Despite growing plastic discharge into the environment, researchers have struggled to detect expected increases of marine plastic debris in sea surfaces, sparking discussions about “missing plastics” and final sinks, which are hypothesized to be coastal and deep-sea sediments. While it holds true that the highest concentrations of plastic particles are found in these locations (103-104 particles m-3 in sediments vs. 0.1-1 particles m-3in the water column), our meta-analysis also highlights that in open oceans, microplastic polymer types segregated in the water column according to their density. Lower density polymers, such as polypropylene and polyethylene, dominated sea surface samples (25% and 42%, respectively) but decreased in abundance through the water column (3% and 2% in the deep-sea, respectively), whereas only denser polymers (i.e.polyesters and acrylics) were enriched with depth (5% in surface seawater vs. 77 % in deep-sea locations). Our meta-analysis demonstrates that some of the most abundant and recalcitrant manufactured plastics are more persistent in the sea surface than previously anticipated and that further research is required to determine the ultimate fate of these polymers as current knowledge does not support the deep sea as the final sink for all polymer types.
The European Union has a legally-binding framework for the establishment of maritime spatial plans in the sea areas covered by the exclusive economic zones of its Member States by 2021. The European Commission is supporting EU Member States in their planning efforts with concrete tools and financing. The European Union is well positioned to use its experience and expertise in promoting international and transboundary maritime spatial planning to help address global and regional governance gaps and challenges in ocean management, thereby contributing to improved international ocean governance. In this paper, the European Commission's Bernhard Friess and Marie Grémaud-Colombier explain the EU's legal framework for maritime spatial planning, and elaborate on how the Commission supports EU Member States in the preparation of their maritime spatial plans and the establishment of lasting mechanisms for cross-border cooperation. They set out how the EU's MSP experience led to intensification of its work on international MSP, including with the adoption of the joint DG MARE – IOC-UNESCO Roadmap on International MSP which sets out a clear forward looking and global perspective towards implementing the Agenda 2030.
Ocean acidification (OA) is already impacting marine organisms and may fundamentally alter marine ecosystems in the coming decades, with major implications for ocean services, such as food provision. Though OA is an emerging concern in coastal zone management, current actions are limited to monitoring and knowledge production. This article presents a framework for addressing coastal zone OA in local-level policy agendas through workshops, and lessons learned and outcome from the implementation of this framework in two cases in southern and northern Norway. The framework includes four components: 1) facilitating knowledge exchange and identify challenges and opportunities relating to OA; 2) ensuring legitimacy of new knowledges; 3) building capacity through learning and skill development; and 4) raise awareness about OA among local decisionmakers. The case studies include local and regional coastal zone management stakeholders and, using OA measurements and modelling, illustrate co-production of new knowledge of coastal ocean acidification and its potential local impacts. Through two rounds of workshops, we demonstrate that the level of OA awareness markedly increases among stakeholders. This awareness manifests in vocal interest for looming projected impacts and their necessary mitigative measures. This concern is compounded by stakeholders who recognize that OA should be treated as a component of water-quality, implying that OA is gaining salience as a local policy issue. However, it is evident that local management faces challenges in addressing such an issue, combined with expectations that higher levels of government take responsibility for mitigative and adaptive actions in response to OA.
The delineation of essential fish habitats is necessary to identify, design and prioritize efficient marine protected area (MPA) networks with fishery objectives, capable, in addition to other possible objectives and functions of MPAs, of sustaining the renewal of marine living resources. Generally, the first step to obtain maps of essential fish habitats consists in choosing one of the numerous existing statistical approaches to build robust habitat suitability models linking relevant descriptors of the marine environment to the spatial distribution of fish presence or density. When these descriptors are exhaustively known, i.e. maps are available for each of them, geo-referenced predictions from these models and their related uncertainty may be imported into Geographic Information Systems for the quantitative identification and characterization of key sites for the marine living resources. The usefulness of such quantitative maps for management purposes is endless. These maps allow for the quantitative identification of the different habitats that are required for these marine resources to complete their life cycles and enable to measure their respective importance for population renewal and conservation. The consequences of anthropogenic pressures, not only fishing but also land reclamation, aggregate extractions or degradation of habitat quality (e.g. nutrient excess or xenobiotics loadings, invasive species or global change), on living resources, may also be simulated from such habitat models. These quantitative maps may serve as input in specific spatial planning software or to spatialise population or fishery dynamics, ecosystem or trophic models that may then be used to simulate various scenarios. Fish habitat maps thus may help decision makers to select relevant protection areas and design coherent MPA networks and management levels which objectives are to sustain fishing resources and fisheries.
How to improve marine oil spill response efficiency to minimize environmental and socioeconomic impacts has been recognized as a growing, critical need worldwide in both scientific and practical fields. The efficiency much depends on how sound the response decisions can be made simultaneously at both systematic (or holistic) (e.g., best use of resources for the entire response system) and individual levels (e.g., optimal operation of skimmers on a spill site). This study proposed a new simulation-based multi-agent particle swarm optimization (SA-PSO) approach for supporting marine spill decision-making through the integrated simulation and optimization of response device allocation and process control. Agent-based modeling as an emerging simulation method was first applied for simulating oil spill fate and response. Particle swarm optimization method was further adopted to optimize response device/vessel allocation and performance with a minimal cost and time. Multi-agent system finally controlled and transmitted the results from agent-based modeling and particle swarm optimization as a dynamic and interactive system. The proposed method was tested by a hypothetical case study in the North Atlantic Ocean with consideration of oil weathering and non-weathering scenarios based on simplified conditions. Through the developed approach, the response time was reduced by 11.7% and 5.9% respectively under the two scenarios for vessel allocation and recovery operations with about 90% decrement of fuel consumption. The results showed the strong capability of the approach for decision makings in oil spill responses by recommending optimal management of resources and efficient response operation in a dynamic manner.
Coastal wetlands are a significant carbon (C) sink since they store carbon in anoxic soils. This ecosystem service is impacted by hydrologic alteration and management of these coastal habitats. Efforts to restore tidal flow to former salt marshes have increased in recent decades and are generally associated with alteration of water inundation levels and salinity. This study examined the effect of water level and salinity changes on soil organic matter decomposition during a 60‐day incubation period. Intact soil cores from impounded fresh water marsh and salt marsh were incubated after addition of either sea water or fresh water under flooded and drained water levels. Elevating fresh water marsh salinity to 6 to 9 ppt enhanced CO2 emission by 50%−80% and most typically decreased CH4 emissions, whereas, decreasing the salinity from 26 ppt to 19 ppt in salt marsh soils had no effect on CO2 or CH4 fluxes. The effect from altering water levels was more pronounced with drained soil cores emitting ~10‐fold more CO2 than the flooded treatment in both marsh sediments. Draining soil cores also increased dissolved organic carbon (DOC) concentrations. Stable carbon isotope analysis of CO2 generated during the incubations of fresh water marsh cores in drained soils demonstrates that relict peat OC that accumulated when the marsh was saline was preferentially oxidized when sea water was introduced. This study suggests that restoration of tidal flow that raises the water level from drained conditions would decrease aerobic decomposition and enhance C sequestration. It is also possible that the restoration would increase soil C decomposition of deeper deposits by anaerobic oxidation, however this impact would be minimal compared to lower emissions expected due to the return of flooding conditions.
An inventory of the marine fish fauna in the extreme northeast of South America was performed, as well as biomass estimates, species richness and environmental variables were collected. Techniques of spatial statistics were used to identify biomass trends and species richness. The main objectives were to generate new information about the specific composition of the fish fauna, allowing the identification of the spatial and temporal distribution of fishing resources, as well as the influence of environmental variables on habitat use, generating information that contributes to establishing measures of management and conservation of the fishing resources of the region. Bottom trawls were conducted on the northern coast of the continental shelf of Rio Grande do Norte (Northeast of Brazil), between May 2002 and November 2004. A total of 20,895 fishes (806.5 kg) distributed within 153 species, 108 genera and 57 families were caught. The number of species identified by trawls ranged from 1 to 46. For species richness, the season of the year, depth, latitude, longitude and distance from the coast were statistically significant. Fish biomass presented values between 0.76 and 6,132 g/km, with highest values occurring between depths of 45 and 65 m during the rainy season, while in dry period higher biomass was found in depths from 35 to 75 m. According to the GLM, season of the year and depth influence the distribution of biomass. Thus, in general terms both models indicated that environmental variables directly influence the occurrence and distribution of the ichthyofauna of the continental shelf of Rio Grande do Norte and therefore should be prioritized in establishing measures for conservation and management of these important resources.
Carbon offset credits, and associated projects, are acclaimed to address economic, environmental and social issues simultaneously. However, critics argue that carbon offset mechanisms are ill equipped to assist developing countries in achieving sustainable development. Social standards now exist to provide robust methods for assessing the social and biodiversity performance of carbon offset projects and credible impact assessments to help ensure positive outcomes for local people and biodiversity. Following such a standard, and simultaneously applying the Sustainable Livelihoods Approach, we develop the Coastal Carbon Impacts Framework (CCIF) as a conceptual framework to document the potential positive and negative impacts of coastal carbon offset projects on local livelihoods. We apply the CCIF to four case studies and derive its main livelihood outcomes as well as describe potential long-term impacts. By using the capitals approach, the CCIF is able to dismantle the different impact areas into smaller entities. This allows a more detailed analysis on the positive and negative impacts a project has on communities – across the natural, financial, social, human, physical, cultural and political capital. While the case studies analysed show mainly positive outcomes, certainly no project is without risk of negatively impacting the community. The CCIF is however able to demonstrate potential social risk areas. If applied to additional coastal carbon offset projects, best practice documents, community engagement and the monitoring and evaluation process of such projects can be improved.
Since the 1970s, the magnitude of turtle cold-stun strandings have increased dramatically within the northwestern Atlantic. Here, we examine oceanic, atmospheric, and biological factors that may affect the increasing trend of cold-stunned Kemp’s ridleys in Cape Cod Bay, Massachusetts, United States of America. Using machine learning and Bayesian inference modeling techniques, we demonstrate higher cold-stunning years occur when the Gulf of Maine has warmer sea surface temperatures in late October through early November. Surprisingly, hatchling numbers in Mexico, a proxy for population abundance, was not identified as an important factor. Further, using our Bayesian count model and forecasted sea surface temperature projections, we predict more than 2,300 Kemp’s ridley turtles may cold-stun annually by 2031 as sea surface temperatures continue to increase within the Gulf of Maine. We suggest warmer sea surface temperatures may have modified the northerly distribution of Kemp’s ridleys and act as an ecological bridge between the Gulf Stream and nearshore waters. While cold-stunning may currently account for a minor proportion of juvenile mortality, we recommend continuing efforts to rehabilitate cold-stunned individuals to maintain population resiliency for this critically endangered species in the face of a changing climate and continuing anthropogenic threats.
In the northeastern United States, flooding arising from wave overtopping poses a constant threat to coastal communities during storm events. The purpose of this study is to construct a novel integrated atmosphere-ocean-coast modeling framework based on the coupled tide, surge and wave model, ADCIRC-SWAN, to assess risk and facilitate coastal adaptation and resilience to flooding in a changing climate in this region. The integrated modeling system was validated against the field observations of water level, wave height and period during the January 2015 North American blizzard. Water level measurements by a sensor in the Avenues Basin behind the Seawall in Scituate, Massachusetts were combined with the basin volume determined by the USGS LIDAR data to verify the model predictions of wave overtopping volume. At the storm peak, the significant wave height was increased by 0.7 m at the coast by tide and surge. The wave setup along the coast varied from 0.1 m to 0.25 m depending on the coastline geometry. The interaction between tide-surge and waves increased the wave overtopping rate by five folds mainly due to increased wave height at the toe of the seawall. The wave overtopping discharge would approximately double in an intermediate sea level rise scenario of 0.36 m by 2050 for a storm like the January 2015 North American blizzard. The wave overtopping discharge would increase by 1.5 times if the seawall crest elevation was raised by the same amount as sea level rise. An increase of 0.9 m in the seawall crest elevation is required to bring the wave overtopping discharge to the current level under a 0.36 m sea level rise scenario, primarily due to larger waves arriving at the seawall without breaking in the presence of larger water depth.