Degradation Of Coastal Environments Research Articles

Exploring the variations in molecular characteristics of dissolved organic matter driven by aquaculture types

In recent decades, global aquaculture has expanded rapidly, raising concerns about coastal environmental degradation due to unregulated or poorly regulated discharge of aquaculture tailwater. Despite the crucial role of dissolved organic matter (DOM) in biogeochemical processes and aquatic biodiversity, the influence of aquaculture type on the molecular characteristics of DOM remains largely unexplored. Herein, this study investigated the variations in chemical and spectroscopic properties as well as molecular characteristics and composition of DOM across different aquaculture types including crustacean, fish and shellfish. Our findings revealed notable differences in DOM quantities among different aquaculture types, with crustacean and fish aquaculture water containing higher DOM amount compared to shellfish aquaculture water. This disparity can be attributed to the more frequent formulated feeds of crustacean and fish in contrast to shellfish aquaculture. Furthermore, distinct differences were also observed in the characteristics and composition of DOM among the different aquaculture waters. Specifically, DOM in shellfish aquaculture water exhibited a higher abundance of unsaturated and reduced molecules as well as increased aromaticity compared to the other two aquaculture waters. Conversely, DOM from fish aquaculture water showed a greater contribution from terrestrial origin characterized by elevated levels of plant-based components such as lignin-like and tannin-like compounds. Interestingly, DOM from shellfish aquaculture water contained lower levels of microbial-derived components such as lipid-like and protein-like compounds, likely due to reduced microorganism populations resulting from lower nutrients availability and higher salinity. Overall, these significant variations in characteristics and composition of DOM underscore the potential impacts of aquaculture type on the DOM biogeochemical cycle and the environmental quality in aquatic ecosystems.

Factors Associated with the Occurrence, Potential Distribution and Conservation of Anoxia orientalis (Coleoptera, Scarabaeidae) at Different Spatial Scales

Anoxia (Protanoxia) orientalis is a beetle of the family Melolonthidae for which Italy represents the western limit of its distribution. The ecology of this species is little known from the quantitative point of view. The ecological correlates of A. orientalis presence in the whole European range and, more specifically, at its western border in Sicily, are analyzed in this paper to develop a potential distribution map for Sicily and to define the habitat selection of this species. There was a clear non-random habitat selection by A. orientalis at both the European and the Sicilian scales and a clear difference in the factors affecting the presence of this species in the larger spatial scale compared to Sicily. At the European scale, the bioclimatic factors were more important than landscape factors, whereas the same was not true at the Sicilian scale. In Sicily, the populations were statistically influenced by a combination of predictors that make their potential optimal distribution very narrow and mostly limited to a few coastal areas, suggesting a region-specific ecological diversification. Since A. orientalis is in strong decline in Italy due to the degradation of coastal environments, it is necessary to minimize the degradation of the dune and back dune environments in Sicily to achieve better management for the populations of this beetle species.

The Evolution of an Ancient Coastal Lake (Lerna, Peloponnese, Greece)

Degradation of coastal environments is an issue that many areas in Europe are facing. In the present work, an ancient coastal lake wetland is investigated, the so-called Lake Lerna in NE Peloponnese, Greece. The area hosted early agricultural populations of modern Greece that started modifying their environment as early as the early–middle Neolithic. Two drill cores in the area of the ancient lake were analysed to establish the sedimentological succession and the depositional environments using sub-fossil assemblages (molluscs and ostracods). Three lithological and faunal units were recovered, the latter being confirmed by the statistical ordination method (non-metric multidimensional scaling). The usage of sub-fossil mollusc species for the first time in the region enriched the dataset and contributed significantly to the delimitation of the faunas. These consist of environments characterised by various levels of humidity (from stagnant waters to freshwater lake) and salinity, with ephemeral intrusions of salt water to the lake, documented by mollusc and ostracod populations. We conclude that the lake and its included fauna and flora were mostly affected by climatic fluctuations rather than human intervention in the area.

Middle Holocene marine and land-tetrapod biodiversity recovered from Galeão shell mound, Guanabara Bay, Brazil

Pristine environmental conditions and wide biodiversity are the best evidence of pre-colonial times, before anthropic interference in the Anthropocene. The Galeão shell mound represents the main example of an insular archaeological site located in the context of the Guanabara Bay in the Middle Holocene. The faunal remains from this shell mound were identified through comparative anatomy, to access the ichthyofauna and also amphibian, reptile and mammal paleodiversity. The diagnostic elements revealed the presence of predominantly demersal teleost fish, typical inhabitants of estuarine and marine systems, along with the usual species inhabiting rocky shores and rocky bottoms. Additionally, it revealed an exceptional diversity of sharks, including the presence of pelagic taxa, as well as stingrays. The local wildlife consists of species commonly found in swampy, mangrove, Brazilian restinga and Atlantic forest biomes. This study shows widely practiced fishery and hunting by the Amerindian using the resources of the Guanabara Bay and indicates specific targets during the Middle Holocene. Degradation of coastal environments and/or overfishing threaten the local biodiversity, with species now absent and some with statuses which go from Vulnerable to Critically Endangered.

Diving tourism in Mexico – Economic and conservation importance

Global coastal environments are highly vulnerable to degradation due to anthropogenic pressures as they host close to half of the world’s population in addition to having rich marine and terrestrial biodiversity. Worldwide degradation of coastal environments causes marine biodiversity to become an increasingly scarce resource. Consequently, locations with rich marine biodiversity have become attractive destinations for non-extractive activities such as diving tourism. For instance, since the invention of SCUBA in 1942, diving tourism has evolved from a niche activity to a thriving industry that lures practitioners with the promise of experiencing pristine wildlife encounters. Despite the number and popularity of diving destinations in Mexico, no study has previously estimated the economic importance of this industry for the Mexican case. This study calculates for the first time the gross and net revenues generated by the Mexican diving industry. We first created the most comprehensive and up-to-date list of diving sites in Mexico. Secondly, via a face-to-face survey, we gathered data on revenues and operation costs from diving operators. The resulting dataset includes 864 diving sites that together generate gross revenues ranging from (2019) USD 455 million and USD 725 million annually which are comparable to those generated by the artisanal and industrial Mexican fisheries together. Mexico simultaneously has high untapped ecotourism potential and the need for a sustainable strategy that delivers growth in both the economy and environmental conservation. Therefore, Mexico is in a position to become a beacon for community-led management through ecotourism, stimulating a sustainable use of marine resources.

A methodological framework of quantifying the cost of environmental degradation driven by coastal flooding and erosion: A case study in West Africa

Coastal environmental degradation – or the reduction of the capacity of coastal environments to meet social and ecological objectives and needs – is both a driver and a consequence of climate-induced disasters. In the West African coastal areas of Côte d’Ivoire, Ghana, Togo and Benin the major drivers of environmental degradation are found to be primarily originating from rapid, inadequately planned and managed urban development – mirroring economic growth – concurrent with high-exposure to coastal flooding and erosion hazards. In addition to decreasing the resilience of coastal ecosystems, the context of widespread coastal environmental degradation in West Africa will undeniably have direct and indirect consequences for economic development and human wellbeing in the region. Furthermore, climate change will place additional increasing pressure on certain West African coastal frontages. The research presented in this paper focuses on the development and implementation, at country level and pilot-site level, of a methodological framework of quantifying the impact of coastal flooding and erosion on environmental degradation in economic terms. Specifically, this framework values the impacts of degradation that occur as a result of flooding and erosion – in absolute (US $, number of people affected) and in relative (as percentage of the countries' GDP) terms. Overall, the aggregated Cost of Coastal Environmental Degradation (CoCED) in the four countries driven by coastal flooding and erosion could amount to over US $ 3 billion by 2100, based on the worst case scenario of regional relative sea-level rise, corresponding to RCP 8.5. Moreover, the number of people affected could in some of the countries experience a 400% increase by 2100 when accounting for demographic growth.

Effect of diet during larval development of Menippe nodifrons Stimpson, 1859 and Callinectes danae Smith, 1869

The worldwide decrease in fishery stocks in recent years is related to the degradation of coastal environments and to the increases in capture effort and extreme natural events. Restocking dilapidated populations with artificial hatchery-reared larvae has arisen in recent years as a viable technique for the reparation and maintenance of stocks of commercially exploited species. One of the first steps in larvae cultivation is the evaluation of an appropriate diet for rearing. We aimed to test viable diets for feeding zoea larvae of the crab Menippe nodifrons and the swimming crab Callinectes danae. We tested five live food treatments, three microalgae (Tetraselmis gracilis, Chaetoceros calcitrans, and Thalassiosira weissflogii), the rotifer Brachionus plicatilis, and Artemia sp. nauplii. The most suitable feeding protocol for rearing M. nodifrons larvae was a combined diet of enriched B. plicatilis up to the zoea III instar with the introduction of hatched Artemia sp. nauplii onwards to the megalopa stage. Larvae of C. danae showed high mortality rates and none achieved the zoea III phase on any of the diets tested. Although our results for C. danae rearing were not conclusive, the data provide additional information on improper rearing diets for this species for future research. Future studies testing other food sources are necessary to improve larvae production.

THE IMPLEMENTATION OF LILIFUK CUSTOMARY LAW TOWARDS COASTAL ENVIRONMENTAL DEGRADATION OF KUPANG BAY

The kuanheun coastal communities have a customary law that help maintain coastal environmental sustainability resourceS called as lilifuk customary law(lilifuk atolan instrument). This research applied empirical method by formulating three problems: what are the values embedded in lilifuk customary law; how is the of lilifuk customary law contribution to prevent coastal environmental degradation; and how is the correlation between lilifuk customary law values and the law provision on coastal areas and small islands management. The result of the research identified the following; the first, L ilifuk customary law contains religious value , ecological value, communal value, social relations value , solidarity and responsibility value , social leadership value , and education al value . Second, the settlement of law violation by lilifuk customary law is conduted by the following steps : reporting; discussion; verdict; and execution. Third, there is a correlation between the lilifuk customary lilifuk values and WP3K Law values . Keywords: lilifuk customary law, environmental degradation, kupang bay

Development of a model to simulate groundwater inundation induced by sea-level rise and high tides in Honolulu, Hawaii

Many of the world's largest cities face risk of sea-level rise (SLR) induced flooding owing to their limited elevations and proximities to the coastline. Within this century, global mean sea level is expected to reach magnitudes that will exceed the ground elevation of some built infrastructure. The concurrent rise of coastal groundwater will produce additional sources of inundation resulting from narrowing and loss of the vertical unsaturated subsurface space. This has implications for the dense network of buried and low-lying infrastructure that exists across urban coastal zones.Here, we describe a modeling approach that simulates narrowing of the unsaturated space and groundwater inundation (GWI) generated by SLR-induced lifting of coastal groundwater. The methodology combines terrain modeling, groundwater monitoring, estimation of tidal influence, and numerical groundwater-flow modeling to simulate future flood scenarios considering user-specified tide stages and magnitudes of SLR.We illustrate the value of the methodology by applying it to the heavily urbanized and low-lying Waikiki area of Honolulu, Hawaii. Results indicate that SLR of nearly 1 m generates GWI across 23% of the 13 km2 study area, threatening $5 billion of taxable real estate and 48 km of roadway. Analysis of current conditions reveals that 86% of 259 active cesspool sites in the study area are likely inundated. This suggests that cesspool effluent is currently entering coastal groundwater, which not only leads to degradation of coastal environments, but also presents a future threat to public health as GWI would introduce effluent at the ground surface.

Coastal Management and Implementation in Taiwan

Majority of the world’s population lives close to the coast and is highly development on coastal resources, which are being exploited at unsustainable rates. Since the martial law was lifted in 1987, the government has permitted development projects in coastal areas. However, rapid growth and overexploitation have led to significant degradation of coastal environments. To protect and sustain marine ecosystem functions, species, and habitats, proactive conservation measures are needed. One of the most effective measures is the establishment of marine protected areas. The government authorities in Taiwan have already created a number of protected areas, areas of interest to protect in coastal areas and to achieve the goal as 10% MPA by 2020. Meanwhile, Taiwan’s government reorganizes to improve and streamline the administrative efficiency in recent years. As regards to the ocean authority, researchers and concern groups are recommend to establish the ocean institute to manage and enforcement the coast areas. This study focuses on the problems of the current situation of coastal areas in Taiwan. Then discuss the mechanisms and functions to establish the marine protected area to ensure sustainable marine futures and coastal governance, especially for those coastal communities who most depend on it. Finally talk about the new institute Ocean Affairs Council (OAC) in the coming future in Taiwan.

Characteristics of Coastal Dune Topography and Vegetation in Environments Recently Modified Using Beach Fill and Vegetation Plantings, Veneto, Italy

Human actions can contribute to degradation of coastal environments or they can increase the likelihood that these environments will be restored. Beach nourishment provides a basis for restoration, but ways must be found to add habitat improvement to projects designed for shore protection. This study examines how beach nourishment projects can help reinstate dune landscapes in locations where beaches and dunes had been replaced by static shore protection structures. Dune topography and vegetation on three nourished sites on the northern Adriatic Coast of Italy are compared to a reference site to evaluate changes after beach fill was emplaced. Results reveal how nourishment projects used for shore protection can restore the space available for dunes to form, increase the likelihood of sediment transfers inland and increase the diversity of topography and vegetation. Beach raking prevents formation and growth of hummocky, incipient backshore dunes that would otherwise evolve into a naturally functioning foredune. Sand-trapping fences can speed the process of foredune development but can be counterproductive if they interfere with transport to beach grass (Ammophila littoralis) planted landward of them. Shore protection structures can provide stability and more time for dune evolution on eroding shores, resulting in greater species richness and longer retention of ecological niches. These structures need not be required if re-nourishment occurs frequently enough to provide a beach wide enough to protect against storm wave uprush.

Fishing through time: population dynamics of plaice (Pleuronectes platessa) in the Kattegat–Skagerrak over a century

AbstractOver the past century, advances in technology and historical events such as climate change have resulted in significant changes in the exploitation pattern, population sizes and the potential yield of fish stocks. These variations provide contrast in the data that improves our knowledge on population dynamics and our ability to develop management strategies for long‐term sustainable exploitation. In this study, we use a standardized scientific trawl survey to obtain a historical time series (1901–2007) of relative abundance, recruitment and size structure for plaice in the Kattegat–Skagerrak. Our work extends the available time series by more than 80 years so that the evaluation of trends is more informative than is possible from the current assessment. We show that the current adult biomass is approximately 40% of the maximum observed at the beginning of the century and during the 1960s. The average maximum individual length has been reduced by 10 cm over the studied time period. An analysis of trends in mean length indicates that fishing mortality was variable during the first half of the century and has increased steadily over the past 20 years. Recruitment has been the highest on record during recent years, suggesting that the alleged link between coastal environmental degradation and juvenile survival is of low importance. The overall findings of our work will provide managers with a historical perspective on the population dynamics of the stock, which will support the long‐term management of plaice in the Kattegat–Skagerrak.

Enregistrement des variations de l'environnement littoral armoricain par le biodétritisme depuis la fin du XVIIIe siècle : conséquences géomorphologiques

In western part of the Armorican Massif, one can observe since the end of the 18th century some modification of the bioclastic particles composition of beach sands. These modifications result of the anthropogenic degradation of coastal environments. It shows locally a reduction of the sediment supply which is in keeping with a regional pattern of terrigenous sedimentary supply deficit. Consequences for sedimentary budget of four beaches are considered. The analyse is based both on the evaluation of bio-sedimentogenesis and the study of bio-detritic particles participation to aeolian flux.

Causes and Effects of Coastal Sand Mining in Ghana

Sand mining is a type of open‐cast mining that provides material for the construction sector in Ghana. The construction sector in the coastal areas of Ghana relies heavily on coastal sand and pebbles in the building of houses, bridges and roads. Its contribution to Ghana’s industrial output has increased from 17.4 per cent in 1986 to 20.8 per cent in 1993. However, the process of sand mining has accelerated coastal environmental degradation to an alarming rate in many areas. As a result the government has been compelled to spend millions of dollars to combat sea erosion. This paper examines the causes and effects of coastal sand mining in three communities in the Ahanta West District of Ghana. It argues that coastal sand needs to be exploited to satisfy human demands but this requires efficient and effective resource management to ensure sustainable development. It also calls for a concerted effort by policy makers, sand contractors, engineers, traditional rulers and local residents to find a solution to the coastal environmental crisis.