Coasts

As several researches indicate, since the 1950s one observed unprecedented warming of the atmosphere and oceans, resulting from greenhouse gas emissions and changes in land use and occupation, leading to sea level rise and impacts on coastal areas. In the municipality of Niterói—Rio de Janeiro, Brazil, where a large urban concentration in coastal areas is observed, a Climate Change Adaptation System was developed, through which mitigation and adaptation strategies are combined, in order to: reduce vulnerabilities; avoid losses and damages; build instruments to allow adaptation of natural, human, productive and infrastructure systems. In this context, this paper aims to measure possible impacts, in the biophysical and socioeconomic spheres, resulting from an eventual 0.50 m rise in mean sea level, which represents an optimistic scenario according to the National Oceanic and Atmospheric Administration. In contrast to similar studies, this work also considered daily and occasional water level variations, represented by the highest astronomical tide and the highest storm surge observed in the studied region. The following data were applied: digital elevation model, 2010 population census data, and real estate information. With the altimetry data, by means of GIS, the census sectors inserted in the affected areas were selected, to obtain data regarding population, number of households, and income. Specialized websites were applied to collect average property values. The simulations revealed that approximately 2950 households and more than 9000 residents could be directly affected, with losses that could exceed R$ 3.60 billion. The Oceanic Region is configured as the most exposed region, susceptible to losses of several ecosystems, economic losses in residential areas and possible destruction of urban infrastructure. Full article

According to the Thailand’s National Strategy (2017-2036) and National Reform Plans, various tools, techniques, or methods are necessary to collect and investigate data for the effective preservation and protection of the country’s natural resources. We aimed to apply various tools and methods for integrated coastal management in Thailand. This study used the InVEST models, including the habitat quality (HQ) and habitat risk assessment (HRA) models, to evaluate the natural habitat quality and cumulative human activity risk in the Sriracha district and Sichang Islands, Thailand. The HQ model revealed the presence of abundant ecological services and high quality natural habitats. We observed habitat degradation in the mooring zone, city area, forests, and coral reefs, with moderate risk to distinct habitats. Our findings identified two potential scenarios. Conservation scenarios exhibited a lower HRA ratio compared to current and development scenarios. Overall, the results showed the effectiveness of the InVEST model in evaluating habitat risk under both present and simulated conditions. Our study highlights the importance of informed management plans and policy-making processes to achieve planned coastal management goals. Full article

Through their accumulated experiences with coastal environments, surfers may be uniquely qualified as a source of local knowledge on surf breaks and wider coastal management topics. Despite popular associations between surfers and the environment, critical enquiries are needed to establish the scope and depth of surfers’ knowledge and the processes that may influence its development. In this study, we expected that relationships between surfers and the coastal environment would be highly variable and dependent upon several outside factors, including individual motivations and biases. This broad hypothesis was tested through an oral history study of 15 New Zealand surfers, which examined the development of coastal environment knowledge through surfing experiences and explored its applications to resource management in New Zealand. Surfers can develop a unique local knowledge of the coast that is often specific to their favourite locations but can also include regional insights obtained through site-scale comparisons. These may include relatively detailed observations that are typically difficult to detect or measure and that are primarily generated through sustained surfing experiences. Socio-cultural factors, including gender stereotypes, localism, equipment bias, and interaction with accessibility, were identified as key influences on individual motivations and knowledge generation contexts. This study argues that surfers’ perspectives are critical to informing management decisions in the coastal environment. Knowledge residing in the surfing community is dependent on individual associations with surf breaks, yet it can be harnessed across meaningful scales to inform coastal management. Moreover, the generation of local knowledge through surfing experiences adds to the societal benefits of protecting surf breaks. Full article

As the interface between land and water, coastlines are highly dynamic and intricately tied to the sediment budget. These regions have a high functional diversity and require enlightened management to preserve their value for the future. In this study we assess changes to the São Paulo State (SE Brazil) coastline over the last 36 years. The study innovatively employs big data remote sensing techniques and multivariate statistical models to evaluate and generate erosion/accretion rates (1985–2021) relative to beach orientation and slope. Shoreline change rates have been obtained for sandy beaches at 485 one-kilometer-spaced transects. Our findings capture the complexity and heterogeneity of the analyzed coastline, at a regional and local scale. No association was found between shoreline changes and beach face orientation. Nonetheless, a dependency relationship was found between dissipative beaches with moderate to high accretion. Beaches facing south, with relative stability, were prone to sediment accumulation. Locations with slow accretion, like sandy spits and tombolo-protected beaches, were associated with dissipative beaches with moderate to high accretion. The southeast-oriented beaches are more prone to erosion due to storm waves from the south. Results provide a broad, fast, and relatively low-cost methodology that can be used in any sandy beach context, bringing essential information for coastal management and decision-making related to the use and occupation of the coastal zones. Full article

Nearshore sandbars are common features along sandy coasts. However, identifying sandbars within a beach profile traditionally requires a large historical dataset or subjective input from an observer. Several existing methodologies rely on reference profiles, which is problematic for new study sites with limited data sets and for nourished beaches that have drastic fluctuations in the cross-shore. This novel technique is suitable for beaches where a reference profile does not exist, as it identifies morphological sandbar features by a quantitative automated process. The technique identifies sandbars with a minimum steepness of 2% grade and a minimum height of 0.2 m. The morphological boundaries of sandbars were previously not well-defined, especially the seaward limit of the sandbar, contributing to difficulty in comparing surveys and sandbar morphologies. This technique standardizes the definitions of the bar limits mathematically via standard MATLAB functions, thus removing subjectivity and allowing results to be replicated. Bar identification is focused on the beach profile below the mean high water line, not cross on-shore positions, making the technique appropriate for nourished shorelines as well as those with large seasonal fluctuations. The automated technique was tested on 840 profiles collected near a recently completed beach nourishment project in Long Branch, NJ, USA. Results indicate success in identifying prominent sandbars within the test data set. Full article

The effects of iron, manganese, zinc, copper, and lead on the chlorophyll content, carbon assimilation, and the antiradical activity of Rhizophora mangle and Laguncularia racemosa were evaluated in regions affected by the Fundão dam disruption in Brazil. The mine waste which settled and accumulated in the sediments could represent long-term contamination. It can be expected that the iron oxyhydroxides deposited in the sediments will be solubilized, leading to chronic contamination by trace metals and the accumulation of these metals in the biota. In this sense, biological indicators prove to be important tools to assess this type of damage. The different bioaccumulation of metals by the species revealed that R. mangle was more impacted by Mn and Cu and that L. racemosa showed alterations in its physiological responses in the presence of Cu, Zn, and Fe. The concentration of these metals in the leaves, with values above previous local reference limits, was associated with reductions in the chlorophyll-a and chlorophyll-b content and carbon assimilation, mainly in L. racemosa. The antiradical activity was also altered, suggesting a lower ability of both species to eliminate reactive oxygen species (ROS). A possible reason for the symptoms of oxidative stress may be due to the reduced efficiency of antioxidant defense by Cu²⁺ and Zn²⁺. In addition, the presence of Pb in the leaf tissue may be toxic to the fauna and the bioaccumulation of this metal and trace elements can be a way to transfer them into the food web by biomagnification. Full article

The temporal and spatial variation in seasonal sea ice in Arctic Bay, Nunavut, are examined using time series and spatial clustering analyses. For the period of 1971 to 2018, a time series of sea ice break-up, and freeze-up, dates and ice-free season length at nine grid points are generated from sea ice charts derived from satellites and other data. These data are analysed temporally and spatially. The temporal analyses indicate an unambiguous response to a warming climate with statistically significant earlier break-up dates, later freeze-up dates, and longer ice-free seasons with clear statistically significant linkages to local air temperature. The rate of change in freeze-up dates and ice-free season length was particularly strong in the early 2000s and less in the 2010s. Spatial clustering analysis indicated a roughly linear pathway of south to north behaviour, following the contours of the bay with the exception of modified behaviour for landfast sea ice near the hamlet of Arctic Bay. The temporal analysis confirms and expands upon an earlier time series analysis of local seasonal sea ice. The spatial analysis indicates that while the ice-free season is increasing, it does not provide clear evidence that there has been a regime change in the seasonal characteristics of how sea ice forms and melts each year. Full article

Among the impacts of climate change in West Africa, coastal erosion is the most threatening disaster apart from floods and the increase in temperatures. The southern coast of the Dakar region, as part of the most threatened coastal zones in West Africa, records the most current coastal damages in Dakar due to its coastline dynamics and low-lying area. This paper investigates the influences of the topography and slope of the beach on shoreline dynamics using remote sensing, cartographic tools and statistical methods such as linear regression. It also states the important role of geomorphologic structures in shoreline dynamics. It was conducted in three littoral cells (Mbao, Bargny and Toubab Dialaw) along the southern coast of Dakar. It helps to understand better the role that topography, slope and geomorphology play in coastal dynamics. The Modified Normalized Difference Water Index (MNDWI) was employed to delineate the coastlines before computing the dynamic rate of the coastline using Digital Shoreline Analysis System (DSAS) software. After that, the topography and slope were determined using a digital elevation model (DEM). Then, the correlation between the coastline dynamic, topography and slope was analyzed using the coefficient of correlation and linear regression model. In the Mbao and Bargny littoral cells where the geomorphology is mostly dominated by soils little or not evolved in situ, there is a significant relationship between the coast line dynamic, topography and slope with a coefficient of correlation of about 0.63 and 0.87, respectively. The relationship is not significant in Toubab Dialaw, where the topography and slope are high, and the geomorphology is mainly characterized by a category of sandstone, with a coefficient of 0.15. We conclude that topography, slope and geomorphology play an important role in the shoreline dynamics in the study area. Full article

Operation of source control measures (SCM) in urban drainage in tropical/transitional climates are still a challenge because of higher rain volumes and more intense rains, as well as constraints from sea-level interference. In this study, the performance of a swale to control runoff was detailed and monitored in such an environment. The data on rain, runoff, and sea levels were acquired at a site located in an island in the south coast of Brazil. The results showed that even with higher rain volumes and more intense rains, the mean capture of the swale was 51.7% of the entrance runoff volume, but it depended on seasonal rain variation and interference of sea/tide level. As a result, the swale might be undersized in summer and oversized in winter. Peak flow retardation was observed in 97% of monitored events. The interference of sea/tide level was not directly correlated with infiltration volumes, but in the principal component analysis, the parameters of sea/tide level, along with the hydrological parameters of rain duration, height, and intensity, explained 60% of the variance in the data. In conclusion, the application of SCMs in tropical regions is suitable, but seasonality should be incorporated in the design. The interference of sea/tide level must be further investigated to verify how to incorporate its influence in the design. Full article

The production and trade of dried fish are important sources of livelihood and employment for poor people engaged in the dried fish value chain. More importantly, half of them are women. Dried fish makes a significant contribution to the food and nutrition security of the poor because it is high in calcium and other vital micronutrients. Despite its importance, work on the dried fish value chain (DFVC) continues to focus on financial value creation and linear interactions among market actors that impede the recognition of human rights, justice, food security, and power across the entire value chain. Such a neoclassical perspective on DFVC tends to undermine the complex human-nature interactions that are contingent upon specific histories, people, places, and practices. Poor fishers and dried fish processors placed at the extractive end of the value chain hold low power in the market and remain vulnerable to changing social-ecological system dynamics. The recent work on a hybrid framework of social-ecological system-oriented dried fish value chain (SESDFVC) makes a departure from the conventional dried fish value chain framework. It values dynamic resource contexts, considers upstream actors as active collaborators, and expands the notion of value to include the social-ecological wellbeing of the value chain actors. This paper, with a mixed method research framework, provides an empirical outlook of the dried fish value chain in relation to SES attributes in the context of the eastern Indian coast of the Bay of Bengal, including Odisha and West Bengal, India. Full article

Hydrobioid gastropods are abundant in coastal systems and ecologically important for ecosystem functioning. We aimed to unravel the relationship between usual and stress-related population attributes of the dominant macrofaunal species Heleobia australis with indicators of environmental quality and coastal pollution. Using Guanabara Bay (GB, Brazil) as a model of a multi-impacted coastal system, our hypothesis is that increased amounts of rainfall during the warm season reduce the bay’s environmental quality and induce shifts in snail population attributes. A suite of environmental variables, population attributes, and sediment quality descriptors was assessed by combining field and laboratory evaluations with literature compilation. Results indicate high organic pollution levels with environmental degradation and reinforce GB status as a severely contaminated system. Some environmental conditions can be applied as seasonal predictors of changes in warm-rainy (rainfall and salinity), intermediate (silicate), and cold-dry seasons (nitrite and nitrate). Three selected usual population attributes (snail density, fecundity, and recruitment) were not affected by changes in environmental conditions, but significant effects were detected on two stress-related attributes (relative penis length index and shell deformity). For the first time, shell deformity was recorded in H. australis snails. Low variation in usual population attributes highlight the high tolerance of H. australis to shifts in environmental conditions. Full article

Oyster farming may impact the estuarine tidal circulation with a series of effects on environmental conditions and cultures’ growth. Hydrodynamic numerical models set up in estuaries integrated the presence of oyster structures by simply increasing the bottom friction coefficient over farming areas. However, for elevated oyster tables in tidal environments, such default calibration ignored the temporal variations of the friction coefficient between the conditions of submerged or unsubmerged structures. Thus, an original formulation of the Chézy coefficient was here proposed to integrate these modulations. Assessed against measured and predicted vertical velocity profiles on a 1/2 scaled model, this formulation was implemented in a simulation of the tidal circulation within the Aber Wrac’h estuary (Brittany, France). Particular attention was dedicated to the changes induced on the current magnitudes and sediment transport. Oyster tables were found to impact current magnitudes in the vicinity of elevated structures, with major differences at times of local peak flood and ebb. These modifications were characterised by (i) a reduction of current magnitudes over oyster farming areas and (ii) a tidal-flow acceleration on both sides of these structures. Increased sediment transport was, therefore, expected in the vicinity of these cultures, with potential implications on seabed morphology and water quality. Full article

Generating accurate estimates of the number of vessels in fishing ports using traditional methods (i.e., ground- and boat-based) can be challenging as observations are distorted by an horizontal perspective. Automated inspection using drones is an emerging research alternative for this type of investigation. However, the drone-based and ground- and boat-based survey methods have not been quantitatively compared for small-scale and commercial fishing fleets in their ports. The objective of this study was to determine the number of fishing vessels and detect onboard fishing gear using three independent sources of data along 41 ports across the Brazilian coastline. Proved by statistical significance, the drone-derived vessel counts revealed 17.9% and 26.6% more fishing vessels than ground- and boat-based surveys, respectively. These differences were further highlighted during the assessment of ports without a ground walkway, causing difficulty, especially for ground-based surveys. Considerable numbers and types of onboard fishing gear were detected using the drone survey, that could not be detected using the ground- and boat-based methods. Although the ground-based survey was associated with a lower cost in comparison with other methods, the drone-based survey required the least time to record fishing fleet features in study ports. Our findings demonstrate that drone surveys can improve the detection and precision of counts for fishing vessels and fishing gear in ports. Further, the magnitude of the discrepancies among the three methods highlights the need for employing drone surveys as a considerable time-reducing approach, and a cost-effective technique for fishery studies. Full article

This study was conducted to propose and identify suggestions for pathways to maintain the sustainability of the pearl industry, a cultural value asset rooted in the region, and to revitalize coastal communities through the pearl industry. Using a qualitative approach, this study sought the opinions of relevant stakeholders based on key themes from the literature review and compiled an agenda for further research and discussion. Specifically, focus group discussions were held with pearl industry stakeholders, local residents, the pearl industry and organizations, tourists, and the public sector, and the views among the four stakeholder groups were analyzed. As a result, the following factors were identified as likely to contribute to the sustainability of the cultured pearl industry: (1) co-creation of value through collaboration between the local stakeholders and local communities (satoumi), (2) efforts to pass on and innovate traditional cultured pearl technology seeking global markets, and (3) enhancement of industrial support measures in coastal areas through collaboration between residents, industry, and government to create an ecology-focused inbound tourism strategy. Stakeholders are strongly aware of the need to promote to the world the value of unique cultured pearls and gemstones that rely on traditional Japanese technology and to attract tourists, along with the development of the next generation of pearl industry leaders, but further systematic intervention is required to achieve this goal. The results of this study are expected to serve as a basis for the next steps in presenting further suggestions through integrated analysis with quantitative economic data. They may also provide guidance for the development of pathways to regional development through the revitalization of local industries and tourism innovation in other coastal regions of the world. Full article

The opening up of the global positioning system (GPS) for non-military uses provided a new impetus for the study of the sea surface topography (SST) and geoid, especially in coastal areas which are important from the viewpoint of the climate crisis. The application of the “GPS/GNSS on boat” method, as an alternative to traditional (indirect and direct) methods, has provided detailed SST maps in coastal and oceanic areas with an accuracy of up to few centimeters. In this work we present the first critical review concerning the evolution of the “GPS/GNSS on boat” method over a period of 27 years. Twenty-one papers, covering the 27 years of related research, are critically reviewed, focusing on the innovations they introduce, the solutions they present and the accuracy they achieve. Further improvement of the method, principally of its accuracy, and the extension of SST measurements to additional coastal environments open new perspectives for the examination of open geophysical problems and climate change. Full article

Barrier islands within sheltered environments are an important natural defense from severe storm impacts for coastal communities worldwide. Despite their importance, these fetch-limited barrier islands remain understudied and their ability to withstand and recover from storms is not well-understood. Here, we present a case study of Sugarloaf Island in North Carolina that demonstrates the operational use of openly accessible LiDAR and aerial imagery data to quantify synoptic habitat, shoreline, and volumetric change between 2014 and 2020, a period that encompasses four hurricanes and a winter storm event. During this time period, our results show: (1) an 11–13% decrease in marsh and shrub habitat, (2) an average landward shoreline migration of 2.9 m yr⁻¹ and up to 5.2 m yr⁻¹ in extreme areas, and (3) a net volume loss of approximately 9800 m³. The results of this study highlight the importance of storms as a driver of morphologic change on Sugarloaf Island and have implications for better understanding the resiliency of fetch-limited barrier islands to storms. This work helps to enhance prerestoration data availability and supports knowledge-based decision-making regarding habitat change, erosional issues, and the efficacy of nature-based solutions to increase the resiliency of a coastal community in North Carolina. Full article

Coasts form the universal stage on which people interact with the global ocean. Our history is inextricably intertwined with the seashore, being a rich tapestry of archaeological sites that paint a vivid picture of people hunting, foraging, fishing and scavenging at the edge of the sea. Seascapes inspire diverse art forms celebrated through the ages. The world’s sandy beaches have a flummoxing duality of anthropocentric purpose—ranging from the horrors when being theatres of war to first love under a rising moon. ‘Man’s Love of the Sea’ continues to draw people towards the shore: the narrow coastal strip contains everything from holiday cottages to mega-cities. This coastal concentration of the human population is problematic when shorelines erode and move inland, a geological process fastened by climate change. Society’s response is often a heavy investment in coastal engineering to complement and enhance the natural storm protection capacity of beaches and dunes. The coast’s immense cultural, social, and economic significance are complemented by a wealth of natural riches. In the public’s eye, these ecological values can pale somewhat compared with more imminent ecosystem services, particularly protecting human properties from storm impacts. To re-balance the picture, here we illustrate how peer-reviewed science can be translated into ‘cool beach facts’, aimed at creating a broader environmental appreciation of ocean shores. The colourful kaleidoscope of coastal values faces a veritable array of anthropogenic stressors, from coastal armouring to environmental harm caused by off-road vehicles. Whilst these threats are not necessarily unique to coastal ecosystems, rarely do the winds of global change blow stiffer than at the edge of the sea, where millions of people have created their fragile homes on shifting sands now being increasingly eroded by rising seas. Natural shorelines accommodate such changing sea levels by moving landwards, a poignant and powerful reminder that protecting the remaining natural land is primus inter pares in coastal management. There is no doubt that coastal ecosystems and coastal communities face august trials to maintain essential ecosystem services in the face of global change. Whilst bureaucracies are not always well equipped to counteract environmental harm effectively, using measures carrying a social license, many communities and individuals have encouragingly deep values connected to living coastlines. Building on these values, and harnessing the fierce protective spirits of people, are pivotal to shaping fresh models that can enhance and re-build resilience for shores that will continue to be a ‘baroque embarrassment of coastal riches’. Full article

Marine ecosystems such as kelp are gaining recognition for providing ecosystem services (ES) along the coastal regions worldwide. Here, we synthesize information from the last four decades of research on the structure, functioning and threats of kelp forests, and the ES they provide in the Humboldt Current System (HCS) where information is scarce. The SALSA (Search, Appraisal, Synthesis and Analysis) framework was used for the literature survey and review. From 86 selected articles, only 4 directly discussed kelp ES in Chile. Supporting services-related articles were the most prevalent (n = 59), followed by provisioning (n = 19), regulating (n = 3) and cultural services (n = 1). ES-related research was mostly conducted in Chile (n = 77). Studies in Peru (n = 5), and in Chile and Peru at same time (n = 4) were scarce. Our search also showed that Lessonia trabeculata presented the highest number of associated taxa (n = 213), followed closely by M. pyrifera (n = 210). However, the number of phyla reported was higher in M. pyrifera (n = 17) than in the Lessonia species (n = 7–13). Natural and anthropic impacts on the biodiversity of kelp forests using novel technologies would facilitate the quantitative study and economic valuations of the services provided by these ecosystems at the Humboldt Current System. Full article