltic Sea, and the North-East Atlantic Ocean. The aim was to provide an expert judgment of how different habitat features could impact restoration success and enhance the recovery of marine habitats. A set of biological and ecological features (i.e., life-history traits, population connectivity, spatial distribution, structural complexity, and the potential for regime shifts) were identified and scored according to their contribution to the successful accomplishment of habitat restoration for five habitats: seagrass meadows, kelp forests, Cystoseira macroalgal beds, coralligenous assemblages and cold-water coral habitats. The expert group concluded that most of the kelp forests features facilitate successful restoration, while the features for the coralligenous assemblages and the cold-water coral habitat did not promote successful restoration. For the other habitats the conclusions were much more variable. The lack of knowledge on the relationship between acting pressures and resulting changes in the ecological state of habitats is a major challenge for implementing restoration actions. This paper provides an overview of essential features that can affect restoration success in marine habitats of key importance for valuable ecosystem services.
Marine protected areas can serve to regulate harvesting and conserve biodiversity. Within large multi‐use MPAs, it is often unclear to what degree critical sites of biodiversity are afforded protection against commercial activities. Addressing this issue is a prerequisite if we are to appropriately assess sites against conservation targets. We evaluated whether the management regime of a large MPA conserved sites (Key Biodiversity Areas, KBAs) supporting the global persistence of top marine predators.
Southwest Atlantic Ocean.
We collated population and tracking data (1,418 tracks) from 14 marine predator species (Procellariiformes, Sphenisciformes, Pinnipedia) that breed at South Georgia and the South Sandwich Islands, and identified hotspots for their conservation under the recently developed KBA framework. We then evaluated the spatiotemporal overlap of these sites and the different management regimes of krill, demersal longline and pelagic trawl fisheries operating within a large MPA, which was created with the intention to protect marine predator species.
We identified 12 new global marine KBAs that are important for this community of top predators, both within and beyond the focal MPA. Only three species consistently used marine areas at a time when a potentially higher‐risk fishery was allowed to operate in that area, while other interactions between fisheries and our target species were mostly precluded by MPA management plans.
We show that current fishery management measures within the MPA contribute to protecting top predators considered in this study and that resource harvesting within the MPA does not pose a major threat—under current climate conditions. Unregulated fisheries beyond the MPA, however, pose a likely threat to identified KBAs. Our approach demonstrates the utility of the KBA guidelines and multispecies tracking data to assess the contributing role of well‐designed MPAs in achieving local and internationally agreed conservation targets.
Marine megafauna, the largest animals in the oceans, serve key roles in ecosystem functioning. Yet, one-third of these animals are at risk of extinction. To better understand the potential consequences of megafaunal loss, here we quantify their current functional diversity, predict future changes under different extinction scenarios, and introduce a new metric [functionally unique, specialized and endangered (FUSE)] that identifies threatened species of particular importance for functional diversity. Simulated extinction scenarios forecast marked declines in functional richness if current trajectories are maintained during the next century (11% globally; up to 24% regionally), with more marked reductions (48% globally; up to 70% at the poles) beyond random expectations if all threatened species eventually go extinct. Among the megafaunal groups, sharks will incur a disproportionate loss of functional richness. We identify top FUSE species and suggest a renewed focus on these species to preserve the ecosystem functions provided by marine megafauna.
Coral reef ecosystems are rapidly changing, and a persistent problem with monitoring changes in reef habitat complexity rests in the spatial resolution and repeatability of measurement techniques. We developed a new approach for high spatial resolution (<1 m) mapping of nearshore bathymetry and three-dimensional habitat complexity (rugosity) using airborne high-fidelity imaging spectroscopy. Using this new method, we mapped coral reef habitat throughout two bays to a maximum depth of 25 m and compared the results to the laser-based SHOALS bathymetry standard. We also compared the results derived from imaging spectroscopy to a more conventional 4-band multispectral dataset. The spectroscopic approach yielded consistent results on repeat flights, despite variability in viewing and solar geometries and sea state conditions. We found that the spectroscopy-based results were comparable to those derived from SHOALS, and they were a major improvement over the multispectral approach. Yet, spectroscopy provided much finer spatial information than that which is available with SHOALS, which is valuable for analyzing changes in benthic composition at the scale of individual coral colonies. Monitoring temporal changes in reef 3D complexity at high spatial resolution will provide an improved means to assess the impacts of climate change and coastal processes that affect reef complexity
Although perfluoroalkyl substances (PFASs) are ubiquitous in the Arctic, their dominant pathways to the Arctic remain unclear. Most modeling studies support major oceanic transport for PFASs in the Arctic seawater, but this conclusion contradicts the rapid response of PFASs to global emissions in some biota species. Sediments, which act as important PFAS sinks for seawater and potential PFAS source to the benthic food web, are important for interpreting the fate of PFASs in the Arctic. Here we investigate the occurrence of 9 PFASs in one core (1945–2014) and 29 surface sediments from the Bering Sea to the western Arctic. Total PFAS concentrations (0.06–1.73 ng/g dw) in surface sediments were dominated by perfluorooctane sulfonate (PFOS), perfluorononanoic acid (PFNA) and perfluorobutyl sulfonate (PFBS), with higher levels in the Bering Sea slope and the northeast Chukchi Sea. Historical trends in PFASs varied among individuals, with PFOS declining in the early 2000s while PFNA showing an increasing up-core trend. Analysis of positive matrix factorization model identified that the major PFAS sources in the sediment core were dominated by the atmospheric oxidation of consumer use of PFOS precursor-based products (45.0%), while the oceanic transport of fluoropolymer manufacture of polyvinylidene fluoride (mainly PFNA) exhibited an increasing trend over time, becoming dominant in surface sediments (42.8%). Besides, local input of possible aqueous fire-fighting foams (mainly PFOS and PFBS) also acted as an important source currently (30.1%) and historically (34.9%). Our study revealed that the pathways of PFASs in Arctic sediments varied greatly for individuals and the conclusion of PFOS originating from mainly atmospheric oxidation was different from seawater modeling results. This, together with the high possibility of sediments as direct source to Arctic food web (supported by similar PFAS compositions and temporal variations), help provide additional evidence regarding PFAS pathways to the Arctic.
Marine and coastal environments provide extensive and essential ecosystem services upon which much of humanity relies, yet the incorporation of human dimensions into marine and coastal policy and management has historically been lacking. As efforts to address the substantial and diverse challenges facing marine and coastal environments continue, recent years have seen a growing call for greater consideration of people, how they interact with the marine environment, and the resultant implications for developing effective policy and management. Indeed, in recent times recognition of the importance of marine social science research, data, evidence and expertise has undergone an upward trajectory. Despite this growing level of awareness of the value of social science to the wider marine and coastal management agenda, effective and meaningful inclusion of marine social science into research and practice has remained a challenge. Here we approach this global challenge as an opportunity to bring the community together to set a forward-looking international research agenda, recognising the role of multiple approaches and diverse methods understanding the relationship between society and the sea, galvanising the research and practice community across marine social sciences and beyond. Furthermore, by bringing together this increasingly active community, we can identify mechanisms of change and pathways to enable inclusion of marine social sciences within global ocean policy. This paper draws on the views of researchers and practitioners from across the marine social science disciplines, brought together through an expert workshop held at the MARE 2019 conference (June 2019) and representing a range of geographical regions and perspectives. Through the workshop, delegates identified a number of priorities for the ongoing development of the marine social science community, including the need to improve capacity for marine social science research globally, the importance of nurturing an inclusive and equitable marine social science research community and the role of networks to continue to raise the profile of marine social science data and evidence for global ocean policy and management. Additionally, the discussions provided valuable insight into existing knowledge gaps and potential research priorities for the future. Finally, the paper presents a future vision and recommendations for an international and interdisciplinary marine social science agenda, calling for collaborative and strategic thinking on marine social sciences from across the marine science and policy interface. Critically, we show how social science needs to be embedded in all aspects of marine and coastal management in order to create truly sustainable solutions to the pervasive environmental challenges we face.