•We evaluated a systematic method to perform stability assessments of marine-food webs.•The framework assesses the trajectories of indicators during perturbation and their performance at detecting ...stability thresholds.•Transfer efficiency and average trophic level of the community indicators performed best at assessing the stability of the tested system.•These indicators can be used to draw scenarios on food-web responses to scenarios of stability loss.•The approach is a suitable methodological standard to inform the Good Environmental Status of marine food-webs.
The European Union Marine Strategy Framework Directive (MSFD) recognises that maintaining marine food-webs in Good Environmental Status (GES) is fundamental to ensure the long-term provision of essential ecosystem goods and services. However, operationalising food-web assessments is challenging due to difficulties in i) implementing simple but complete monitoring programmes, ii) identifying thresholds in monitoring indicators that inform when perturbations are diverting food-web state from GES and iii) in providing an integrative and complete picture of the (health) status of food-webs. In this context, stability assessments of marine food-webs could be useful to identifying the indicators that best track perturbation-induced changes in food-web state and the threshold boundaries that should not be exceeded to minimise the likelihood of losing stability. Yet, there is still a lack of systematic methods to perform such assessments. Here, we evaluate the potential of a simulation-based protocol to be used as a methodological standard for assessing the stability of marine food-webs. The protocol draws on the principles of ecological stability theory and provides a framework for assessing the trajectories of individual indicators during perturbation regimes and their robustness in detecting stability thresholds for marine food-webs. We tested the protocol on an open-ocean and deep-sea food-web modelled with the Ecopath with Ecosim suite. We concluded that indicators that quantify transfer efficiency through the food-web and measure the average trophic level of the community are optimal proxies for trophic functioning and structure to assess the stability of the system. Furthermore, we show how the approach can be applied to i) determine the impact of a loss of stability on the balance between trophic levels and ii) identify the biological components of the food-web that are most affected in scenarios of stability loss. Our findings could be useful for the ongoing debate on how trophic models and derived indicators can play a concrete and practical role in the food-web assessments in European seas.
The identification of biodiversity hotspots and their management for conservation have been hypothesized as effective ways to protect many species. There has been a significant effort to identify and ...map these areas at a global scale, but the coarse resolution of most datasets masks the small-scale patterns associated with coastal habitats or seamounts. Here we used tuna longline observer data to investigate the role of seamounts in aggregating large pelagic biodiversity and to identify which pelagic species are associated with seamounts. Our analysis indicates that seamounts are hotspots of pelagic biodiversity. Higher species richness was detected in association with seamounts than with coastal or oceanic areas. Seamounts were found to have higher species diversity within 30–40 km of the summit, whereas for sets close to coastal habitat the diversity was lower and fairly constant with distance. Higher probability of capture and higher number of fish caught were detected for some shark, billfish, tuna, and other by-catch species. The study supports hypotheses that seamounts may be areas of special interest for management for marine pelagic predators.
Anthropogenic litter is present in all marine habitats, from beaches to the most remote points in the oceans. On the seafloor, marine litter, particularly plastic, can accumulate in high densities ...with deleterious consequences for its inhabitants. Yet, because of the high cost involved with sampling the seafloor, no large-scale assessment of distribution patterns was available to date. Here, we present data on litter distribution and density collected during 588 video and trawl surveys across 32 sites in European waters. We found litter to be present in the deepest areas and at locations as remote from land as the Charlie-Gibbs Fracture Zone across the Mid-Atlantic Ridge. The highest litter density occurs in submarine canyons, whilst the lowest density can be found on continental shelves and on ocean ridges. Plastic was the most prevalent litter item found on the seafloor. Litter from fishing activities (derelict fishing lines and nets) was particularly common on seamounts, banks, mounds and ocean ridges. Our results highlight the extent of the problem and the need for action to prevent increasing accumulation of litter in marine environments.
With increasing demand for mineral resources, extraction of polymetallic sulphides at hydrothermal vents, cobalt-rich ferromanganese crusts at seamounts, and polymetallic nodules on abyssal plains ...may be imminent. Here, we shortly introduce ecosystem characteristics of mining areas, report on recent mining developments, and identify potential stress and disturbances created by mining. We analyze species’ potential resistance to future mining and perform meta-analyses on population density and diversity recovery after disturbances most similar to mining: volcanic eruptions at vents, fisheries on seamounts, and experiments that mimic nodule mining on abyssal plains. We report wide variation in recovery rates among taxa, size, and mobility of fauna. While densities and diversities of some taxa can recover to or even exceed pre-disturbance levels, community composition remains affected after decades. The loss of hard substrata or alteration of substrata composition may cause substantial community shifts that persist over geological timescales at mined sites.
•Deep-sea mineral exploration and exploitation licenses have been issued recently.•Mining will modify the abiotic and biotic environment.•At directly mined sites, species are removed and cannot resist disturbance.•Recovery is highly variable in distinct ecosystems and among benthic taxa.•Community changes may persist over geological time-scales at directly mined sites.
A global biogeographic classification of the mesopelagic zone Sutton, Tracey T.; Clark, Malcolm R.; Dunn, Daniel C. ...
Deep-sea research. Part 1. Oceanographic research papers/Deep sea research. Part I, Oceanographic research papers,
August 2017, 2017-08-00, Letnik:
126
Journal Article
Recenzirano
Odprti dostop
We have developed a global biogeographic classification of the mesopelagic zone to reflect the regional scales over which the ocean interior varies in terms of biodiversity and function. An ...integrated approach was necessary, as global gaps in information and variable sampling methods preclude strictly statistical approaches. A panel combining expertise in oceanography, geospatial mapping, and deep-sea biology convened to collate expert opinion on the distributional patterns of pelagic fauna relative to environmental proxies (temperature, salinity, and dissolved oxygen at mesopelagic depths). An iterative Delphi Method integrating additional biological and physical data was used to classify biogeographic ecoregions and to identify the location of ecoregion boundaries or inter-regions gradients. We define 33 global mesopelagic ecoregions. Of these, 20 are oceanic while 13 are ‘distant neritic.’ While each is driven by a complex of controlling factors, the putative primary driver of each ecoregion was identified. While work remains to be done to produce a comprehensive and robust mesopelagic biogeography (i.e., reflecting temporal variation), we believe that the classification set forth in this study will prove to be a useful and timely input to policy planning and management for conservation of deep-pelagic marine resources. In particular, it gives an indication of the spatial scale at which faunal communities are expected to be broadly similar in composition, and hence can inform application of ecosystem-based management approaches, marine spatial planning and the distribution and spacing of networks of representative protected areas.
•A biogeographic classification of the global mesopelagic zone comprising 33 ecoregions is presented.•Ecoregions are grouped by major biomes, then described individually.•This classification schema extends the depth range of our current biogeographical knowledge.•Management and conservation applications of the proposed classification are discussed.
► We present new estimates of the global mean depth of fishing. ► Our results showed a stronger shift to deeper water than previously estimated. ► Deep water species are under more serious threat ...from fishing than hitherto assumed.
New estimates of the global mean depth of fishing, which consider both the between and within species changes over time, showed a stronger shift to deeper water than estimated previously based only on between-species changes. The new estimates show a linear increase in the mean depth of fishing of 62.5mdecade−1, corresponding to an increase of about 350m for the period since 1950. These values are about 5 times higher than those obtained by using between-species change in catch composition over time, suggesting that deep water species and habitats are under a more serious threat from fishing than hitherto assumed.
Climate change manifestation in the ocean, through warming, oxygen loss, increasing acidification, and changing particulate organic carbon flux (one metric of altered food supply), is projected to ...affect most deep‐ocean ecosystems concomitantly with increasing direct human disturbance. Climate drivers will alter deep‐sea biodiversity and associated ecosystem services, and may interact with disturbance from resource extraction activities or even climate geoengineering. We suggest that to ensure the effective management of increasing use of the deep ocean (e.g., for bottom fishing, oil and gas extraction, and deep‐seabed mining), environmental management and developing regulations must consider climate change. Strategic planning, impact assessment and monitoring, spatial management, application of the precautionary approach, and full‐cost accounting of extraction activities should embrace climate consciousness. Coupled climate and biological modeling approaches applied in the water and on the seafloor can help accomplish this goal. For example, Earth‐System Model projections of climate‐change parameters at the seafloor reveal heterogeneity in projected climate hazard and time of emergence (beyond natural variability) in regions targeted for deep‐seabed mining. Models that combine climate‐induced changes in ocean circulation with particle tracking predict altered transport of early life stages (larvae) under climate change. Habitat suitability models can help assess the consequences of altered larval dispersal, predict climate refugia, and identify vulnerable regions for multiple species under climate change. Engaging the deep observing community can support the necessary data provisioning to mainstream climate into the development of environmental management plans. To illustrate this approach, we focus on deep‐seabed mining and the International Seabed Authority, whose mandates include regulation of all mineral‐related activities in international waters and protecting the marine environment from the harmful effects of mining. However, achieving deep‐ocean sustainability under the UN Sustainable Development Goals will require integration of climate consideration across all policy sectors.
As use of the deep sea and its resources intensifies, consideration of climate change should become integral to planning and management. A suite of climate and biological modeling tools can inform holistic environmental management and decision making for the deep ocean on multiple fronts.
The deep ocean below 200 m water depth is the least observed, but largest habitat on our planet by volume and area. Over 150 years of exploration has revealed that this dynamic system provides ...critical climate regulation, houses a wealth of energy, mineral, and biological resources, and represents a vast repository of biological diversity. A long history of deep-ocean exploration and observation led to the initial concept for the Deep-Ocean Observing Strategy (DOOS), under the auspices of the Global Ocean Observing System (GOOS). Here we discuss the scientific need for globally integrated deep-ocean observing, its status, and the key scientific questions and societal mandates driving observing requirements over the next decade. We consider the Essential Ocean Variables (EOVs) needed to address deep-ocean challenges within the physical, biogeochemical, and biological/ecosystem sciences according to the Framework for Ocean Observing (FOO), and map these onto scientific questions. Opportunities for new and expanded synergies among deep-ocean stakeholders are discussed, including academic-industry partnerships with the oil and gas, mining, cable and fishing industries, the ocean exploration and mapping community, and biodiversity conservation initiatives. Future deep-ocean observing will benefit from the greater integration across traditional disciplines and sectors, achieved through demonstration projects and facilitated reuse and repurposing of existing deep-sea data efforts. We highlight examples of existing and emerging deep-sea methods and technologies, noting key challenges associated with data volume, preservation, standardization, and accessibility. Emerging technologies relevant to deep-ocean sustainability and the blue economy include novel genomics approaches, imaging technologies, and ultra-deep hydrographic measurements. Capacity building will be necessary to integrate capabilities into programs and projects at a global scale. Progress can be facilitated by Open Science and Findable, Accessible, Interoperable, Reusable (FAIR) data principles and converge on agreed to data standards, practices, vocabularies, and registries. We envision expansion of the deep-ocean observing community to embrace the participation of academia, industry, NGOs, national governments, international governmental organizations, and the public at large in order to unlock critical knowledge contained in the deep ocean over coming decades, and to realize the mutual benefits of thoughtful deep-ocean observing for all elements of a sustainable ocean.
Living resources in the sea are essential to the economic, nutritional, recreational, and health needs of billions of people. Variation in the biodiversity that characterizes marine systems, and ...which underlies numerous ecosystem services provided to humans, is being rapidly altered by changing environmental factors and human activity. Understanding the underlying causes of these patterns, and forecasting where future changes are likely to occur, requires monitoring of patterns of organism abundance, diversity, distribution and health; productivity and ecosystem function; and allelic diversity and genetic expression. To achieve this goal it is necessary that these observations are accompanied by metrics of environmental and socio-economic drivers. However, existing global ocean observing activities often do not explicitly consider observations of marine biodiversity and associated processes. Implementing operational programs to observe life in the sea is increasingly critical to understanding responses of species and ecosystems to stressors, and overall impacts on critical natural capital, ecosystem services, and human welfare. Here we describe efforts in the global community to advance broad partnerships, shared approaches and best practices toward a standardized yet flexible, integrated observing system that serves information needs of resource managers and decision-makers, scientists and educators, from local to global scales.
Cold-water corals and sponges aggregations are important features of the deep sea, recently classified as vulnerable marine ecosystems (VMEs). VMEs increase habitat complexity, believed to act as ...feeding, reproductive, nursery and refuge areas for a high number of invertebrates and fish species. In the Azores archipelago (NE Atlantic), VMEs are prevalent but their ecological role has not received much attention. The objective of this study was to investigate the importance of VMEs in influencing the distribution of demersal fish in the Azores. With data collected during experimental longline surveys , we modeled the catch of six demersal fish species of commercial value (Helicolenus dactylopterus, Pagellus bogaraveo, Mora moro, Conger conger, Phycis phycis, Pontinus kuhlii) in relation to the presence of VMEs and other environmental factors using General Additive Models (GAMs). Our study demonstrated that total fish catch was higher inside VMEs but the relationship between fish and VMEs varied among fish species. Species specific models showed that catch was strongly influenced by environmental factors, mainly depth, whilst the presence of VMEs was only important for two rockfish species; juvenile and adult P. kuhlii and juvenile H. dactylopterus. Although the association between deep-sea demersal fish and VMEs may be an exception to the rule, we suggest that VMEs act as an important habitat for two commercially important species in the Azores.
•The association of six deep-sea fish species with VMEs was assessed using GAM.•Two species of rockfish showed an association with VMEs.•The association of Helicolenus dactylopterus was only significant for juveniles.•Depth was the most important factor in shaping fish distribution.•Results are important for fisheries management and to guide MPA planning.
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