Most larger water bodies worldwide are used for navigation, and the intensity of commercial and recreational navigation is expected to further increase. Navigation profoundly affects aquatic ecosystems. To facilitate navigation, rivers are trained and developed, and the direct effects of navigation include chemical and biological impacts (e.g., inputs of toxic substances and dispersal of non-native species, respectively). Furthermore, propagating ships create hydrodynamic alterations, often simply summarized as waves. Although ship-induced waves are recognized as influential stressors, knowledge on their effects is poorly synthesized. We present here a review on the effects of ship-induced waves on the structure, function and services of aquatic ecosystems based on more than 200 peer reviewed publications and technical reports. Ship-induced waves act at multiple organizational levels and different spatial and temporal scales. All the abiotic and biotic components of aquatic ecosystems are affected, from the sediment and nutrient budget to the planktonic, benthic and fish communities. We highlight how the effects of ship-induced waves cascade through ecosystems and how different effects interact and feed back into the ecosystem finally leading to altered ecosystem services and human health effects. Based on this synthesis of wave effects, we discuss strategies for mitigation. This may help to develop scientifically based and target-oriented management plans for navigational waters that optimize abiotic and biotic integrity and their ecosystem services and uses.
The excessive combustion of fossil fuels for energy provision have altered natural planetary functions, resulting in adverse biophysical and societal implications. Such implications have prompted many governments globally to advocate for the adoption of renewable energy systems in order to reduce GHG emissions. While renewable energy technologies such as solar and biogases have been thoroughly researched and deployed, tidal current turbines (TCTs) that harness kinetic energy from the lateral movement of the tides are a comparatively emerging renewable energy technology, and thus has received relatively less attention with respect to their potential to supplement the renewable energy transition. This paper examines the physics behind tidal movements and cycles, and the technological operation of TCTs. Environmental impacts and economic barriers are analyzed. Best practices of MSP from world leading nations are examined, along with current deploy-andmonitor-consenting regimes of TCT test facilities. An optimal TCT design is suggested based on a synthesis of information from proceeding sections. Finally, an analysis of the implementation of TCTs in Canada, China, and Norway is presented, the results of which demonstrate that harnessing the accessible and sustainably extractable resource of each nation can result in an aggregate installed capacity of 9076 MW through the deployment of 7564 TCTs at a cost of $5,740,964,430, thereby creating 14,467 jobs. This would produce 29,829,711 MW h/yr of electricity sold at approximately 22 cents/kWh, eliminating a total of 14,914,855,258 kg of CO2e, approximately 0.1%. of the projected global electricity demand for 2016.
Plastics in the marine environment have become a major concern because of their persistence at sea, and adverse consequences to marine life and potentially human health. Implementing mitigation strategies requires an understanding and quantification of marine plastic sources, taking spatial and temporal variability into account. Here we present a global model of plastic inputs from rivers into oceans based on waste management, population density and hydrological information. Our model is calibrated against measurements available in the literature. We estimate that between 1.15 and 2.41 million tonnes of plastic waste currently enters the ocean every year from rivers, with over 74% of emissions occurring between May and October. The top 20 polluting rivers, mostly located in Asia, account for 67% of the global total. The findings of this study provide baseline data for ocean plastic mass balance exercises, and assist in prioritizing future plastic debris monitoring and mitigation strategies.
Plastic waste that ends up in the oceans as marine litter is a tangible and urgent environmental pressure reaching even the most remote parts of the global oceans. It impacts marine life from plankton to whales and turtles to albatrosses. Public awareness on how the modern lifestyle and the use of plastics in all sectors of society has influenced the marine ecosystems in the last decades is growing, and an emerging discourse about countermeasures of all types can be seen in policies enacted by authorities in national, regional, and international policy arenas. Different coastal areas have launched Regional Action Plans (RAP) on marine litter that provide structured measures that need to be taken and general advice adapted to the respective region. However, the scale of the problem is not only global in dimension, it also cuts across all sectors in society, and until the use of materials in society becomes sustainable, plastic waste will continues to flow into the seas. This report focuses on how marine plastic litter affects Small Island Developing States (SIDS) because these are considered to be more directly vulnerable to environmental changes, including marine litter, than other countries.
This report was commissioned by the Swedish Agency for Marine and Water management and written by analysts at the Swedish Institute for the Marine Environment (affiliated with the University of Gothenburg, Lund University, and Chalmers University of Technology). In this report, it is documented how marine plastic litter reaches even the most remote parts of the oceans, such as some of the small island states, and how SIDS are especially vulnerable to environmental impacts such as climate change and marine litter. The origin and composition of marine plastic litter and its environmental and economic impacts are described. Finally, measures are discussed that can be launched to mitigate the problem, both from state agencies and private corporations. Here, measures from existing RAPs on marine litter are reviewed and examples of private initiatives are mentioned. Further, the corresponding legal framework is given and side effects of marine litter measures on the Sustainable Development Goals of the UN are debated.
Anthropogenic noise is a pollutant of international concern, with mounting evidence of disturbance and impacts on animal behaviour and physiology. However, empirical studies measuring survival consequences are rare. We use a field experiment to investigate how repeated motorboat-noise playback affects parental behaviour and offspring survival in the spiny chromis (Acanthochromis polyacanthus), a brooding coral reef fish. Repeated observations were made for 12 days at 38 natural nests with broods of young. Exposure to motorboat-noise playback compared to ambient-sound playback increased defensive acts, and reduced both feeding and offspring interactions by brood-guarding males. Anthropogenic noise did not affect the growth of developing offspring, but reduced the likelihood of offspring survival; while offspring survived at all 19 nests exposed to ambient-sound playback, six of the 19 nests exposed to motorboat-noise playback suffered complete brood mortality. Our study, providing field-based experimental evidence of the consequences of anthropogenic noise, suggests potential fitness consequences of this global pollutant.
Despite the environmental risks posed by microplastic pollution, there are presently few standardized protocols for monitoring these materials within marine and coastal habitats. We provide a robust comparison of methods for sampling microplastics on sandy beaches using pellets as a model and attempt to define a framework for reliable standing stock estimation. We performed multiple comparisons to determine: (1) the optimal size of sampling equipment, (2) the depth to which samples should be obtained, (3) the optimal sample resolution for cross-shore transects, and (4) the number of transects required to yield reproducible along-shore estimates across the entire sections of a beach. Results affirmed that the use of a manual auger with a 20-cm diameter yielded the best compromise between reproducibility (i.e., standard deviation) and sampling/processing time. Secondly, we suggest that sediments should be profiled to a depth of at least 1 m to fully assess the depth distribution of pellets. Thirdly, although sample resolution did not have major consequence for overall density estimates, using 7-m intervals provides an optimal balance between precision (SD) and effort (total sampling time). Finally, and perhaps most importantly, comparing the minimum detectable difference yielded by different numbers of transects along a given section of beach suggests that estimating absolute particle density is probably unviable for most systems and that monitoring might be better accomplished through hierarchical or time series sampling efforts. Overall, while our study provides practical information that can improve sampling efforts, the heterogeneous nature of microplastic pollution poses a major conundrum to reproducible monitoring and management of this significant and growing problem.
Scuba diving tourism has the potential to be a sustainable source of income for developing countries. Around the world, tourists pay significant amounts of money to see coral reefs or iconic, large animals such as sharks and manta rays. Scuba diving tourism is broadening and becoming increasingly popular, a novel type of scuba diving which little is known about, is muck diving. Muck diving focuses on finding rare, cryptic species that are seldom seen on coral reefs. This study investigates the value of muck diving, its participant and employee demographics and potential threats to the industry. Results indicate that muck dive tourism is worth more than USD$ 150 million annually in Indonesia and the Philippines combined. It employs over 2200 people and attracts more than 100,000 divers per year. Divers participating in muck dive tourism are experienced, well-educated, have high incomes, and are willing to pay for the protection of species crucial to the industry. Overcrowding of dive sites, pollution and conflicts with fishermen are reported as potential threats to the industry, but limited knowledge on these impacts warrants further research. This study shows that muck dive tourism is a sustainable form of nature based tourism in developing countries, particularly in areas where little or no potential for traditional coral reef scuba diving exists.
Although aquatic mammals are elusive subjects, long-term studies of cetaceans have revealed remarkable life-history traits, including long life spans, bisexual philopatry, prolonged maternal care, and even menopause. Long-term cetacean research, defined here as studies lasting ≥ 10 years, has also helped shape our understanding of large multilevel societies, fission–fusion dynamics, cultural processes, complex sociality, and cognition. Yet relative to their terrestrial counterparts, little is known about many cetacean societies, especially pelagic species; similarly, collection of biological samples (such as blood, feces, urine) from live subjects is rarely possible. Cetaceans have been severely impacted by human activities, from commercial whaling to fisheries bycatch, prey depletion, habitat loss, and chemical and noise pollution. Longitudinal research, defined as measuring the same individuals repeatedly over time, can provide vital information necessary for devising viable solutions for mitigating these impacts and promoting sustainable practices. This review evaluates key findings gleaned from continuous and systematic longitudinal studies of free-living cetaceans. We present examples for each topic, though our condensed review cannot be comprehensive. Given their adaptations to the marine environment, slow life histories, and complex societies, continued investment in long-term research is vital for both understanding and protecting this taxonomic group.
The objective of this paper is to present a method that qualifies the degree of visibility of an offshore wind farm from an observer located along the coast. In many cases, the deployment of an offshore wind farm leads to public opposition. This entails the need for the development of appropriate methods that might present in the most intelligible way the impacts of an offshore wind farm. Amongst many factors to take into account, the visual impact of such farms is surely a factor to take into account. We introduce a visual operator that integrates several parameters that mainly depend on the distance of the wind farm to the coast. We apply a measure that evaluates the horizon surface impact modulated by the number of distinguishable turbines and an aesthetic index based on turbine alignments. The whole method is implemented on top of Geographical Information System (GIS) and provides a decision-aid mechanism oriented to decision-makers. The whole approach is experimented in the context of a wind farm in North West France.
The establishment of Marine Protected Areas (MPAs) is seen as a chosen strategy in managing marine resources in Southeast Asia (SEA). The region has some of the most extensive coastline and diverse coral reef ecosystems that remain highly threatened. The need to protect these areas is definite, but establishment of a MPA often involves conflicts with its stakeholders that highly depend on the ecosystem. This paper reviews 32 studies that evaluated the MPA strategy implemented in various SEA countries since the 1980's to the present. The objective of this paper is to determine the effectiveness of the MPA strategy within the context of SEA. Biological, socioeconomic and governance indicators provided by The World Conservation Union (IUCN) were used in this paper as measures of MPA effectiveness. It was found that the MPA strategy may be ideally suited for some areas but may also be inappropriate for others. The three indicators are highly related to each other in determining a MPA success. An integrated study of these three aspects is believed to provide greater knowledge for future implementation of MPAs.