Anthropocene Coasts最新文献

There is a void in the knowledge of the acidification status of Eastern Canada's coastal waters. This knowledge is crucial to evaluating the threats posed to marine life, particularly oyster farming, a flagship of New Brunswick seafood production. In this study, we measured the temporal variability of pH and related environmental parameters in three bays of Northeastern New Brunswick. We also evaluated the potential impact of the observed pH levels on the Eastern oyster (Crassostrea virginica Gmelin, 1791), based on the available literature on this species’ sensitivity to acidification. We investigated the presence of inherent cycles of pH with the Fourier transform and the spectral filtering technique. Our results show that pH is highly variable in the studied area, with values ranging from 7.31 to 8.90. A seasonal effect was apparent, as the pH fluctuations were set at the lowest level in winter when the cover of ice and snow on the bay was present. The spectral analysis revealed a clear semidiurnal tidal pattern of pH, this variable being inversely related to the water level in summer and directly related to it in winter. The spectral subtraction of all the tidal components allowed the detection of a circadian rhythm that was not in pace with the alternation between day and night but rather slowly drifted so that the pH troughs occurred at night during the full moon period. Short periodicities of circa 8 and 6 h also existed in two of the three bays. Based on current knowledge of C. virginica’s sensitivity to acidification, this species’ recruitment, growth, and survival are unlikely to be impacted by the present pH levels in the studied area. However, further acidification might overcome the resilience of C. virginica, especially that of the larvae that are produced during the winter in commercial hatcheries.

The United Nations estimate that by 2030 about half of the world’s population would be comprised of the middle-class, who mostly live in the increasing number of megacities around the world. Southeast Asian megacities, such as Metropolitan Manila, have long been troubled by rapid urbanization, increasing disaster risk, and the looming impacts of climate change. As a response, there is a growing focus on disaster and climate resilient policies in megacities, most of which have only centered on how future disasters and climate uncertainty would impact vulnerable communities. This has resulted in policies that cater towards relocation of the poor to combat disasters and climate change. This exploratory study attempts to elucidate how the middle-class views disasters and land reclamation in Metro Manila, the Philippines. Using an online questionnaire survey of 425 middle-class respondents, the study shows that middle-class perception of risk potentially amplifies vulnerability and reduces the resilience of the poor. While knowledge about the risks is high, the capacity of the middle class to act is low, especially compared to vulnerable communities. Also, climate change and disasters are viewed primarily as environmental issues, which is compounded by inadequate defenses. Land reclamation, along with coastal informal settlements, are viewed as an intrusion into the environment. This study finds that the middle-class’s perception of risk may marginalize the poor by favoring eviction of vulnerable communities in coastal areas, including those targeted for land reclamation, under the pretext of controlling the city’s population growth and environmental impact.

Globally, coastal managers are challenged to make informed decisions when selecting coastal infrastructure to respond to climate-induced sea-level rise and associated coastal hazards like coastal erosion and flooding. Classifying the types of coastal infrastructure permits the comparison of their potential efficiency, environmental and socioeconomic impacts, and long-term response to sea-level rise. At present, information on coastal infrastructure implemented along the coastal area of Ghana is not known thus creating a research gap to catalog this information. To achieve this, we combined satellite images from Google Earth Pro and the use of ArcGIS capabilities to conduct a national assessment of coastal infrastructure and its distribution along the coast of Ghana. Even though similar approaches have been applied in different geographic contexts, this article focuses on evaluating coastal infrastructure in Ghana. Results show that between 2004 and 2022, at least 110 km or approximately 20% of the coast of Ghana has been protected using grey infrastructure, distributed as groins 35.9 km (6.5%), revetments and seawalls 50 km (9%), and jetties and port breakwaters 25 km (4.5%) of the 550 Km coastline. These do not include the numerous private recreational infrastructure that could increase coastal vulnerability. The increasing use of grey infrastructure, particularly seawalls, and revetments along the coast has adverse impacts on overall coastal evolution and causes socioeconomic challenges. This study supports coastal managers to review coastal adaptation policy and develop shoreline management plans for the coast of Ghana.

Grain size distributions are widely used to describe sedimentary geochemistry, depositional environment, and sediment transportation. The objective of this study is to analyze grain size distributions of modern sandy beach sediments in Sri Lanka. Sediment samples (n = 90) were collected from beach berm, representing the entire coastline of Sri Lanka. Grain sizes were determined by the dry-sieving method. Statistical parameters such as mean size, sorting, skewness, and kurtosis were calculated using GRADISTAT_V9.1 software for all the sieved sediment samples. Grain size variations (108.2 – 609.8 µm) show that Sri Lanka mainly consists of medium sand, whereas the northeast part of the country mixes with fine sand due to the influence of Bengal fan sediments. The variations of skewness (-0.229 – 0.446) and sorting (1.305 – 2.436) indicate symmetrical distributed moderately sorted samples. These variations specify a moderate energy depositional environment/wave action around the coastline of Sri Lanka. In addition, grain size analysis confirmed relatively high and low energy deposition environments on the west and east coasts, respectively. Accordingly, the west coast is more vulnerable to coastal erosion compared to the east coast of Sri Lanka. Therefore, this study provides the baseline grain size distribution data that can be used in decision-making for coastal zone management by mitigating beach erosion.