The Arctic stratospheric polar vortex usually forms in autumn, reaches its peak intensity in mid-winter and decays in spring. The polar vortex strength and persistence in the winter–spring period play an important role in stratospheric ozone depletion with the return of solar radiation in late winter. The polar vortex breakdown in most cases occurs under the influence of vertically propagating planetary Rossby waves. The increased activity of planetary waves was observed in 1984/1985, 1998/1999 and 2012/2013 and led to the polar vortex breakdown in mid-winter, after which it was not observed for more than a month. In this study, Arctic sea ice loss is considered as the most likely cause of the increased activity of planetary waves resulting in the unusual weakening of the Arctic polar vortex. Arctic sea ice extent was a record low in autumn 1984, 1998 and 2012 in the Beaufort Sea, the Canadian Arctic Archipelago and the Central Arctic.
The octopus fishery is one of the most important fisheries in the Gulf of México, particularly in the Campeche Bank. By 1980, the octopus yields appeared to be stabilized at approximately 8,000 t per year, and the catches were almost completely composed of Octopus maya. After a regime shift, the catches increased, averaging 19,000 t per year of O. maya and 6,500 t of O. vulgaris over the last two decades. In this contribution, it is evidenced that the increases in the annual yields of O. maya since the 1990s, which reflect the changes in biomass, are related to climate change. The warming trend and the increase in irradiance after 1980 favoured both growth and individual robustness, which, in addition to the significant decreases in the main predators, suggest a positive effect on the survival and recruitment of the octopus stock.
In the present paper, we study the hydrodynamic noise generated by a ship propeller in open sea conditions. We use Large Eddy Simulation for the hydrodynamic field whereas the acoustic field is reconstructed by applying the advective form of the Ffowcs-Williams and Hawkings equation. A dynamic Lagrangian model is adopted for the closure of the subgrid-scale stresses and a wall-layer model allows to skip the resolution of the viscous sub-layer. The acoustic equation is formulated in the integral form and solved through direct integration of the volume terms. The propeller herein considered is a benchmark case, whose fluid dynamic data are available in the literature. A grid of about 3 ×106 cells is able to reproduce accurately both integral quantities like thrust and torque over the propeller, and turbulence propagating downstream in the wake.
Different noise generation mechanisms are investigated separately. The linear terms give rise to a narrow-band noise spectrum, with a mean peak at the blade frequency and other peaks at frequencies multiple of the rotational one. The non-linear quadrupole term reveals a broad band noise spectrum; the shaft vortex provides the largest contribution to the non-linear part of the noise propagated in the far field.
Considering the visibility of infrastructural projects as a means of coastal protection against urban sea level change, this paper draws attention to dyking as both a form of ‘defense’ and as a means of ‘dwelling’ or living with/from water. By tracing the emergence of a recent donor-funded polder dyke in Metro Manila (Philippines), the paper focuses on the infrastructural politics of coastal protection in a delta megacity, often technocratically framed as a global disaster capital. It illustrates how, as a socio-technological object, a dyke might serve as a distinct mode of governing everyday life along high density urban coastlines. Combining insights from Evolutionary Governance Theory (EGT) and infrastructural anthropology, the paper traces the materialization of the dyke as an evolving ‘living’ infrastructure, placing it against a broader canvas of urban transformations encompassing contestations around disaster risk reduction, land use, uneven livelihood access, tenurial rights, and neoliberal aesthetics. As a means of transcending the defense/dwelling binary, a typology of four interrelated frames are presented with which to trace localised meanings and practices of dyking as a mode of everyday governance, namely as: a) a line of defence for protective living; b) urban spectacle; c) a buffer zone or marker for land acquisition and; d) a fluid borderland, which at times ruptures the very material fixities and aqua-terrestrial distinctions upon which hard engineering infrastructural solutions are often premised.
Since the industrial revolution in the eighteenth to nineteenth centuries, humans have greatly increased the flux of lead (Pb) to the atmosphere and ocean, mainly through the combustion of coals and leaded gasoline. Although such anthropogenic Pb emissions gave little harmful consequences in the open ocean, there have been apparent changes in Pb concentration and its stable isotopic ratios in seawater. Time-series Pb records in the surface oceans have been and will be constructed by the measurement of not only seawaters but corals recording the past seawater Pb during their growth. The Pb concentrations in the North Atlantic surface water, which showed tenfold increase between 1880 and 1970 reflecting the anthropogenic Pb inputs, have decreased drastically since the middle of 1970s due to the prohibition of leaded gasoline in U.S. and European countries. On the other hand, surface waters of northern and tropical Indian Ocean as well as those in the western Pacific Ocean showed significantly higher Pb concentrations than those of the North Atlantic Ocean, implying recent rapid industrialization and a late phase-out of leaded gasoline in developing countries in Asia.
Reef dwelling algae employ a variety of physical and chemical defenses against herbivory, and the response to wounding is extremely important in algal communities. Wound healing mechanisms in crustose coralline algae (CCA) are related to skeletal growth and net calcification rate. Ocean acidification (OA) is known to affect rates of net calcification in a number of calcifying organisms, including CCA. Reduced rates of net calcification in CCA are likely to alter wound healing, and thus affect the consequences of herbivore-CCA interactions on coral reefs. The response of the tropical CCA Porolithon onkodes to OA and artificial wounding was quantified in a 51-day laboratory experiment. Eight artificially wounded (cut to a mean depth of 182 μm) and eight non-wounded samples of P. onkodes were randomly placed into each of four treatments (n = 64 samples total). Each treatment was maintained at a different pCO2 level representative of either ambient conditions or end-of-the-century, predicted conditions (IPCC, 2014); 429.31 ± 20.84 (ambient), 636.54 ± 27.29 (RCP4.5), 827.33 ± 38.51 (RCP6.0), and 1179.39 ± 88.85 μatm (RCP8.5; mean ± standard error). Elevated pCO2 significantly reduced rates of net calcification in both wounded and non-wounded samples of P. onkodes (slopes = −6.4 × 10−4 and −5.5 × 10−4 mg cm−2 d−1 per μatm pCO2, respectively over 51 days). There also was a significant reduction in the rate of vertical regeneration of thallus tissue within the wounds as pCO2 increased (slope = −1.5 × 10−3 μm d−1 per μatm pCO2 over 51 days). This study provides evidence that elevated pCO2 could reduce the ability of this important alga to recover from wounding. Because wounding by herbivores plays an important role in determining CCA community structure, we propose reduced wound healing as a mechanism by which OA might affect the structure and functional roles of CCA communities on coral reefs.
This paper investigates the optimum tidal energy converter array density at a tidal inlet by applying surrogate-based optimisation. The SBO procedure comprises problem formulation, design of experiments, numerical simulations, surrogate model construction and constrained optimisation. This study presents an example for the Faro-Olhão Inlet in the Ria Formosa (Portugal), a potential site for tidal in-stream energy extraction. A 35 kW Evopod™ floating tidal energy converter from Oceanflow Energy Ltd. has been used for array size calculations considering two design variables: (1) number of array rows, and (2) number of tidal energy converter per row. Arrays up to 13 rows with 6–11 tidal energy converters each are studied to assess their impacts on array performance, inlets discharges and bathymetry changes. The analysis identified the positive/negative feedbacks between the two design variables in real case complex flow fields under variable bathymetry and channel morphology. The non-uniformity of tidal currents along the array region causes the variability of the resource in each row, as well as makes it difficult to predict the resultant array configuration interactions. Four different multi-objective optimisation models are formulated subject to a set of performance and environmental constraints. Results from the optimisation models imply that the largest array size that meets the environmental constraints is made of 5 rows with 6 tidal energy converter each and an overall capacity factor of 11.6% resulting in an energy production of 1.01 GWh year−1. On the other hand, a higher energy production (1.20 GWh year−1) is achieved by an optimum array configuration, made of 3 rows with 10 tidal energy converters per row, which maximises power output satisfying environmental and performance restrictions. This optimal configuration permits a good level of energy extraction while having a reduced effect on the hydrodynamic functioning of the multi-inlet system. These results prove the suitability and the potential wide use of the surrogate-based optimisation method to define array characteristics that enhance power production and at the same time respect the environmental surrounding conditions.
Cetacean communities face significant threats from adverse interactions with human activities such as bycatch, vessel collision, and environmental pollution. Monitoring of marine mammal populations can help to assess and safeguard marine biodiversity for future generations. Traditional surveys can be costly and time-consuming to undertake, but we explore the ability of citizen science to inform environmental assessments and subsequent conservation management. We use data collected from platforms of opportunity within the Bay of Biscay to investigate spatial changes in cetacean diversity, with the aim of identifying hotspots which may be suitable for further investigation and conservation. Seventeen species of cetaceans were recorded over a ten year period, many of which are data deficient in European waters (e.g. Bottlenose dolphin, Short-beaked common dolphin, Striped dolphin, Risso's dolphin, Long-finned pilot whale, Killer whale, Northern bottlenose whale, Cuvier's beaked whale, Sowerby's beaked whale and True's beaked whale). Biodiversity (determined by Simpson's Diversity index) ranged from 0.19 to 0.77. The central and southern areas of the survey area indicated the highest biodiversity (0.65–0.77), and these locations may benefit most from protection as Important Marine Mammal Areas. We present a case for this designation, and discuss the benefits and limitations of citizen science for informing conservation action.
In a context of growing concern about climate change and its potential consequences for coastal systems, adaptation is becoming more important than ever before. This paper presents a national planning framework for adaptation to climate change, which is pioneer in the field as it is multi-sectoral and focuses specifically on coastal areas, pursuing the safety of their communities in an uncertain future. The strategy is statutory as it emanates from the new Spanish Coastal Law, which in addition to many other implications includes the compulsory development of a Spanish Strategy for Coastal Adaptation to Climate Change (SSCACC) and its submission to Strategic Environmental Assessment. This paper covers the fundamental aspects of both the SSCACC and the accompanying Strategic Environmental Study, providing recommendations on the assessment of coastal risks triggered by climate change and extreme events, adaptation and risk reduction planning and implementation, and monitoring. Additionally, this work gives insight into the wide-ranging consultation process carried out prior to the SSCACC's approval and the stakeholders involved, and how the SSCACC handles climate change uncertainty and struggles for overcoming barriers.
Most of cigarettes used in the world have filters. Following smoking, the cigarette butts (CBs) are often littered as wastes in the environment. CBs generally contain several toxic substances that are trapped in the cigarette filter. Filters are made of non-biodegradable materials and remain in the environment for a long time. Within this study, it is attempted to systematically review the articles on CBs and find out the answers to the problems associated with the factors including quantity, distribution, origin and toxicity of CBs in the environment. It is estimated that approximately 5.5 trillion cigarettes are being produced annually in the world and the CB wastes would reach 1.2 million tons and increase by 50% until 2025. CBs contain thousands of dangerous chemicals such as arsenic, benzene, hydrogen cyanide, PAHs, pyridine, heavy metals and so forth. It is also believed that eachCB can pollute 1000 liters of water. Given the inadequacy of mechanical equipment as well as the cost of collecting these wastes, there should be a special focus on these items as follows: producing cigarettes with degradable filters, reducing the rate of smoking in the world, reducing the toxic and chemical substances in the process of plant growth, processing and production of cigarettes, training people to discard CBs properly, putting legal and financial pressures on cigarettes production, and the last but not least, providing effective solutions for collecting CBs.
Despite progressive policies and continued advances in ocean management, numerous shifts associated with global changes have been observed in marine ecosystems in recent years, including warming, ocean acidification, and deoxygenation. As global change accelerates, science is needed to inform evidence-based management strategies for continued ecosystem services. Resilience management, in which actions are undertaken to promote the resistance and recovery responses of populations and ecosystems to disturbance, has been suggested as a possible strategy. However, empirical evidence for effective resilience management is still limited. To inform effective management strategies, mechanisms that underlie resilience to global change that can be influenced by management-ready actions must be identified and tested through observations, experiments, and modeling. Here, we discuss the potential links between three common management strategies (i.e., spatial restrictions such as marine protected areas, coordinated spatial protections, and fisheries management approaches) and potential mechanisms of resilience for marine populations and ecosystems, and provide guidance for future research on resilience management for a changing ocean drawing on insight gained by the Partnership for Interdisciplinary Studies of Coastal Oceans’ work at the science-policy interface in the California Current Large Marine Ecosystem.
Coastal upwelling ecosystems around the world are defined by wind-generated currents that bring deep, nutrient-rich waters to the surface ocean where they fuel exceptionally productive food webs. These ecosystems are also now understood to share a common vulnerability to ocean acidification and hypoxia (OAH). In the California Current Large Marine Ecosystem (CCLME), reports of marine life die-offs by fishers and resource managers triggered research that led to an understanding of the risks posed by hypoxia. Similarly, unprecedented losses from shellfish hatcheries led to novel insights into the coastal expression of ocean acidification. Partnership for Interdisciplinary Studies of Coastal Oceans (PISCO) scientists and other researchers in the CCLME responded to the rise of OAH with new ocean observations and experiments. This work revealed insights into the expression of OAH as coupled environmental stressors, their temporal and spatial variability, and impacts on species, ecological communities, and fisheries. Sustained investigations also deepened the understanding of connections between climate change and the intensification of hypoxia, and are beginning to inform the ecological and eco-evolutionary processes that can structure responses to the progression of ocean acidification and other pathways of global change. Moreover, because the severity of the die-offs and hatchery failures and the subsequent scientific understanding combined to galvanize public attention, these scientific advances have fostered policy advances. Across the CCLME, policymakers are now translating the evolving scientific understanding of OAH into new management actions.
Indonesia is part of a marine biodiversity hotspot where millions of coastal communities rely on marine resources for food security and livelihoods. The overarching objective of this study is to explore policy interventions that might help small-scale fishing communities in Indonesia to avoid or escape from an undesirable livelihood state. Selayar Island in South Sulawesi was used as a case study where intensive fishing activity occurs at the proximity of marine reserves and presenting problems and responses that are difficult to interpret due to the lack of data for this region. This four-year study used qualitative and quantitative data collection methods and the principles of systems thinking to examine the social-ecological systems that drive trends in the condition of the marine resources and the associated livelihoods.
Sharks and their cartilaginous relatives (Class Chondrichthyes, herein ‘sharks’) are one of the world's most threatened species groups. Their slow life history traits and vulnerability to capture make them particularly susceptible to overfishing, and they are widely caught in both target and by-catch fisheries. Fisheries management measures that can effectively reduce shark fishing mortality are urgently required to halt population declines and species extinctions. We provide an overview of typical measures for understanding and managing risks to sharks, and highlight critical gaps relating to incorporating socio-economic factors in to research and management. We argue that neglecting these factors hinders effective shark conservation, and has negative consequences for people. We emphasise the importance of a holistic approach, which explicitly considers socio-economic factors in decision-making. Based on this, we propose the first framework for assessing feasibility in a shark management context, which could be integrated with traditional fisheries risk assessments in order to bridge this gap. This framework considers key dimensions of the costs, benefits and overall enabling environment for shark management in a given fishery. Overall, managers and policy makers must consider socio-economic factors in shark conservation efforts to deliver better outcomes for sharks and people. Our simple feasibility framework can support this by enabling costs, benefits and context to be explicitly considered in planning and policy-making, alongside the typical biological and technical risks to sharks in fisheries.
The Lithuanian sea space belongs to the smallest sea areas in Europe. The sea space incorporates multiple marine ecosystem services (MES) that support human-wellbeing and sustain maritime economies, but is also subjected to intensive anthropogenic activities that can affect its vulnerable ecological components. We present a flexible geospatial methodology to assess MES richness (MESR) and to analyse areas of exposure of MES to human impacts using a MES exposure index (MESEx). Source of anthropogenic threats to MES were firstly derived from the Marine Strategy Framework Directive and include marine litter (from ports and shipping), underwater noise (from offshore pile driving and shipping) and hazardous substances (from oil extraction platforms). Results were presented for the three main planning areas in Lithuania, the Lithuanian Coastal Stripe, territorial waters and EEZ. In detail, areas of highest MESR are located in the coastal areas of the Lithuanian Mainland Coast that are particularly rich in ecosystem services such as nursery function from for Baltic Herring and cultural services related to valuable recreational resorts, landscape aesthetic values and natural heritage sites. Modelled pressure exposure on selected MES show that cultural ecosystem services in proximity of Klaipėda Port can be particularly affected by marine litter accumulation phenomena, while transboundary effects of potential oil spills from D6-Platform (Kaliningrad Region) can affect valuable fish provisioning areas and coastal cultural values in the Curonian Spit. Results were discussed for the relevance in MES assessment for marine spatial planning in small sea areas and the methodological outlook of the application of geospatial techniques on cumulative impacts assessment within this region of the Baltic Sea.
Coastal development in small islands needs adapting to climate and ecosystem changes in the Anthropocene era. Understanding variability of coastal vulnerability along the entire coastline informs coastal planning and management at an island-wide scale as some coastal stretches are more appropriate for big-scale development, while others require additional coastal protection and/or ecosystem conservation. To date, few researches focused on developing macro-scale coastal vulnerability index at an island or archipelagic-scale. This paper fills a knowledge gap by developing an integrated coastal vulnerability index (ICVI) for nine small islands in the Azores archipelago. Considering that degree of vulnerability varies according to human-environment traits of each coastal stretch, this paper characterises integrated coastal vulnerability according to three broad attributes, i.e. exposure to external stressors, biophysical features and socioeconomic characteristics. Using field work, semi-quantitative analysis and GIS, ICVI is a simple and relatively quick approach that provides a broad overview of coastal vulnerability in small island context. A set of six accessible and representative parameters was employed as indicators for this vulnerability assessment, i.e. type of cliff; type of beach; coastal defences; exposure to swell/storm waves; outcrop flooded and land-use. The entire coastline of each island was divided into segments according to their geomorphic compartments and subsequently assigned with a relative ICVI value. Each segment was ranked into five classes ranging from very low to very high based on its relative degree of vulnerability. While majority of the coasts are of moderate relative vulnerability in the Azores, vulnerability varies broadly along the coast between low, moderate and high. The ICVI approach serves as a useful decision support tool to facilitate effective planning and management for the Azores small islands and the methodology has the flexibility of being scaled deep by adding more indicators where necessary and available or scaled out to other small islands.
We examine the dive and movement behavior of blue, fin, and humpback whales along the US West Coast in regions with high ship traffic where ship strikes have been identified as a major concern. All three species are known to feed in coastal waters near areas of high ship traffic. We analyzed data from 33 archival tag deployments representing over 3,000 h of data that were attached with suction-cups or short darts for periods >20 h and recorded depth (≥ 1 Hz), fast-lock GPS positions and other sensors. There were clear differences among the three species but all showed a distinct diurnal difference in diving behavior. While dive depth varied among animals based on where prey was located, whales spent a high proportion of their time closer to the surface where they would be more vulnerable to ship strikes at night than in the day. This was most pronounced for blue whales where vulnerability was twice as high at night compared to the day. We also found differences in movement patterns of whales between day and night. Movements were more localized to specific areas in the day near prey resources while at night these movements often involved directional movements (though sometimes returning to the same area). We show how in several specific areas like the Santa Barbara Channel, these differences in movements and locations translate to a very different overlap with shipping lanes at night compared to the daytime locations, which is the basis for most sighting data.
Offshore oil and gas platforms are found on continental shelves throughout the world’s oceans. Over the course of their decades-long life-spans, these platforms become ecologically important artificial reefs, supporting a variety of marine life. When offshore platforms are no longer active they are decommissioned, which usually requires the removal of the entire platform from the marine environment, destroying the artificial reef that has been created and potentially resulting in the loss of important ecosystem services. While some countries allow for these platforms to be converted into artificial reefs under Rigs-to-Reefs programs, they face significant resistance from various stakeholders. The presence of offshore platforms and the associated marine life alters the ecosystem from that which existed prior to the installation of the platform, and there may be factors which make restoration of the ecosystem unfeasible or even detrimental to the environment. In these cases, a novel ecosystem has emerged with potentially significant ecological value. In restoration ecology, ecosystems altered in this way can be classified and managed using the novel ecosystems concept, which recognizes the value of the new ecosystem functions and services and allows for the ecosystem to be managed in its novel state, instead of being restored. Offshore platforms can be assessed under the novel ecosystems concept using existing decommissioning decision analysis models as a base. With thousands of platforms to be decommissioned around the world in coming decades, the novel ecosystems concept provides a mechanism for recognizing the ecological role played by offshore platforms.
Climate change impacts on fisheries will undoubtedly have socio-economic impacts on coastal communities and the seafood market. However, it is a challenge to integrate climate change information in a form that can be used efficiently by adaptation planners, policy makers, and fishery managers. In this study, we frame a climate change impact assessment using a geographical perspective based on the management units of the dominant fishery, in this case, American lobster in Nova Scotia, Canada. The information considered here includes economic dependence on the fishery, population size, diversity of the fishery revenue, status of harbor infrastructure, total replacement cost of each harbor, increased relative sea level and flooding, and the vulnerability of offshore lobster to ocean warming and changes in zooplankton composition and anticipatory changes in fishery productivity across management borders. Using two ocean models to provide multi-decadal scale projections of bottom temperature, changes in offshore lobster distribution are projected to have a neutral, or positive impact on the region as a whole. However, when lobster vulnerability is combined with climate change related vulnerabilities of coastal fishing communities, it is evident that adaptation planning is needed for long-term sustainability. This impact assessment provides both a framework and information for further in-depth analyses by climate change adaptation planners and fishery managers.
Fishing pressure is often expressed in terms of a vessels physical attributes, like tonnage and engine power, while a common definition of fishing capacity identifies vessel size as a convenient proxy for the size of the gear used. Nevertheless, these definitions remain arguable, and the refinement of these fishing descriptors is increasingly being considered. A stronger understanding of the relationship between the standard measures of effort and capacity and fishing mortality remains a primary objective, followed by the need to overcome a traditional approach that simply describes effort, capacity and mortality as linearly related, conferring a greater fishing power to larger vessels. In this perspective, the analysis of trawlers’ technical features in relation to the size and power of the vessel might constitute an essential step. This study specifically investigated a collection of trawling gears’ technical specifications collected by CNR-IRBIM, Ancona. The dataset used includes records from several Mediterranean fisheries, and involves three trawling techniques, including single trawling, twin trawling and pair trawling, and diverse trawling gear categories, comprising demersal/bottom 2-panel trawls (OTB2), demersal/bottom 4-panel trawls (OTB4), pelagic 4-panel trawls (PTM4), semi-pelagic 2-panel trawls (OTM2), semi-pelagic 4-panel trawls (OTM4), and a Mediterranean bottom beam trawl (TBB). We analyzed and described the relationships between vessels’ technical features (LOA, towing force, and engine power), some among the main trawl-metrics (headline length, footrope length, trawl length, square width; fishing circle) and the otterboard’s technical features (height, width, and projected area) in an attempt to enhance fishing capacity definition through the inclusion of the fishing gear deployed. Self-organizing maps (SOM) were used to explore the empirical relationships among different parts of the fishing trawl gears, as well as between some of these parts, the otterboard size and the engine power of the vessel.